toki: pona

Demonstrates pattern matching

.gitignore

@@ -1,3 +1,10 @@
+
+# Visual Studio Code config
+.vscode
+
+# Rust
 **/Cargo.lock
 target
+
+# Pest files generated by Grammatical
 *.p*st

Cargo.toml

@@ -1,20 +1,24 @@
 [workspace]
 members = [
-    "cl-repl",
-    "cl-typeck",
-    "cl-interpret",
-    "cl-structures",
-    "cl-token",
-    "cl-ast",
-    "cl-parser",
-    "cl-lexer",
+    "compiler/cl-repl",
+    "compiler/cl-typeck",
+    "compiler/cl-interpret",
+    "compiler/cl-structures",
+    "compiler/cl-token",
+    "compiler/cl-ast",
+    "compiler/cl-parser",
+    "compiler/cl-lexer",
+    "repline",
 ]
 resolver = "2"
 
 [workspace.package]
 repository = "https://git.soft.fish/j/Conlang"
-version = "0.0.5"
+version = "0.0.9"
 authors = ["John Breaux <j@soft.fish>"]
 edition = "2021"
 license = "MIT"
 publish = ["soft-fish"]
+
+[profile.dev]
+opt-level = 1

cl-ast/src/ast_impl.rs

@@ -1,643 +0,0 @@
-//! Implementations of AST nodes and traits
-use super::*;
-
-mod display {
-    //! Implements [Display] for [AST](super::super) Types
-    use super::*;
-    pub use delimiters::*;
-    use std::{
-        borrow::Borrow,
-        fmt::{Display, Write},
-    };
-    mod delimiters {
-        #![allow(dead_code)]
-        #[derive(Clone, Copy, Debug)]
-        pub struct Delimiters<'t> {
-            pub open: &'t str,
-            pub close: &'t str,
-        }
-        /// Delimits with braces decorated with spaces  `" {n"`, ..., `"\n}"`
-        pub const SPACED_BRACES: Delimiters = Delimiters { open: " {\n", close: "\n}" };
-        /// Delimits with braces on separate lines `{\n`, ..., `\n}`
-        pub const BRACES: Delimiters = Delimiters { open: "{\n", close: "\n}" };
-        /// Delimits with parentheses on separate lines `{\n`, ..., `\n}`
-        pub const PARENS: Delimiters = Delimiters { open: "(\n", close: "\n)" };
-        /// Delimits with square brackets on separate lines `{\n`, ..., `\n}`
-        pub const SQUARE: Delimiters = Delimiters { open: "[\n", close: "\n]" };
-        /// Delimits with braces on the same line `{ `, ..., ` }`
-        pub const INLINE_BRACES: Delimiters = Delimiters { open: "{ ", close: " }" };
-        /// Delimits with parentheses on the same line `( `, ..., ` )`
-        pub const INLINE_PARENS: Delimiters = Delimiters { open: "(", close: ")" };
-        /// Delimits with square brackets on the same line `[ `, ..., ` ]`
-        pub const INLINE_SQUARE: Delimiters = Delimiters { open: "[", close: "]" };
-    }
-    fn delimit<'a>(
-        func: impl Fn(&mut std::fmt::Formatter<'_>) -> std::fmt::Result + 'a,
-        delim: Delimiters<'a>,
-    ) -> impl Fn(&mut std::fmt::Formatter<'_>) -> std::fmt::Result + 'a {
-        move |f| {
-            write!(f, "{}", delim.open)?;
-            func(f)?;
-            write!(f, "{}", delim.close)
-        }
-    }
-    fn separate<'iterable, I>(
-        iterable: &'iterable [I],
-        sep: impl Display + 'iterable,
-    ) -> impl Fn(&mut std::fmt::Formatter<'_>) -> std::fmt::Result + 'iterable
-    where
-        I: Display,
-    {
-        move |f| {
-            for (idx, item) in iterable.iter().enumerate() {
-                if idx > 0 {
-                    write!(f, "{sep}")?;
-                }
-                item.fmt(f)?;
-            }
-            Ok(())
-        }
-    }
-
-    impl Display for Mutability {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            match self {
-                Mutability::Not => Ok(()),
-                Mutability::Mut => "mut ".fmt(f),
-            }
-        }
-    }
-    impl Display for Visibility {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            match self {
-                Visibility::Private => Ok(()),
-                Visibility::Public => "pub ".fmt(f),
-            }
-        }
-    }
-
-    impl Display for File {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            separate(&self.items, "\n")(f)
-        }
-    }
-
-    impl Display for Attrs {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { meta } = self;
-            if meta.is_empty() {
-                return Ok(());
-            }
-            "#".fmt(f)?;
-            delimit(separate(meta, ", "), INLINE_SQUARE)(f)?;
-            "\n".fmt(f)
-        }
-    }
-    impl Display for Meta {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { name, kind } = self;
-            write!(f, "{name}{kind}")
-        }
-    }
-    impl Display for MetaKind {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            match self {
-                MetaKind::Plain => Ok(()),
-                MetaKind::Equals(v) => write!(f, " = {v}"),
-                MetaKind::Func(args) => delimit(separate(args, ", "), INLINE_PARENS)(f),
-            }
-        }
-    }
-
-    impl Display for Item {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { extents: _, attrs, vis, kind } = self;
-            attrs.fmt(f)?;
-            vis.fmt(f)?;
-            match kind {
-                ItemKind::Alias(v) => v.fmt(f),
-                ItemKind::Const(v) => v.fmt(f),
-                ItemKind::Static(v) => v.fmt(f),
-                ItemKind::Module(v) => v.fmt(f),
-                ItemKind::Function(v) => v.fmt(f),
-                ItemKind::Struct(v) => v.fmt(f),
-                ItemKind::Enum(v) => v.fmt(f),
-                ItemKind::Impl(v) => v.fmt(f),
-            }
-        }
-    }
-    impl Display for Alias {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { to, from } = self;
-            match from {
-                Some(from) => write!(f, "type {to} = {from};"),
-                None => write!(f, "type {to};"),
-            }
-        }
-    }
-    impl Display for Const {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { name, ty, init } = self;
-            write!(f, "const {name}: {ty} = {init}")
-        }
-    }
-    impl Display for Static {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { mutable, name, ty, init } = self;
-            write!(f, "static {mutable}{name}: {ty} = {init}")
-        }
-    }
-    impl Display for Module {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { name, kind } = self;
-            write!(f, "mod {name}{kind}")
-        }
-    }
-    impl Display for ModuleKind {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            match self {
-                ModuleKind::Inline(items) => {
-                    ' '.fmt(f)?;
-                    delimit(|f| items.fmt(f), BRACES)(f)
-                }
-                ModuleKind::Outline => ';'.fmt(f),
-            }
-        }
-    }
-    impl Display for Function {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { name, args, body, rety } = self;
-            write!(f, "fn {name} ")?;
-            delimit(separate(args, ", "), INLINE_PARENS)(f)?;
-            if let Some(rety) = rety {
-                write!(f, " -> {rety}")?;
-            }
-            match body {
-                Some(body) => write!(f, " {body}"),
-                None => ';'.fmt(f),
-            }
-        }
-    }
-    impl Display for Param {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { mutability, name, ty } = self;
-            write!(f, "{mutability}{name}: {ty}")
-        }
-    }
-    impl Display for Struct {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { name, kind } = self;
-            write!(f, "struct {name}{kind}")
-        }
-    }
-    impl Display for StructKind {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            match self {
-                StructKind::Empty => ';'.fmt(f),
-                StructKind::Tuple(v) => delimit(separate(v, ", "), INLINE_PARENS)(f),
-                StructKind::Struct(v) => delimit(separate(v, ",\n"), SPACED_BRACES)(f),
-            }
-        }
-    }
-    impl Display for StructMember {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { vis, name, ty } = self;
-            write!(f, "{vis}{name}: {ty}")
-        }
-    }
-    impl Display for Enum {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { name, kind } = self;
-            write!(f, "enum {name}{kind}")
-        }
-    }
-    impl Display for EnumKind {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            match self {
-                EnumKind::NoVariants => ';'.fmt(f),
-                EnumKind::Variants(v) => delimit(separate(v, ",\n"), SPACED_BRACES)(f),
-            }
-        }
-    }
-    impl Display for Variant {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { name, kind } = self;
-            write!(f, "{name}{kind}")
-        }
-    }
-    impl Display for VariantKind {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            match self {
-                VariantKind::Plain => Ok(()),
-                VariantKind::CLike(n) => write!(f, " = {n}"),
-                VariantKind::Tuple(v) => delimit(separate(v, ", "), INLINE_PARENS)(f),
-                VariantKind::Struct(v) => delimit(separate(v, ", "), INLINE_BRACES)(f),
-            }
-        }
-    }
-    impl Display for Impl {
-        fn fmt(&self, _f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            todo!("impl Display for Impl")
-        }
-    }
-
-    impl Display for Ty {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            match &self.kind {
-                TyKind::Never => "!".fmt(f),
-                TyKind::Empty => "()".fmt(f),
-                TyKind::SelfTy => "Self".fmt(f),
-                TyKind::Path(v) => v.fmt(f),
-                TyKind::Tuple(v) => v.fmt(f),
-                TyKind::Ref(v) => v.fmt(f),
-                TyKind::Fn(v) => v.fmt(f),
-            }
-        }
-    }
-    impl Display for TyTuple {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            delimit(separate(&self.types, ", "), INLINE_PARENS)(f)
-        }
-    }
-    impl Display for TyRef {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { count: _, to } = self;
-            for _ in 0..self.count {
-                f.write_char('&')?;
-            }
-            write!(f, "{to}")
-        }
-    }
-    impl Display for TyFn {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { args, rety } = self;
-            write!(f, "fn {args}")?;
-            match rety {
-                Some(v) => write!(f, " -> {v}"),
-                None => Ok(()),
-            }
-        }
-    }
-
-    impl Display for Stmt {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Stmt { extents: _, kind, semi } = self;
-            match kind {
-                StmtKind::Empty => Ok(()),
-                StmtKind::Local(v) => v.fmt(f),
-                StmtKind::Item(v) => v.fmt(f),
-                StmtKind::Expr(v) => v.fmt(f),
-            }?;
-            match semi {
-                Semi::Terminated => ';'.fmt(f),
-                Semi::Unterminated => Ok(()),
-            }
-        }
-    }
-    impl Display for Let {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { mutable, name, ty, init } = self;
-            write!(f, "let {mutable}{name}")?;
-            if let Some(value) = ty {
-                write!(f, ": {value}")?;
-            }
-            if let Some(value) = init {
-                write!(f, " = {value}")?;
-            }
-            Ok(())
-        }
-    }
-
-    impl Display for Expr {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            self.kind.fmt(f)
-        }
-    }
-    impl Display for ExprKind {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            match self {
-                ExprKind::Assign(v) => v.fmt(f),
-                ExprKind::Binary(v) => v.fmt(f),
-                ExprKind::Unary(v) => v.fmt(f),
-                ExprKind::Index(v) => v.fmt(f),
-                ExprKind::Path(v) => v.fmt(f),
-                ExprKind::Literal(v) => v.fmt(f),
-                ExprKind::Array(v) => v.fmt(f),
-                ExprKind::ArrayRep(v) => v.fmt(f),
-                ExprKind::AddrOf(v) => v.fmt(f),
-                ExprKind::Block(v) => v.fmt(f),
-                ExprKind::Empty => "()".fmt(f),
-                ExprKind::Group(v) => v.fmt(f),
-                ExprKind::Tuple(v) => v.fmt(f),
-                ExprKind::While(v) => v.fmt(f),
-                ExprKind::If(v) => v.fmt(f),
-                ExprKind::For(v) => v.fmt(f),
-                ExprKind::Break(v) => v.fmt(f),
-                ExprKind::Return(v) => v.fmt(f),
-                ExprKind::Continue(_) => "continue".fmt(f),
-            }
-        }
-    }
-    impl Display for Assign {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { kind, parts } = self;
-            write!(f, "{} {kind} {}", parts.0, parts.1)
-        }
-    }
-    impl Display for AssignKind {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            match self {
-                AssignKind::Plain => "=",
-                AssignKind::Mul => "*=",
-                AssignKind::Div => "/=",
-                AssignKind::Rem => "%=",
-                AssignKind::Add => "+=",
-                AssignKind::Sub => "-=",
-                AssignKind::And => "&=",
-                AssignKind::Or => "|=",
-                AssignKind::Xor => "^=",
-                AssignKind::Shl => "<<=",
-                AssignKind::Shr => ">>=",
-            }
-            .fmt(f)
-        }
-    }
-    impl Display for Binary {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { kind, parts } = self;
-            let (head, tail) = parts.borrow();
-            match kind {
-                BinaryKind::Dot => write!(f, "{head}{kind}{tail}"),
-                BinaryKind::Call => write!(f, "{head}{tail}"),
-                _ => write!(f, "{head} {kind} {tail}"),
-            }
-        }
-    }
-    impl Display for BinaryKind {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            match self {
-                BinaryKind::Lt => "<",
-                BinaryKind::LtEq => "<=",
-                BinaryKind::Equal => "==",
-                BinaryKind::NotEq => "!=",
-                BinaryKind::GtEq => ">=",
-                BinaryKind::Gt => ">",
-                BinaryKind::RangeExc => "..",
-                BinaryKind::RangeInc => "..=",
-                BinaryKind::LogAnd => "&&",
-                BinaryKind::LogOr => "||",
-                BinaryKind::LogXor => "^^",
-                BinaryKind::BitAnd => "&",
-                BinaryKind::BitOr => "|",
-                BinaryKind::BitXor => "^",
-                BinaryKind::Shl => "<<",
-                BinaryKind::Shr => ">>",
-                BinaryKind::Add => "+",
-                BinaryKind::Sub => "-",
-                BinaryKind::Mul => "*",
-                BinaryKind::Div => "/",
-                BinaryKind::Rem => "%",
-                BinaryKind::Dot => ".",
-                BinaryKind::Call => "()",
-            }
-            .fmt(f)
-        }
-    }
-    impl Display for Unary {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { kind, tail } = self;
-            write!(f, "{kind}{tail}")
-        }
-    }
-    impl Display for UnaryKind {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            match self {
-                UnaryKind::Deref => "*",
-                UnaryKind::Neg => "-",
-                UnaryKind::Not => "!",
-                UnaryKind::At => "@",
-                UnaryKind::Tilde => "~",
-            }
-            .fmt(f)
-        }
-    }
-    impl Display for Tuple {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            delimit(separate(&self.exprs, ", "), INLINE_PARENS)(f)
-        }
-    }
-    impl Display for Index {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { head, indices } = self;
-            write!(f, "{head}")?;
-            for indices in indices {
-                indices.fmt(f)?;
-            }
-            Ok(())
-        }
-    }
-    impl Display for Path {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { absolute, parts } = self;
-            if *absolute {
-                "::".fmt(f)?;
-            }
-            separate(parts, "::")(f)
-        }
-    }
-    impl Display for PathPart {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            match self {
-                PathPart::SuperKw => "super".fmt(f),
-                PathPart::SelfKw => "self".fmt(f),
-                PathPart::Ident(id) => id.fmt(f),
-            }
-        }
-    }
-    impl Display for Identifier {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            self.0.fmt(f)
-        }
-    }
-    impl Display for Literal {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            match self {
-                Literal::Bool(v) => v.fmt(f),
-                Literal::Char(v) => write!(f, "'{v}'"),
-                Literal::Int(v) => v.fmt(f),
-                Literal::String(v) => write!(f, "\"{v}\""),
-            }
-        }
-    }
-    impl Display for Array {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            delimit(separate(&self.values, ", "), INLINE_SQUARE)(f)
-        }
-    }
-    impl Display for ArrayRep {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { value, repeat } = self;
-            write!(f, "[{value}; {repeat}]")
-        }
-    }
-    impl Display for AddrOf {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { count, mutable, expr } = self;
-            for _ in 0..*count {
-                f.write_char('&')?;
-            }
-            write!(f, "{mutable}{expr}")
-        }
-    }
-    impl Display for Block {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            delimit(separate(&self.stmts, "\n"), BRACES)(f)
-        }
-    }
-    impl Display for Group {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            write!(f, "({})", self.expr)
-        }
-    }
-    impl Display for While {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { cond, pass, fail } = self;
-            write!(f, "while {cond} {pass}{fail}")
-        }
-    }
-    impl Display for If {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { cond, pass, fail } = self;
-            write!(f, "if {cond} {pass}{fail}")
-        }
-    }
-    impl Display for For {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { bind, cond, pass, fail } = self;
-            write!(f, "for {bind} in {cond} {pass}{fail}")
-        }
-    }
-    impl Display for Else {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            match &self.body {
-                Some(body) => write!(f, " else {body}"),
-                _ => Ok(()),
-            }
-        }
-    }
-    impl Display for Break {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            write!(f, "break")?;
-            match &self.body {
-                Some(body) => write!(f, " {body}"),
-                _ => Ok(()),
-            }
-        }
-    }
-    impl Display for Return {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            write!(f, "return")?;
-            match &self.body {
-                Some(body) => write!(f, " {body}"),
-                _ => Ok(()),
-            }
-        }
-    }
-}
-
-mod convert {
-    //! Converts between major enums and enum variants
-    use super::*;
-
-    impl<T: AsRef<str>> From<T> for Identifier {
-        fn from(value: T) -> Self {
-            Identifier(value.as_ref().into())
-        }
-    }
-
-    macro impl_from ($(impl From for $T:ty {$($from:ty => $to:expr),*$(,)?})*) {$($(
-        impl From<$from> for $T {
-            fn from(value: $from) -> Self {
-                $to(value.into()) // Uses *tuple constructor*
-            }
-        }
-        impl From<Box<$from>> for $T {
-            fn from(value: Box<$from>) -> Self {
-                $to((*value).into())
-            }
-        }
-    )*)*}
-
-    impl_from! {
-        impl From for ItemKind {
-            Alias => ItemKind::Alias,
-            Const => ItemKind::Const,
-            Static => ItemKind::Static,
-            Module => ItemKind::Module,
-            Function => ItemKind::Function,
-            Struct => ItemKind::Struct,
-            Enum => ItemKind::Enum,
-            Impl => ItemKind::Impl,
-        }
-        impl From for StructKind {
-            Vec<Ty> => StructKind::Tuple,
-            // TODO: Struct members in struct
-        }
-        impl From for EnumKind {
-            Vec<Variant> => EnumKind::Variants,
-        }
-        impl From for VariantKind {
-            u128 => VariantKind::CLike,
-            Vec<Ty> => VariantKind::Tuple,
-            // TODO: enum struct variants
-        }
-        impl From for TyKind {
-            Path => TyKind::Path,
-            TyTuple => TyKind::Tuple,
-            TyRef => TyKind::Ref,
-            TyFn => TyKind::Fn,
-        }
-        impl From for StmtKind {
-            Let => StmtKind::Local,
-            Item => StmtKind::Item,
-            Expr => StmtKind::Expr,
-        }
-        impl From for ExprKind {
-            Assign => ExprKind::Assign,
-            Binary => ExprKind::Binary,
-            Unary => ExprKind::Unary,
-            Index => ExprKind::Index,
-            Path => ExprKind::Path,
-            Literal => ExprKind::Literal,
-            Array => ExprKind::Array,
-            ArrayRep => ExprKind::ArrayRep,
-            AddrOf => ExprKind::AddrOf,
-            Block => ExprKind::Block,
-            Group => ExprKind::Group,
-            Tuple => ExprKind::Tuple,
-            While => ExprKind::While,
-            If => ExprKind::If,
-            For => ExprKind::For,
-            Break => ExprKind::Break,
-            Return => ExprKind::Return,
-            Continue => ExprKind::Continue,
-        }
-        impl From for Literal {
-            bool => Literal::Bool,
-            char => Literal::Char,
-            u128 => Literal::Int,
-            String => Literal::String,
-        }
-    }
-
-    impl From<Option<Expr>> for Else {
-        fn from(value: Option<Expr>) -> Self {
-            Self { body: value.map(Into::into) }
-        }
-    }
-    impl From<Expr> for Else {
-        fn from(value: Expr) -> Self {
-            Self { body: Some(value.into()) }
-        }
-    }
-}

cl-ast/src/format.rs

@@ -1,106 +0,0 @@
-use std::{
-    fmt::{Result as FmtResult, Write as FmtWrite},
-    io::{Result as IoResult, Write as IoWrite},
-};
-
-/// Trait which adds a function to [fmt Writers](FmtWrite) to turn them into [Prettifier]
-pub trait FmtPretty: FmtWrite {
-    /// Indents code according to the number of matched curly braces
-    fn pretty(self) -> Prettifier<'static, Self>
-    where Self: Sized {
-        Prettifier::new(self)
-    }
-}
-/// Trait which adds a function to [io Writers](IoWrite) to turn them into [Prettifier]
-pub trait IoPretty: IoWrite {
-    /// Indents code according to the number of matched curly braces
-    fn pretty(self) -> Prettifier<'static, Self>
-    where Self: Sized;
-}
-impl<W: FmtWrite> FmtPretty for W {}
-impl<W: IoWrite> IoPretty for W {
-    fn pretty(self) -> Prettifier<'static, Self> {
-        Prettifier::new(self)
-    }
-}
-
-/// Intercepts calls to either [std::io::Write] or [std::fmt::Write],
-/// and inserts indentation between matched parentheses
-pub struct Prettifier<'i, T: ?Sized> {
-    level: isize,
-    indent: &'i str,
-    writer: T,
-}
-
-impl<'i, W> Prettifier<'i, W> {
-    pub fn new(writer: W) -> Self {
-        Self { level: 0, indent: "    ", writer }
-    }
-    pub fn with_indent(indent: &'i str, writer: W) -> Self {
-        Self { level: 0, indent, writer }
-    }
-}
-
-impl<'i, W: FmtWrite> Prettifier<'i, W> {
-    #[inline]
-    fn fmt_write_indentation(&mut self) -> FmtResult {
-        let Self { level, indent, writer } = self;
-        for _ in 0..*level {
-            writer.write_str(indent)?;
-        }
-        Ok(())
-    }
-}
-impl<'i, W: IoWrite> Prettifier<'i, W> {
-    pub fn io_write_indentation(&mut self) -> IoResult<usize> {
-        let Self { level, indent, writer } = self;
-        let mut count = 0;
-        for _ in 0..*level {
-            count += writer.write(indent.as_bytes())?;
-        }
-        Ok(count)
-    }
-}
-
-impl<'i, W: FmtWrite> FmtWrite for Prettifier<'i, W> {
-    fn write_str(&mut self, s: &str) -> FmtResult {
-        for s in s.split_inclusive(['{', '}']) {
-            match s.as_bytes().last() {
-                Some(b'{') => self.level += 1,
-                Some(b'}') => self.level -= 1,
-                _ => (),
-            }
-            for s in s.split_inclusive('\n') {
-                self.writer.write_str(s)?;
-                if let Some(b'\n') = s.as_bytes().last() {
-                    self.fmt_write_indentation()?;
-                }
-            }
-        }
-        Ok(())
-    }
-}
-
-impl<'i, W: IoWrite> IoWrite for Prettifier<'i, W> {
-    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
-        let mut size = 0;
-        for buf in buf.split_inclusive(|b| b"{}".contains(b)) {
-            match buf.last() {
-                Some(b'{') => self.level += 1,
-                Some(b'}') => self.level -= 1,
-                _ => (),
-            }
-            for buf in buf.split_inclusive(|b| b'\n' == *b) {
-                size += self.writer.write(buf)?;
-                if let Some(b'\n') = buf.last() {
-                    self.io_write_indentation()?;
-                }
-            }
-        }
-        Ok(size)
-    }
-
-    fn flush(&mut self) -> std::io::Result<()> {
-        self.writer.flush()
-    }
-}

cl-interpret/src/builtin.rs

@@ -1,239 +0,0 @@
-//! Implementations of built-in functions
-
-use super::{
-    env::Environment,
-    error::{Error, IResult},
-    temp_type_impl::ConValue,
-    BuiltIn, Callable,
-};
-use std::io::{stdout, Write};
-
-builtins! {
-    const MISC;
-    /// Unstable variadic print function
-    pub fn print<_, args> () -> IResult<ConValue> {
-        let mut out = stdout().lock();
-        for arg in args {
-            write!(out, "{arg}").ok();
-        }
-        writeln!(out).ok();
-        Ok(ConValue::Empty)
-    }
-    /// Prints the [Debug](std::fmt::Debug) version of the input values
-    pub fn dbg<_, args> () -> IResult<ConValue> {
-        let mut out = stdout().lock();
-        for arg in args {
-            writeln!(out, "{arg:?}").ok();
-        }
-        Ok(args.into())
-    }
-    /// Dumps info from the environment
-    pub fn dump<env, _>() -> IResult<ConValue> {
-        println!("{}", *env);
-        Ok(ConValue::Empty)
-    }
-}
-builtins! {
-    const BINARY;
-    /// Multiplication `a * b`
-    pub fn mul(lhs, rhs) -> IResult<ConValue> {
-        Ok(match (lhs, rhs) {
-            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
-            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a * b),
-            _ => Err(Error::TypeError)?
-        })
-    }
-    /// Division `a / b`
-    pub fn div(lhs, rhs) -> IResult<ConValue> {
-        Ok(match (lhs, rhs){
-            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
-            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a / b),
-            _ => Err(Error::TypeError)?
-        })
-    }
-    /// Remainder `a % b`
-    pub fn rem(lhs, rhs) -> IResult<ConValue> {
-        Ok(match (lhs, rhs) {
-            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
-            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a % b),
-            _ => Err(Error::TypeError)?,
-        })
-    }
-
-    /// Addition `a + b`
-    pub fn add(lhs, rhs) -> IResult<ConValue> {
-        Ok(match (lhs, rhs) {
-            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
-            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a + b),
-            (ConValue::String(a), ConValue::String(b)) => ConValue::String(a.to_string() + b),
-            _ => Err(Error::TypeError)?
-        })
-    }
-    /// Subtraction `a - b`
-    pub fn sub(lhs, rhs) -> IResult<ConValue> {
-        Ok(match (lhs, rhs) {
-            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
-            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a - b),
-            _ => Err(Error::TypeError)?,
-        })
-    }
-
-    /// Shift Left `a << b`
-    pub fn shl(lhs, rhs) -> IResult<ConValue> {
-        Ok(match (lhs, rhs) {
-            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
-            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a << b),
-            _ => Err(Error::TypeError)?,
-        })
-    }
-    /// Shift Right `a >> b`
-    pub fn shr(lhs, rhs) -> IResult<ConValue> {
-        Ok(match (lhs, rhs) {
-            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
-            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a >> b),
-            _ => Err(Error::TypeError)?,
-        })
-    }
-
-    /// Bitwise And `a & b`
-    pub fn and(lhs, rhs) -> IResult<ConValue> {
-        Ok(match (lhs, rhs) {
-            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
-            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a & b),
-            (ConValue::Bool(a), ConValue::Bool(b)) => ConValue::Bool(a & b),
-            _ => Err(Error::TypeError)?,
-        })
-    }
-    /// Bitwise Or `a | b`
-    pub fn or(lhs, rhs) -> IResult<ConValue> {
-        Ok(match (lhs, rhs) {
-            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
-            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a | b),
-            (ConValue::Bool(a), ConValue::Bool(b)) => ConValue::Bool(a | b),
-            _ => Err(Error::TypeError)?,
-        })
-    }
-    /// Bitwise Exclusive Or `a ^ b`
-    pub fn xor(lhs, rhs) -> IResult<ConValue> {
-        Ok(match (lhs, rhs) {
-            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
-            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a ^ b),
-            (ConValue::Bool(a), ConValue::Bool(b)) => ConValue::Bool(a ^ b),
-            _ => Err(Error::TypeError)?,
-        })
-    }
-
-    /// Tests whether `a < b`
-    pub fn lt(lhs, rhs) -> IResult<ConValue> {
-        cmp!(lhs, rhs, false, <)
-    }
-    /// Tests whether `a <= b`
-    pub fn lt_eq(lhs, rhs) -> IResult<ConValue> {
-        cmp!(lhs, rhs, true, <=)
-    }
-    /// Tests whether `a == b`
-    pub fn eq(lhs, rhs) -> IResult<ConValue> {
-        cmp!(lhs, rhs, true, ==)
-    }
-    /// Tests whether `a != b`
-    pub fn neq(lhs, rhs) -> IResult<ConValue> {
-        cmp!(lhs, rhs, false, !=)
-    }
-    /// Tests whether `a <= b`
-    pub fn gt_eq(lhs, rhs) -> IResult<ConValue> {
-        cmp!(lhs, rhs, true, >=)
-    }
-    /// Tests whether `a < b`
-    pub fn gt(lhs, rhs) -> IResult<ConValue> {
-        cmp!(lhs, rhs, false, >)
-    }
-}
-builtins! {
-    const RANGE;
-    /// Exclusive Range `a..b`
-    pub fn range_exc(lhs, rhs) -> IResult<ConValue> {
-        let (&ConValue::Int(lhs), &ConValue::Int(rhs)) = (lhs, rhs) else {
-            Err(Error::TypeError)?
-        };
-        Ok(ConValue::RangeExc(lhs, rhs.saturating_sub(1)))
-    }
-    /// Inclusive Range `a..=b`
-    pub fn range_inc(lhs, rhs) -> IResult<ConValue> {
-        let (&ConValue::Int(lhs), &ConValue::Int(rhs)) = (lhs, rhs) else {
-            Err(Error::TypeError)?
-        };
-        Ok(ConValue::RangeInc(lhs, rhs))
-    }
-}
-builtins! {
-    const UNARY;
-    /// Negates the ConValue
-    pub fn neg(tail) -> IResult<ConValue> {
-        Ok(match tail {
-            ConValue::Empty => ConValue::Empty,
-            ConValue::Int(v) => ConValue::Int(-v),
-            _ => Err(Error::TypeError)?,
-        })
-    }
-    /// Inverts the ConValue
-    pub fn not(tail) -> IResult<ConValue> {
-        Ok(match tail {
-            ConValue::Empty => ConValue::Empty,
-            ConValue::Int(v) => ConValue::Int(!v),
-            ConValue::Bool(v) => ConValue::Bool(!v),
-            _ => Err(Error::TypeError)?,
-        })
-    }
-}
-
-/// Turns an argument slice into an array with the (inferred) correct number of elements
-pub fn to_args<const N: usize>(args: &[ConValue]) -> IResult<&[ConValue; N]> {
-    args.try_into()
-        .map_err(|_| Error::ArgNumber { want: N, got: args.len() })
-}
-
-/// Turns function definitions into ZSTs which implement [Callable] and [BuiltIn]
-macro builtins (
-    $(prefix = $prefix:literal)?
-    const $defaults:ident $( = [$($additional_builtins:expr),*$(,)?])?;
-    $(
-        $(#[$meta:meta])*$vis:vis fn $name:ident$(<$env:tt, $args:tt>)? ( $($($arg:tt),+$(,)?)? ) $(-> $rety:ty)?
-            $body:block
-    )*
-) {
-    /// Builtins to load when a new interpreter is created
-    pub const $defaults: &[&dyn BuiltIn] = &[$(&$name,)* $($additional_builtins)*];
-    $(
-        $(#[$meta])* #[allow(non_camel_case_types)] #[derive(Clone, Debug)]
-        /// ```rust,ignore
-        #[doc = stringify!(builtin! fn $name($($($arg),*)?) $(-> $rety)? $body)]
-        /// ```
-        $vis struct $name;
-        impl BuiltIn for $name {
-            fn description(&self) -> &str { concat!("builtin ", stringify!($name), stringify!(($($($arg),*)?) )) }
-        }
-        impl Callable for $name {
-            #[allow(unused)]
-            fn call(&self, env: &mut Environment, args: &[ConValue]) $(-> $rety)? {
-                // println!("{}", stringify!($name), );
-                $(let $env = env;
-                let $args = args;)?
-                $(let [$($arg),*] = to_args(args)?;)?
-                $body
-            }
-            fn name(&self) -> &str { stringify!($name) }
-        }
-    )*
-}
-
-/// Templates comparison functions for [ConValue]
-macro cmp ($a:expr, $b:expr, $empty:literal, $op:tt) {
-    match ($a, $b) {
-        (ConValue::Empty, ConValue::Empty) => Ok(ConValue::Bool($empty)),
-        (ConValue::Int(a), ConValue::Int(b)) => Ok(ConValue::Bool(a $op b)),
-        (ConValue::Bool(a), ConValue::Bool(b)) => Ok(ConValue::Bool(a $op b)),
-        (ConValue::Char(a), ConValue::Char(b)) => Ok(ConValue::Bool(a $op b)),
-        (ConValue::String(a), ConValue::String(b)) => Ok(ConValue::Bool(a $op b)),
-        _ => Err(Error::TypeError)
-    }
-}

cl-interpret/src/interpret.rs

@@ -1,447 +0,0 @@
-//! A work-in-progress tree walk interpreter for Conlang
-//!
-//! Currently, major parts of the interpreter are not yet implemented, and major parts will never be
-//! implemented in its current form. Namely, since no [ConValue] has a stable location, it's
-//! meaningless to get a pointer to one, and would be undefined behavior to dereference a pointer to
-//! one in any situation.
-
-use std::borrow::Borrow;
-
-use super::*;
-use cl_ast::*;
-/// A work-in-progress tree walk interpreter for Conlang
-pub trait Interpret {
-    /// Interprets this thing in the given [`Environment`].
-    ///
-    /// Everything returns a value!™
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue>;
-}
-
-impl Interpret for File {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        for item in &self.items {
-            item.interpret(env)?;
-        }
-        Ok(ConValue::Empty)
-    }
-}
-impl Interpret for Item {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        match &self.kind {
-            ItemKind::Alias(item) => item.interpret(env),
-            ItemKind::Const(item) => item.interpret(env),
-            ItemKind::Static(item) => item.interpret(env),
-            ItemKind::Module(item) => item.interpret(env),
-            ItemKind::Function(item) => item.interpret(env),
-            ItemKind::Struct(item) => item.interpret(env),
-            ItemKind::Enum(item) => item.interpret(env),
-            ItemKind::Impl(item) => item.interpret(env),
-        }
-    }
-}
-impl Interpret for Alias {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        todo!("Interpret type alias in {env}")
-    }
-}
-impl Interpret for Const {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        todo!("interpret const in {env}")
-    }
-}
-impl Interpret for Static {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        todo!("interpret static in {env}")
-    }
-}
-impl Interpret for Module {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        // TODO: Enter this module's namespace
-        match &self.kind {
-            ModuleKind::Inline(file) => file.interpret(env),
-            ModuleKind::Outline => todo!("Load and parse external files"),
-        }
-    }
-}
-impl Interpret for Function {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        // register the function in the current environment
-        env.insert_fn(self);
-        Ok(ConValue::Empty)
-    }
-}
-impl Interpret for Struct {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        todo!("Interpret structs in {env}")
-    }
-}
-impl Interpret for Enum {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        todo!("Interpret enums in {env}")
-    }
-}
-impl Interpret for Impl {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        todo!("Enter a struct's namespace and insert function definitions into it in {env}");
-    }
-}
-impl Interpret for Stmt {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        let Self { extents: _, kind, semi } = self;
-        let out = match kind {
-            StmtKind::Empty => ConValue::Empty,
-            StmtKind::Local(stmt) => stmt.interpret(env)?,
-            StmtKind::Item(stmt) => stmt.interpret(env)?,
-            StmtKind::Expr(stmt) => stmt.interpret(env)?,
-        };
-        Ok(match semi {
-            Semi::Terminated => ConValue::Empty,
-            Semi::Unterminated => out,
-        })
-    }
-}
-impl Interpret for Let {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        let Let { mutable: _, name: Identifier(name), ty: _, init } = self;
-        let init = init.as_ref().map(|i| i.interpret(env)).transpose()?;
-        env.insert(name, init);
-        Ok(ConValue::Empty)
-    }
-}
-impl Interpret for Expr {
-    #[inline]
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        let Self { extents: _, kind } = self;
-        kind.interpret(env)
-    }
-}
-impl Interpret for ExprKind {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        match self {
-            ExprKind::Assign(v) => v.interpret(env),
-            ExprKind::Binary(v) => v.interpret(env),
-            ExprKind::Unary(v) => v.interpret(env),
-            ExprKind::Index(v) => v.interpret(env),
-            ExprKind::Path(v) => v.interpret(env),
-            ExprKind::Literal(v) => v.interpret(env),
-            ExprKind::Array(v) => v.interpret(env),
-            ExprKind::ArrayRep(v) => v.interpret(env),
-            ExprKind::AddrOf(v) => v.interpret(env),
-            ExprKind::Block(v) => v.interpret(env),
-            ExprKind::Empty => Ok(ConValue::Empty),
-            ExprKind::Group(v) => v.interpret(env),
-            ExprKind::Tuple(v) => v.interpret(env),
-            ExprKind::While(v) => v.interpret(env),
-            ExprKind::If(v) => v.interpret(env),
-            ExprKind::For(v) => v.interpret(env),
-            ExprKind::Break(v) => v.interpret(env),
-            ExprKind::Return(v) => v.interpret(env),
-            ExprKind::Continue(v) => v.interpret(env),
-        }
-    }
-}
-impl Interpret for Assign {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        let Assign { kind: op, parts } = self;
-        let (head, tail) = parts.borrow();
-        // Resolve the head pattern
-        let head = match &head {
-            ExprKind::Path(Path { parts, .. }) if parts.len() == 1 => {
-                match parts.last().expect("parts should not be empty") {
-                    PathPart::SuperKw => Err(Error::NotAssignable)?,
-                    PathPart::SelfKw => todo!("Assignment to `self`"),
-                    PathPart::Ident(Identifier(s)) => s,
-                }
-            }
-            ExprKind::Index(_) => todo!("Assignment to an index operation"),
-            ExprKind::Path(_) => todo!("Path expression resolution (IMPORTANT)"),
-            ExprKind::Empty | ExprKind::Group(_) | ExprKind::Tuple(_) => {
-                todo!("Pattern Destructuring?")
-            }
-            _ => Err(Error::NotAssignable)?,
-        };
-        // Get the initializer and the tail
-        let init = tail.interpret(env)?;
-        let target = env.get_mut(head)?;
-
-        if let AssignKind::Plain = op {
-            use std::mem::discriminant as variant;
-            // runtime typecheck
-            match target {
-                Some(value) if variant(value) == variant(&init) => {
-                    *value = init;
-                }
-                value @ None => *value = Some(init),
-                _ => Err(Error::TypeError)?,
-            }
-            return Ok(ConValue::Empty);
-        }
-        let Some(target) = target else {
-            return Err(Error::NotInitialized(head.into()));
-        };
-
-        match op {
-            AssignKind::Add => target.add_assign(init)?,
-            AssignKind::Sub => target.sub_assign(init)?,
-            AssignKind::Mul => target.mul_assign(init)?,
-            AssignKind::Div => target.div_assign(init)?,
-            AssignKind::Rem => target.rem_assign(init)?,
-            AssignKind::And => target.bitand_assign(init)?,
-            AssignKind::Or => target.bitor_assign(init)?,
-            AssignKind::Xor => target.bitxor_assign(init)?,
-            AssignKind::Shl => target.shl_assign(init)?,
-            AssignKind::Shr => target.shr_assign(init)?,
-            _ => (),
-        }
-        Ok(ConValue::Empty)
-    }
-}
-impl Interpret for Binary {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        let Binary { kind, parts } = self;
-        let (head, tail) = parts.borrow();
-
-        let head = head.interpret(env)?;
-
-        // Short-circuiting ops
-        match kind {
-            BinaryKind::LogAnd => {
-                return if head.truthy()? {
-                    tail.interpret(env)
-                } else {
-                    Ok(head)
-                }; // Short circuiting
-            }
-            BinaryKind::LogOr => {
-                return if !head.truthy()? {
-                    tail.interpret(env)
-                } else {
-                    Ok(head)
-                }; // Short circuiting
-            }
-            BinaryKind::LogXor => {
-                return Ok(ConValue::Bool(
-                    head.truthy()? ^ tail.interpret(env)?.truthy()?,
-                ));
-            }
-            _ => {}
-        }
-        let tail = tail.interpret(env)?;
-        match kind {
-            BinaryKind::Mul => env.call("mul", &[head, tail]),
-            BinaryKind::Div => env.call("div", &[head, tail]),
-            BinaryKind::Rem => env.call("rem", &[head, tail]),
-            BinaryKind::Add => env.call("add", &[head, tail]),
-            BinaryKind::Sub => env.call("sub", &[head, tail]),
-            BinaryKind::Shl => env.call("shl", &[head, tail]),
-            BinaryKind::Shr => env.call("shr", &[head, tail]),
-            BinaryKind::BitAnd => env.call("and", &[head, tail]),
-            BinaryKind::BitOr => env.call("or", &[head, tail]),
-            BinaryKind::BitXor => env.call("xor", &[head, tail]),
-            BinaryKind::RangeExc => env.call("range_exc", &[head, tail]),
-            BinaryKind::RangeInc => env.call("range_inc", &[head, tail]),
-            BinaryKind::Lt => env.call("lt", &[head, tail]),
-            BinaryKind::LtEq => env.call("lt_eq", &[head, tail]),
-            BinaryKind::Equal => env.call("eq", &[head, tail]),
-            BinaryKind::NotEq => env.call("neq", &[head, tail]),
-            BinaryKind::GtEq => env.call("gt_eq", &[head, tail]),
-            BinaryKind::Gt => env.call("gt", &[head, tail]),
-            BinaryKind::Dot => todo!("search within a type's namespace!"),
-            BinaryKind::Call => match tail {
-                ConValue::Empty => head.call(env, &[]),
-                ConValue::Tuple(args) => head.call(env, &args),
-                _ => Err(Error::TypeError),
-            },
-            _ => Ok(head),
-        }
-    }
-}
-
-impl Interpret for Unary {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        let Unary { kind, tail } = self;
-        let operand = tail.interpret(env)?;
-        match kind {
-            UnaryKind::Deref => env.call("deref", &[operand]),
-            UnaryKind::Neg => env.call("neg", &[operand]),
-            UnaryKind::Not => env.call("not", &[operand]),
-            UnaryKind::At => {
-                println!("{operand}");
-                Ok(operand)
-            }
-            UnaryKind::Tilde => unimplemented!("Tilde operator"),
-        }
-    }
-}
-impl Interpret for Index {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        let Self { head, indices } = self;
-        let mut head = head.interpret(env)?;
-        for index in indices {
-            head = head.index(&index.interpret(env)?)?;
-        }
-        Ok(head)
-    }
-}
-impl Interpret for Path {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        let Self { absolute: _, parts } = self;
-
-        if parts.len() == 1 {
-            match parts.last().expect("parts should not be empty") {
-                PathPart::SuperKw | PathPart::SelfKw => todo!("Path navigation"),
-                PathPart::Ident(Identifier(s)) => env.get(s).cloned(),
-            }
-        } else {
-            todo!("Path navigation!")
-        }
-    }
-}
-impl Interpret for Literal {
-    fn interpret(&self, _env: &mut Environment) -> IResult<ConValue> {
-        Ok(match self {
-            Literal::String(value) => ConValue::from(value.as_str()),
-            Literal::Char(value) => ConValue::Char(*value),
-            Literal::Bool(value) => ConValue::Bool(*value),
-            // Literal::Float(value) => todo!("Float values in interpreter: {value:?}"),
-            Literal::Int(value) => ConValue::Int(*value as _),
-        })
-    }
-}
-impl Interpret for Array {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        let Self { values } = self;
-        let mut out = vec![];
-        for expr in values {
-            out.push(expr.interpret(env)?)
-        }
-        Ok(ConValue::Array(out))
-    }
-}
-impl Interpret for ArrayRep {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        let Self { value, repeat } = self;
-        let repeat = match repeat.interpret(env)? {
-            ConValue::Int(v) => v,
-            _ => Err(Error::TypeError)?,
-        };
-        let value = value.interpret(env)?;
-        Ok(ConValue::Array(vec![value; repeat as usize]))
-    }
-}
-impl Interpret for AddrOf {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        let Self { count: _, mutable: _, expr } = self;
-        // this is stupid
-        todo!("Create reference\nfrom expr: {expr}\nin env:\n{env}\n")
-    }
-}
-impl Interpret for Block {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        let Self { stmts } = self;
-        let mut env = env.frame("block");
-        let mut out = ConValue::Empty;
-        for stmt in stmts {
-            out = stmt.interpret(&mut env)?;
-        }
-        Ok(out)
-    }
-}
-impl Interpret for Group {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        let Self { expr } = self;
-        expr.interpret(env)
-    }
-}
-impl Interpret for Tuple {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        let Self { exprs } = self;
-        Ok(ConValue::Tuple(exprs.iter().try_fold(
-            vec![],
-            |mut out, element| {
-                out.push(element.interpret(env)?);
-                Ok(out)
-            },
-        )?))
-    }
-}
-impl Interpret for While {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        let Self { cond, pass, fail } = self;
-        while cond.interpret(env)?.truthy()? {
-            match pass.interpret(env) {
-                Err(Error::Break(value)) => return Ok(value),
-                Err(Error::Continue) => continue,
-                e => e?,
-            };
-        }
-        fail.interpret(env)
-    }
-}
-impl Interpret for If {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        let Self { cond, pass, fail } = self;
-        if cond.interpret(env)?.truthy()? {
-            pass.interpret(env)
-        } else {
-            fail.interpret(env)
-        }
-    }
-}
-impl Interpret for For {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        let Self { bind: Identifier(name), cond, pass, fail } = self;
-        // TODO: A better iterator model
-        let bounds = match cond.interpret(env)? {
-            ConValue::RangeExc(a, b) => a..=b,
-            ConValue::RangeInc(a, b) => a..=b,
-            _ => Err(Error::TypeError)?,
-        };
-        {
-            let mut env = env.frame("loop variable");
-            for loop_var in bounds {
-                env.insert(name, Some(loop_var.into()));
-                match pass.interpret(&mut env) {
-                    Err(Error::Break(value)) => return Ok(value),
-                    Err(Error::Continue) => continue,
-                    result => result?,
-                };
-            }
-        }
-        fail.interpret(env)
-    }
-}
-impl Interpret for Else {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        let Self { body } = self;
-        match body {
-            Some(body) => body.interpret(env),
-            None => Ok(ConValue::Empty),
-        }
-    }
-}
-impl Interpret for Continue {
-    fn interpret(&self, _env: &mut Environment) -> IResult<ConValue> {
-        Err(Error::Continue)
-    }
-}
-impl Interpret for Return {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        let Self { body } = self;
-        Err(Error::Return(
-            body.as_ref()
-                .map(|body| body.interpret(env))
-                .unwrap_or(Ok(ConValue::Empty))?,
-        ))
-    }
-}
-impl Interpret for Break {
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        let Self { body } = self;
-        Err(Error::Break(
-            body.as_ref()
-                .map(|body| body.interpret(env))
-                .unwrap_or(Ok(ConValue::Empty))?,
-        ))
-    }
-}

cl-interpret/src/lib.rs

@@ -1,614 +0,0 @@
-//! Walks a Conlang AST, interpreting it as a program.
-#![warn(clippy::all)]
-#![feature(decl_macro)]
-
-use env::Environment;
-use error::{Error, IResult};
-use interpret::Interpret;
-use temp_type_impl::ConValue;
-
-/// Callable types can be called from within a Conlang program
-pub trait Callable: std::fmt::Debug {
-    /// Calls this [Callable] in the provided [Environment], with [ConValue] args  \
-    /// The Callable is responsible for checking the argument count and validating types
-    fn call(&self, interpreter: &mut Environment, args: &[ConValue]) -> IResult<ConValue>;
-    /// Returns the common name of this identifier.
-    fn name(&self) -> &str;
-}
-
-/// [BuiltIn]s are [Callable]s with bespoke definitions
-pub trait BuiltIn: std::fmt::Debug + Callable {
-    fn description(&self) -> &str;
-}
-
-pub mod temp_type_impl {
-    //! Temporary implementations of Conlang values
-    //!
-    //! The most permanent fix is a temporary one.
-    use super::{
-        error::{Error, IResult},
-        function::Function,
-        BuiltIn, Callable, Environment,
-    };
-    use std::ops::*;
-
-    type Integer = isize;
-
-    /// A Conlang value
-    ///
-    /// This is a hack to work around the fact that Conlang doesn't
-    /// have a functioning type system yet :(
-    #[derive(Clone, Debug, Default)]
-    pub enum ConValue {
-        /// The empty/unit `()` type
-        #[default]
-        Empty,
-        /// An integer
-        Int(Integer),
-        /// A boolean
-        Bool(bool),
-        /// A unicode character
-        Char(char),
-        /// A string
-        String(String),
-        /// An Array
-        Array(Vec<ConValue>),
-        /// A tuple
-        Tuple(Vec<ConValue>),
-        /// An exclusive range
-        RangeExc(Integer, Integer),
-        /// An inclusive range
-        RangeInc(Integer, Integer),
-        /// A callable thing
-        Function(Function),
-        /// A built-in function
-        BuiltIn(&'static dyn BuiltIn),
-    }
-    impl ConValue {
-        /// Gets whether the current value is true or false
-        pub fn truthy(&self) -> IResult<bool> {
-            match self {
-                ConValue::Bool(v) => Ok(*v),
-                _ => Err(Error::TypeError)?,
-            }
-        }
-        pub fn range_exc(self, other: Self) -> IResult<Self> {
-            let (Self::Int(a), Self::Int(b)) = (self, other) else {
-                Err(Error::TypeError)?
-            };
-            Ok(Self::RangeExc(a, b.saturating_sub(1)))
-        }
-        pub fn range_inc(self, other: Self) -> IResult<Self> {
-            let (Self::Int(a), Self::Int(b)) = (self, other) else {
-                Err(Error::TypeError)?
-            };
-            Ok(Self::RangeInc(a, b))
-        }
-        pub fn index(&self, index: &Self) -> IResult<ConValue> {
-            let Self::Int(index) = index else {
-                Err(Error::TypeError)?
-            };
-            let Self::Array(arr) = self else {
-                Err(Error::TypeError)?
-            };
-            arr.get(*index as usize)
-                .cloned()
-                .ok_or(Error::OobIndex(*index as usize, arr.len()))
-        }
-        cmp! {
-            lt: false, <;
-            lt_eq: true, <=;
-            eq: true, ==;
-            neq: false, !=;
-            gt_eq: true, >=;
-            gt: false, >;
-        }
-        assign! {
-            add_assign: +;
-            bitand_assign: &;
-            bitor_assign: |;
-            bitxor_assign: ^;
-            div_assign: /;
-            mul_assign: *;
-            rem_assign: %;
-            shl_assign: <<;
-            shr_assign: >>;
-            sub_assign: -;
-        }
-    }
-
-    impl Callable for ConValue {
-        fn name(&self) -> &str {
-            match self {
-                ConValue::Function(func) => func.name(),
-                ConValue::BuiltIn(func) => func.name(),
-                _ => "",
-            }
-        }
-        fn call(&self, interpreter: &mut Environment, args: &[ConValue]) -> IResult<ConValue> {
-            match self {
-                Self::Function(func) => func.call(interpreter, args),
-                Self::BuiltIn(func) => func.call(interpreter, args),
-                _ => Err(Error::NotCallable(self.clone())),
-            }
-        }
-    }
-    /// Templates comparison functions for [ConValue]
-    macro cmp ($($fn:ident: $empty:literal, $op:tt);*$(;)?) {$(
-        /// TODO: Remove when functions are implemented:
-        ///       Desugar into function calls
-        pub fn $fn(&self, other: &Self) -> IResult<Self> {
-            match (self, other) {
-                (Self::Empty, Self::Empty) => Ok(Self::Bool($empty)),
-                (Self::Int(a), Self::Int(b)) => Ok(Self::Bool(a $op b)),
-                (Self::Bool(a), Self::Bool(b)) => Ok(Self::Bool(a $op b)),
-                (Self::Char(a), Self::Char(b)) => Ok(Self::Bool(a $op b)),
-                (Self::String(a), Self::String(b)) => Ok(Self::Bool(a $op b)),
-                _ => Err(Error::TypeError)
-            }
-        }
-    )*}
-    macro assign($( $fn: ident: $op: tt );*$(;)?) {$(
-        pub fn $fn(&mut self, other: Self) -> IResult<()> {
-            *self = (std::mem::take(self) $op other)?;
-            Ok(())
-        }
-    )*}
-    /// Implements [From] for an enum with 1-tuple variants
-    macro from ($($T:ty => $v:expr),*$(,)?) {
-        $(impl From<$T> for ConValue {
-            fn from(value: $T) -> Self { $v(value.into()) }
-        })*
-    }
-    from! {
-        Integer => ConValue::Int,
-        bool => ConValue::Bool,
-        char => ConValue::Char,
-        &str => ConValue::String,
-        String => ConValue::String,
-        Function => ConValue::Function,
-        Vec<ConValue> => ConValue::Tuple,
-        &'static dyn BuiltIn => ConValue::BuiltIn,
-    }
-    impl From<()> for ConValue {
-        fn from(_: ()) -> Self {
-            Self::Empty
-        }
-    }
-    impl From<&[ConValue]> for ConValue {
-        fn from(value: &[ConValue]) -> Self {
-            match value.len() {
-                0 => Self::Empty,
-                1 => value[0].clone(),
-                _ => Self::Tuple(value.into()),
-            }
-        }
-    }
-
-    /// Implements binary [std::ops] traits for [ConValue]
-    ///
-    /// TODO: Desugar operators into function calls
-    macro ops($($trait:ty: $fn:ident = [$($match:tt)*])*) {
-        $(impl $trait for ConValue {
-            type Output = IResult<Self>;
-            /// TODO: Desugar operators into function calls
-            fn $fn(self, rhs: Self) -> Self::Output {Ok(match (self, rhs) {$($match)*})}
-        })*
-    }
-    ops! {
-        Add: add = [
-            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
-            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a + b),
-            (ConValue::String(a), ConValue::String(b)) => ConValue::String(a + &b),
-            _ => Err(Error::TypeError)?
-            ]
-        BitAnd: bitand = [
-            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
-            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a & b),
-            (ConValue::Bool(a), ConValue::Bool(b)) => ConValue::Bool(a & b),
-            _ => Err(Error::TypeError)?
-        ]
-        BitOr: bitor = [
-            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
-            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a | b),
-            (ConValue::Bool(a), ConValue::Bool(b)) => ConValue::Bool(a | b),
-            _ => Err(Error::TypeError)?
-        ]
-        BitXor: bitxor = [
-            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
-            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a ^ b),
-            (ConValue::Bool(a), ConValue::Bool(b)) => ConValue::Bool(a ^ b),
-            _ => Err(Error::TypeError)?
-        ]
-        Div: div = [
-            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
-            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a / b),
-            _ => Err(Error::TypeError)?
-        ]
-        Mul: mul = [
-            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
-            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a * b),
-            _ => Err(Error::TypeError)?
-        ]
-        Rem: rem = [
-            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
-            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a % b),
-            _ => Err(Error::TypeError)?
-        ]
-        Shl: shl = [
-            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
-            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a << b),
-            _ => Err(Error::TypeError)?
-        ]
-        Shr: shr = [
-            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
-            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a >> b),
-            _ => Err(Error::TypeError)?
-        ]
-        Sub: sub = [
-            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
-            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a - b),
-            _ => Err(Error::TypeError)?
-        ]
-    }
-    impl std::fmt::Display for ConValue {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            match self {
-                ConValue::Empty => "Empty".fmt(f),
-                ConValue::Int(v) => v.fmt(f),
-                ConValue::Bool(v) => v.fmt(f),
-                ConValue::Char(v) => v.fmt(f),
-                ConValue::String(v) => v.fmt(f),
-                ConValue::Array(array) => {
-                    '['.fmt(f)?;
-                    for (idx, element) in array.iter().enumerate() {
-                        if idx > 0 {
-                            ", ".fmt(f)?
-                        }
-                        element.fmt(f)?
-                    }
-                    ']'.fmt(f)
-                }
-                ConValue::RangeExc(a, b) => write!(f, "{a}..{}", b + 1),
-                ConValue::RangeInc(a, b) => write!(f, "{a}..={b}"),
-                ConValue::Tuple(tuple) => {
-                    '('.fmt(f)?;
-                    for (idx, element) in tuple.iter().enumerate() {
-                        if idx > 0 {
-                            ", ".fmt(f)?
-                        }
-                        element.fmt(f)?
-                    }
-                    ')'.fmt(f)
-                }
-                ConValue::Function(func) => {
-                    use cl_ast::format::*;
-                    use std::fmt::Write;
-                    write!(f.pretty(), "{}", func.decl())
-                }
-                ConValue::BuiltIn(func) => {
-                    write!(f, "{}", func.description())
-                }
-            }
-        }
-    }
-}
-
-pub mod interpret;
-
-pub mod function {
-    //! Represents a block of code which lives inside the Interpreter
-    use super::{Callable, ConValue, Environment, Error, IResult, Interpret};
-    use cl_ast::{Function as FnDecl, Identifier, Param};
-    /// Represents a block of code which persists inside the Interpreter
-    #[derive(Clone, Debug)]
-    pub struct Function {
-        /// Stores the contents of the function declaration
-        decl: Box<FnDecl>,
-        // /// Stores the enclosing scope of the function
-        // env: Box<Environment>,
-    }
-
-    impl Function {
-        pub fn new(decl: &FnDecl) -> Self {
-            Self { decl: decl.clone().into() }
-        }
-        pub fn decl(&self) -> &FnDecl {
-            &self.decl
-        }
-    }
-
-    impl Callable for Function {
-        fn name(&self) -> &str {
-            let FnDecl { name: Identifier(ref name), .. } = *self.decl;
-            name
-        }
-        fn call(&self, env: &mut Environment, args: &[ConValue]) -> IResult<ConValue> {
-            let FnDecl { name: Identifier(name), args: declargs, body, rety: _ } = &*self.decl;
-            // Check arg mapping
-            if args.len() != declargs.len() {
-                return Err(Error::ArgNumber { want: declargs.len(), got: args.len() });
-            }
-            let Some(body) = body else {
-                return Err(Error::NotDefined(name.into()));
-            };
-            // TODO: completely refactor data storage
-            let mut frame = env.frame("fn args");
-            for (Param { mutability: _, name: Identifier(name), ty: _ }, value) in
-                declargs.iter().zip(args)
-            {
-                frame.insert(name, Some(value.clone()));
-            }
-            match body.interpret(&mut frame) {
-                Err(Error::Return(value)) => Ok(value),
-                Err(Error::Break(value)) => Err(Error::BadBreak(value)),
-                result => result,
-            }
-        }
-    }
-}
-
-pub mod builtin;
-
-pub mod env {
-    //! Lexical and non-lexical scoping for variables
-    use super::{
-        builtin::{BINARY, MISC, RANGE, UNARY},
-        error::{Error, IResult},
-        function::Function,
-        temp_type_impl::ConValue,
-        BuiltIn, Callable, Interpret,
-    };
-    use cl_ast::{Function as FnDecl, Identifier};
-    use std::{
-        collections::HashMap,
-        fmt::Display,
-        ops::{Deref, DerefMut},
-    };
-
-    /// Implements a nested lexical scope
-    #[derive(Clone, Debug)]
-    pub struct Environment {
-        frames: Vec<(HashMap<String, Option<ConValue>>, &'static str)>,
-    }
-
-    impl Display for Environment {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            for (frame, name) in self.frames.iter().rev() {
-                writeln!(f, "--- {name} ---")?;
-                for (var, val) in frame {
-                    write!(f, "{var}: ")?;
-                    match val {
-                        Some(value) => writeln!(f, "\t{value}"),
-                        None => writeln!(f, "<undefined>"),
-                    }?
-                }
-            }
-            Ok(())
-        }
-    }
-    impl Default for Environment {
-        fn default() -> Self {
-            Self {
-                frames: vec![
-                    (to_hashmap(RANGE), "range ops"),
-                    (to_hashmap(UNARY), "unary ops"),
-                    (to_hashmap(BINARY), "binary ops"),
-                    (to_hashmap(MISC), "builtins"),
-                    (HashMap::new(), "globals"),
-                ],
-            }
-        }
-    }
-    fn to_hashmap(from: &[&'static dyn BuiltIn]) -> HashMap<String, Option<ConValue>> {
-        from.iter()
-            .map(|&v| (v.name().into(), Some(v.into())))
-            .collect()
-    }
-
-    impl Environment {
-        pub fn new() -> Self {
-            Self::default()
-        }
-        /// Creates an [Environment] with no [builtins](super::builtin)
-        pub fn no_builtins(name: &'static str) -> Self {
-            Self { frames: vec![(Default::default(), name)] }
-        }
-
-        pub fn eval(&mut self, node: &impl Interpret) -> IResult<ConValue> {
-            node.interpret(self)
-        }
-
-        /// Calls a function inside the interpreter's scope,
-        /// and returns the result
-        pub fn call(&mut self, name: &str, args: &[ConValue]) -> IResult<ConValue> {
-            // FIXME: Clone to satisfy the borrow checker
-            let function = self.get(name)?.clone();
-            function.call(self, args)
-        }
-        /// Enters a nested scope, returning a [`Frame`] stack-guard.
-        ///
-        /// [`Frame`] implements Deref/DerefMut for [`Environment`].
-        pub fn frame(&mut self, name: &'static str) -> Frame {
-            Frame::new(self, name)
-        }
-        /// Resolves a variable mutably.
-        ///
-        /// Returns a mutable reference to the variable's record, if it exists.
-        pub fn get_mut(&mut self, id: &str) -> IResult<&mut Option<ConValue>> {
-            for (frame, _) in self.frames.iter_mut().rev() {
-                if let Some(var) = frame.get_mut(id) {
-                    return Ok(var);
-                }
-            }
-            Err(Error::NotDefined(id.into()))
-        }
-        /// Resolves a variable immutably.
-        ///
-        /// Returns a reference to the variable's contents, if it is defined and initialized.
-        pub fn get(&self, id: &str) -> IResult<&ConValue> {
-            for (frame, _) in self.frames.iter().rev() {
-                match frame.get(id) {
-                    Some(Some(var)) => return Ok(var),
-                    Some(None) => return Err(Error::NotInitialized(id.into())),
-                    _ => (),
-                }
-            }
-            Err(Error::NotDefined(id.into()))
-        }
-        /// Inserts a new [ConValue] into this [Environment]
-        pub fn insert(&mut self, id: &str, value: Option<ConValue>) {
-            if let Some((frame, _)) = self.frames.last_mut() {
-                frame.insert(id.into(), value);
-            }
-        }
-        /// A convenience function for registering a [FnDecl] as a [Function]
-        pub fn insert_fn(&mut self, decl: &FnDecl) {
-            let FnDecl { name: Identifier(name), .. } = decl;
-            let (name, function) = (name.clone(), Some(Function::new(decl).into()));
-            if let Some((frame, _)) = self.frames.last_mut() {
-                frame.insert(name, function);
-            }
-        }
-    }
-
-    /// Functions which aid in the implementation of [`Frame`]
-    impl Environment {
-        /// Enters a scope, creating a new namespace for variables
-        fn enter(&mut self, name: &'static str) -> &mut Self {
-            self.frames.push((Default::default(), name));
-            self
-        }
-
-        /// Exits the scope, destroying all local variables and
-        /// returning the outer scope, if there is one
-        fn exit(&mut self) -> &mut Self {
-            if self.frames.len() > 2 {
-                self.frames.pop();
-            }
-            self
-        }
-    }
-
-    /// Represents a stack frame
-    #[derive(Debug)]
-    pub struct Frame<'scope> {
-        scope: &'scope mut Environment,
-    }
-    impl<'scope> Frame<'scope> {
-        fn new(scope: &'scope mut Environment, name: &'static str) -> Self {
-            Self { scope: scope.enter(name) }
-        }
-    }
-    impl<'scope> Deref for Frame<'scope> {
-        type Target = Environment;
-        fn deref(&self) -> &Self::Target {
-            self.scope
-        }
-    }
-    impl<'scope> DerefMut for Frame<'scope> {
-        fn deref_mut(&mut self) -> &mut Self::Target {
-            self.scope
-        }
-    }
-    impl<'scope> Drop for Frame<'scope> {
-        fn drop(&mut self) {
-            self.scope.exit();
-        }
-    }
-}
-
-pub mod error {
-    //! The [Error] type represents any error thrown by the [Environment](super::Environment)
-
-    use super::temp_type_impl::ConValue;
-
-    pub type IResult<T> = Result<T, Error>;
-
-    /// Represents any error thrown by the [Environment](super::Environment)
-    #[derive(Clone, Debug)]
-    pub enum Error {
-        /// Propagate a Return value
-        Return(ConValue),
-        /// Propagate a Break value
-        Break(ConValue),
-        /// Break propagated across function bounds
-        BadBreak(ConValue),
-        /// Continue to the next iteration of a loop
-        Continue,
-        /// Underflowed the stack
-        StackUnderflow,
-        /// Exited the last scope
-        ScopeExit,
-        /// Type incompatibility
-        // TODO: store the type information in this error
-        TypeError,
-        /// In clause of For loop didn't yield a Range
-        NotIterable,
-        /// A value could not be indexed
-        NotIndexable,
-        /// An array index went out of bounds
-        OobIndex(usize, usize),
-        /// An expression is not assignable
-        NotAssignable,
-        /// A name was not defined in scope before being used
-        NotDefined(String),
-        /// A name was defined but not initialized
-        NotInitialized(String),
-        /// A value was called, but is not callable
-        NotCallable(ConValue),
-        /// A function was called with the wrong number of arguments
-        ArgNumber {
-            want: usize,
-            got: usize,
-        },
-        NullPointer,
-    }
-
-    impl std::error::Error for Error {}
-    impl std::fmt::Display for Error {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            match self {
-                Error::Return(value) => write!(f, "return {value}"),
-                Error::Break(value) => write!(f, "break {value}"),
-                Error::BadBreak(value) => write!(f, "rogue break: {value}"),
-                Error::Continue => "continue".fmt(f),
-                Error::StackUnderflow => "Stack underflow".fmt(f),
-                Error::ScopeExit => "Exited the last scope. This is a logic bug.".fmt(f),
-                Error::TypeError => "Incompatible types".fmt(f),
-                Error::NotIterable => "`in` clause of `for` loop did not yield an iterable".fmt(f),
-                Error::NotIndexable => {
-                    write!(f, "expression cannot be indexed")
-                }
-                Error::OobIndex(idx, len) => {
-                    write!(f, "Index out of bounds: index was {idx}. but len is {len}")
-                }
-                Error::NotAssignable => {
-                    write!(f, "expression is not assignable")
-                }
-                Error::NotDefined(value) => {
-                    write!(f, "{value} not bound. Did you mean `let {value};`?")
-                }
-                Error::NotInitialized(value) => {
-                    write!(f, "{value} bound, but not initialized")
-                }
-                Error::NotCallable(value) => {
-                    write!(f, "{value} is not callable.")
-                }
-                Error::ArgNumber { want, got } => {
-                    write!(
-                        f,
-                        "Expected {want} argument{}, got {got}",
-                        if *want == 1 { "" } else { "s" }
-                    )
-                }
-                Error::NullPointer => {
-                    write!(f, "Attempted to dereference a null pointer?")
-                }
-            }
-        }
-    }
-}
-
-#[cfg(test)]
-mod tests;

cl-repl/examples/typeck.rs

@@ -1,109 +0,0 @@
-use cl_lexer::Lexer;
-use cl_parser::Parser;
-use cl_repl::repline::{error::Error as RlError, Repline};
-use cl_typeck::{name_collector::NameCollector, project::Project};
-use std::error::Error;
-
-fn main() -> Result<(), Box<dyn Error>> {
-    let mut prj = Project::default();
-    let mut tcol = NameCollector::new(&mut prj);
-
-    println!(
-        "--- {} v{} 💪🦈 ---",
-        env!("CARGO_BIN_NAME"),
-        env!("CARGO_PKG_VERSION"),
-    );
-
-    read_and(
-        "\x1b[33m",
-        "cl>",
-        "? >",
-        |line| -> Result<_, Box<dyn Error>> {
-            if line.trim_start().is_empty() {
-                query(&tcol)?;
-                return Ok(Response::Deny);
-            }
-            let mut parser = Parser::new(Lexer::new(line));
-            let code = match parser.file() {
-                Ok(code) => code,
-                Err(e) => Err(e)?,
-            };
-            tcol.file(&code)?;
-            Ok(Response::Accept)
-        },
-    )
-}
-
-pub enum Response {
-    Accept,
-    Deny,
-    Break,
-}
-
-fn read_and(
-    color: &str,
-    begin: &str,
-    again: &str,
-    mut f: impl FnMut(&str) -> Result<Response, Box<dyn Error>>,
-) -> Result<(), Box<dyn Error>> {
-    let mut rl = Repline::new(color, begin, again);
-    loop {
-        let line = match rl.read() {
-            Err(RlError::CtrlC(_)) => break,
-            Err(RlError::CtrlD(line)) => {
-                rl.deny();
-                line
-            }
-            Ok(line) => line,
-            Err(e) => Err(e)?,
-        };
-        print!("\x1b[G\x1b[J");
-        match f(&line) {
-            Ok(Response::Accept) => rl.accept(),
-            Ok(Response::Deny) => rl.deny(),
-            Ok(Response::Break) => break,
-            Err(e) => print!("\x1b[40G\x1bJ\x1b[91m{e}\x1b[0m"),
-        }
-    }
-    Ok(())
-}
-
-fn query(prj: &Project) -> Result<(), Box<dyn Error>> {
-    use cl_typeck::{
-        definition::{Def, DefKind},
-        type_kind::TypeKind,
-    };
-    read_and("\x1b[35m", "qy>", "? >", |line| {
-        if line.trim_start().is_empty() {
-            return Ok(Response::Break);
-        }
-        match line {
-            "$all\n" => println!("{prj:#?}"),
-            _ => {
-                // parse it as a path, and convert the path into a borrowed path
-                let path = Parser::new(Lexer::new(line)).path()?;
-
-                let Some((type_id, path)) = prj.get_type((&path).into(), prj.module_root) else {
-                    return Ok(Response::Deny);
-                };
-                let Def { name, vis, meta: _, kind, source: _, module } = &prj[type_id];
-                match (kind, prj.get_value(path, type_id)) {
-                    (_, Some((val, path))) => {
-                        println!("value {}; {path}\n{:#?}", usize::from(val), prj[val])
-                    }
-                    (DefKind::Type(TypeKind::Module), None) => println!(
-                        "{vis}mod \"{name}\" (#{}); {path}\n{:#?}",
-                        usize::from(type_id),
-                        module
-                    ),
-                    (_, None) => println!(
-                        "type {name}(#{}); {path}\n{:#?}",
-                        usize::from(type_id),
-                        prj.pool[type_id]
-                    ),
-                };
-            }
-        }
-        Ok(Response::Accept)
-    })
-}

cl-repl/src/bin/conlang.rs

@@ -1,13 +0,0 @@
-use cl_repl::{cli::run, tools::is_terminal};
-use std::error::Error;
-
-fn main() -> Result<(), Box<dyn Error>> {
-    if is_terminal() {
-        println!(
-            "--- {} v{} 💪🦈 ---",
-            env!("CARGO_BIN_NAME"),
-            env!("CARGO_PKG_VERSION"),
-        );
-    }
-    run(argh::from_env())
-}

cl-repl/src/lib.rs

@@ -1,462 +0,0 @@
-//! Utilities for cl-frontend
-//!
-//! # TODO
-//! - [ ] Readline-like line editing
-//! - [ ] Raw mode?
-#![warn(clippy::all)]
-
-pub mod ansi {
-    // ANSI color escape sequences
-    pub const ANSI_RED: &str = "\x1b[31m";
-    pub const ANSI_GREEN: &str = "\x1b[32m"; // the color of type checker mode
-    pub const ANSI_CYAN: &str = "\x1b[36m";
-    // pub const ANSI_BRIGHT_GREEN: &str = "\x1b[92m";
-    pub const ANSI_BRIGHT_BLUE: &str = "\x1b[94m";
-    pub const ANSI_BRIGHT_MAGENTA: &str = "\x1b[95m";
-    // const ANSI_BRIGHT_CYAN: &str = "\x1b[96m";
-    pub const ANSI_RESET: &str = "\x1b[0m";
-    pub const ANSI_OUTPUT: &str = "\x1b[38;5;117m";
-
-    pub const ANSI_CLEAR_LINES: &str = "\x1b[G\x1b[J";
-}
-
-pub mod args {
-    use crate::tools::is_terminal;
-    use argh::FromArgs;
-    use std::{path::PathBuf, str::FromStr};
-
-    /// The Conlang prototype debug interface
-    #[derive(Clone, Debug, FromArgs, PartialEq, Eq, PartialOrd, Ord)]
-    pub struct Args {
-        /// the main source file
-        #[argh(positional)]
-        pub file: Option<PathBuf>,
-
-        /// files to include
-        #[argh(option, short = 'I')]
-        pub include: Vec<PathBuf>,
-
-        /// the Repl mode to start in
-        #[argh(option, short = 'm', default = "Default::default()")]
-        pub mode: Mode,
-
-        /// whether to start the repl (`true` or `false`)
-        #[argh(option, short = 'r', default = "is_terminal()")]
-        pub repl: bool,
-    }
-
-    /// The CLI's operating mode
-    #[derive(Clone, Copy, Debug, Default, PartialEq, Eq, PartialOrd, Ord)]
-    pub enum Mode {
-        Tokenize,
-        Beautify,
-        #[default]
-        Interpret,
-    }
-
-    impl Mode {
-        pub fn ansi_color(self) -> &'static str {
-            use super::ansi::*;
-            match self {
-                Mode::Tokenize => ANSI_BRIGHT_BLUE,
-                Mode::Beautify => ANSI_BRIGHT_MAGENTA,
-                // Mode::Resolve => ANSI_GREEN,
-                Mode::Interpret => ANSI_CYAN,
-            }
-        }
-    }
-
-    impl FromStr for Mode {
-        type Err = &'static str;
-        fn from_str(s: &str) -> Result<Self, &'static str> {
-            Ok(match s {
-                "i" | "interpret" | "r" | "run" => Mode::Interpret,
-                "b" | "beautify" | "p" | "pretty" => Mode::Beautify,
-                // "r" | "resolve" | "typecheck" | "type" => Mode::Resolve,
-                "t" | "tokenize" | "token" => Mode::Tokenize,
-                _ => Err("Recognized modes are: 'r' \"run\", 'p' \"pretty\", 't' \"token\"")?,
-            })
-        }
-    }
-}
-
-pub mod program {
-    use cl_interpret::{
-        env::Environment, error::IResult, interpret::Interpret, temp_type_impl::ConValue,
-    };
-
-    use cl_ast::{self as ast, format::*};
-    use cl_lexer::Lexer;
-    use cl_parser::{error::PResult, Parser};
-    // use conlang::resolver::{error::TyResult, Resolver};
-    use std::{fmt::Display, io::Write};
-
-    pub struct Parsable;
-
-    pub enum Parsed {
-        File(ast::File),
-        Stmt(ast::Stmt),
-        Expr(ast::Expr),
-    }
-
-    pub struct Program<'t, Variant> {
-        text: &'t str,
-        data: Variant,
-    }
-    impl<'t, V> Program<'t, V> {
-        pub fn lex(&self) -> Lexer {
-            Lexer::new(self.text)
-        }
-    }
-
-    impl<'t> Program<'t, Parsable> {
-        pub fn new(text: &'t str) -> Self {
-            Self { text, data: Parsable }
-        }
-        pub fn parse(self) -> PResult<Program<'t, Parsed>> {
-            self.parse_file().or_else(|_| self.parse_stmt())
-        }
-        pub fn parse_expr(&self) -> PResult<Program<'t, Parsed>> {
-            Ok(Program { data: Parsed::Expr(Parser::new(self.lex()).expr()?), text: self.text })
-        }
-        pub fn parse_stmt(&self) -> PResult<Program<'t, Parsed>> {
-            Ok(Program { data: Parsed::Stmt(Parser::new(self.lex()).stmt()?), text: self.text })
-        }
-        pub fn parse_file(&self) -> PResult<Program<'t, Parsed>> {
-            Ok(Program { data: Parsed::File(Parser::new(self.lex()).file()?), text: self.text })
-        }
-    }
-
-    impl<'t> Program<'t, Parsed> {
-        pub fn debug(&self) {
-            match &self.data {
-                Parsed::File(v) => eprintln!("{v:?}"),
-                Parsed::Stmt(v) => eprintln!("{v:?}"),
-                Parsed::Expr(v) => eprintln!("{v:?}"),
-            }
-        }
-        pub fn print(&self) {
-            let mut f = std::io::stdout().pretty();
-            let _ = match &self.data {
-                Parsed::File(v) => writeln!(f, "{v}"),
-                Parsed::Stmt(v) => writeln!(f, "{v}"),
-                Parsed::Expr(v) => writeln!(f, "{v}"),
-            };
-            // println!("{self}")
-        }
-
-        pub fn run(&self, env: &mut Environment) -> IResult<ConValue> {
-            match &self.data {
-                Parsed::File(v) => v.interpret(env),
-                Parsed::Stmt(v) => v.interpret(env),
-                Parsed::Expr(v) => v.interpret(env),
-            }
-        }
-
-        // pub fn resolve(&mut self, resolver: &mut Resolver) -> TyResult<()> {
-        //     match &mut self.data {
-        //         Parsed::Program(start) => start.resolve(resolver),
-        //         Parsed::Expr(expr) => expr.resolve(resolver),
-        //     }
-        //     .map(|ty| println!("{ty}"))
-        // }
-    }
-
-    impl<'t> Display for Program<'t, Parsed> {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            match &self.data {
-                Parsed::File(v) => write!(f, "{v}"),
-                Parsed::Stmt(v) => write!(f, "{v}"),
-                Parsed::Expr(v) => write!(f, "{v}"),
-            }
-        }
-    }
-}
-
-pub mod cli {
-    //! Implement's the command line interface
-    use crate::{
-        args::{Args, Mode},
-        program::{Parsable, Program},
-        repl::Repl,
-        tools::print_token,
-    };
-    use cl_interpret::{env::Environment, temp_type_impl::ConValue};
-    use cl_lexer::Lexer;
-    use cl_parser::Parser;
-    use std::{error::Error, path::Path};
-
-    /// Run the command line interface
-    pub fn run(args: Args) -> Result<(), Box<dyn Error>> {
-        let Args { file, include, mode, repl } = args;
-
-        let mut env = Environment::new();
-        for path in include {
-            load_file(&mut env, path)?;
-        }
-
-        if repl {
-            if let Some(file) = file {
-                load_file(&mut env, file)?;
-            }
-            Repl::with_env(mode, env).repl()
-        } else {
-            let code = match &file {
-                Some(file) => std::fs::read_to_string(file)?,
-                None => std::io::read_to_string(std::io::stdin())?,
-            };
-            let code = Program::new(&code);
-
-            match mode {
-                Mode::Tokenize => tokenize(code, file),
-                Mode::Beautify => beautify(code),
-                Mode::Interpret => interpret(code, &mut env),
-            }?;
-        }
-        Ok(())
-    }
-
-    fn load_file(
-        env: &mut Environment,
-        path: impl AsRef<Path>,
-    ) -> Result<ConValue, Box<dyn Error>> {
-        let file = std::fs::read_to_string(path)?;
-        let code = Parser::new(Lexer::new(&file)).file()?;
-        env.eval(&code).map_err(Into::into)
-    }
-
-    fn tokenize(
-        code: Program<Parsable>,
-        path: Option<impl AsRef<Path>>,
-    ) -> Result<(), Box<dyn Error>> {
-        for token in code.lex() {
-            if let Some(ref path) = path {
-                print!("{}:", path.as_ref().display());
-            }
-            match token {
-                Ok(token) => print_token(&token),
-                Err(e) => println!("{e}"),
-            }
-        }
-        Ok(())
-    }
-
-    fn beautify(code: Program<Parsable>) -> Result<(), Box<dyn Error>> {
-        code.parse()?.print();
-        Ok(())
-    }
-
-    fn interpret(code: Program<Parsable>, env: &mut Environment) -> Result<(), Box<dyn Error>> {
-        match code.parse()?.run(env)? {
-            ConValue::Empty => {}
-            ret => println!("{ret}"),
-        }
-        if env.get("main").is_ok() {
-            match env.call("main", &[])? {
-                ConValue::Empty => {}
-                ret => println!("{ret}"),
-            }
-        }
-        Ok(())
-    }
-}
-
-pub mod repl {
-    use crate::{
-        ansi::*,
-        args::Mode,
-        program::{Parsable, Parsed, Program},
-        tools::print_token,
-    };
-    use cl_interpret::{env::Environment, temp_type_impl::ConValue};
-    use std::fmt::Display;
-
-    /// Implements the interactive interpreter
-    #[derive(Clone, Debug)]
-    pub struct Repl {
-        prompt_again: &'static str, // " ?>"
-        prompt_begin: &'static str, // "cl>"
-        prompt_error: &'static str, // "! >"
-        prompt_succs: &'static str, // " ->"
-        env: Environment,
-        mode: Mode,
-    }
-
-    impl Default for Repl {
-        fn default() -> Self {
-            Self {
-                prompt_begin: "cl>",
-                prompt_again: " ?>",
-                prompt_error: "! >",
-                prompt_succs: " =>",
-                env: Default::default(),
-                mode: Default::default(),
-            }
-        }
-    }
-
-    /// Prompt functions
-    impl Repl {
-        pub fn prompt_result<T: Display, E: Display>(&self, res: Result<T, E>) {
-            match &res {
-                Ok(v) => self.prompt_succs(v),
-                Err(e) => self.prompt_error(e),
-            }
-        }
-        pub fn prompt_error(&self, err: &impl Display) {
-            let Self { prompt_error: prompt, .. } = self;
-            println!("{ANSI_CLEAR_LINES}{ANSI_RED}{prompt} {err}{ANSI_RESET}")
-        }
-        pub fn prompt_succs(&self, value: &impl Display) {
-            let Self { prompt_succs: _prompt, .. } = self;
-            println!("{ANSI_GREEN}{value}{ANSI_RESET}")
-        }
-        /// Resets the cursor to the start of the line, clears the terminal,
-        /// and sets the output color
-        pub fn begin_output(&self) {
-            print!("{ANSI_CLEAR_LINES}{ANSI_OUTPUT}")
-        }
-        pub fn clear_line(&self) {}
-    }
-    /// The actual REPL
-    impl Repl {
-        /// Constructs a new [Repl] with the provided [Mode]
-        pub fn new(mode: Mode) -> Self {
-            Self { mode, ..Default::default() }
-        }
-        /// Constructs a new [Repl] with the provided [Mode] and [Environment]
-        pub fn with_env(mode: Mode, env: Environment) -> Self {
-            Self { mode, env, ..Default::default() }
-        }
-        /// Runs the main REPL loop
-        pub fn repl(&mut self) {
-            use crate::repline::{error::Error, Repline};
-
-            let mut rl = Repline::new(self.mode.ansi_color(), self.prompt_begin, self.prompt_again);
-            fn clear_line() {
-                print!("\x1b[G\x1b[J");
-            }
-            loop {
-                let buf = match rl.read() {
-                    Ok(buf) => buf,
-                    // Ctrl-C: break if current line is empty
-                    Err(Error::CtrlC(buf)) => {
-                        if buf.is_empty() || buf.ends_with('\n') {
-                            return;
-                        }
-                        rl.accept();
-                        println!("Cancelled. (Press Ctrl+C again to quit.)");
-                        continue;
-                    }
-                    // Ctrl-D: reset input, and parse it for errors
-                    Err(Error::CtrlD(buf)) => {
-                        rl.deny();
-                        if let Err(e) = Program::new(&buf).parse() {
-                            clear_line();
-                            self.prompt_error(&e);
-                        }
-                        continue;
-                    }
-                    Err(e) => {
-                        self.prompt_error(&e);
-                        return;
-                    }
-                };
-
-                self.begin_output();
-                if self.command(&buf) {
-                    rl.deny();
-                    rl.set_color(self.mode.ansi_color());
-                    continue;
-                }
-                let code = Program::new(&buf);
-                if self.mode == Mode::Tokenize {
-                    self.tokenize(&code);
-                    rl.deny();
-                    continue;
-                }
-                match code.lex().into_iter().find(|l| l.is_err()) {
-                    None => {}
-                    Some(Ok(_)) => unreachable!(),
-                    Some(Err(error)) => {
-                        rl.deny();
-                        self.prompt_error(&error);
-                        continue;
-                    }
-                }
-                if let Ok(mut code) = code.parse() {
-                    rl.accept();
-                    self.dispatch(&mut code);
-                }
-            }
-        }
-
-        fn help(&self) {
-            println!(
-                "Commands:\n- $tokens\n    Tokenize Mode:\n    Outputs information derived by the Lexer\n- $pretty\n    Beautify Mode:\n    Pretty-prints the input\n- $type\n    Resolve Mode:\n    Attempts variable resolution and type-checking on the input\n- $run\n    Interpret Mode:\n    Interprets the input using Conlang\'s work-in-progress interpreter\n- $mode\n    Prints the current mode\n- $help\n    Prints this help message"
-            );
-        }
-        fn command(&mut self, line: &str) -> bool {
-            let Some(line) = line.trim().strip_prefix('$') else {
-                return false;
-            };
-            if let Ok(mode) = line.parse() {
-                self.mode = mode;
-            } else {
-                match line {
-                    "$run" => self.mode = Mode::Interpret,
-                    "mode" => println!("{:?} Mode", self.mode),
-                    "help" => self.help(),
-                    _ => return false,
-                }
-            }
-            true
-        }
-        /// Dispatches calls to repl functions based on the program
-        fn dispatch(&mut self, code: &mut Program<Parsed>) {
-            match self.mode {
-                Mode::Tokenize => {}
-                Mode::Beautify => self.beautify(code),
-                Mode::Interpret => self.interpret(code),
-            }
-        }
-        fn tokenize(&mut self, code: &Program<Parsable>) {
-            for token in code.lex() {
-                match token {
-                    Ok(token) => print_token(&token),
-                    Err(e) => println!("{e}"),
-                }
-            }
-        }
-        fn interpret(&mut self, code: &Program<Parsed>) {
-            match code.run(&mut self.env) {
-                Ok(ConValue::Empty) => {}
-                res => self.prompt_result(res),
-            }
-        }
-        fn beautify(&mut self, code: &Program<Parsed>) {
-            code.print()
-        }
-    }
-}
-
-pub mod tools {
-    use cl_token::Token;
-    use std::io::IsTerminal;
-    /// Prints a token in the particular way cl-repl does
-    pub fn print_token(t: &Token) {
-        println!(
-            "{:02}:{:02}: {:#19} │{}│",
-            t.line(),
-            t.col(),
-            t.ty(),
-            t.data(),
-        )
-    }
-    /// gets whether stdin AND stdout are a terminal, for pipelining
-    pub fn is_terminal() -> bool {
-        std::io::stdin().is_terminal() && std::io::stdout().is_terminal()
-    }
-}
-
-pub mod repline;

cl-repl/src/repline.rs

@@ -1,636 +0,0 @@
-//! A small pseudo-multiline editing library
-// #![allow(unused)]
-
-pub mod error {
-    /// Result type for Repline
-    pub type ReplResult<T> = std::result::Result<T, Error>;
-    /// Borrowed error (does not implement [Error](std::error::Error)!)
-    #[derive(Debug)]
-    pub enum Error {
-        /// User broke with Ctrl+C
-        CtrlC(String),
-        /// User broke with Ctrl+D
-        CtrlD(String),
-        /// Invalid unicode codepoint
-        BadUnicode(u32),
-        /// Error came from [std::io]
-        IoFailure(std::io::Error),
-        /// End of input
-        EndOfInput,
-    }
-
-    impl std::error::Error for Error {}
-    impl std::fmt::Display for Error {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            match self {
-                Error::CtrlC(_) => write!(f, "Ctrl+C"),
-                Error::CtrlD(_) => write!(f, "Ctrl+D"),
-                Error::BadUnicode(u) => write!(f, "0x{u:x} is not a valid unicode codepoint"),
-                Error::IoFailure(s) => write!(f, "{s}"),
-                Error::EndOfInput => write!(f, "End of input"),
-            }
-        }
-    }
-    impl From<std::io::Error> for Error {
-        fn from(value: std::io::Error) -> Self {
-            Self::IoFailure(value)
-        }
-    }
-}
-
-pub mod ignore {
-    //! Does nothing, universally.
-    //!
-    //! Introduces the [Ignore] trait, and its singular function, [ignore](Ignore::ignore),
-    //! which does nothing.
-    impl<T> Ignore for T {}
-    /// Does nothing
-    ///
-    /// # Examples
-    /// ```rust
-    /// #![deny(unused_must_use)]
-    /// # use cl_repl::repline::ignore::Ignore;
-    /// ().ignore();
-    /// Err::<(), &str>("Foo").ignore();
-    /// Some("Bar").ignore();
-    /// 42.ignore();
-    ///
-    /// #[must_use]
-    /// fn the_meaning() -> usize {
-    ///     42
-    /// }
-    /// the_meaning().ignore();
-    /// ```
-    pub trait Ignore {
-        /// Does nothing
-        fn ignore(&self) {}
-    }
-}
-
-pub mod chars {
-    //! Converts an <code>[Iterator]<Item = [u8]></code> into an
-    //! <code>[Iterator]<Item = [char]></code>
-
-    use super::error::*;
-
-    /// Converts an <code>[Iterator]<Item = [u8]></code> into an
-    /// <code>[Iterator]<Item = [char]></code>
-    #[derive(Clone, Debug)]
-    pub struct Chars<I: Iterator<Item = u8>>(pub I);
-    impl<I: Iterator<Item = u8>> Chars<I> {
-        pub fn new(bytes: I) -> Self {
-            Self(bytes)
-        }
-    }
-    impl<I: Iterator<Item = u8>> Iterator for Chars<I> {
-        type Item = ReplResult<char>;
-        fn next(&mut self) -> Option<Self::Item> {
-            let Self(bytes) = self;
-            let start = bytes.next()? as u32;
-            let (mut out, count) = match start {
-                start if start & 0x80 == 0x00 => (start, 0), // ASCII valid range
-                start if start & 0xe0 == 0xc0 => (start & 0x1f, 1), // 1 continuation byte
-                start if start & 0xf0 == 0xe0 => (start & 0x0f, 2), // 2 continuation bytes
-                start if start & 0xf8 == 0xf0 => (start & 0x07, 3), // 3 continuation bytes
-                _ => return None,
-            };
-            for _ in 0..count {
-                let cont = bytes.next()? as u32;
-                if cont & 0xc0 != 0x80 {
-                    return None;
-                }
-                out = out << 6 | (cont & 0x3f);
-            }
-            Some(char::from_u32(out).ok_or(Error::BadUnicode(out)))
-        }
-    }
-}
-
-pub mod flatten {
-    //! Flattens an [Iterator] returning [`Result<T, E>`](Result) or [`Option<T>`](Option)
-    //! into a *non-[FusedIterator](std::iter::FusedIterator)* over `T`
-
-    /// Flattens an [Iterator] returning [`Result<T, E>`](Result) or [`Option<T>`](Option)
-    /// into a *non-[FusedIterator](std::iter::FusedIterator)* over `T`
-    pub struct Flatten<T, I: Iterator<Item = T>>(pub I);
-    impl<T, E, I: Iterator<Item = Result<T, E>>> Iterator for Flatten<Result<T, E>, I> {
-        type Item = T;
-        fn next(&mut self) -> Option<Self::Item> {
-            self.0.next()?.ok()
-        }
-    }
-    impl<T, I: Iterator<Item = Option<T>>> Iterator for Flatten<Option<T>, I> {
-        type Item = T;
-        fn next(&mut self) -> Option<Self::Item> {
-            self.0.next()?
-        }
-    }
-}
-
-pub mod raw {
-    //! Sets the terminal to [`raw`] mode for the duration of the returned object's lifetime.
-
-    /// Sets the terminal to raw mode for the duration of the returned object's lifetime.
-    pub fn raw() -> impl Drop {
-        Raw::default()
-    }
-    struct Raw();
-    impl Default for Raw {
-        fn default() -> Self {
-            std::thread::yield_now();
-            crossterm::terminal::enable_raw_mode()
-                .expect("should be able to transition into raw mode");
-            Raw()
-        }
-    }
-    impl Drop for Raw {
-        fn drop(&mut self) {
-            crossterm::terminal::disable_raw_mode()
-                .expect("should be able to transition out of raw mode");
-            // std::thread::yield_now();
-        }
-    }
-}
-
-mod out {
-    #![allow(unused)]
-    use std::io::{Result, Write};
-
-    /// A [Writer](Write) that flushes after every wipe
-    #[derive(Clone, Debug)]
-    pub(super) struct EagerWriter<W: Write> {
-        out: W,
-    }
-    impl<W: Write> EagerWriter<W> {
-        pub fn new(writer: W) -> Self {
-            Self { out: writer }
-        }
-    }
-    impl<W: Write> Write for EagerWriter<W> {
-        fn write(&mut self, buf: &[u8]) -> Result<usize> {
-            let out = self.out.write(buf)?;
-            self.out.flush()?;
-            Ok(out)
-        }
-        fn flush(&mut self) -> Result<()> {
-            self.out.flush()
-        }
-    }
-}
-
-use self::{chars::Chars, editor::Editor, error::*, flatten::Flatten, ignore::Ignore, raw::raw};
-use std::{
-    collections::VecDeque,
-    io::{stdout, Bytes, Read, Result, Write},
-};
-
-pub struct Repline<'a, R: Read> {
-    input: Chars<Flatten<Result<u8>, Bytes<R>>>,
-
-    history: VecDeque<String>, // previous lines
-    hindex: usize,             // current index into the history buffer
-
-    ed: Editor<'a>, // the current line buffer
-}
-
-impl<'a, R: Read> Repline<'a, R> {
-    /// Constructs a [Repline] with the given [Reader](Read), color, begin, and again prompts.
-    pub fn with_input(input: R, color: &'a str, begin: &'a str, again: &'a str) -> Self {
-        Self {
-            input: Chars(Flatten(input.bytes())),
-            history: Default::default(),
-            hindex: 0,
-            ed: Editor::new(color, begin, again),
-        }
-    }
-    /// Set the terminal prompt color
-    pub fn set_color(&mut self, color: &'a str) {
-        self.ed.color = color
-    }
-    /// Reads in a line, and returns it for validation
-    pub fn read(&mut self) -> ReplResult<String> {
-        const INDENT: &str = "    ";
-        let mut stdout = stdout().lock();
-        let stdout = &mut stdout;
-        let _make_raw = raw();
-        // self.ed.begin_frame(stdout)?;
-        // self.ed.redraw_frame(stdout)?;
-        self.ed.print_head(stdout)?;
-        loop {
-            stdout.flush()?;
-            match self.input.next().ok_or(Error::EndOfInput)?? {
-                // Ctrl+C: End of Text. Immediately exits.
-                // Ctrl+D: End of Transmission. Ends the current line.
-                '\x03' => {
-                    drop(_make_raw);
-                    writeln!(stdout)?;
-                    return Err(Error::CtrlC(self.ed.to_string()));
-                }
-                '\x04' => {
-                    drop(_make_raw);
-                    writeln!(stdout)?;
-                    return Err(Error::CtrlD(self.ed.to_string()));
-                }
-                // Tab: extend line by 4 spaces
-                '\t' => {
-                    self.ed.extend(INDENT.chars(), stdout)?;
-                }
-                // ignore newlines, process line feeds. Not sure how cross-platform this is.
-                '\n' => {}
-                '\r' => {
-                    self.ed.push('\n', stdout)?;
-                    return Ok(self.ed.to_string());
-                }
-                // Escape sequence
-                '\x1b' => self.escape(stdout)?,
-                // backspace
-                '\x08' | '\x7f' => {
-                    let ed = &mut self.ed;
-                    if ed.ends_with(INDENT.chars()) {
-                        for _ in 0..INDENT.len() {
-                            ed.pop(stdout)?;
-                        }
-                    } else {
-                        ed.pop(stdout)?;
-                    }
-                }
-                c if c.is_ascii_control() => {
-                    if cfg!(debug_assertions) {
-                        eprint!("\\x{:02x}", c as u32);
-                    }
-                }
-                c => {
-                    self.ed.push(c, stdout)?;
-                }
-            }
-        }
-    }
-    /// Handle ANSI Escape
-    fn escape<W: Write>(&mut self, w: &mut W) -> ReplResult<()> {
-        match self.input.next().ok_or(Error::EndOfInput)?? {
-            '[' => self.csi(w)?,
-            'O' => todo!("Process alternate character mode"),
-            other => self.ed.extend(['\x1b', other], w)?,
-        }
-        Ok(())
-    }
-    /// Handle ANSI Control Sequence Introducer
-    fn csi<W: Write>(&mut self, w: &mut W) -> ReplResult<()> {
-        match self.input.next().ok_or(Error::EndOfInput)?? {
-            'A' => {
-                self.hindex = self.hindex.saturating_sub(1);
-                self.restore_history(w)?
-            }
-            'B' => {
-                self.hindex = self
-                    .hindex
-                    .saturating_add(1)
-                    .min(self.history.len().saturating_sub(1));
-                self.restore_history(w)?
-            }
-            'C' => self.ed.cursor_forward(1, w)?,
-            'D' => self.ed.cursor_back(1, w)?,
-            'H' => self.ed.home(w)?,
-            'F' => self.ed.end(w)?,
-            '3' => {
-                if let '~' = self.input.next().ok_or(Error::EndOfInput)?? {
-                    self.ed.delete(w).ignore()
-                }
-            }
-            other => {
-                if cfg!(debug_assertions) {
-                    eprint!("{}", other.escape_unicode());
-                }
-            }
-        }
-        Ok(())
-    }
-    /// Restores the currently selected history
-    pub fn restore_history<W: Write>(&mut self, w: &mut W) -> ReplResult<()> {
-        let Self { history, hindex, ed, .. } = self;
-        if !(0..history.len()).contains(hindex) {
-            return Ok(());
-        };
-        ed.undraw(w)?;
-        ed.clear();
-        ed.print_head(w)?;
-        ed.extend(
-            history
-                .get(*hindex)
-                .expect("history should contain index")
-                .chars(),
-            w,
-        )
-    }
-
-    /// Append line to history and clear it
-    pub fn accept(&mut self) {
-        self.history_append(self.ed.iter().collect());
-        self.ed.clear();
-        self.hindex = self.history.len();
-    }
-    /// Append line to history
-    pub fn history_append(&mut self, mut buf: String) {
-        while buf.ends_with(char::is_whitespace) {
-            buf.pop();
-        }
-        if !self.history.contains(&buf) {
-            self.history.push_back(buf)
-        }
-        while self.history.len() > 20 {
-            self.history.pop_front();
-        }
-    }
-    /// Clear the line
-    pub fn deny(&mut self) {
-        self.ed.clear()
-    }
-}
-
-impl<'a> Repline<'a, std::io::Stdin> {
-    pub fn new(color: &'a str, begin: &'a str, again: &'a str) -> Self {
-        Self::with_input(std::io::stdin(), color, begin, again)
-    }
-}
-
-pub mod editor {
-    use crossterm::{cursor::*, execute, queue, style::*, terminal::*};
-    use std::{collections::VecDeque, fmt::Display, io::Write};
-
-    use super::error::{Error, ReplResult};
-
-    fn is_newline(c: &char) -> bool {
-        *c == '\n'
-    }
-
-    fn write_chars<'a, W: Write>(
-        c: impl IntoIterator<Item = &'a char>,
-        w: &mut W,
-    ) -> std::io::Result<()> {
-        for c in c {
-            write!(w, "{c}")?;
-        }
-        Ok(())
-    }
-
-    #[derive(Debug)]
-    pub struct Editor<'a> {
-        head: VecDeque<char>,
-        tail: VecDeque<char>,
-
-        pub color: &'a str,
-        begin: &'a str,
-        again: &'a str,
-    }
-
-    impl<'a> Editor<'a> {
-        pub fn new(color: &'a str, begin: &'a str, again: &'a str) -> Self {
-            Self { head: Default::default(), tail: Default::default(), color, begin, again }
-        }
-        pub fn iter(&self) -> impl Iterator<Item = &char> {
-            self.head.iter()
-        }
-        pub fn undraw<W: Write>(&self, w: &mut W) -> ReplResult<()> {
-            let Self { head, .. } = self;
-            match head.iter().copied().filter(is_newline).count() {
-                0 => write!(w, "\x1b[0G"),
-                lines => write!(w, "\x1b[{}F", lines),
-            }?;
-            queue!(w, Clear(ClearType::FromCursorDown))?;
-            // write!(w, "\x1b[0J")?;
-            Ok(())
-        }
-        pub fn redraw<W: Write>(&self, w: &mut W) -> ReplResult<()> {
-            let Self { head, tail, color, begin, again } = self;
-            write!(w, "{color}{begin}\x1b[0m ")?;
-            // draw head
-            for c in head {
-                match c {
-                    '\n' => write!(w, "\r\n{color}{again}\x1b[0m "),
-                    _ => w.write_all({ *c as u32 }.to_le_bytes().as_slice()),
-                }?
-            }
-            // save cursor
-            execute!(w, SavePosition)?;
-            // draw tail
-            for c in tail {
-                match c {
-                    '\n' => write!(w, "\r\n{color}{again}\x1b[0m "),
-                    _ => write!(w, "{c}"),
-                }?
-            }
-            // restore cursor
-            execute!(w, RestorePosition)?;
-            Ok(())
-        }
-        pub fn prompt<W: Write>(&self, w: &mut W) -> ReplResult<()> {
-            let Self { head, color, begin, again, .. } = self;
-            queue!(
-                w,
-                MoveToColumn(0),
-                Print(color),
-                Print(if head.is_empty() { begin } else { again }),
-                ResetColor,
-                Print(' '),
-            )?;
-            Ok(())
-        }
-        pub fn print_head<W: Write>(&self, w: &mut W) -> ReplResult<()> {
-            self.prompt(w)?;
-            write_chars(
-                self.head.iter().skip(
-                    self.head
-                        .iter()
-                        .rposition(is_newline)
-                        .unwrap_or(self.head.len())
-                        + 1,
-                ),
-                w,
-            )?;
-            Ok(())
-        }
-        pub fn print_tail<W: Write>(&self, w: &mut W) -> ReplResult<()> {
-            let Self { tail, .. } = self;
-            queue!(w, SavePosition, Clear(ClearType::UntilNewLine))?;
-            write_chars(tail.iter().take_while(|&c| !is_newline(c)), w)?;
-            queue!(w, RestorePosition)?;
-            Ok(())
-        }
-        pub fn push<W: Write>(&mut self, c: char, w: &mut W) -> ReplResult<()> {
-            // Tail optimization: if the tail is empty,
-            //we don't have to undraw and redraw on newline
-            if self.tail.is_empty() {
-                self.head.push_back(c);
-                match c {
-                    '\n' => {
-                        write!(w, "\r\n")?;
-                        self.print_head(w)?;
-                    }
-                    c => {
-                        queue!(w, Print(c))?;
-                    }
-                };
-                return Ok(());
-            }
-
-            if '\n' == c {
-                self.undraw(w)?;
-            }
-            self.head.push_back(c);
-            match c {
-                '\n' => self.redraw(w)?,
-                _ => {
-                    write!(w, "{c}")?;
-                    self.print_tail(w)?;
-                }
-            }
-            Ok(())
-        }
-        pub fn pop<W: Write>(&mut self, w: &mut W) -> ReplResult<Option<char>> {
-            if let Some('\n') = self.head.back() {
-                self.undraw(w)?;
-            }
-            let c = self.head.pop_back();
-            // if the character was a newline, we need to go back a line
-            match c {
-                Some('\n') => self.redraw(w)?,
-                Some(_) => {
-                    // go back a char
-                    queue!(w, MoveLeft(1), Print(' '), MoveLeft(1))?;
-                    self.print_tail(w)?;
-                }
-                None => {}
-            }
-            Ok(c)
-        }
-
-        pub fn extend<T: IntoIterator<Item = char>, W: Write>(
-            &mut self,
-            iter: T,
-            w: &mut W,
-        ) -> ReplResult<()> {
-            for c in iter {
-                self.push(c, w)?;
-            }
-            Ok(())
-        }
-        pub fn restore(&mut self, s: &str) {
-            self.clear();
-            self.head.extend(s.chars())
-        }
-        pub fn clear(&mut self) {
-            self.head.clear();
-            self.tail.clear();
-        }
-        pub fn delete<W: Write>(&mut self, w: &mut W) -> ReplResult<char> {
-            match self.tail.front() {
-                Some('\n') => {
-                    self.undraw(w)?;
-                    let out = self.tail.pop_front();
-                    self.redraw(w)?;
-                    out
-                }
-                _ => {
-                    let out = self.tail.pop_front();
-                    self.print_tail(w)?;
-                    out
-                }
-            }
-            .ok_or(Error::EndOfInput)
-        }
-        pub fn len(&self) -> usize {
-            self.head.len() + self.tail.len()
-        }
-        pub fn is_empty(&self) -> bool {
-            self.head.is_empty() && self.tail.is_empty()
-        }
-        pub fn ends_with(&self, iter: impl DoubleEndedIterator<Item = char>) -> bool {
-            let mut iter = iter.rev();
-            let mut head = self.head.iter().rev();
-            loop {
-                match (iter.next(), head.next()) {
-                    (None, _) => break true,
-                    (Some(_), None) => break false,
-                    (Some(a), Some(b)) if a != *b => break false,
-                    (Some(_), Some(_)) => continue,
-                }
-            }
-        }
-        /// Moves the cursor back `steps` steps
-        pub fn cursor_back<W: Write>(&mut self, steps: usize, w: &mut W) -> ReplResult<()> {
-            for _ in 0..steps {
-                if let Some('\n') = self.head.back() {
-                    self.undraw(w)?;
-                }
-                let Some(c) = self.head.pop_back() else {
-                    return Ok(());
-                };
-                self.tail.push_front(c);
-                match c {
-                    '\n' => self.redraw(w)?,
-                    _ => queue!(w, MoveLeft(1))?,
-                }
-            }
-            Ok(())
-        }
-        /// Moves the cursor forward `steps` steps
-        pub fn cursor_forward<W: Write>(&mut self, steps: usize, w: &mut W) -> ReplResult<()> {
-            for _ in 0..steps {
-                if let Some('\n') = self.tail.front() {
-                    self.undraw(w)?
-                }
-                let Some(c) = self.tail.pop_front() else {
-                    return Ok(());
-                };
-                self.head.push_back(c);
-                match c {
-                    '\n' => self.redraw(w)?,
-                    _ => queue!(w, MoveRight(1))?,
-                }
-            }
-            Ok(())
-        }
-        /// Goes to the beginning of the current line
-        pub fn home<W: Write>(&mut self, w: &mut W) -> ReplResult<()> {
-            loop {
-                match self.head.back() {
-                    Some('\n') | None => break Ok(()),
-                    Some(_) => self.cursor_back(1, w)?,
-                }
-            }
-        }
-        /// Goes to the end of the current line
-        pub fn end<W: Write>(&mut self, w: &mut W) -> ReplResult<()> {
-            loop {
-                match self.tail.front() {
-                    Some('\n') | None => break Ok(()),
-                    Some(_) => self.cursor_forward(1, w)?,
-                }
-            }
-        }
-    }
-
-    impl<'a, 'e> IntoIterator for &'e Editor<'a> {
-        type Item = &'e char;
-        type IntoIter = std::iter::Chain<
-            std::collections::vec_deque::Iter<'e, char>,
-            std::collections::vec_deque::Iter<'e, char>,
-        >;
-        fn into_iter(self) -> Self::IntoIter {
-            self.head.iter().chain(self.tail.iter())
-        }
-    }
-    impl<'a> Display for Editor<'a> {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            use std::fmt::Write;
-            let Self { head, tail, .. } = self;
-            for c in head {
-                f.write_char(*c)?;
-            }
-            for c in tail {
-                f.write_char(*c)?;
-            }
-            Ok(())
-        }
-    }
-}

cl-structures/src/intern_pool.rs

@@ -1,131 +0,0 @@
-//! Trivially-copyable, easily comparable typed indices, and a [Pool] to contain them
-//!
-//! # Examples
-//!
-//! ```rust
-//! # use cl_structures::intern_pool::*;
-//! // first, create a new InternKey type (this ensures type safety)
-//! make_intern_key!{
-//!     NumbersKey
-//! }
-//!
-//! // then, create a pool with that type
-//! let mut numbers: Pool<i32, NumbersKey> = Pool::new();
-//! let first = numbers.insert(1);
-//! let second = numbers.insert(2);
-//! let third = numbers.insert(3);
-//!
-//! // You can access elements immutably with `get`
-//! assert_eq!(Some(&3), numbers.get(third));
-//! assert_eq!(Some(&2), numbers.get(second));
-//! // or by indexing
-//! assert_eq!(1, numbers[first]);
-//!
-//! // Or mutably
-//! *numbers.get_mut(first).unwrap() = 100000;
-//!
-//! assert_eq!(Some(&100000), numbers.get(first));
-//! ```
-
-/// Creates newtype indices over [`usize`] for use as [Pool] keys.
-#[macro_export]
-macro_rules! make_intern_key {($($(#[$meta:meta])* $name:ident),*$(,)?) => {$(
-    $(#[$meta])*
-    #[repr(transparent)]
-    #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
-    pub struct $name(usize);
-
-    impl $crate::intern_pool::InternKey for $name {
-        #[doc = concat!("Constructs a [`", stringify!($name), "`] from a [`usize`] without checking bounds.\n")]
-        /// # Safety
-        ///
-        /// The provided value should be within the bounds of its associated container
-        unsafe fn from_raw_unchecked(value: usize) -> Self {
-            Self(value)
-        }
-        fn get(&self) -> usize {
-            self.0
-        }
-    }
-    impl From< $name > for usize {
-        fn from(value: $name) -> Self {
-            value.0
-        }
-    }
-)*}}
-use std::ops::{Index, IndexMut};
-
-pub use make_intern_key;
-
-/// An index into a [Pool]. For full type-safety,
-/// there should be a unique [InternKey] for each [Pool]
-pub trait InternKey: std::fmt::Debug {
-    /// Constructs an [`InternKey`] from a [`usize`] without checking bounds.
-    ///
-    /// # Safety
-    ///
-    /// The provided value should be within the bounds of its associated container.
-    // ID::from_raw_unchecked here isn't *actually* unsafe, since bounds should always be
-    // checked, however, the function has unverifiable preconditions.
-    unsafe fn from_raw_unchecked(value: usize) -> Self;
-    /// Gets the index of the [`InternKey`] by value
-    fn get(&self) -> usize;
-}
-
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub struct Pool<T, ID: InternKey> {
-    pool: Vec<T>,
-    id_type: std::marker::PhantomData<ID>,
-}
-
-impl<T, ID: InternKey> Pool<T, ID> {
-    pub fn new() -> Self {
-        Self::default()
-    }
-    pub fn get(&self, index: ID) -> Option<&T> {
-        self.pool.get(index.get())
-    }
-    pub fn get_mut(&mut self, index: ID) -> Option<&mut T> {
-        self.pool.get_mut(index.get())
-    }
-
-    pub fn iter(&self) -> impl Iterator<Item = &T> {
-        self.pool.iter()
-    }
-    pub fn iter_mut(&mut self) -> impl Iterator<Item = &mut T> {
-        self.pool.iter_mut()
-    }
-
-    pub fn insert(&mut self, value: T) -> ID {
-        let id = self.pool.len();
-        self.pool.push(value);
-
-        // Safety: value was pushed to `self.pool[id]`
-        unsafe { ID::from_raw_unchecked(id) }
-    }
-}
-
-impl<T, ID: InternKey> Default for Pool<T, ID> {
-    fn default() -> Self {
-        Self { pool: vec![], id_type: std::marker::PhantomData }
-    }
-}
-
-impl<T, ID: InternKey> Index<ID> for Pool<T, ID> {
-    type Output = T;
-
-    fn index(&self, index: ID) -> &Self::Output {
-        match self.pool.get(index.get()) {
-            None => panic!("Index {:?} out of bounds in pool!", index),
-            Some(value) => value,
-        }
-    }
-}
-impl<T, ID: InternKey> IndexMut<ID> for Pool<T, ID> {
-    fn index_mut(&mut self, index: ID) -> &mut Self::Output {
-        match self.pool.get_mut(index.get()) {
-            None => panic!("Index {:?} out of bounds in pool!", index),
-            Some(value) => value,
-        }
-    }
-}

cl-structures/src/lib.rs

@@ -1,14 +0,0 @@
-//! # Universally useful structures
-//! - [Span](struct@span::Span): Stores a start and end [Loc](struct@span::Loc)
-//! - [Loc](struct@span::Loc): Stores the index in a stream
-#![warn(clippy::all)]
-#![feature(inline_const, dropck_eyepatch, decl_macro)]
-#![deny(unsafe_op_in_unsafe_fn)]
-
-pub mod span;
-
-pub mod tree;
-
-pub mod stack;
-
-pub mod intern_pool;

cl-token/src/token_type.rs

@@ -1,237 +0,0 @@
-//! Stores a [Token's](super::Token) lexical information
-use std::{fmt::Display, str::FromStr};
-
-/// Stores a [Token's](super::Token) lexical information
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
-pub enum TokenKind {
-    /// Invalid sequence
-    Invalid,
-    /// Any kind of comment
-    Comment,
-    /// Any tokenizable literal (See [TokenData](super::TokenData))
-    Literal,
-    /// A non-keyword identifier
-    Identifier,
-    // A keyword
-    Break,
-    Cl,
-    Const,
-    Continue,
-    Else,
-    Enum,
-    False,
-    For,
-    Fn,
-    If,
-    Impl,
-    In,
-    Let,
-    Mod,
-    Mut,
-    Pub,
-    Return,
-    SelfKw,
-    SelfTy,
-    Static,
-    Struct,
-    Super,
-    True,
-    Type,
-    While,
-    /// Delimiter or punctuation
-    Punct(Punct),
-}
-
-/// An operator character (delimiter, punctuation)
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
-pub enum Punct {
-    LCurly,     // {
-    RCurly,     // }
-    LBrack,     // [
-    RBrack,     // ]
-    LParen,     // (
-    RParen,     // )
-    Amp,        // &
-    AmpAmp,     // &&
-    AmpEq,      // &=
-    Arrow,      // ->
-    At,         // @
-    Backslash,  // \
-    Bang,       // !
-    BangBang,   // !!
-    BangEq,     // !=
-    Bar,        // |
-    BarBar,     // ||
-    BarEq,      // |=
-    Colon,      // :
-    ColonColon, // ::
-    Comma,      // ,
-    Dot,        // .
-    DotDot,     // ..
-    DotDotEq,   // ..=
-    Eq,         // =
-    EqEq,       // ==
-    FatArrow,   // =>
-    Grave,      // `
-    Gt,         // >
-    GtEq,       // >=
-    GtGt,       // >>
-    GtGtEq,     // >>=
-    Hash,       // #
-    HashBang,   // #!
-    Lt,         // <
-    LtEq,       // <=
-    LtLt,       // <<
-    LtLtEq,     // <<=
-    Minus,      // -
-    MinusEq,    // -=
-    Plus,       // +
-    PlusEq,     // +=
-    Question,   // ?
-    Rem,        // %
-    RemEq,      // %=
-    Semi,       // ;
-    Slash,      // /
-    SlashEq,    // /=
-    Star,       // *
-    StarEq,     // *=
-    Tilde,      // ~
-    Xor,        // ^
-    XorEq,      // ^=
-    XorXor,     // ^^
-}
-
-impl Display for TokenKind {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            TokenKind::Invalid => "invalid".fmt(f),
-            TokenKind::Comment => "comment".fmt(f),
-            TokenKind::Literal => "literal".fmt(f),
-            TokenKind::Identifier => "identifier".fmt(f),
-
-            TokenKind::Break => "break".fmt(f),
-            TokenKind::Cl => "cl".fmt(f),
-            TokenKind::Const => "const".fmt(f),
-            TokenKind::Continue => "continue".fmt(f),
-            TokenKind::Else => "else".fmt(f),
-            TokenKind::Enum => "enum".fmt(f),
-            TokenKind::False => "false".fmt(f),
-            TokenKind::For => "for".fmt(f),
-            TokenKind::Fn => "fn".fmt(f),
-            TokenKind::If => "if".fmt(f),
-            TokenKind::Impl => "impl".fmt(f),
-            TokenKind::In => "in".fmt(f),
-            TokenKind::Let => "let".fmt(f),
-            TokenKind::Mod => "mod".fmt(f),
-            TokenKind::Mut => "mut".fmt(f),
-            TokenKind::Pub => "pub".fmt(f),
-            TokenKind::Return => "return".fmt(f),
-            TokenKind::SelfKw => "self".fmt(f),
-            TokenKind::SelfTy => "Self".fmt(f),
-            TokenKind::Static => "static".fmt(f),
-            TokenKind::Struct => "struct".fmt(f),
-            TokenKind::Super => "super".fmt(f),
-            TokenKind::True => "true".fmt(f),
-            TokenKind::Type => "type".fmt(f),
-            TokenKind::While => "while".fmt(f),
-
-            TokenKind::Punct(op) => op.fmt(f),
-        }
-    }
-}
-impl FromStr for TokenKind {
-    /// [FromStr] can only fail when an identifier isn't a keyword
-    type Err = ();
-    /// Parses a string s to return a Keyword
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        Ok(match s {
-            "break" => Self::Break,
-            "cl" => Self::Cl,
-            "const" => Self::Const,
-            "continue" => Self::Continue,
-            "else" => Self::Else,
-            "enum" => Self::Enum,
-            "false" => Self::False,
-            "for" => Self::For,
-            "fn" => Self::Fn,
-            "if" => Self::If,
-            "impl" => Self::Impl,
-            "in" => Self::In,
-            "let" => Self::Let,
-            "mod" => Self::Mod,
-            "mut" => Self::Mut,
-            "pub" => Self::Pub,
-            "return" => Self::Return,
-            "self" => Self::SelfKw,
-            "Self" => Self::SelfTy,
-            "static" => Self::Static,
-            "struct" => Self::Struct,
-            "super" => Self::Super,
-            "true" => Self::True,
-            "type" => Self::Type,
-            "while" => Self::While,
-            _ => Err(())?,
-        })
-    }
-}
-
-impl Display for Punct {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            Punct::LCurly => "{".fmt(f),
-            Punct::RCurly => "}".fmt(f),
-            Punct::LBrack => "[".fmt(f),
-            Punct::RBrack => "]".fmt(f),
-            Punct::LParen => "(".fmt(f),
-            Punct::RParen => ")".fmt(f),
-            Punct::Amp => "&".fmt(f),
-            Punct::AmpAmp => "&&".fmt(f),
-            Punct::AmpEq => "&=".fmt(f),
-            Punct::Arrow => "->".fmt(f),
-            Punct::At => "@".fmt(f),
-            Punct::Backslash => "\\".fmt(f),
-            Punct::Bang => "!".fmt(f),
-            Punct::BangBang => "!!".fmt(f),
-            Punct::BangEq => "!=".fmt(f),
-            Punct::Bar => "|".fmt(f),
-            Punct::BarBar => "||".fmt(f),
-            Punct::BarEq => "|=".fmt(f),
-            Punct::Colon => ":".fmt(f),
-            Punct::ColonColon => "::".fmt(f),
-            Punct::Comma => ",".fmt(f),
-            Punct::Dot => ".".fmt(f),
-            Punct::DotDot => "..".fmt(f),
-            Punct::DotDotEq => "..=".fmt(f),
-            Punct::Eq => "=".fmt(f),
-            Punct::EqEq => "==".fmt(f),
-            Punct::FatArrow => "=>".fmt(f),
-            Punct::Grave => "`".fmt(f),
-            Punct::Gt => ">".fmt(f),
-            Punct::GtEq => ">=".fmt(f),
-            Punct::GtGt => ">>".fmt(f),
-            Punct::GtGtEq => ">>=".fmt(f),
-            Punct::Hash => "#".fmt(f),
-            Punct::HashBang => "#!".fmt(f),
-            Punct::Lt => "<".fmt(f),
-            Punct::LtEq => "<=".fmt(f),
-            Punct::LtLt => "<<".fmt(f),
-            Punct::LtLtEq => "<<=".fmt(f),
-            Punct::Minus => "-".fmt(f),
-            Punct::MinusEq => "-=".fmt(f),
-            Punct::Plus => "+".fmt(f),
-            Punct::PlusEq => "+=".fmt(f),
-            Punct::Question => "?".fmt(f),
-            Punct::Rem => "%".fmt(f),
-            Punct::RemEq => "%=".fmt(f),
-            Punct::Semi => ";".fmt(f),
-            Punct::Slash => "/".fmt(f),
-            Punct::SlashEq => "/=".fmt(f),
-            Punct::Star => "*".fmt(f),
-            Punct::StarEq => "*=".fmt(f),
-            Punct::Tilde => "~".fmt(f),
-            Punct::Xor => "^".fmt(f),
-            Punct::XorEq => "^=".fmt(f),
-            Punct::XorXor => "^^".fmt(f),
-        }
-    }
-}

cl-typeck/src/lib.rs

@@ -1,909 +0,0 @@
-//! # The Conlang Type Checker
-//!
-//! As a statically typed language, Conlang requires a robust type checker to enforce correctness.
-#![feature(debug_closure_helpers)]
-#![warn(clippy::all)]
-
-/*
-
-The type checker keeps track of a *global intern pool* for Types and Values
-References to the intern pool are held by ID, and items cannot be freed from the pool EVER.
-
-Items are inserted into their respective pools,
-
-
-*/
-
-pub mod key {
-    use cl_structures::intern_pool::*;
-
-    // define the index types
-    make_intern_key! {
-        /// Uniquely represents a [Def][1] in the [Def][1] [Pool]
-        ///
-        /// [1]: crate::definition::Def
-        DefID,
-    }
-}
-
-pub mod definition {
-    use crate::{key::DefID, module::Module, type_kind::TypeKind, value_kind::ValueKind};
-    use cl_ast::{format::FmtPretty, Item, Meta, Visibility};
-    use std::fmt::Write;
-
-    #[derive(Clone, PartialEq, Eq)]
-    pub struct Def {
-        pub name: String,
-        pub vis: Visibility,
-        pub meta: Vec<Meta>,
-        pub kind: DefKind,
-        pub source: Option<Item>,
-        pub module: Module,
-    }
-
-    impl Default for Def {
-        fn default() -> Self {
-            Self {
-                name: Default::default(),
-                vis: Default::default(),
-                meta: Default::default(),
-                kind: DefKind::Type(TypeKind::Module),
-                source: Default::default(),
-                module: Default::default(),
-            }
-        }
-    }
-
-    impl Def {
-        pub fn new_module(
-            name: String,
-            vis: Visibility,
-            meta: Vec<Meta>,
-            parent: Option<DefID>,
-        ) -> Self {
-            Self {
-                name,
-                vis,
-                meta,
-                kind: DefKind::Type(TypeKind::Module),
-                source: None,
-                module: Module { parent, ..Default::default() },
-            }
-        }
-    }
-
-    impl std::fmt::Debug for Def {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { name, vis, meta, kind, source, module } = self;
-            f.debug_struct("Def")
-                .field("name", &name)
-                .field("vis", &vis)
-                .field_with("meta", |f| write!(f, "{meta:?}"))
-                .field("kind", &kind)
-                .field_with("source", |f| match source {
-                    Some(item) => write!(f.pretty(), "{{\n{item}\n}}"),
-                    None => todo!(),
-                })
-                .field("module", &module)
-                .finish()
-        }
-    }
-
-    #[derive(Clone, Debug, PartialEq, Eq)]
-    pub enum DefKind {
-        /// A type, such as a ``
-        Type(TypeKind),
-        /// A value, such as a `const`, `static`, or `fn`
-        Value(ValueKind),
-    }
-
-    impl DefKind {
-        pub fn is_type(&self) -> bool {
-            matches!(self, Self::Type(_))
-        }
-        pub fn ty(&self) -> Option<&TypeKind> {
-            match self {
-                DefKind::Type(t) => Some(t),
-                _ => None,
-            }
-        }
-        pub fn is_value(&self) -> bool {
-            matches!(self, Self::Value(_))
-        }
-        pub fn value(&self) -> Option<&ValueKind> {
-            match self {
-                DefKind::Value(v) => Some(v),
-                _ => None,
-            }
-        }
-    }
-}
-
-pub mod type_kind {
-    //! A [TypeKind] represents an item in the Type Namespace
-    //! (a component of a [Project](crate::project::Project)).
-
-    use cl_ast::Visibility;
-    use std::{fmt::Debug, str::FromStr};
-
-    use crate::key::DefID;
-
-    /// The kind of a type
-    #[derive(Clone, Debug, PartialEq, Eq)]
-    pub enum TypeKind {
-        /// A type which has not yet been resolved
-        Undecided,
-        /// An alias for an already-defined type
-        Alias(Option<DefID>),
-        /// A primitive type, built-in to the compiler
-        Intrinsic(Intrinsic),
-        /// A user-defined abstract data type
-        Adt(Adt),
-        /// A reference to an already-defined type: &T
-        Ref(DefID),
-        /// A contiguous view of dynamically sized memory
-        Slice(DefID),
-        /// A function pointer which accepts multiple inputs and produces an output
-        FnPtr { args: Vec<DefID>, rety: DefID },
-        /// The unit type
-        Empty,
-        /// The never type
-        Never,
-        /// The Self type
-        SelfTy,
-        /// An untyped module
-        Module,
-    }
-
-    /// A user-defined Abstract Data Type
-    #[derive(Clone, Debug, PartialEq, Eq)]
-    pub enum Adt {
-        /// A union-like enum type
-        Enum(Vec<(String, DefID)>),
-        CLikeEnum(Vec<(String, u128)>),
-        /// An enum with no fields, which can never be constructed
-        FieldlessEnum,
-
-        /// A structural product type with named members
-        Struct(Vec<(String, Visibility, DefID)>),
-        /// A structural product type with unnamed members
-        TupleStruct(Vec<(Visibility, DefID)>),
-        /// A structural product type of neither named nor unnamed members
-        UnitStruct,
-
-        /// A choose your own undefined behavior type
-        /// TODO: should unions be a language feature?
-        Union(Vec<(String, DefID)>),
-    }
-
-    /// The set of compiler-intrinsic types.
-    /// These primitive types have native implementations of the basic operations.
-    #[allow(non_camel_case_types)]
-    #[derive(Clone, Debug, PartialEq, Eq)]
-    pub enum Intrinsic {
-        /// An 8-bit signed integer: `#[intrinsic = "i8"]`
-        I8,
-        /// A 16-bit signed integer: `#[intrinsic = "i16"]`
-        I16,
-        /// A 32-bit signed integer: `#[intrinsic = "i32"]`
-        I32,
-        /// A 64-bit signed integer: `#[intrinsic = "i32"]`
-        I64,
-        // /// A 128-bit signed integer: `#[intrinsic = "i32"]`
-        // I128,
-        /// An 8-bit unsigned integer: `#[intrinsic = "u8"]`
-        U8,
-        /// A 16-bit unsigned integer: `#[intrinsic = "u16"]`
-        U16,
-        /// A 32-bit unsigned integer: `#[intrinsic = "u32"]`
-        U32,
-        /// A 64-bit unsigned integer: `#[intrinsic = "u64"]`
-        U64,
-        // /// A 128-bit unsigned integer: `#[intrinsic = "u128"]`
-        // U128,
-        /// A boolean (`true` or `false`): `#[intrinsic = "bool"]`
-        Bool,
-    }
-
-    impl FromStr for Intrinsic {
-        type Err = ();
-
-        fn from_str(s: &str) -> Result<Self, Self::Err> {
-            Ok(match s {
-                "i8" => Intrinsic::I8,
-                "i16" => Intrinsic::I16,
-                "i32" => Intrinsic::I32,
-                "i64" => Intrinsic::I64,
-                "u8" => Intrinsic::U8,
-                "u16" => Intrinsic::U16,
-                "u32" => Intrinsic::U32,
-                "u64" => Intrinsic::U64,
-                "bool" => Intrinsic::Bool,
-                _ => Err(())?,
-            })
-        }
-    }
-
-    #[derive(Clone, Debug, PartialEq, Eq)]
-    pub enum Float {
-        F32 = 0x20,
-        F64,
-    }
-}
-
-pub mod value_kind {
-    //! A [ValueKind] represents an item in the Value Namespace
-    //! (a component of a [Project](crate::project::Project)).
-
-    use crate::typeref::TypeRef;
-    use cl_ast::Block;
-
-    #[derive(Clone, Debug, PartialEq, Eq)]
-    pub enum ValueKind {
-        Undecided,
-        Const(TypeRef),
-        Static(TypeRef),
-        Fn {
-            // TODO: Store the variable bindings here!
-            args: Vec<TypeRef>,
-            rety: TypeRef,
-            body: Block,
-        },
-    }
-}
-
-pub mod module {
-    //! A [Module] is a node in the Module Tree (a component of a
-    //! [Project](crate::project::Project))
-    use crate::key::DefID;
-    use std::collections::HashMap;
-
-    /// A [Module] is a node in the Module Tree (a component of a
-    /// [Project](crate::project::Project)).
-    #[derive(Clone, Debug, Default, PartialEq, Eq)]
-    pub struct Module {
-        pub parent: Option<DefID>,
-        pub types: HashMap<String, DefID>,
-        pub values: HashMap<String, DefID>,
-    }
-
-    impl Module {
-        pub fn new(parent: DefID) -> Self {
-            Self { parent: Some(parent), ..Default::default() }
-        }
-    }
-}
-
-pub mod path {
-    use cl_ast::{Path as AstPath, PathPart};
-
-    #[derive(Clone, Copy, Debug, PartialEq, Eq)]
-    pub struct Path<'p> {
-        pub absolute: bool,
-        pub parts: &'p [PathPart],
-    }
-
-    impl<'p> Path<'p> {
-        pub fn new(path: &'p AstPath) -> Self {
-            let AstPath { absolute, parts } = path;
-            Self { absolute: *absolute, parts }
-        }
-        pub fn relative(self) -> Self {
-            Self { absolute: false, ..self }
-        }
-        pub fn pop_front(self) -> Option<Self> {
-            let Self { absolute, parts } = self;
-            Some(Self { absolute, parts: parts.get(1..)? })
-        }
-        pub fn is_empty(&self) -> bool {
-            self.parts.is_empty()
-        }
-        pub fn len(&self) -> usize {
-            self.parts.len()
-        }
-        pub fn front(&self) -> Option<&PathPart> {
-            self.parts.first()
-        }
-    }
-
-    impl<'p> From<&'p AstPath> for Path<'p> {
-        fn from(value: &'p AstPath) -> Self {
-            Self::new(value)
-        }
-    }
-    impl std::fmt::Display for Path<'_> {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            const SEPARATOR: &str = "::";
-            let Self { absolute, parts } = self;
-            if *absolute {
-                write!(f, "{SEPARATOR}")?
-            }
-            for (idx, part) in parts.iter().enumerate() {
-                write!(f, "{}{part}", if idx > 0 { SEPARATOR } else { "" })?;
-            }
-            Ok(())
-        }
-    }
-}
-
-pub mod project {
-    use crate::{
-        definition::{Def, DefKind},
-        key::DefID,
-        path::Path,
-        type_kind::TypeKind,
-    };
-    use cl_ast::{Identifier, PathPart, Visibility};
-    use cl_structures::intern_pool::Pool;
-    use std::ops::{Index, IndexMut};
-
-    #[derive(Clone, Debug, PartialEq, Eq)]
-    pub struct Project {
-        pub pool: Pool<Def, DefID>,
-        pub module_root: DefID,
-    }
-
-    impl Project {
-        pub fn new() -> Self {
-            Self::default()
-        }
-    }
-    impl Default for Project {
-        fn default() -> Self {
-            let mut pool = Pool::default();
-            let module_root = pool.insert(Def::default());
-            // Insert the Never(!) type
-            let never = pool.insert(Def {
-                name: String::from("!"),
-                vis: Visibility::Public,
-                kind: DefKind::Type(TypeKind::Never),
-                ..Default::default()
-            });
-            pool[module_root]
-                .module
-                .types
-                .insert(String::from("!"), never);
-            Self { pool, module_root }
-        }
-    }
-
-    impl Project {
-        pub fn parent_of(&self, module: DefID) -> Option<DefID> {
-            self[module].module.parent
-        }
-        pub fn root_of(&self, module: DefID) -> DefID {
-            match self.parent_of(module) {
-                Some(module) => self.root_of(module),
-                None => module,
-            }
-        }
-        /// Resolves a path within a module tree, finding the innermost module.
-        /// Returns the remaining path parts.
-        pub fn get_type<'a>(&self, path: Path<'a>, within: DefID) -> Option<(DefID, Path<'a>)> {
-            // TODO: Cache module lookups
-            if path.absolute {
-                self.get_type(path.relative(), self.root_of(within))
-            } else if let Some(front) = path.front() {
-                let module = &self[within].module;
-                match front {
-                    PathPart::SelfKw => self.get_type(path.pop_front()?, within),
-                    PathPart::SuperKw => self.get_type(path.pop_front()?, module.parent?),
-                    PathPart::Ident(Identifier(name)) => match module.types.get(name) {
-                        Some(&submodule) => self.get_type(path.pop_front()?, submodule),
-                        None => Some((within, path)),
-                    },
-                }
-            } else {
-                Some((within, path))
-            }
-        }
-
-        pub fn get_value<'a>(&self, path: Path<'a>, within: DefID) -> Option<(DefID, Path<'a>)> {
-            match path.front()? {
-                PathPart::Ident(Identifier(name)) => Some((
-                    self[within].module.values.get(name).copied()?,
-                    path.pop_front()?,
-                )),
-                _ => None,
-            }
-        }
-
-        #[rustfmt::skip]
-        pub fn insert_type(&mut self, name: String, value: Def, parent: DefID) -> Option<DefID> {
-            let id = self.pool.insert(value);
-            self[parent].module.types.insert(name, id)
-        }
-        #[rustfmt::skip]
-        pub fn insert_value(&mut self, name: String, value: Def, parent: DefID) -> Option<DefID> {
-            let id = self.pool.insert(value);
-            self[parent].module.values.insert(name, id)
-        }
-    }
-
-    /// Implements [Index] and [IndexMut] for [Project]: `self.table[ID] -> Definition`
-    macro_rules! impl_index {
-        ($(self.$table:ident[$idx:ty] -> $out:ty),*$(,)?) => {$(
-            impl Index<$idx> for Project {
-                type Output = $out;
-                fn index(&self, index: $idx) -> &Self::Output {
-                    &self.$table[index]
-                }
-            }
-            impl IndexMut<$idx> for Project {
-                fn index_mut(&mut self, index: $idx) -> &mut Self::Output {
-                    &mut self.$table[index]
-                }
-            }
-        )*};
-    }
-    impl_index! {
-        self.pool[DefID] -> Def,
-        // self.types[TypeID] -> TypeDef,
-        // self.values[ValueID] -> ValueDef,
-    }
-}
-
-pub mod name_collector {
-    //! Performs step 1 of type checking: Collecting all the names of things into [Module] units
-
-    use crate::{
-        definition::{Def, DefKind},
-        key,
-        project::Project,
-        type_kind::{Adt, TypeKind},
-        value_kind::ValueKind,
-    };
-    use cl_ast::*;
-    use std::ops::{Deref, DerefMut};
-
-    /// Collects types for future use
-    #[derive(Debug, PartialEq, Eq)]
-    pub struct NameCollector<'prj> {
-        /// A stack of the current modules
-        pub mod_stack: Vec<key::DefID>,
-        /// The [Project], the type checker and resolver's central data store
-        pub project: &'prj mut Project,
-    }
-
-    impl<'prj> NameCollector<'prj> {
-        pub fn new(project: &'prj mut Project) -> Self {
-            // create a root module
-            Self { mod_stack: vec![project.module_root], project }
-        }
-
-        /// Gets the currently traversed parent module
-        pub fn parent(&self) -> Option<key::DefID> {
-            self.mod_stack.last().copied()
-        }
-    }
-
-    impl Deref for NameCollector<'_> {
-        type Target = Project;
-        fn deref(&self) -> &Self::Target {
-            self.project
-        }
-    }
-    impl DerefMut for NameCollector<'_> {
-        fn deref_mut(&mut self) -> &mut Self::Target {
-            self.project
-        }
-    }
-
-    impl NameCollector<'_> {
-        pub fn file(&mut self, f: &File) -> Result<(), &'static str> {
-            let parent = self.parent().ok_or("No parent to add item to")?;
-
-            for item in &f.items {
-                let def = match &item.kind {
-                    // modules
-                    // types
-                    ItemKind::Module(_) => {
-                        self.module(item)?;
-                        continue;
-                    }
-                    ItemKind::Enum(_) => Some(self.ty_enum(item)?),
-                    ItemKind::Alias(_) => Some(self.ty_alias(item)?),
-                    ItemKind::Struct(_) => Some(self.ty_struct(item)?),
-                    // values processed by the value collector
-                    ItemKind::Const(_) => Some(self.val_const(item)?),
-                    ItemKind::Static(_) => Some(self.val_static(item)?),
-                    ItemKind::Function(_) => Some(self.val_function(item)?),
-                    ItemKind::Impl(_) => None,
-                };
-                let Some(def) = def else { continue };
-                match def.kind {
-                    DefKind::Type(_) => {
-                        if let Some(v) = self.insert_type(def.name.clone(), def, parent) {
-                            panic!("Redefinition of type {} ({v:?})!", self[v].name)
-                        }
-                    }
-                    DefKind::Value(_) => {
-                        if let Some(v) = self.insert_value(def.name.clone(), def, parent) {
-                            panic!("Redefinition of value {} ({v:?})!", self[v].name)
-                        }
-                    }
-                }
-            }
-            Ok(())
-        }
-
-        /// Collects a [Module]
-        pub fn module(&mut self, m: &Item) -> Result<(), &'static str> {
-            let Item { kind: ItemKind::Module(Module { name, kind }), vis, attrs, .. } = m else {
-                Err("module called on Item which was not an ItemKind::Module")?
-            };
-            let ModuleKind::Inline(kind) = kind else {
-                Err("Out-of-line modules not yet supported")?
-            };
-            let parent = self.parent().ok_or("No parent to add module to")?;
-
-            let module = self.pool.insert(Def::new_module(
-                name.0.clone(),
-                *vis,
-                attrs.meta.clone(),
-                Some(parent),
-            ));
-
-            self[parent]
-                .module
-                .types
-                .insert(name.0.clone(), module)
-                .is_some()
-                .then(|| panic!("Error: redefinition of module {name}"));
-
-            self.mod_stack.push(module);
-            let out = self.file(kind);
-            self.mod_stack.pop();
-
-            out
-        }
-    }
-    /// Type collection
-    impl NameCollector<'_> {
-        /// Collects an [Item] of type [ItemKind::Enum]
-        pub fn ty_enum(&mut self, item: &Item) -> Result<Def, &'static str> {
-            let Item { kind: ItemKind::Enum(Enum { name, kind }), vis, attrs, .. } = item else {
-                Err("Enum called on item which was not ItemKind::Enum")?
-            };
-            let kind = match kind {
-                EnumKind::NoVariants => DefKind::Type(TypeKind::Adt(Adt::FieldlessEnum)),
-                EnumKind::Variants(_) => DefKind::Type(TypeKind::Undecided),
-            };
-
-            Ok(Def {
-                name: name.0.clone(),
-                vis: *vis,
-                meta: attrs.meta.clone(),
-                kind,
-                source: Some(item.clone()),
-                module: Default::default(),
-            })
-        }
-
-        /// Collects an [Item] of type [ItemKind::Alias]
-        pub fn ty_alias(&mut self, item: &Item) -> Result<Def, &'static str> {
-            let Item { kind: ItemKind::Alias(Alias { to: name, from }), vis, attrs, .. } = item
-            else {
-                Err("Alias called on Item which was not ItemKind::Alias")?
-            };
-
-            let mut kind = match from {
-                Some(_) => DefKind::Type(TypeKind::Undecided),
-                None => DefKind::Type(TypeKind::Alias(None)),
-            };
-
-            for meta in &attrs.meta {
-                let Meta { name: meta_name, kind: meta_kind } = meta;
-                match (meta_name.0.as_str(), meta_kind) {
-                    ("intrinsic", MetaKind::Equals(Literal::String(intrinsic))) => {
-                        kind = DefKind::Type(TypeKind::Intrinsic(
-                            intrinsic.parse().map_err(|_| "unknown intrinsic type")?,
-                        ));
-                    }
-                    ("intrinsic", MetaKind::Plain) => {
-                        kind = DefKind::Type(TypeKind::Intrinsic(
-                            name.0.parse().map_err(|_| "Unknown intrinsic type")?,
-                        ))
-                    }
-                    _ => {}
-                }
-            }
-
-            Ok(Def {
-                name: name.0.clone(),
-                vis: *vis,
-                meta: attrs.meta.clone(),
-                kind,
-                source: Some(item.clone()),
-                module: Default::default(),
-            })
-        }
-
-        /// Collects an [Item] of type [ItemKind::Struct]
-        pub fn ty_struct(&mut self, item: &Item) -> Result<Def, &'static str> {
-            let Item { kind: ItemKind::Struct(Struct { name, kind }), vis, attrs, .. } = item
-            else {
-                Err("Struct called on item which was not ItemKind::Struct")?
-            };
-            let kind = match kind {
-                StructKind::Empty => DefKind::Type(TypeKind::Adt(Adt::UnitStruct)),
-                StructKind::Tuple(_) => DefKind::Type(TypeKind::Undecided),
-                StructKind::Struct(_) => DefKind::Type(TypeKind::Undecided),
-            };
-
-            Ok(Def {
-                name: name.0.clone(),
-                vis: *vis,
-                meta: attrs.meta.clone(),
-                kind,
-                source: Some(item.clone()),
-                module: Default::default(),
-            })
-        }
-    }
-    /// Value collection
-    impl NameCollector<'_> {
-        pub fn val_const(&mut self, item: &Item) -> Result<Def, &'static str> {
-            let Item { kind: ItemKind::Const(Const { name, .. }), vis, attrs, .. } = item else {
-                Err("Const called on Item which was not ItemKind::Const")?
-            };
-
-            Ok(Def {
-                name: name.0.clone(),
-                vis: *vis,
-                meta: attrs.meta.clone(),
-                kind: DefKind::Value(ValueKind::Undecided),
-                source: Some(item.clone()),
-                module: Default::default(),
-            })
-        }
-
-        pub fn val_static(&mut self, item: &Item) -> Result<Def, &'static str> {
-            let Item { kind: ItemKind::Static(Static { name, .. }), vis, attrs, .. } = item else {
-                Err("Static called on Item which was not ItemKind::Static")?
-            };
-            Ok(Def {
-                name: name.0.clone(),
-                vis: *vis,
-                meta: attrs.meta.clone(),
-                kind: DefKind::Type(TypeKind::Undecided),
-                source: Some(item.clone()),
-                module: Default::default(),
-            })
-        }
-
-        pub fn val_function(&mut self, item: &Item) -> Result<Def, &'static str> {
-            // TODO: treat function bodies like modules with internal items
-            let Item { kind: ItemKind::Function(Function { name, .. }), vis, attrs, .. } = item
-            else {
-                Err("val_function called on Item which was not ItemKind::Function")?
-            };
-            Ok(Def {
-                name: name.0.clone(),
-                vis: *vis,
-                meta: attrs.meta.clone(),
-                kind: DefKind::Value(ValueKind::Undecided),
-                source: Some(item.clone()),
-                module: Default::default(),
-            })
-        }
-    }
-}
-
-pub mod type_resolver {
-    //! Performs step 2 of type checking: Evaluating type definitions
-    #![allow(unused)]
-    use std::ops::{Deref, DerefMut};
-
-    use cl_ast::*;
-
-    use crate::{definition::Def, key::DefID, project::Project};
-
-    pub struct TypeResolver<'prj> {
-        pub project: &'prj mut Project,
-    }
-
-    impl Deref for TypeResolver<'_> {
-        type Target = Project;
-        fn deref(&self) -> &Self::Target {
-            self.project
-        }
-    }
-    impl DerefMut for TypeResolver<'_> {
-        fn deref_mut(&mut self) -> &mut Self::Target {
-            self.project
-        }
-    }
-
-    impl TypeResolver<'_> {
-        pub fn resolve(&mut self) -> Result<bool, &str> {
-            #![allow(unused)]
-            for typedef in self.pool.iter_mut().filter(|v| v.kind.is_type()) {
-                let Def { name, vis, meta: attr, kind, source: Some(ref definition), module: _ } =
-                    typedef
-                else {
-                    continue;
-                };
-                match &definition.kind {
-                    ItemKind::Alias(Alias { to: _, from: Some(from) }) => match &from.kind {
-                        TyKind::Never => todo!(),
-                        TyKind::Empty => todo!(),
-                        TyKind::SelfTy => todo!(),
-                        TyKind::Path(_) => todo!(),
-                        TyKind::Tuple(_) => todo!(),
-                        TyKind::Ref(_) => todo!(),
-                        TyKind::Fn(_) => todo!(),
-                    },
-                    ItemKind::Alias(_) => {}
-                    ItemKind::Const(_) => todo!(),
-                    ItemKind::Static(_) => todo!(),
-                    ItemKind::Module(_) => todo!(),
-                    ItemKind::Function(_) => {}
-                    ItemKind::Struct(_) => {}
-                    ItemKind::Enum(_) => {}
-                    ItemKind::Impl(_) => {}
-                }
-            }
-            Ok(true)
-        }
-
-        pub fn get_type(&self, kind: &TyKind) -> Option<DefID> {
-            match kind {
-                TyKind::Never => todo!(),
-                TyKind::Empty => todo!(),
-                TyKind::SelfTy => todo!(),
-                TyKind::Path(_) => todo!(),
-                TyKind::Tuple(_) => todo!(),
-                TyKind::Ref(_) => todo!(),
-                TyKind::Fn(_) => todo!(),
-            }
-            None
-        }
-    }
-}
-
-pub mod typeref {
-    //! Stores type and reference info
-
-    use crate::key::DefID;
-
-    /// The Type struct represents all valid types, and can be trivially equality-compared
-    #[derive(Clone, Debug, PartialEq, Eq)]
-    pub struct TypeRef {
-        /// You can only have a pointer chain 65535 pointers long.
-        ref_depth: u16,
-        /// Types can be [Generic](RefKind::Generic) or [Concrete](RefKind::Concrete)
-        kind: RefKind,
-    }
-
-    /// Types can be [Generic](RefKind::Generic) or [Concrete](RefKind::Concrete)
-    #[derive(Clone, Debug, PartialEq, Eq)]
-    pub enum RefKind {
-        /// A Concrete type has an associated [Def](super::definition::Def)
-        Concrete(DefID),
-        /// A Generic type is a *locally unique* comparable value,
-        /// valid only until the end of its typing context.
-        /// This is usually the surrounding function.
-        Generic(usize),
-    }
-}
-
-/*
-/// What is an inference rule?
-/// An inference rule is a specification with a set of predicates and a judgement
-
-/// Let's give every type an ID
-struct TypeID(usize);
-
-/// Let's give every type some data:
-
-struct TypeDef<'def> {
-    name: String,
-    definition: &'def Item,
-}
-
-and store them in a big vector of type descriptions:
-
-struct TypeMap<'def> {
-    types: Vec<TypeDef<'def>>,
-}
-// todo: insertion of a type should yield a TypeID
-// todo: impl index with TypeID
-
-Let's store type information as either a concrete type or a generic type:
-
-/// The Type struct represents all valid types, and can be trivially equality-compared
-pub struct Type {
-    /// You can only have a pointer chain 65535 pointers long.
-    ref_depth: u16,
-    kind: TKind,
-}
-pub enum TKind {
-    Concrete(TypeID),
-    Generic(usize),
-}
-
-And assume I can specify a rule based on its inputs and outputs:
-
-Rule {
-    operation: If,
-    /// The inputs field is populated by
-    inputs: [Concrete(BOOL), Generic(0), Generic(0)],
-    outputs: Generic(0),
-    /// This rule is compiler-intrinsic!
-    through: None,
-}
-
-Rule {
-    operation: Add,
-    inputs: [Concrete(I32), Concrete(I32)],
-    outputs: Concrete(I32),
-    /// This rule is not compiler-intrinsic (it is overloaded!)
-    through: Some(&ImplAddForI32::Add),
-}
-
-
-
-These rules can be stored in some kind of rule database:
-
-let rules: Hashmap<Operation, Vec<Rule>> {
-
-}
-
-*/
-
-pub mod rule {
-    use crate::{key::DefID, typeref::TypeRef};
-
-    pub struct Rule {
-        /// What is this Rule for?
-        pub operation: (),
-        /// What inputs does it take?
-        pub inputs: Vec<TypeRef>,
-        /// What output does it produce?
-        pub output: TypeRef,
-        /// Where did this rule come from?
-        pub through: Origin,
-    }
-
-    // TODO: Genericize
-    pub enum Operation {
-        Mul,
-        Div,
-        Rem,
-        Add,
-        Sub,
-
-        Deref,
-        Neg,
-        Not,
-        At,
-        Tilde,
-
-        Index,
-
-        If,
-        While,
-        For,
-    }
-
-    pub enum Origin {
-        /// This rule is built into the compiler
-        Intrinsic,
-        /// This rule is derived from an implementation on a type
-        Extrinsic(DefID),
-    }
-}
-
-pub mod typeck {
-    #![allow(unused)]
-    use cl_ast::*;
-
-    pub struct Context {
-        rules: (),
-    }
-
-    trait TypeCheck {}
-}
-
-//

compiler/cl-ast/src/ast.rs

@@ -5,20 +5,18 @@
 //! - [Item] and [ItemKind]: Top-level constructs
 //! - [Stmt] and [StmtKind]: Statements
 //! - [Expr] and [ExprKind]: Expressions
-//!   - [Assign], [Binary], and [Unary] expressions
-//!   - [AssignKind], [BinaryKind], and [UnaryKind] operators
+//!   - [Assign], [Modify], [Binary], and [Unary] expressions
+//!   - [ModifyKind], [BinaryKind], and [UnaryKind] operators
 //! - [Ty] and [TyKind]: Type qualifiers
+//! - [Pattern]: Pattern matching operators
 //! - [Path]: Path expressions
-#![warn(clippy::all)]
-#![feature(decl_macro)]
+use cl_structures::{intern::interned::Interned, span::*};
 
-use cl_structures::span::*;
-
-pub mod ast_impl;
-pub mod format;
+/// An [Interned] static [str], used in place of an identifier
+pub type Sym = Interned<'static, str>;
 
 /// Whether a binding ([Static] or [Let]) or reference is mutable or not
-#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Hash)]
 pub enum Mutability {
     #[default]
     Not,
@@ -26,34 +24,44 @@ pub enum Mutability {
 }
 
 /// Whether an [Item] is visible outside of the current [Module]
-#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Hash)]
 pub enum Visibility {
     #[default]
     Private,
     Public,
 }
 
+/// A [Literal]: 0x42, 1e123, 2.4, "Hello"
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub enum Literal {
+    Bool(bool),
+    Char(char),
+    Int(u128),
+    Float(u64),
+    String(String),
+}
+
 /// A list of [Item]s
-#[derive(Clone, Debug, Default, PartialEq, Eq)]
+#[derive(Clone, Debug, Default, PartialEq, Eq, Hash)]
 pub struct File {
     pub items: Vec<Item>,
 }
 
-// Metadata decorators
-#[derive(Clone, Debug, Default, PartialEq, Eq)]
+/// A list of [Meta] decorators
+#[derive(Clone, Debug, Default, PartialEq, Eq, Hash)]
 pub struct Attrs {
     pub meta: Vec<Meta>,
 }
 
 /// A metadata decorator
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Meta {
-    pub name: Identifier,
+    pub name: Sym,
     pub kind: MetaKind,
 }
 
 /// Information attached to [Meta]data
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub enum MetaKind {
     Plain,
     Equals(Literal),
@@ -62,7 +70,7 @@ pub enum MetaKind {
 
 // Items
 /// Anything that can appear at the top level of a [File]
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Item {
     pub extents: Span,
     pub attrs: Attrs,
@@ -71,9 +79,8 @@ pub struct Item {
 }
 
 /// What kind of [Item] is this?
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub enum ItemKind {
-    // TODO: Import declaration ("use") item
     // TODO: Trait declaration ("trait") item?
     /// A [module](Module)
     Module(Module),
@@ -91,95 +98,96 @@ pub enum ItemKind {
     Function(Function),
     /// An [implementation](Impl)
     Impl(Impl),
+    /// An [import](Use)
+    Use(Use),
 }
 
 /// An alias to another [Ty]
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Alias {
-    pub to: Identifier,
+    pub to: Sym,
     pub from: Option<Box<Ty>>,
 }
 
 /// A compile-time constant
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Const {
-    pub name: Identifier,
+    pub name: Sym,
     pub ty: Box<Ty>,
     pub init: Box<Expr>,
 }
 
 /// A `static` variable
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Static {
     pub mutable: Mutability,
-    pub name: Identifier,
+    pub name: Sym,
     pub ty: Box<Ty>,
     pub init: Box<Expr>,
 }
 
 /// An ordered collection of [Items](Item)
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Module {
-    pub name: Identifier,
+    pub name: Sym,
     pub kind: ModuleKind,
 }
 
 /// The contents of a [Module], if they're in the same file
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub enum ModuleKind {
     Inline(File),
     Outline,
 }
 
 /// Code, and the interface to that code
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Function {
-    pub name: Identifier,
-    pub args: Vec<Param>,
+    pub name: Sym,
+    pub sign: TyFn,
+    pub bind: Vec<Param>,
     pub body: Option<Block>,
-    pub rety: Option<Box<Ty>>,
 }
 
 /// A single parameter for a [Function]
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Param {
     pub mutability: Mutability,
-    pub name: Identifier,
-    pub ty: Box<Ty>,
+    pub name: Sym,
 }
 
 /// A user-defined product type
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Struct {
-    pub name: Identifier,
+    pub name: Sym,
     pub kind: StructKind,
 }
 
 /// Either a [Struct]'s [StructMember]s or tuple [Ty]pes, if present.
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub enum StructKind {
     Empty,
     Tuple(Vec<Ty>),
     Struct(Vec<StructMember>),
 }
 
-/// The [Visibility], [Identifier], and [Ty]pe of a single [Struct] member
-#[derive(Clone, Debug, PartialEq, Eq)]
+/// The [Visibility], [Sym], and [Ty]pe of a single [Struct] member
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct StructMember {
     pub vis: Visibility,
-    pub name: Identifier,
+    pub name: Sym,
     pub ty: Ty,
 }
 
 /// A user-defined sum type
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Enum {
-    pub name: Identifier,
+    pub name: Sym,
     pub kind: EnumKind,
 }
 
 /// An [Enum]'s [Variant]s, if it has a variant block
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub enum EnumKind {
     /// Represents an enum with no variants
     NoVariants,
@@ -187,145 +195,180 @@ pub enum EnumKind {
 }
 
 /// A single [Enum] variant
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Variant {
-    pub name: Identifier,
+    pub name: Sym,
     pub kind: VariantKind,
 }
 
 /// Whether the [Variant] has a C-like constant value, a tuple, or [StructMember]s
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub enum VariantKind {
     Plain,
     CLike(u128),
-    Tuple(Vec<Ty>),
+    Tuple(Ty),
     Struct(Vec<StructMember>),
 }
 
 /// Sub-[items](Item) (associated functions, etc.) for a [Ty]
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Impl {
-    pub target: Ty,
-    pub body: Vec<Item>,
+    pub target: ImplKind,
+    pub body: File,
 }
 
 // TODO: `impl` Trait for <Target> { }
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub enum ImplKind {
-    Type(Box<Ty>),
+    Type(Ty),
     Trait { impl_trait: Path, for_type: Box<Ty> },
 }
 
+/// An import of nonlocal [Item]s
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub struct Use {
+    pub absolute: bool,
+    pub tree: UseTree,
+}
+
+/// A tree of [Item] imports
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub enum UseTree {
+    Tree(Vec<UseTree>),
+    Path(PathPart, Box<UseTree>),
+    Alias(Sym, Sym),
+    Name(Sym),
+    Glob,
+}
+
 /// A type expression
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Ty {
     pub extents: Span,
     pub kind: TyKind,
 }
 
 /// Information about a [Ty]pe expression
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub enum TyKind {
     Never,
     Empty,
-    SelfTy,
     Path(Path),
+    Array(TyArray),
+    Slice(TySlice),
     Tuple(TyTuple),
     Ref(TyRef),
     Fn(TyFn),
 }
 
+/// An array of [`T`](Ty)
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub struct TyArray {
+    pub ty: Box<TyKind>,
+    pub count: usize,
+}
+
+/// A [Ty]pe slice expression: `[T]`
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub struct TySlice {
+    pub ty: Box<TyKind>,
+}
+
 /// A tuple of [Ty]pes
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct TyTuple {
-    pub types: Vec<Ty>,
+    pub types: Vec<TyKind>,
 }
 
 /// A [Ty]pe-reference expression as (number of `&`, [Path])
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct TyRef {
+    pub mutable: Mutability,
     pub count: u16,
     pub to: Path,
 }
 
 /// The args and return value for a function pointer [Ty]pe
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct TyFn {
-    pub args: TyTuple,
+    pub args: Box<TyKind>,
     pub rety: Option<Box<Ty>>,
 }
 
 /// A path to an [Item] in the [Module] tree
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, Default, PartialEq, Eq, Hash)]
 pub struct Path {
     pub absolute: bool,
     pub parts: Vec<PathPart>,
 }
 
 /// A single component of a [Path]
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub enum PathPart {
     SuperKw,
     SelfKw,
-    Ident(Identifier),
+    SelfTy,
+    Ident(Sym),
 }
 
-// TODO: Capture token?
-/// A name
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub struct Identifier(pub String);
-
 /// An abstract statement, and associated metadata
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Stmt {
     pub extents: Span,
     pub kind: StmtKind,
     pub semi: Semi,
 }
 
+/// Whether the [Stmt] is a [Let], [Item], or [Expr] statement
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub enum StmtKind {
+    Empty,
+    Item(Box<Item>),
+    Expr(Box<Expr>),
+}
+
 /// Whether or not a [Stmt] is followed by a semicolon
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub enum Semi {
     Terminated,
     Unterminated,
 }
 
-/// Whether the [Stmt] is a [Let], [Item], or [Expr] statement
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub enum StmtKind {
-    Empty,
-    Local(Let),
-    Item(Box<Item>),
-    Expr(Box<Expr>),
-}
-
-/// A local variable declaration [Stmt]
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub struct Let {
-    pub mutable: Mutability,
-    pub name: Identifier,
-    pub ty: Option<Box<Ty>>,
-    pub init: Option<Box<Expr>>,
-}
-
 /// An expression, the beating heart of the language
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Expr {
     pub extents: Span,
     pub kind: ExprKind,
 }
 
 /// Any of the different [Expr]essions
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Default, Debug, PartialEq, Eq, Hash)]
 pub enum ExprKind {
-    /// An [Assign]ment expression: [`Expr`] ([`AssignKind`] [`Expr`])\+
+    /// An empty expression: `(` `)`
+    #[default]
+    Empty,
+    /// A backtick-quoted expression
+    Quote(Quote),
+    /// A local bind instruction, `let` [`Sym`] `=` [`Expr`]
+    Let(Let),
+    /// A [Match] expression: `match` [Expr] `{` ([MatchArm] `,`)* [MatchArm]? `}`
+    Match(Match),
+    /// An [Assign]ment expression: [`Expr`] (`=` [`Expr`])\+
     Assign(Assign),
+    /// A [Modify]-assignment expression: [`Expr`] ([`ModifyKind`] [`Expr`])\+
+    Modify(Modify),
     /// A [Binary] expression: [`Expr`] ([`BinaryKind`] [`Expr`])\+
     Binary(Binary),
     /// A [Unary] expression: [`UnaryKind`]\* [`Expr`]
     Unary(Unary),
+    /// A [Cast] expression: [`Expr`] `as` [`Ty`]
+    Cast(Cast),
+    /// A [Member] access expression: [`Expr`] [`MemberKind`]\*
+    Member(Member),
     /// An Array [Index] expression: a[10, 20, 30]
     Index(Index),
+    /// A [Struct creation](Structor) expression: [Path] `{` ([Fielder] `,`)* [Fielder]? `}`
+    Structor(Structor),
     /// A [path expression](Path): `::`? [PathPart] (`::` [PathPart])*
     Path(Path),
     /// A [Literal]: 0x42, 1e123, 2.4, "Hello"
@@ -339,8 +382,6 @@ pub enum ExprKind {
     AddrOf(AddrOf),
     /// A [Block] expression: `{` [`Stmt`]\* [`Expr`]? `}`
     Block(Block),
-    /// An empty expression: `(` `)`
-    Empty,
     /// A [Grouping](Group) expression `(` [`Expr`] `)`
     Group(Group),
     /// A [Tuple] expression: `(` [`Expr`] (`,` [`Expr`])+ `)`
@@ -356,20 +397,61 @@ pub enum ExprKind {
     /// A [Return] expression `return` [`Expr`]?
     Return(Return),
     /// A continue expression: `continue`
-    Continue(Continue),
+    Continue,
 }
 
-/// An [Assign]ment expression: [`Expr`] ([`AssignKind`] [`Expr`])\+
-#[derive(Clone, Debug, PartialEq, Eq)]
+/// A backtick-quoted subexpression-literal
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub struct Quote {
+    pub quote: Box<ExprKind>,
+}
+
+/// A local variable declaration [Stmt]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub struct Let {
+    pub mutable: Mutability,
+    pub name: Pattern,
+    pub ty: Option<Box<Ty>>,
+    pub init: Option<Box<Expr>>,
+}
+
+/// A [Pattern] meta-expression (any [`ExprKind`] that fits pattern rules)
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub enum Pattern {
+    Path(Path),
+    Literal(Literal),
+    Ref(Mutability, Box<Pattern>),
+    Tuple(Vec<Pattern>),
+    Array(Vec<Pattern>),
+    Struct(Path, Vec<(Path, Option<Pattern>)>),
+}
+
+/// A `match` expression: `match` `{` ([MatchArm] `,`)* [MatchArm]? `}`
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub struct Match {
+    pub scrutinee: Box<Expr>,
+    pub arms: Vec<MatchArm>,
+}
+
+/// A single arm of a [Match] expression: [`Pattern`] `=>` [`Expr`]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub struct MatchArm(pub Pattern, pub Expr);
+
+/// An [Assign]ment expression: [`Expr`] ([`ModifyKind`] [`Expr`])\+
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Assign {
-    pub kind: AssignKind,
     pub parts: Box<(ExprKind, ExprKind)>,
 }
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
-pub enum AssignKind {
-    /// Standard Assignment with no read-back
-    Plain,
+/// A [Modify]-assignment expression: [`Expr`] ([`ModifyKind`] [`Expr`])\+
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub struct Modify {
+    pub kind: ModifyKind,
+    pub parts: Box<(ExprKind, ExprKind)>,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub enum ModifyKind {
     And,
     Or,
     Xor,
@@ -383,14 +465,14 @@ pub enum AssignKind {
 }
 
 /// A [Binary] expression: [`Expr`] ([`BinaryKind`] [`Expr`])\+
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Binary {
     pub kind: BinaryKind,
     pub parts: Box<(ExprKind, ExprKind)>,
 }
 
 /// A [Binary] operator
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
 pub enum BinaryKind {
     Lt,
     LtEq,
@@ -413,86 +495,114 @@ pub enum BinaryKind {
     Mul,
     Div,
     Rem,
-    Dot,
     Call,
 }
 
 /// A [Unary] expression: [`UnaryKind`]\* [`Expr`]
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Unary {
     pub kind: UnaryKind,
     pub tail: Box<ExprKind>,
 }
 
 /// A [Unary] operator
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
 pub enum UnaryKind {
     Deref,
     Neg,
     Not,
+    /// A Loop expression: `loop` [`Block`]
+    Loop,
     /// Unused
     At,
     /// Unused
     Tilde,
 }
+
+/// A cast expression: [`Expr`] `as` [`Ty`]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub struct Cast {
+    pub head: Box<ExprKind>,
+    pub ty: Ty,
+}
+
+/// A [Member] access expression: [`Expr`] [`MemberKind`]\*
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub struct Member {
+    pub head: Box<ExprKind>,
+    pub kind: MemberKind,
+}
+
+/// The kind of [Member] access
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub enum MemberKind {
+    Call(Sym, Tuple),
+    Struct(Sym),
+    Tuple(Literal),
+}
+
 /// A repeated [Index] expression: a[10, 20, 30][40, 50, 60]
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Index {
     pub head: Box<ExprKind>,
     pub indices: Vec<Expr>,
 }
 
-/// A [Literal]: 0x42, 1e123, 2.4, "Hello"
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub enum Literal {
-    Bool(bool),
-    Char(char),
-    Int(u128),
-    String(String),
+/// A [Struct creation](Structor) expression: [Path] `{` ([Fielder] `,`)* [Fielder]? `}`
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub struct Structor {
+    pub to: Path,
+    pub init: Vec<Fielder>,
+}
+
+/// A [Struct field initializer] expression: [Sym] (`=` [Expr])?
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub struct Fielder {
+    pub name: Sym,
+    pub init: Option<Box<Expr>>,
 }
 
 /// An [Array] literal: `[` [`Expr`] (`,` [`Expr`])\* `]`
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Array {
     pub values: Vec<Expr>,
 }
 
 /// An Array literal constructed with [repeat syntax](ArrayRep)
 /// `[` [Expr] `;` [Literal] `]`
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct ArrayRep {
     pub value: Box<ExprKind>,
     pub repeat: Box<ExprKind>,
 }
 
 /// An address-of expression: `&` `mut`? [`Expr`]
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct AddrOf {
-    pub count: usize,
     pub mutable: Mutability,
     pub expr: Box<ExprKind>,
 }
 
 /// A [Block] expression: `{` [`Stmt`]\* [`Expr`]? `}`
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Block {
     pub stmts: Vec<Stmt>,
 }
 
 /// A [Grouping](Group) expression `(` [`Expr`] `)`
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Group {
     pub expr: Box<ExprKind>,
 }
 
 /// A [Tuple] expression: `(` [`Expr`] (`,` [`Expr`])+ `)`
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Tuple {
     pub exprs: Vec<Expr>,
 }
 
 /// A [While] expression: `while` [`Expr`] [`Block`] [`Else`]?
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct While {
     pub cond: Box<Expr>,
     pub pass: Box<Block>,
@@ -500,7 +610,7 @@ pub struct While {
 }
 
 /// An [If] expression: `if` [`Expr`] [`Block`] [`Else`]?
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct If {
     pub cond: Box<Expr>,
     pub pass: Box<Block>,
@@ -508,32 +618,28 @@ pub struct If {
 }
 
 /// A [For] expression: `for` Pattern `in` [`Expr`] [`Block`] [`Else`]?
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct For {
-    pub bind: Identifier, // TODO: Patterns?
+    pub bind: Sym, // TODO: Patterns?
     pub cond: Box<Expr>,
     pub pass: Box<Block>,
     pub fail: Else,
 }
 
 /// The (optional) `else` clause of a [While], [If], or [For] expression
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Else {
     pub body: Option<Box<Expr>>,
 }
 
 /// A [Break] expression: `break` [`Expr`]?
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Break {
     pub body: Option<Box<Expr>>,
 }
 
 /// A [Return] expression `return` [`Expr`]?
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Return {
     pub body: Option<Box<Expr>>,
 }
-
-/// A continue expression: `continue`
-#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
-pub struct Continue;

compiler/cl-ast/src/ast_visitor.rs

@@ -0,0 +1,8 @@
+//! Contains an [immutable visitor](Visit) and an [owned folder](Fold) trait,
+//! with default implementations across the entire AST
+
+pub mod fold;
+pub mod visit;
+
+pub use fold::Fold;
+pub use visit::Visit;

compiler/cl-ast/src/ast_visitor/fold.rs

@@ -0,0 +1,608 @@
+//! A folder (implementer of the [Fold] trait) maps ASTs to ASTs
+
+use crate::ast::*;
+use cl_structures::span::Span;
+
+/// Deconstructs the entire AST, and reconstructs it from scratch.
+///
+/// Each method acts as a customization point.
+///
+/// There are a set of default implementations for enums
+/// under the name [`or_fold_`*](or_fold_expr_kind),
+/// provided for ease of use.
+///
+/// For all other nodes, traversal is *explicit*.
+pub trait Fold {
+    fn fold_span(&mut self, extents: Span) -> Span {
+        extents
+    }
+    fn fold_mutability(&mut self, mutability: Mutability) -> Mutability {
+        mutability
+    }
+    fn fold_visibility(&mut self, visibility: Visibility) -> Visibility {
+        visibility
+    }
+    fn fold_sym(&mut self, ident: Sym) -> Sym {
+        ident
+    }
+    fn fold_literal(&mut self, lit: Literal) -> Literal {
+        or_fold_literal(self, lit)
+    }
+    fn fold_bool(&mut self, b: bool) -> bool {
+        b
+    }
+    fn fold_char(&mut self, c: char) -> char {
+        c
+    }
+    fn fold_int(&mut self, i: u128) -> u128 {
+        i
+    }
+    fn fold_smuggled_float(&mut self, f: u64) -> u64 {
+        f
+    }
+    fn fold_string(&mut self, s: String) -> String {
+        s
+    }
+    fn fold_file(&mut self, f: File) -> File {
+        let File { items } = f;
+        File { items: items.into_iter().map(|i| self.fold_item(i)).collect() }
+    }
+    fn fold_attrs(&mut self, a: Attrs) -> Attrs {
+        let Attrs { meta } = a;
+        Attrs { meta: meta.into_iter().map(|m| self.fold_meta(m)).collect() }
+    }
+    fn fold_meta(&mut self, m: Meta) -> Meta {
+        let Meta { name, kind } = m;
+        Meta { name: self.fold_sym(name), kind: self.fold_meta_kind(kind) }
+    }
+    fn fold_meta_kind(&mut self, kind: MetaKind) -> MetaKind {
+        or_fold_meta_kind(self, kind)
+    }
+    fn fold_item(&mut self, i: Item) -> Item {
+        let Item { extents, attrs, vis, kind } = i;
+        Item {
+            extents: self.fold_span(extents),
+            attrs: self.fold_attrs(attrs),
+            vis: self.fold_visibility(vis),
+            kind: self.fold_item_kind(kind),
+        }
+    }
+    fn fold_item_kind(&mut self, kind: ItemKind) -> ItemKind {
+        or_fold_item_kind(self, kind)
+    }
+    fn fold_alias(&mut self, a: Alias) -> Alias {
+        let Alias { to, from } = a;
+        Alias { to: self.fold_sym(to), from: from.map(|from| Box::new(self.fold_ty(*from))) }
+    }
+    fn fold_const(&mut self, c: Const) -> Const {
+        let Const { name, ty, init } = c;
+        Const {
+            name: self.fold_sym(name),
+            ty: Box::new(self.fold_ty(*ty)),
+            init: Box::new(self.fold_expr(*init)),
+        }
+    }
+    fn fold_static(&mut self, s: Static) -> Static {
+        let Static { mutable, name, ty, init } = s;
+        Static {
+            mutable: self.fold_mutability(mutable),
+            name: self.fold_sym(name),
+            ty: Box::new(self.fold_ty(*ty)),
+            init: Box::new(self.fold_expr(*init)),
+        }
+    }
+    fn fold_module(&mut self, m: Module) -> Module {
+        let Module { name, kind } = m;
+        Module { name: self.fold_sym(name), kind: self.fold_module_kind(kind) }
+    }
+    fn fold_module_kind(&mut self, m: ModuleKind) -> ModuleKind {
+        match m {
+            ModuleKind::Inline(f) => ModuleKind::Inline(self.fold_file(f)),
+            ModuleKind::Outline => ModuleKind::Outline,
+        }
+    }
+    fn fold_function(&mut self, f: Function) -> Function {
+        let Function { name, sign, bind, body } = f;
+        Function {
+            name: self.fold_sym(name),
+            sign: self.fold_ty_fn(sign),
+            bind: bind.into_iter().map(|p| self.fold_param(p)).collect(),
+            body: body.map(|b| self.fold_block(b)),
+        }
+    }
+    fn fold_param(&mut self, p: Param) -> Param {
+        let Param { mutability, name } = p;
+        Param { mutability: self.fold_mutability(mutability), name: self.fold_sym(name) }
+    }
+    fn fold_struct(&mut self, s: Struct) -> Struct {
+        let Struct { name, kind } = s;
+        Struct { name: self.fold_sym(name), kind: self.fold_struct_kind(kind) }
+    }
+    fn fold_struct_kind(&mut self, kind: StructKind) -> StructKind {
+        match kind {
+            StructKind::Empty => StructKind::Empty,
+            StructKind::Tuple(tys) => {
+                StructKind::Tuple(tys.into_iter().map(|t| self.fold_ty(t)).collect())
+            }
+            StructKind::Struct(mem) => StructKind::Struct(
+                mem.into_iter()
+                    .map(|m| self.fold_struct_member(m))
+                    .collect(),
+            ),
+        }
+    }
+    fn fold_struct_member(&mut self, m: StructMember) -> StructMember {
+        let StructMember { vis, name, ty } = m;
+        StructMember {
+            vis: self.fold_visibility(vis),
+            name: self.fold_sym(name),
+            ty: self.fold_ty(ty),
+        }
+    }
+    fn fold_enum(&mut self, e: Enum) -> Enum {
+        let Enum { name, kind } = e;
+        Enum { name: self.fold_sym(name), kind: self.fold_enum_kind(kind) }
+    }
+    fn fold_enum_kind(&mut self, kind: EnumKind) -> EnumKind {
+        or_fold_enum_kind(self, kind)
+    }
+    fn fold_variant(&mut self, v: Variant) -> Variant {
+        let Variant { name, kind } = v;
+
+        Variant { name: self.fold_sym(name), kind: self.fold_variant_kind(kind) }
+    }
+    fn fold_variant_kind(&mut self, kind: VariantKind) -> VariantKind {
+        or_fold_variant_kind(self, kind)
+    }
+    fn fold_impl(&mut self, i: Impl) -> Impl {
+        let Impl { target, body } = i;
+        Impl { target: self.fold_impl_kind(target), body: self.fold_file(body) }
+    }
+    fn fold_impl_kind(&mut self, kind: ImplKind) -> ImplKind {
+        or_fold_impl_kind(self, kind)
+    }
+    fn fold_use(&mut self, u: Use) -> Use {
+        let Use { absolute, tree } = u;
+        Use { absolute, tree: self.fold_use_tree(tree) }
+    }
+    fn fold_use_tree(&mut self, tree: UseTree) -> UseTree {
+        or_fold_use_tree(self, tree)
+    }
+    fn fold_ty(&mut self, t: Ty) -> Ty {
+        let Ty { extents, kind } = t;
+        Ty { extents: self.fold_span(extents), kind: self.fold_ty_kind(kind) }
+    }
+    fn fold_ty_kind(&mut self, kind: TyKind) -> TyKind {
+        or_fold_ty_kind(self, kind)
+    }
+    fn fold_ty_array(&mut self, a: TyArray) -> TyArray {
+        let TyArray { ty, count } = a;
+        TyArray { ty: Box::new(self.fold_ty_kind(*ty)), count }
+    }
+    fn fold_ty_slice(&mut self, s: TySlice) -> TySlice {
+        let TySlice { ty } = s;
+        TySlice { ty: Box::new(self.fold_ty_kind(*ty)) }
+    }
+    fn fold_ty_tuple(&mut self, t: TyTuple) -> TyTuple {
+        let TyTuple { types } = t;
+        TyTuple {
+            types: types
+                .into_iter()
+                .map(|kind| self.fold_ty_kind(kind))
+                .collect(),
+        }
+    }
+    fn fold_ty_ref(&mut self, t: TyRef) -> TyRef {
+        let TyRef { mutable, count, to } = t;
+        TyRef { mutable: self.fold_mutability(mutable), count, to: self.fold_path(to) }
+    }
+    fn fold_ty_fn(&mut self, t: TyFn) -> TyFn {
+        let TyFn { args, rety } = t;
+        TyFn {
+            args: Box::new(self.fold_ty_kind(*args)),
+            rety: rety.map(|t| Box::new(self.fold_ty(*t))),
+        }
+    }
+    fn fold_path(&mut self, p: Path) -> Path {
+        let Path { absolute, parts } = p;
+        Path { absolute, parts: parts.into_iter().map(|p| self.fold_path_part(p)).collect() }
+    }
+    fn fold_path_part(&mut self, p: PathPart) -> PathPart {
+        match p {
+            PathPart::SuperKw => PathPart::SuperKw,
+            PathPart::SelfKw => PathPart::SelfKw,
+            PathPart::SelfTy => PathPart::SelfTy,
+            PathPart::Ident(i) => PathPart::Ident(self.fold_sym(i)),
+        }
+    }
+    fn fold_stmt(&mut self, s: Stmt) -> Stmt {
+        let Stmt { extents, kind, semi } = s;
+        Stmt {
+            extents: self.fold_span(extents),
+            kind: self.fold_stmt_kind(kind),
+            semi: self.fold_semi(semi),
+        }
+    }
+    fn fold_stmt_kind(&mut self, kind: StmtKind) -> StmtKind {
+        or_fold_stmt_kind(self, kind)
+    }
+    fn fold_semi(&mut self, s: Semi) -> Semi {
+        s
+    }
+    fn fold_expr(&mut self, e: Expr) -> Expr {
+        let Expr { extents, kind } = e;
+        Expr { extents: self.fold_span(extents), kind: self.fold_expr_kind(kind) }
+    }
+    fn fold_expr_kind(&mut self, kind: ExprKind) -> ExprKind {
+        or_fold_expr_kind(self, kind)
+    }
+    fn fold_let(&mut self, l: Let) -> Let {
+        let Let { mutable, name, ty, init } = l;
+        Let {
+            mutable: self.fold_mutability(mutable),
+            name: self.fold_pattern(name),
+            ty: ty.map(|t| Box::new(self.fold_ty(*t))),
+            init: init.map(|e| Box::new(self.fold_expr(*e))),
+        }
+    }
+
+    fn fold_pattern(&mut self, p: Pattern) -> Pattern {
+        match p {
+            Pattern::Path(path) => Pattern::Path(self.fold_path(path)),
+            Pattern::Literal(literal) => Pattern::Literal(self.fold_literal(literal)),
+            Pattern::Ref(mutability, pattern) => Pattern::Ref(
+                self.fold_mutability(mutability),
+                Box::new(self.fold_pattern(*pattern)),
+            ),
+            Pattern::Tuple(patterns) => {
+                Pattern::Tuple(patterns.into_iter().map(|p| self.fold_pattern(p)).collect())
+            }
+            Pattern::Array(patterns) => {
+                Pattern::Array(patterns.into_iter().map(|p| self.fold_pattern(p)).collect())
+            }
+            Pattern::Struct(path, items) => Pattern::Struct(
+                self.fold_path(path),
+                items
+                    .into_iter()
+                    .map(|(name, bind)| (name, bind.map(|p| self.fold_pattern(p))))
+                    .collect(),
+            ),
+        }
+    }
+
+    fn fold_match(&mut self, m: Match) -> Match {
+        let Match { scrutinee, arms } = m;
+        Match {
+            scrutinee: self.fold_expr(*scrutinee).into(),
+            arms: arms
+                .into_iter()
+                .map(|arm| self.fold_match_arm(arm))
+                .collect(),
+        }
+    }
+
+    fn fold_match_arm(&mut self, a: MatchArm) -> MatchArm {
+        let MatchArm(pat, expr) = a;
+        MatchArm(self.fold_pattern(pat), self.fold_expr(expr))
+    }
+    
+    fn fold_assign(&mut self, a: Assign) -> Assign {
+        let Assign { parts } = a;
+        let (head, tail) = *parts;
+        Assign { parts: Box::new((self.fold_expr_kind(head), self.fold_expr_kind(tail))) }
+    }
+    fn fold_modify(&mut self, m: Modify) -> Modify {
+        let Modify { kind, parts } = m;
+        let (head, tail) = *parts;
+        Modify {
+            kind: self.fold_modify_kind(kind),
+            parts: Box::new((self.fold_expr_kind(head), self.fold_expr_kind(tail))),
+        }
+    }
+    fn fold_modify_kind(&mut self, kind: ModifyKind) -> ModifyKind {
+        kind
+    }
+    fn fold_binary(&mut self, b: Binary) -> Binary {
+        let Binary { kind, parts } = b;
+        let (head, tail) = *parts;
+        Binary {
+            kind: self.fold_binary_kind(kind),
+            parts: Box::new((self.fold_expr_kind(head), self.fold_expr_kind(tail))),
+        }
+    }
+    fn fold_binary_kind(&mut self, kind: BinaryKind) -> BinaryKind {
+        kind
+    }
+    fn fold_unary(&mut self, u: Unary) -> Unary {
+        let Unary { kind, tail } = u;
+        Unary { kind: self.fold_unary_kind(kind), tail: Box::new(self.fold_expr_kind(*tail)) }
+    }
+    fn fold_unary_kind(&mut self, kind: UnaryKind) -> UnaryKind {
+        kind
+    }
+    fn fold_cast(&mut self, cast: Cast) -> Cast {
+        let Cast { head, ty } = cast;
+        Cast { head: Box::new(self.fold_expr_kind(*head)), ty: self.fold_ty(ty) }
+    }
+    fn fold_member(&mut self, m: Member) -> Member {
+        let Member { head, kind } = m;
+        Member { head: Box::new(self.fold_expr_kind(*head)), kind: self.fold_member_kind(kind) }
+    }
+    fn fold_member_kind(&mut self, kind: MemberKind) -> MemberKind {
+        or_fold_member_kind(self, kind)
+    }
+    fn fold_index(&mut self, i: Index) -> Index {
+        let Index { head, indices } = i;
+        Index {
+            head: Box::new(self.fold_expr_kind(*head)),
+            indices: indices.into_iter().map(|e| self.fold_expr(e)).collect(),
+        }
+    }
+
+    fn fold_structor(&mut self, s: Structor) -> Structor {
+        let Structor { to, init } = s;
+        Structor {
+            to: self.fold_path(to),
+            init: init.into_iter().map(|f| self.fold_fielder(f)).collect(),
+        }
+    }
+
+    fn fold_fielder(&mut self, f: Fielder) -> Fielder {
+        let Fielder { name, init } = f;
+        Fielder { name: self.fold_sym(name), init: init.map(|e| Box::new(self.fold_expr(*e))) }
+    }
+    fn fold_array(&mut self, a: Array) -> Array {
+        let Array { values } = a;
+        Array { values: values.into_iter().map(|e| self.fold_expr(e)).collect() }
+    }
+    fn fold_array_rep(&mut self, a: ArrayRep) -> ArrayRep {
+        let ArrayRep { value, repeat } = a;
+        ArrayRep {
+            value: Box::new(self.fold_expr_kind(*value)),
+            repeat: Box::new(self.fold_expr_kind(*repeat)),
+        }
+    }
+    fn fold_addrof(&mut self, a: AddrOf) -> AddrOf {
+        let AddrOf { mutable, expr } = a;
+        AddrOf {
+            mutable: self.fold_mutability(mutable),
+            expr: Box::new(self.fold_expr_kind(*expr)),
+        }
+    }
+    fn fold_block(&mut self, b: Block) -> Block {
+        let Block { stmts } = b;
+        Block { stmts: stmts.into_iter().map(|s| self.fold_stmt(s)).collect() }
+    }
+    fn fold_group(&mut self, g: Group) -> Group {
+        let Group { expr } = g;
+        Group { expr: Box::new(self.fold_expr_kind(*expr)) }
+    }
+    fn fold_tuple(&mut self, t: Tuple) -> Tuple {
+        let Tuple { exprs } = t;
+        Tuple { exprs: exprs.into_iter().map(|e| self.fold_expr(e)).collect() }
+    }
+    fn fold_while(&mut self, w: While) -> While {
+        let While { cond, pass, fail } = w;
+        While {
+            cond: Box::new(self.fold_expr(*cond)),
+            pass: Box::new(self.fold_block(*pass)),
+            fail: self.fold_else(fail),
+        }
+    }
+    fn fold_if(&mut self, i: If) -> If {
+        let If { cond, pass, fail } = i;
+        If {
+            cond: Box::new(self.fold_expr(*cond)),
+            pass: Box::new(self.fold_block(*pass)),
+            fail: self.fold_else(fail),
+        }
+    }
+    fn fold_for(&mut self, f: For) -> For {
+        let For { bind, cond, pass, fail } = f;
+        For {
+            bind: self.fold_sym(bind),
+            cond: Box::new(self.fold_expr(*cond)),
+            pass: Box::new(self.fold_block(*pass)),
+            fail: self.fold_else(fail),
+        }
+    }
+    fn fold_else(&mut self, e: Else) -> Else {
+        let Else { body } = e;
+        Else { body: body.map(|e| Box::new(self.fold_expr(*e))) }
+    }
+    fn fold_break(&mut self, b: Break) -> Break {
+        let Break { body } = b;
+        Break { body: body.map(|e| Box::new(self.fold_expr(*e))) }
+    }
+    fn fold_return(&mut self, r: Return) -> Return {
+        let Return { body } = r;
+        Return { body: body.map(|e| Box::new(self.fold_expr(*e))) }
+    }
+}
+
+#[inline]
+/// Folds a [Literal] in the default way
+pub fn or_fold_literal<F: Fold + ?Sized>(folder: &mut F, lit: Literal) -> Literal {
+    match lit {
+        Literal::Bool(b) => Literal::Bool(folder.fold_bool(b)),
+        Literal::Char(c) => Literal::Char(folder.fold_char(c)),
+        Literal::Int(i) => Literal::Int(folder.fold_int(i)),
+        Literal::Float(f) => Literal::Float(folder.fold_smuggled_float(f)),
+        Literal::String(s) => Literal::String(folder.fold_string(s)),
+    }
+}
+
+#[inline]
+/// Folds a [MetaKind] in the default way
+pub fn or_fold_meta_kind<F: Fold + ?Sized>(folder: &mut F, kind: MetaKind) -> MetaKind {
+    match kind {
+        MetaKind::Plain => MetaKind::Plain,
+        MetaKind::Equals(l) => MetaKind::Equals(folder.fold_literal(l)),
+        MetaKind::Func(lits) => {
+            MetaKind::Func(lits.into_iter().map(|l| folder.fold_literal(l)).collect())
+        }
+    }
+}
+
+#[inline]
+/// Folds an [ItemKind] in the default way
+pub fn or_fold_item_kind<F: Fold + ?Sized>(folder: &mut F, kind: ItemKind) -> ItemKind {
+    match kind {
+        ItemKind::Module(m) => ItemKind::Module(folder.fold_module(m)),
+        ItemKind::Alias(a) => ItemKind::Alias(folder.fold_alias(a)),
+        ItemKind::Enum(e) => ItemKind::Enum(folder.fold_enum(e)),
+        ItemKind::Struct(s) => ItemKind::Struct(folder.fold_struct(s)),
+        ItemKind::Const(c) => ItemKind::Const(folder.fold_const(c)),
+        ItemKind::Static(s) => ItemKind::Static(folder.fold_static(s)),
+        ItemKind::Function(f) => ItemKind::Function(folder.fold_function(f)),
+        ItemKind::Impl(i) => ItemKind::Impl(folder.fold_impl(i)),
+        ItemKind::Use(u) => ItemKind::Use(folder.fold_use(u)),
+    }
+}
+
+#[inline]
+/// Folds a [ModuleKind] in the default way
+pub fn or_fold_module_kind<F: Fold + ?Sized>(folder: &mut F, kind: ModuleKind) -> ModuleKind {
+    match kind {
+        ModuleKind::Inline(f) => ModuleKind::Inline(folder.fold_file(f)),
+        ModuleKind::Outline => ModuleKind::Outline,
+    }
+}
+
+#[inline]
+/// Folds a [StructKind] in the default way
+pub fn or_fold_struct_kind<F: Fold + ?Sized>(folder: &mut F, kind: StructKind) -> StructKind {
+    match kind {
+        StructKind::Empty => StructKind::Empty,
+        StructKind::Tuple(tys) => {
+            StructKind::Tuple(tys.into_iter().map(|t| folder.fold_ty(t)).collect())
+        }
+        StructKind::Struct(mem) => StructKind::Struct(
+            mem.into_iter()
+                .map(|m| folder.fold_struct_member(m))
+                .collect(),
+        ),
+    }
+}
+
+#[inline]
+/// Folds an [EnumKind] in the default way
+pub fn or_fold_enum_kind<F: Fold + ?Sized>(folder: &mut F, kind: EnumKind) -> EnumKind {
+    match kind {
+        EnumKind::NoVariants => EnumKind::NoVariants,
+        EnumKind::Variants(v) => {
+            EnumKind::Variants(v.into_iter().map(|v| folder.fold_variant(v)).collect())
+        }
+    }
+}
+
+#[inline]
+/// Folds a [VariantKind] in the default way
+pub fn or_fold_variant_kind<F: Fold + ?Sized>(folder: &mut F, kind: VariantKind) -> VariantKind {
+    match kind {
+        VariantKind::Plain => VariantKind::Plain,
+        VariantKind::CLike(n) => VariantKind::CLike(n),
+        VariantKind::Tuple(t) => VariantKind::Tuple(folder.fold_ty(t)),
+        VariantKind::Struct(mem) => VariantKind::Struct(
+            mem.into_iter()
+                .map(|m| folder.fold_struct_member(m))
+                .collect(),
+        ),
+    }
+}
+
+#[inline]
+/// Folds an [ImplKind] in the default way
+pub fn or_fold_impl_kind<F: Fold + ?Sized>(folder: &mut F, kind: ImplKind) -> ImplKind {
+    match kind {
+        ImplKind::Type(t) => ImplKind::Type(folder.fold_ty(t)),
+        ImplKind::Trait { impl_trait, for_type } => ImplKind::Trait {
+            impl_trait: folder.fold_path(impl_trait),
+            for_type: Box::new(folder.fold_ty(*for_type)),
+        },
+    }
+}
+
+#[inline]
+pub fn or_fold_use_tree<F: Fold + ?Sized>(folder: &mut F, tree: UseTree) -> UseTree {
+    match tree {
+        UseTree::Tree(tree) => UseTree::Tree(
+            tree.into_iter()
+                .map(|tree| folder.fold_use_tree(tree))
+                .collect(),
+        ),
+        UseTree::Path(path, rest) => UseTree::Path(
+            folder.fold_path_part(path),
+            Box::new(folder.fold_use_tree(*rest)),
+        ),
+        UseTree::Alias(path, name) => UseTree::Alias(folder.fold_sym(path), folder.fold_sym(name)),
+        UseTree::Name(name) => UseTree::Name(folder.fold_sym(name)),
+        UseTree::Glob => UseTree::Glob,
+    }
+}
+
+#[inline]
+/// Folds a [TyKind] in the default way
+pub fn or_fold_ty_kind<F: Fold + ?Sized>(folder: &mut F, kind: TyKind) -> TyKind {
+    match kind {
+        TyKind::Never => TyKind::Never,
+        TyKind::Empty => TyKind::Empty,
+        TyKind::Path(p) => TyKind::Path(folder.fold_path(p)),
+        TyKind::Array(a) => TyKind::Array(folder.fold_ty_array(a)),
+        TyKind::Slice(s) => TyKind::Slice(folder.fold_ty_slice(s)),
+        TyKind::Tuple(t) => TyKind::Tuple(folder.fold_ty_tuple(t)),
+        TyKind::Ref(t) => TyKind::Ref(folder.fold_ty_ref(t)),
+        TyKind::Fn(t) => TyKind::Fn(folder.fold_ty_fn(t)),
+    }
+}
+
+#[inline]
+/// Folds a [StmtKind] in the default way
+pub fn or_fold_stmt_kind<F: Fold + ?Sized>(folder: &mut F, kind: StmtKind) -> StmtKind {
+    match kind {
+        StmtKind::Empty => StmtKind::Empty,
+        StmtKind::Item(i) => StmtKind::Item(Box::new(folder.fold_item(*i))),
+        StmtKind::Expr(e) => StmtKind::Expr(Box::new(folder.fold_expr(*e))),
+    }
+}
+#[inline]
+/// Folds an [ExprKind] in the default way
+pub fn or_fold_expr_kind<F: Fold + ?Sized>(folder: &mut F, kind: ExprKind) -> ExprKind {
+    match kind {
+        ExprKind::Empty => ExprKind::Empty,
+        ExprKind::Quote(q) => ExprKind::Quote(q), // quoted expressions are left unmodified
+        ExprKind::Let(l) => ExprKind::Let(folder.fold_let(l)),
+        ExprKind::Match(m) => ExprKind::Match(folder.fold_match(m)),
+        ExprKind::Assign(a) => ExprKind::Assign(folder.fold_assign(a)),
+        ExprKind::Modify(m) => ExprKind::Modify(folder.fold_modify(m)),
+        ExprKind::Binary(b) => ExprKind::Binary(folder.fold_binary(b)),
+        ExprKind::Unary(u) => ExprKind::Unary(folder.fold_unary(u)),
+        ExprKind::Cast(c) => ExprKind::Cast(folder.fold_cast(c)),
+        ExprKind::Member(m) => ExprKind::Member(folder.fold_member(m)),
+        ExprKind::Index(i) => ExprKind::Index(folder.fold_index(i)),
+        ExprKind::Structor(s) => ExprKind::Structor(folder.fold_structor(s)),
+        ExprKind::Path(p) => ExprKind::Path(folder.fold_path(p)),
+        ExprKind::Literal(l) => ExprKind::Literal(folder.fold_literal(l)),
+        ExprKind::Array(a) => ExprKind::Array(folder.fold_array(a)),
+        ExprKind::ArrayRep(a) => ExprKind::ArrayRep(folder.fold_array_rep(a)),
+        ExprKind::AddrOf(a) => ExprKind::AddrOf(folder.fold_addrof(a)),
+        ExprKind::Block(b) => ExprKind::Block(folder.fold_block(b)),
+        ExprKind::Group(g) => ExprKind::Group(folder.fold_group(g)),
+        ExprKind::Tuple(t) => ExprKind::Tuple(folder.fold_tuple(t)),
+        ExprKind::While(w) => ExprKind::While(folder.fold_while(w)),
+        ExprKind::If(i) => ExprKind::If(folder.fold_if(i)),
+        ExprKind::For(f) => ExprKind::For(folder.fold_for(f)),
+        ExprKind::Break(b) => ExprKind::Break(folder.fold_break(b)),
+        ExprKind::Return(r) => ExprKind::Return(folder.fold_return(r)),
+        ExprKind::Continue => ExprKind::Continue,
+    }
+}
+pub fn or_fold_member_kind<F: Fold + ?Sized>(folder: &mut F, kind: MemberKind) -> MemberKind {
+    match kind {
+        MemberKind::Call(name, args) => {
+            MemberKind::Call(folder.fold_sym(name), folder.fold_tuple(args))
+        }
+        MemberKind::Struct(name) => MemberKind::Struct(folder.fold_sym(name)),
+        MemberKind::Tuple(name) => MemberKind::Tuple(folder.fold_literal(name)),
+    }
+}

compiler/cl-ast/src/ast_visitor/visit.rs

@@ -0,0 +1,529 @@
+//! A [visitor](Visit) (implementer of the [Visit] trait) walks the immutable AST, mutating itself.
+
+use crate::ast::*;
+use cl_structures::span::Span;
+
+/// Immutably walks the entire AST
+///
+/// Each method acts as a customization point.
+///
+/// There are a set of default implementations for enums
+/// under the name [`or_visit_`*](or_visit_expr_kind),
+/// provided for ease of use.
+///
+/// For all other nodes, traversal is *explicit*.
+pub trait Visit<'a>: Sized {
+    fn visit_span(&mut self, _extents: &'a Span) {}
+    fn visit_mutability(&mut self, _mutable: &'a Mutability) {}
+    fn visit_visibility(&mut self, _vis: &'a Visibility) {}
+    fn visit_sym(&mut self, _name: &'a Sym) {}
+    fn visit_literal(&mut self, l: &'a Literal) {
+        or_visit_literal(self, l)
+    }
+    fn visit_bool(&mut self, _b: &'a bool) {}
+    fn visit_char(&mut self, _c: &'a char) {}
+    fn visit_int(&mut self, _i: &'a u128) {}
+    fn visit_smuggled_float(&mut self, _f: &'a u64) {}
+    fn visit_string(&mut self, _s: &'a str) {}
+    fn visit_file(&mut self, f: &'a File) {
+        let File { items } = f;
+        items.iter().for_each(|i| self.visit_item(i));
+    }
+    fn visit_attrs(&mut self, a: &'a Attrs) {
+        let Attrs { meta } = a;
+        meta.iter().for_each(|m| self.visit_meta(m));
+    }
+    fn visit_meta(&mut self, m: &'a Meta) {
+        let Meta { name, kind } = m;
+        self.visit_sym(name);
+        self.visit_meta_kind(kind);
+    }
+    fn visit_meta_kind(&mut self, kind: &'a MetaKind) {
+        or_visit_meta_kind(self, kind)
+    }
+    fn visit_item(&mut self, i: &'a Item) {
+        let Item { extents, attrs, vis, kind } = i;
+        self.visit_span(extents);
+        self.visit_attrs(attrs);
+        self.visit_visibility(vis);
+        self.visit_item_kind(kind);
+    }
+    fn visit_item_kind(&mut self, kind: &'a ItemKind) {
+        or_visit_item_kind(self, kind)
+    }
+    fn visit_alias(&mut self, a: &'a Alias) {
+        let Alias { to, from } = a;
+        self.visit_sym(to);
+        if let Some(t) = from {
+            self.visit_ty(t)
+        }
+    }
+    fn visit_const(&mut self, c: &'a Const) {
+        let Const { name, ty, init } = c;
+        self.visit_sym(name);
+        self.visit_ty(ty);
+        self.visit_expr(init);
+    }
+    fn visit_static(&mut self, s: &'a Static) {
+        let Static { mutable, name, ty, init } = s;
+        self.visit_mutability(mutable);
+        self.visit_sym(name);
+        self.visit_ty(ty);
+        self.visit_expr(init);
+    }
+    fn visit_module(&mut self, m: &'a Module) {
+        let Module { name, kind } = m;
+        self.visit_sym(name);
+        self.visit_module_kind(kind);
+    }
+    fn visit_module_kind(&mut self, kind: &'a ModuleKind) {
+        or_visit_module_kind(self, kind)
+    }
+    fn visit_function(&mut self, f: &'a Function) {
+        let Function { name, sign, bind, body } = f;
+        self.visit_sym(name);
+        self.visit_ty_fn(sign);
+        bind.iter().for_each(|p| self.visit_param(p));
+        if let Some(b) = body {
+            self.visit_block(b)
+        }
+    }
+    fn visit_param(&mut self, p: &'a Param) {
+        let Param { mutability, name } = p;
+        self.visit_mutability(mutability);
+        self.visit_sym(name);
+    }
+    fn visit_struct(&mut self, s: &'a Struct) {
+        let Struct { name, kind } = s;
+        self.visit_sym(name);
+        self.visit_struct_kind(kind);
+    }
+    fn visit_struct_kind(&mut self, kind: &'a StructKind) {
+        or_visit_struct_kind(self, kind)
+    }
+    fn visit_struct_member(&mut self, m: &'a StructMember) {
+        let StructMember { vis, name, ty } = m;
+        self.visit_visibility(vis);
+        self.visit_sym(name);
+        self.visit_ty(ty);
+    }
+    fn visit_enum(&mut self, e: &'a Enum) {
+        let Enum { name, kind } = e;
+        self.visit_sym(name);
+        self.visit_enum_kind(kind);
+    }
+    fn visit_enum_kind(&mut self, kind: &'a EnumKind) {
+        or_visit_enum_kind(self, kind)
+    }
+    fn visit_variant(&mut self, v: &'a Variant) {
+        let Variant { name, kind } = v;
+        self.visit_sym(name);
+        self.visit_variant_kind(kind);
+    }
+    fn visit_variant_kind(&mut self, kind: &'a VariantKind) {
+        or_visit_variant_kind(self, kind)
+    }
+    fn visit_impl(&mut self, i: &'a Impl) {
+        let Impl { target, body } = i;
+        self.visit_impl_kind(target);
+        self.visit_file(body);
+    }
+    fn visit_impl_kind(&mut self, target: &'a ImplKind) {
+        or_visit_impl_kind(self, target)
+    }
+    fn visit_use(&mut self, u: &'a Use) {
+        let Use { absolute: _, tree } = u;
+        self.visit_use_tree(tree);
+    }
+    fn visit_use_tree(&mut self, tree: &'a UseTree) {
+        or_visit_use_tree(self, tree)
+    }
+    fn visit_ty(&mut self, t: &'a Ty) {
+        let Ty { extents, kind } = t;
+        self.visit_span(extents);
+        self.visit_ty_kind(kind);
+    }
+    fn visit_ty_kind(&mut self, kind: &'a TyKind) {
+        or_visit_ty_kind(self, kind)
+    }
+    fn visit_ty_array(&mut self, a: &'a TyArray) {
+        let TyArray { ty, count: _ } = a;
+        self.visit_ty_kind(ty);
+    }
+    fn visit_ty_slice(&mut self, s: &'a TySlice) {
+        let TySlice { ty } = s;
+        self.visit_ty_kind(ty)
+    }
+    fn visit_ty_tuple(&mut self, t: &'a TyTuple) {
+        let TyTuple { types } = t;
+        types.iter().for_each(|kind| self.visit_ty_kind(kind))
+    }
+    fn visit_ty_ref(&mut self, t: &'a TyRef) {
+        let TyRef { mutable, count: _, to } = t;
+        self.visit_mutability(mutable);
+        self.visit_path(to);
+    }
+    fn visit_ty_fn(&mut self, t: &'a TyFn) {
+        let TyFn { args, rety } = t;
+        self.visit_ty_kind(args);
+        if let Some(rety) = rety {
+            self.visit_ty(rety);
+        }
+    }
+    fn visit_path(&mut self, p: &'a Path) {
+        let Path { absolute: _, parts } = p;
+        parts.iter().for_each(|p| self.visit_path_part(p))
+    }
+    fn visit_path_part(&mut self, p: &'a PathPart) {
+        match p {
+            PathPart::SuperKw => {}
+            PathPart::SelfKw => {}
+            PathPart::SelfTy => {}
+            PathPart::Ident(i) => self.visit_sym(i),
+        }
+    }
+    fn visit_stmt(&mut self, s: &'a Stmt) {
+        let Stmt { extents, kind, semi } = s;
+        self.visit_span(extents);
+        self.visit_stmt_kind(kind);
+        self.visit_semi(semi);
+    }
+    fn visit_stmt_kind(&mut self, kind: &'a StmtKind) {
+        or_visit_stmt_kind(self, kind)
+    }
+    fn visit_semi(&mut self, _s: &'a Semi) {}
+    fn visit_expr(&mut self, e: &'a Expr) {
+        let Expr { extents, kind } = e;
+        self.visit_span(extents);
+        self.visit_expr_kind(kind)
+    }
+    fn visit_expr_kind(&mut self, e: &'a ExprKind) {
+        or_visit_expr_kind(self, e)
+    }
+    fn visit_let(&mut self, l: &'a Let) {
+        let Let { mutable, name, ty, init } = l;
+        self.visit_mutability(mutable);
+        self.visit_pattern(name);
+        if let Some(ty) = ty {
+            self.visit_ty(ty);
+        }
+        if let Some(init) = init {
+            self.visit_expr(init)
+        }
+    }
+
+    fn visit_pattern(&mut self, p: &'a Pattern) {
+        match p {
+            Pattern::Path(path) => self.visit_path(path),
+            Pattern::Literal(literal) => self.visit_literal(literal),
+            Pattern::Ref(mutability, pattern) => {
+                self.visit_mutability(mutability);
+                self.visit_pattern(pattern);
+            }
+            Pattern::Tuple(patterns) => {
+                patterns.iter().for_each(|p| self.visit_pattern(p));
+            }
+            Pattern::Array(patterns) => {
+                patterns.iter().for_each(|p| self.visit_pattern(p));
+            }
+            Pattern::Struct(path, items) => {
+                self.visit_path(path);
+                items.iter().for_each(|(_name, bind)| {
+                    bind.as_ref().inspect(|bind| {
+                        self.visit_pattern(bind);
+                    });
+                });
+            }
+        }
+    }
+
+    fn visit_match(&mut self, m: &'a Match) {
+        let Match { scrutinee, arms } = m;
+        self.visit_expr(scrutinee);
+        arms.iter().for_each(|arm| self.visit_match_arm(arm));
+    }
+
+    fn visit_match_arm(&mut self, a: &'a MatchArm) {
+        let MatchArm(pat, expr) = a;
+        self.visit_pattern(pat);
+        self.visit_expr(expr);
+    }
+    
+    fn visit_assign(&mut self, a: &'a Assign) {
+        let Assign { parts } = a;
+        let (head, tail) = parts.as_ref();
+        self.visit_expr_kind(head);
+        self.visit_expr_kind(tail);
+    }
+    fn visit_modify(&mut self, m: &'a Modify) {
+        let Modify { kind, parts } = m;
+        let (head, tail) = parts.as_ref();
+        self.visit_modify_kind(kind);
+        self.visit_expr_kind(head);
+        self.visit_expr_kind(tail);
+    }
+    fn visit_modify_kind(&mut self, _kind: &'a ModifyKind) {}
+    fn visit_binary(&mut self, b: &'a Binary) {
+        let Binary { kind, parts } = b;
+        let (head, tail) = parts.as_ref();
+        self.visit_binary_kind(kind);
+        self.visit_expr_kind(head);
+        self.visit_expr_kind(tail);
+    }
+    fn visit_binary_kind(&mut self, _kind: &'a BinaryKind) {}
+    fn visit_unary(&mut self, u: &'a Unary) {
+        let Unary { kind, tail } = u;
+        self.visit_unary_kind(kind);
+        self.visit_expr_kind(tail);
+    }
+    fn visit_unary_kind(&mut self, _kind: &'a UnaryKind) {}
+    fn visit_cast(&mut self, cast: &'a Cast) {
+        let Cast { head, ty } = cast;
+        self.visit_expr_kind(head);
+        self.visit_ty(ty);
+    }
+    fn visit_member(&mut self, m: &'a Member) {
+        let Member { head, kind } = m;
+        self.visit_expr_kind(head);
+        self.visit_member_kind(kind);
+    }
+    fn visit_member_kind(&mut self, kind: &'a MemberKind) {
+        or_visit_member_kind(self, kind)
+    }
+    fn visit_index(&mut self, i: &'a Index) {
+        let Index { head, indices } = i;
+        self.visit_expr_kind(head);
+        indices.iter().for_each(|e| self.visit_expr(e));
+    }
+    fn visit_structor(&mut self, s: &'a Structor) {
+        let Structor { to, init } = s;
+        self.visit_path(to);
+        init.iter().for_each(|e| self.visit_fielder(e))
+    }
+    fn visit_fielder(&mut self, f: &'a Fielder) {
+        let Fielder { name, init } = f;
+        self.visit_sym(name);
+        if let Some(init) = init {
+            self.visit_expr(init);
+        }
+    }
+    fn visit_array(&mut self, a: &'a Array) {
+        let Array { values } = a;
+        values.iter().for_each(|e| self.visit_expr(e))
+    }
+    fn visit_array_rep(&mut self, a: &'a ArrayRep) {
+        let ArrayRep { value, repeat } = a;
+        self.visit_expr_kind(value);
+        self.visit_expr_kind(repeat);
+    }
+    fn visit_addrof(&mut self, a: &'a AddrOf) {
+        let AddrOf { mutable, expr } = a;
+        self.visit_mutability(mutable);
+        self.visit_expr_kind(expr);
+    }
+    fn visit_block(&mut self, b: &'a Block) {
+        let Block { stmts } = b;
+        stmts.iter().for_each(|s| self.visit_stmt(s));
+    }
+    fn visit_group(&mut self, g: &'a Group) {
+        let Group { expr } = g;
+        self.visit_expr_kind(expr)
+    }
+    fn visit_tuple(&mut self, t: &'a Tuple) {
+        let Tuple { exprs } = t;
+        exprs.iter().for_each(|e| self.visit_expr(e))
+    }
+    fn visit_while(&mut self, w: &'a While) {
+        let While { cond, pass, fail } = w;
+        self.visit_expr(cond);
+        self.visit_block(pass);
+        self.visit_else(fail);
+    }
+    fn visit_if(&mut self, i: &'a If) {
+        let If { cond, pass, fail } = i;
+        self.visit_expr(cond);
+        self.visit_block(pass);
+        self.visit_else(fail);
+    }
+    fn visit_for(&mut self, f: &'a For) {
+        let For { bind, cond, pass, fail } = f;
+        self.visit_sym(bind);
+        self.visit_expr(cond);
+        self.visit_block(pass);
+        self.visit_else(fail);
+    }
+    fn visit_else(&mut self, e: &'a Else) {
+        let Else { body } = e;
+        if let Some(body) = body {
+            self.visit_expr(body)
+        }
+    }
+    fn visit_break(&mut self, b: &'a Break) {
+        let Break { body } = b;
+        if let Some(body) = body {
+            self.visit_expr(body)
+        }
+    }
+    fn visit_return(&mut self, r: &'a Return) {
+        let Return { body } = r;
+        if let Some(body) = body {
+            self.visit_expr(body)
+        }
+    }
+    fn visit_continue(&mut self) {}
+}
+
+pub fn or_visit_literal<'a, V: Visit<'a>>(visitor: &mut V, l: &'a Literal) {
+    match l {
+        Literal::Bool(b) => visitor.visit_bool(b),
+        Literal::Char(c) => visitor.visit_char(c),
+        Literal::Int(i) => visitor.visit_int(i),
+        Literal::Float(f) => visitor.visit_smuggled_float(f),
+        Literal::String(s) => visitor.visit_string(s),
+    }
+}
+
+pub fn or_visit_meta_kind<'a, V: Visit<'a>>(visitor: &mut V, kind: &'a MetaKind) {
+    match kind {
+        MetaKind::Plain => {}
+        MetaKind::Equals(l) => visitor.visit_literal(l),
+        MetaKind::Func(lits) => lits.iter().for_each(|l| visitor.visit_literal(l)),
+    }
+}
+
+pub fn or_visit_item_kind<'a, V: Visit<'a>>(visitor: &mut V, kind: &'a ItemKind) {
+    match kind {
+        ItemKind::Module(m) => visitor.visit_module(m),
+        ItemKind::Alias(a) => visitor.visit_alias(a),
+        ItemKind::Enum(e) => visitor.visit_enum(e),
+        ItemKind::Struct(s) => visitor.visit_struct(s),
+        ItemKind::Const(c) => visitor.visit_const(c),
+        ItemKind::Static(s) => visitor.visit_static(s),
+        ItemKind::Function(f) => visitor.visit_function(f),
+        ItemKind::Impl(i) => visitor.visit_impl(i),
+        ItemKind::Use(u) => visitor.visit_use(u),
+    }
+}
+
+pub fn or_visit_module_kind<'a, V: Visit<'a>>(visitor: &mut V, kind: &'a ModuleKind) {
+    match kind {
+        ModuleKind::Inline(f) => visitor.visit_file(f),
+        ModuleKind::Outline => {}
+    }
+}
+
+pub fn or_visit_struct_kind<'a, V: Visit<'a>>(visitor: &mut V, kind: &'a StructKind) {
+    match kind {
+        StructKind::Empty => {}
+        StructKind::Tuple(ty) => ty.iter().for_each(|t| visitor.visit_ty(t)),
+        StructKind::Struct(m) => m.iter().for_each(|m| visitor.visit_struct_member(m)),
+    }
+}
+
+pub fn or_visit_enum_kind<'a, V: Visit<'a>>(visitor: &mut V, kind: &'a EnumKind) {
+    match kind {
+        EnumKind::NoVariants => {}
+        EnumKind::Variants(variants) => variants.iter().for_each(|v| visitor.visit_variant(v)),
+    }
+}
+
+pub fn or_visit_variant_kind<'a, V: Visit<'a>>(visitor: &mut V, kind: &'a VariantKind) {
+    match kind {
+        VariantKind::Plain => {}
+        VariantKind::CLike(_) => {}
+        VariantKind::Tuple(t) => visitor.visit_ty(t),
+        VariantKind::Struct(m) => m.iter().for_each(|m| visitor.visit_struct_member(m)),
+    }
+}
+
+pub fn or_visit_impl_kind<'a, V: Visit<'a>>(visitor: &mut V, target: &'a ImplKind) {
+    match target {
+        ImplKind::Type(t) => visitor.visit_ty(t),
+        ImplKind::Trait { impl_trait, for_type } => {
+            visitor.visit_path(impl_trait);
+            visitor.visit_ty(for_type)
+        }
+    }
+}
+
+pub fn or_visit_use_tree<'a, V: Visit<'a>>(visitor: &mut V, tree: &'a UseTree) {
+    match tree {
+        UseTree::Tree(tree) => {
+            tree.iter().for_each(|tree| visitor.visit_use_tree(tree));
+        }
+        UseTree::Path(path, rest) => {
+            visitor.visit_path_part(path);
+            visitor.visit_use_tree(rest)
+        }
+        UseTree::Alias(path, name) => {
+            visitor.visit_sym(path);
+            visitor.visit_sym(name);
+        }
+        UseTree::Name(name) => {
+            visitor.visit_sym(name);
+        }
+        UseTree::Glob => {}
+    }
+}
+
+pub fn or_visit_ty_kind<'a, V: Visit<'a>>(visitor: &mut V, kind: &'a TyKind) {
+    match kind {
+        TyKind::Never => {}
+        TyKind::Empty => {}
+        TyKind::Path(p) => visitor.visit_path(p),
+        TyKind::Array(t) => visitor.visit_ty_array(t),
+        TyKind::Slice(t) => visitor.visit_ty_slice(t),
+        TyKind::Tuple(t) => visitor.visit_ty_tuple(t),
+        TyKind::Ref(t) => visitor.visit_ty_ref(t),
+        TyKind::Fn(t) => visitor.visit_ty_fn(t),
+    }
+}
+
+pub fn or_visit_stmt_kind<'a, V: Visit<'a>>(visitor: &mut V, kind: &'a StmtKind) {
+    match kind {
+        StmtKind::Empty => {}
+        StmtKind::Item(i) => visitor.visit_item(i),
+        StmtKind::Expr(e) => visitor.visit_expr(e),
+    }
+}
+
+pub fn or_visit_expr_kind<'a, V: Visit<'a>>(visitor: &mut V, e: &'a ExprKind) {
+    match e {
+        ExprKind::Empty => {}
+        ExprKind::Quote(_q) => {} // Quoted expressions are left unvisited
+        ExprKind::Let(l) => visitor.visit_let(l),
+        ExprKind::Match(m) => visitor.visit_match(m),
+        ExprKind::Assign(a) => visitor.visit_assign(a),
+        ExprKind::Modify(m) => visitor.visit_modify(m),
+        ExprKind::Binary(b) => visitor.visit_binary(b),
+        ExprKind::Unary(u) => visitor.visit_unary(u),
+        ExprKind::Cast(c) => visitor.visit_cast(c),
+        ExprKind::Member(m) => visitor.visit_member(m),
+        ExprKind::Index(i) => visitor.visit_index(i),
+        ExprKind::Structor(s) => visitor.visit_structor(s),
+        ExprKind::Path(p) => visitor.visit_path(p),
+        ExprKind::Literal(l) => visitor.visit_literal(l),
+        ExprKind::Array(a) => visitor.visit_array(a),
+        ExprKind::ArrayRep(a) => visitor.visit_array_rep(a),
+        ExprKind::AddrOf(a) => visitor.visit_addrof(a),
+        ExprKind::Block(b) => visitor.visit_block(b),
+        ExprKind::Group(g) => visitor.visit_group(g),
+        ExprKind::Tuple(t) => visitor.visit_tuple(t),
+        ExprKind::While(w) => visitor.visit_while(w),
+        ExprKind::If(i) => visitor.visit_if(i),
+        ExprKind::For(f) => visitor.visit_for(f),
+        ExprKind::Break(b) => visitor.visit_break(b),
+        ExprKind::Return(r) => visitor.visit_return(r),
+        ExprKind::Continue => visitor.visit_continue(),
+    }
+}
+pub fn or_visit_member_kind<'a, V: Visit<'a>>(visitor: &mut V, kind: &'a MemberKind) {
+    match kind {
+        MemberKind::Call(field, args) => {
+            visitor.visit_sym(field);
+            visitor.visit_tuple(args);
+        }
+        MemberKind::Struct(field) => visitor.visit_sym(field),
+        MemberKind::Tuple(field) => visitor.visit_literal(field),
+    }
+}

compiler/cl-ast/src/desugar.rs

@@ -0,0 +1,9 @@
+//! Desugaring passes for Conlang
+
+pub mod path_absoluter;
+pub mod squash_groups;
+pub mod while_else;
+
+pub use path_absoluter::NormalizePaths;
+pub use squash_groups::SquashGroups;
+pub use while_else::WhileElseDesugar;

compiler/cl-ast/src/desugar/path_absoluter.rs

@@ -0,0 +1,54 @@
+use crate::{ast::*, ast_visitor::Fold};
+
+/// Converts relative paths into absolute paths
+pub struct NormalizePaths {
+    path: Path,
+}
+
+impl NormalizePaths {
+    pub fn new() -> Self {
+        Self { path: Path { absolute: true, parts: vec![] } }
+    }
+    /// Normalizes paths as if they came from within the provided paths
+    pub fn in_path(path: Path) -> Self {
+        Self { path }
+    }
+}
+
+impl Default for NormalizePaths {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl Fold for NormalizePaths {
+    fn fold_module(&mut self, m: Module) -> Module {
+        let Module { name, kind } = m;
+        self.path.push(PathPart::Ident(name));
+
+        let (name, kind) = (self.fold_sym(name), self.fold_module_kind(kind));
+
+        self.path.pop();
+        Module { name, kind }
+    }
+
+    fn fold_path(&mut self, p: Path) -> Path {
+        if p.absolute {
+            p
+        } else {
+            self.path.clone().concat(&p)
+        }
+    }
+
+    fn fold_use(&mut self, u: Use) -> Use {
+        let Use { absolute, mut tree } = u;
+
+        if !absolute {
+            for segment in self.path.parts.iter().rev() {
+                tree = UseTree::Path(segment.clone(), Box::new(tree))
+            }
+        }
+
+        Use { absolute: true, tree: self.fold_use_tree(tree) }
+    }
+}

compiler/cl-ast/src/desugar/squash_groups.rs

@@ -0,0 +1,14 @@
+//! Squashes group expressions
+use crate::{ast::*, ast_visitor::fold::*};
+
+/// Squashes group expressions
+pub struct SquashGroups;
+
+impl Fold for SquashGroups {
+    fn fold_expr_kind(&mut self, kind: ExprKind) -> ExprKind {
+        match kind {
+            ExprKind::Group(Group { expr }) => self.fold_expr_kind(*expr),
+            _ => or_fold_expr_kind(self, kind),
+        }
+    }
+}

compiler/cl-ast/src/desugar/while_else.rs

@@ -0,0 +1,34 @@
+//! Desugars `while {...} else` expressions
+//! into `loop if {...} else break` expressions
+
+use crate::{ast::*, ast_visitor::fold::Fold};
+use cl_structures::span::Span;
+
+/// Desugars while-else expressions
+/// into loop-if-else-break expressions
+pub struct WhileElseDesugar;
+
+impl Fold for WhileElseDesugar {
+    fn fold_expr(&mut self, e: Expr) -> Expr {
+        let Expr { extents, kind } = e;
+        let kind = desugar_while(extents, kind);
+        Expr { extents: self.fold_span(extents), kind: self.fold_expr_kind(kind) }
+    }
+}
+
+/// Desugars while(-else) expressions into loop-if-else-break expressions
+fn desugar_while(extents: Span, kind: ExprKind) -> ExprKind {
+    match kind {
+        // work backwards: fail -> break -> if -> loop
+        ExprKind::While(While { cond, pass, fail: Else { body } }) => {
+            // Preserve the else-expression's extents, if present, or use the parent's extents
+            let fail_span = body.as_ref().map(|body| body.extents).unwrap_or(extents);
+            let break_expr = Expr { extents: fail_span, kind: ExprKind::Break(Break { body }) };
+
+            let loop_body = If { cond, pass, fail: Else { body: Some(Box::new(break_expr)) } };
+            let loop_body = ExprKind::If(loop_body);
+            ExprKind::Unary(Unary { kind: UnaryKind::Loop, tail: Box::new(loop_body) })
+        }
+        _ => kind,
+    }
+}

compiler/cl-ast/src/format.rs

@@ -0,0 +1,82 @@
+use delimiters::Delimiters;
+use std::fmt::Write;
+
+impl<W: Write + ?Sized> FmtAdapter for W {}
+pub trait FmtAdapter: Write {
+    fn indent(&mut self) -> Indent<Self> {
+        Indent { f: self }
+    }
+
+    fn delimit(&mut self, delim: Delimiters) -> Delimit<Self> {
+        Delimit::new(self, delim)
+    }
+
+    fn delimit_with(&mut self, open: &'static str, close: &'static str) -> Delimit<Self> {
+        Delimit::new(self, Delimiters { open, close })
+    }
+}
+
+/// Pads text with leading indentation after every newline
+pub struct Indent<'f, F: Write + ?Sized> {
+    f: &'f mut F,
+}
+
+impl<F: Write + ?Sized> Write for Indent<'_, F> {
+    fn write_str(&mut self, s: &str) -> std::fmt::Result {
+        for s in s.split_inclusive('\n') {
+            self.f.write_str(s)?;
+            if s.ends_with('\n') {
+                self.f.write_str("    ")?;
+            }
+        }
+        Ok(())
+    }
+}
+
+/// Prints [Delimiters] around anything formatted with this. Implies [Indent]
+pub struct Delimit<'f, F: Write + ?Sized> {
+    f: Indent<'f, F>,
+    delim: Delimiters,
+}
+impl<'f, F: Write + ?Sized> Delimit<'f, F> {
+    pub fn new(f: &'f mut F, delim: Delimiters) -> Self {
+        let mut f = f.indent();
+        let _ = f.write_str(delim.open);
+        Self { f, delim }
+    }
+}
+impl<F: Write + ?Sized> Drop for Delimit<'_, F> {
+    fn drop(&mut self) {
+        let Self { f: Indent { f, .. }, delim } = self;
+        let _ = f.write_str(delim.close);
+    }
+}
+
+impl<F: Write + ?Sized> Write for Delimit<'_, F> {
+    fn write_str(&mut self, s: &str) -> std::fmt::Result {
+        self.f.write_str(s)
+    }
+}
+
+pub mod delimiters {
+    #![allow(dead_code)]
+    #[derive(Clone, Copy, Debug)]
+    pub struct Delimiters {
+        pub open: &'static str,
+        pub close: &'static str,
+    }
+    /// Delimits with braces decorated with spaces  `" {\n"`, ..., `"\n}"`
+    pub const SPACED_BRACES: Delimiters = Delimiters { open: " {\n", close: "\n}" };
+    /// Delimits with braces on separate lines `{\n`, ..., `\n}`
+    pub const BRACES: Delimiters = Delimiters { open: "{\n", close: "\n}" };
+    /// Delimits with parentheses on separate lines `{\n`, ..., `\n}`
+    pub const PARENS: Delimiters = Delimiters { open: "(\n", close: "\n)" };
+    /// Delimits with square brackets on separate lines `{\n`, ..., `\n}`
+    pub const SQUARE: Delimiters = Delimiters { open: "[\n", close: "\n]" };
+    /// Delimits with braces on the same line `{ `, ..., ` }`
+    pub const INLINE_BRACES: Delimiters = Delimiters { open: "{ ", close: " }" };
+    /// Delimits with parentheses on the same line `( `, ..., ` )`
+    pub const INLINE_PARENS: Delimiters = Delimiters { open: "(", close: ")" };
+    /// Delimits with square brackets on the same line `[ `, ..., ` ]`
+    pub const INLINE_SQUARE: Delimiters = Delimiters { open: "[", close: "]" };
+}

compiler/cl-ast/src/lib.rs

@@ -0,0 +1,22 @@
+//! # The Abstract Syntax Tree
+//! Contains definitions of Conlang AST Nodes.
+//!
+//! # Notable nodes
+//! - [Item] and [ItemKind]: Top-level constructs
+//! - [Stmt] and [StmtKind]: Statements
+//! - [Expr] and [ExprKind]: Expressions
+//!   - [Assign], [Binary], and [Unary] expressions
+//!   - [ModifyKind], [BinaryKind], and [UnaryKind] operators
+//! - [Ty] and [TyKind]: Type qualifiers
+//! - [Pattern]: Pattern matching operators
+//! - [Path]: Path expressions
+#![warn(clippy::all)]
+#![feature(decl_macro)]
+
+pub use ast::*;
+
+pub mod ast;
+pub mod ast_impl;
+pub mod ast_visitor;
+pub mod desugar;
+pub mod format;

compiler/cl-interpret/examples/conlang-run.rs

@@ -0,0 +1,56 @@
+//! A bare-minimum harness to evaluate a Conlang program
+
+use std::{error::Error, path::PathBuf};
+
+use cl_ast::Expr;
+use cl_interpret::{convalue::ConValue, env::Environment};
+use cl_lexer::Lexer;
+use cl_parser::{inliner::ModuleInliner, Parser};
+
+fn main() -> Result<(), Box<dyn Error>> {
+    let mut args = std::env::args();
+
+    let prog = args.next().unwrap();
+    let Some(path) = args.next().map(PathBuf::from) else {
+        println!("Usage: {prog} `file.cl` [ args... ]");
+        return Ok(());
+    };
+
+    let parent = path.parent().unwrap_or("".as_ref());
+
+    let code = std::fs::read_to_string(&path)?;
+    let code = Parser::new(Lexer::new(&code)).parse()?;
+    let code = match ModuleInliner::new(parent).inline(code) {
+        Ok(code) => code,
+        Err((code, ioerrs, perrs)) => {
+            for (p, err) in ioerrs {
+                eprintln!("{}:{err}", p.display());
+            }
+            for (p, err) in perrs {
+                eprintln!("{}:{err}", p.display());
+            }
+            code
+        }
+    };
+
+    let mut env = Environment::new();
+    env.eval(&code)?;
+
+    let main = "main".into();
+    if env.get(main).is_ok() {
+        let args = args
+            .flat_map(|arg| {
+                Parser::new(Lexer::new(&arg))
+                    .parse::<Expr>()
+                    .map(|arg| env.eval(&arg))
+            })
+            .collect::<Result<Vec<_>, _>>()?;
+
+        match env.call(main, &args)? {
+            ConValue::Empty => {}
+            retval => println!("{retval}"),
+        }
+    }
+
+    Ok(())
+}

compiler/cl-interpret/src/builtin.rs

@@ -0,0 +1,337 @@
+#![allow(non_upper_case_globals)]
+
+use crate::{
+    convalue::ConValue,
+    env::Environment,
+    error::{Error, IResult},
+};
+use std::{
+    io::{stdout, Write},
+    slice,
+};
+
+/// A function built into the interpreter.
+#[derive(Clone, Copy)]
+pub struct Builtin {
+    /// An identifier to be used during registration
+    pub name: &'static str,
+    /// The signature, displayed when the builtin is printed
+    pub desc: &'static str,
+    /// The function to be run when called
+    pub func: &'static dyn Fn(&mut Environment, &[ConValue]) -> IResult<ConValue>,
+}
+
+impl Builtin {
+    /// Constructs a new Builtin
+    pub const fn new(
+        name: &'static str,
+        desc: &'static str,
+        func: &'static impl Fn(&mut Environment, &[ConValue]) -> IResult<ConValue>,
+    ) -> Builtin {
+        Builtin { name, desc, func }
+    }
+
+    pub const fn description(&self) -> &'static str {
+        self.desc
+    }
+}
+
+impl std::fmt::Debug for Builtin {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("Builtin")
+            .field("description", &self.desc)
+            .finish_non_exhaustive()
+    }
+}
+
+impl super::Callable for Builtin {
+    fn call(&self, interpreter: &mut Environment, args: &[ConValue]) -> IResult<ConValue> {
+        (self.func)(interpreter, args)
+    }
+
+    fn name(&self) -> cl_ast::Sym {
+        self.name.into()
+    }
+}
+
+/// Turns a function definition into a [Builtin].
+///
+/// ```rust
+/// # use cl_interpret::{builtin2::builtin, convalue::ConValue};
+/// let my_builtin = builtin! {
+///     /// Use the `@env` suffix to bind the environment!
+///     /// (needed for recursive calls)
+///     fn my_builtin(ConValue::Bool(b), rest @ ..) @env {
+///         // This is all Rust code!
+///         eprintln!("my_builtin({b}, ..)");
+///         match rest {
+///             [] => Ok(ConValue::Empty),
+///             _ => my_builtin(env, rest), // Can be called as a normal function!
+///         }
+///     }
+/// };
+/// ```
+pub macro builtin(
+    $(#[$($meta:tt)*])*
+    fn $name:ident ($($arg:pat),*$(,)?) $(@$env:tt)? $body:block
+) {{
+    $(#[$($meta)*])*
+    fn $name(_env: &mut Environment, _args: &[ConValue]) -> IResult<ConValue> {
+        // Set up the builtin! environment
+        $(let $env = _env;)?
+        // Allow for single argument `fn foo(args @ ..)` pattern
+        #[allow(clippy::redundant_at_rest_pattern, irrefutable_let_patterns)]
+        let [$($arg),*] = _args else {
+            Err($crate::error::Error::TypeError)?
+        };
+        $body.map(Into::into)
+    }
+    Builtin {
+        name: stringify!($name),
+        desc: stringify![builtin fn $name($($arg),*)],
+        func: &$name,
+    }
+}}
+
+/// Constructs an array of [Builtin]s from pseudo-function definitions
+pub macro builtins($(
+    $(#[$($meta:tt)*])*
+    fn $name:ident ($($args:tt)*) $(@$env:tt)? $body:block
+)*) {
+    [$(builtin!($(#[$($meta)*])* fn $name ($($args)*) $(@$env)? $body)),*]
+}
+
+/// Creates an [Error::BuiltinDebug] using interpolation of runtime expressions.
+/// See [std::format].
+pub macro error_format ($($t:tt)*) {
+    $crate::error::Error::BuiltinDebug(format!($($t)*))
+}
+
+pub const Builtins: &[Builtin] = &builtins![
+    /// Unstable variadic format function
+    fn fmt(args @ ..) {
+        use std::fmt::Write;
+        let mut out = String::new();
+        if let Err(e) = args.iter().try_for_each(|arg| write!(out, "{arg}")) {
+            eprintln!("{e}");
+        }
+        Ok(out)
+    }
+
+    /// Prints the arguments in-order, with no separators
+    fn print(args @ ..) {
+        let mut out = stdout().lock();
+        args.iter().try_for_each(|arg| write!(out, "{arg}") ).ok();
+        Ok(())
+    }
+
+    /// Prints the arguments in-order, followed by a newline
+    fn println(args @ ..) {
+        let mut out = stdout().lock();
+        args.iter().try_for_each(|arg| write!(out, "{arg}") ).ok();
+        writeln!(out).ok();
+        Ok(())
+    }
+
+    /// Debug-prints the argument, returning a copy
+    fn dbg(arg) {
+        println!("{arg:?}");
+        Ok(arg.clone())
+    }
+
+    /// Debug-prints the argument
+    fn dbgp(args @ ..) {
+        let mut out = stdout().lock();
+        args.iter().try_for_each(|arg| writeln!(out, "{arg:#?}") ).ok();
+        Ok(())
+    }
+
+    /// Dumps the environment
+    fn dump() @env {
+        println!("{env}");
+        Ok(())
+    }
+
+    fn builtins() @env {
+        for builtin in env.builtins().values().flatten() {
+            println!("{builtin}");
+        }
+        Ok(())
+    }
+
+    /// Returns the length of the input list as a [ConValue::Int]
+    fn len(list) @env {
+        Ok(match list {
+            ConValue::Empty => 0,
+            ConValue::String(s) => s.chars().count() as _,
+            ConValue::Ref(r) => return len(env, slice::from_ref(r.as_ref())),
+            ConValue::Array(t) => t.len() as _,
+            ConValue::Tuple(t) => t.len() as _,
+            ConValue::RangeExc(start, end) => (end - start) as _,
+            ConValue::RangeInc(start, end) => (end - start + 1) as _,
+            _ => Err(Error::TypeError)?,
+        })
+    }
+
+    fn dump_symbols() {
+        println!("{}", cl_structures::intern::string_interner::StringInterner::global());
+        Ok(ConValue::Empty)
+    }
+
+    /// Returns a shark
+    fn shark() {
+        Ok('\u{1f988}')
+    }
+];
+
+pub const Math: &[Builtin] = &builtins![
+    /// Multiplication `a * b`
+    fn mul(lhs, rhs) {
+        Ok(match (lhs, rhs) {
+            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
+            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a * b),
+            _ => Err(Error::TypeError)?
+        })
+    }
+
+    /// Division `a / b`
+    fn div(lhs, rhs) {
+        Ok(match (lhs, rhs){
+            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
+            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a / b),
+            _ => Err(Error::TypeError)?
+        })
+    }
+
+    /// Remainder `a % b`
+    fn rem(lhs, rhs) {
+        Ok(match (lhs, rhs) {
+            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
+            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a % b),
+            _ => Err(Error::TypeError)?,
+        })
+    }
+
+    /// Addition `a + b`
+    fn add(lhs, rhs) {
+        Ok(match (lhs, rhs) {
+            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
+            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a + b),
+            (ConValue::String(a), ConValue::String(b)) => (a.to_string() + &b.to_string()).into(),
+            _ => Err(Error::TypeError)?
+        })
+    }
+
+    /// Subtraction `a - b`
+    fn sub(lhs, rhs) {
+        Ok(match (lhs, rhs) {
+            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
+            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a - b),
+            _ => Err(Error::TypeError)?,
+        })
+    }
+
+    /// Shift Left `a << b`
+    fn shl(lhs, rhs) {
+        Ok(match (lhs, rhs) {
+            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
+            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a << b),
+            _ => Err(Error::TypeError)?,
+        })
+    }
+
+    /// Shift Right `a >> b`
+    fn shr(lhs, rhs) {
+        Ok(match (lhs, rhs) {
+            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
+            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a >> b),
+            _ => Err(Error::TypeError)?,
+        })
+    }
+
+    /// Bitwise And `a & b`
+    fn and(lhs, rhs) {
+        Ok(match (lhs, rhs) {
+            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
+            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a & b),
+            (ConValue::Bool(a), ConValue::Bool(b)) => ConValue::Bool(a & b),
+            _ => Err(Error::TypeError)?,
+        })
+    }
+
+    /// Bitwise Or `a | b`
+    fn or(lhs, rhs) {
+        Ok(match (lhs, rhs) {
+            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
+            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a | b),
+            (ConValue::Bool(a), ConValue::Bool(b)) => ConValue::Bool(a | b),
+            _ => Err(Error::TypeError)?,
+        })
+    }
+
+    /// Bitwise Exclusive Or `a ^ b`
+    fn xor(lhs, rhs) {
+        Ok(match (lhs, rhs) {
+            (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
+            (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a ^ b),
+            (ConValue::Bool(a), ConValue::Bool(b)) => ConValue::Bool(a ^ b),
+            _ => Err(Error::TypeError)?,
+        })
+    }
+
+    /// Exclusive Range `a..b`
+    fn range_exc(from, to) {
+        let (&ConValue::Int(from), &ConValue::Int(to)) = (from, to) else {
+            Err(Error::TypeError)?
+        };
+        Ok(ConValue::RangeExc(from, to))
+    }
+
+    /// Inclusive Range `a..=b`
+    fn range_inc(from, to) {
+        let (&ConValue::Int(from), &ConValue::Int(to)) = (from, to) else {
+            Err(Error::TypeError)?
+        };
+        Ok(ConValue::RangeInc(from, to))
+    }
+
+    /// Negates the ConValue
+    fn neg(tail) {
+        Ok(match tail {
+            ConValue::Empty => ConValue::Empty,
+            ConValue::Int(v) => ConValue::Int(v.wrapping_neg()),
+            ConValue::Float(v) => ConValue::Float(-v),
+            _ => Err(Error::TypeError)?,
+        })
+    }
+
+    /// Inverts the ConValue
+    fn not(tail) {
+        Ok(match tail {
+            ConValue::Empty => ConValue::Empty,
+            ConValue::Int(v) => ConValue::Int(!v),
+            ConValue::Bool(v) => ConValue::Bool(!v),
+            _ => Err(Error::TypeError)?,
+        })
+    }
+
+    /// Compares two values
+    fn cmp(head, tail) {
+        Ok(ConValue::Int(match (head, tail) {
+            (ConValue::Int(a), ConValue::Int(b)) => a.cmp(b) as _,
+            (ConValue::Bool(a), ConValue::Bool(b)) => a.cmp(b) as _,
+            (ConValue::Char(a), ConValue::Char(b)) => a.cmp(b) as _,
+            (ConValue::String(a), ConValue::String(b)) => a.cmp(b) as _,
+            _ => Err(error_format!("Incomparable values: {head}, {tail}"))?
+        }))
+    }
+
+    /// Does the opposite of `&`
+    fn deref(tail) {
+        use std::rc::Rc;
+        Ok(match tail {
+            ConValue::Ref(v) => Rc::as_ref(v).clone(),
+            _ => tail.clone(),
+        })
+    }
+];

compiler/cl-interpret/src/convalue.rs

@@ -0,0 +1,336 @@
+//! Values in the dynamically typed AST interpreter.
+//!
+//! The most permanent fix is a temporary one.
+use cl_ast::{format::FmtAdapter, ExprKind, Sym};
+
+use super::{
+    builtin::Builtin,
+    error::{Error, IResult},
+    function::Function, Callable, Environment,
+};
+use std::{collections::HashMap, ops::*, rc::Rc};
+
+type Integer = isize;
+
+/// A Conlang value stores data in the interpreter
+#[derive(Clone, Debug, Default)]
+pub enum ConValue {
+    /// The empty/unit `()` type
+    #[default]
+    Empty,
+    /// An integer
+    Int(Integer),
+    /// A floating point number
+    Float(f64),
+    /// A boolean
+    Bool(bool),
+    /// A unicode character
+    Char(char),
+    /// A string
+    String(Sym),
+    /// A reference
+    Ref(Rc<ConValue>),
+    /// An Array
+    Array(Box<[ConValue]>),
+    /// A tuple
+    Tuple(Box<[ConValue]>),
+    /// An exclusive range
+    RangeExc(Integer, Integer),
+    /// An inclusive range
+    RangeInc(Integer, Integer),
+    /// A value of a product type
+    Struct(Box<(Sym, HashMap<Sym, ConValue>)>),
+    /// An entire namespace
+    Module(Box<HashMap<Sym, Option<ConValue>>>),
+    /// A quoted expression
+    Quote(Box<ExprKind>),
+    /// A callable thing
+    Function(Rc<Function>),
+    /// A built-in function
+    Builtin(&'static Builtin),
+}
+
+impl ConValue {
+    /// Gets whether the current value is true or false
+    pub fn truthy(&self) -> IResult<bool> {
+        match self {
+            ConValue::Bool(v) => Ok(*v),
+            _ => Err(Error::TypeError)?,
+        }
+    }
+    pub fn range_exc(self, other: Self) -> IResult<Self> {
+        let (Self::Int(a), Self::Int(b)) = (self, other) else {
+            Err(Error::TypeError)?
+        };
+        Ok(Self::RangeExc(a, b))
+    }
+    pub fn range_inc(self, other: Self) -> IResult<Self> {
+        let (Self::Int(a), Self::Int(b)) = (self, other) else {
+            Err(Error::TypeError)?
+        };
+        Ok(Self::RangeInc(a, b))
+    }
+    pub fn index(&self, index: &Self) -> IResult<ConValue> {
+        let Self::Int(index) = index else {
+            Err(Error::TypeError)?
+        };
+        match self {
+            ConValue::String(string) => string
+                .chars()
+                .nth(*index as _)
+                .map(ConValue::Char)
+                .ok_or(Error::OobIndex(*index as usize, string.chars().count())),
+            ConValue::Array(arr) => arr
+                .get(*index as usize)
+                .cloned()
+                .ok_or(Error::OobIndex(*index as usize, arr.len())),
+            _ => Err(Error::TypeError),
+        }
+    }
+    cmp! {
+        lt: false, <;
+        lt_eq: true, <=;
+        eq: true, ==;
+        neq: false, !=;
+        gt_eq: true, >=;
+        gt: false, >;
+    }
+    assign! {
+        add_assign: +;
+        bitand_assign: &;
+        bitor_assign: |;
+        bitxor_assign: ^;
+        div_assign: /;
+        mul_assign: *;
+        rem_assign: %;
+        shl_assign: <<;
+        shr_assign: >>;
+        sub_assign: -;
+    }
+}
+
+impl Callable for ConValue {
+    fn name(&self) -> Sym {
+        match self {
+            ConValue::Function(func) => func.name(),
+            ConValue::Builtin(func) => func.name(),
+            _ => "".into(),
+        }
+    }
+    fn call(&self, interpreter: &mut Environment, args: &[ConValue]) -> IResult<ConValue> {
+        match self {
+            Self::Function(func) => func.call(interpreter, args),
+            Self::Builtin(func) => func.call(interpreter, args),
+            _ => Err(Error::NotCallable(self.clone())),
+        }
+    }
+}
+/// Templates comparison functions for [ConValue]
+macro cmp ($($fn:ident: $empty:literal, $op:tt);*$(;)?) {$(
+    /// TODO: Remove when functions are implemented:
+    ///       Desugar into function calls
+    pub fn $fn(&self, other: &Self) -> IResult<Self> {
+        match (self, other) {
+            (Self::Empty, Self::Empty) => Ok(Self::Bool($empty)),
+            (Self::Int(a), Self::Int(b)) => Ok(Self::Bool(a $op b)),
+            (Self::Float(a), Self::Float(b)) => Ok(Self::Bool(a $op b)),
+            (Self::Bool(a), Self::Bool(b)) => Ok(Self::Bool(a $op b)),
+            (Self::Char(a), Self::Char(b)) => Ok(Self::Bool(a $op b)),
+            (Self::String(a), Self::String(b)) => Ok(Self::Bool(&**a $op &**b)),
+            _ => Err(Error::TypeError)
+        }
+    }
+)*}
+macro assign($( $fn: ident: $op: tt );*$(;)?) {$(
+    pub fn $fn(&mut self, other: Self) -> IResult<()> {
+        *self = (std::mem::take(self) $op other)?;
+        Ok(())
+    }
+)*}
+/// Implements [From] for an enum with 1-tuple variants
+macro from ($($T:ty => $v:expr),*$(,)?) {
+    $(impl From<$T> for ConValue {
+        fn from(value: $T) -> Self { $v(value.into()) }
+    })*
+}
+impl From<&Sym> for ConValue {
+    fn from(value: &Sym) -> Self {
+        ConValue::String(*value)
+    }
+}
+from! {
+    Integer => ConValue::Int,
+    f64 => ConValue::Float,
+    bool => ConValue::Bool,
+    char => ConValue::Char,
+    Sym => ConValue::String,
+    &str => ConValue::String,
+    String => ConValue::String,
+    Rc<str> => ConValue::String,
+    ExprKind => ConValue::Quote,
+    Function => ConValue::Function,
+    Vec<ConValue> => ConValue::Tuple,
+    &'static Builtin => ConValue::Builtin,
+}
+impl From<()> for ConValue {
+    fn from(_: ()) -> Self {
+        Self::Empty
+    }
+}
+impl From<&[ConValue]> for ConValue {
+    fn from(value: &[ConValue]) -> Self {
+        match value.len() {
+            0 => Self::Empty,
+            1 => value[0].clone(),
+            _ => Self::Tuple(value.into()),
+        }
+    }
+}
+
+/// Implements binary [std::ops] traits for [ConValue]
+///
+/// TODO: Desugar operators into function calls
+macro ops($($trait:ty: $fn:ident = [$($match:tt)*])*) {
+    $(impl $trait for ConValue {
+        type Output = IResult<Self>;
+        /// TODO: Desugar operators into function calls
+        fn $fn(self, rhs: Self) -> Self::Output {Ok(match (self, rhs) {$($match)*})}
+    })*
+}
+ops! {
+    Add: add = [
+        (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
+        (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a.wrapping_add(b)),
+        (ConValue::Float(a), ConValue::Float(b)) => ConValue::Float(a + b),
+        (ConValue::String(a), ConValue::String(b)) => (a.to_string() + &*b).into(),
+        (ConValue::String(s), ConValue::Char(c)) => { let mut s = s.to_string(); s.push(c); s.into() }
+        (ConValue::Char(a), ConValue::Char(b)) => {
+            ConValue::String([a, b].into_iter().collect::<String>().into())
+        }
+        _ => Err(Error::TypeError)?
+        ]
+    BitAnd: bitand = [
+        (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
+        (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a & b),
+        (ConValue::Bool(a), ConValue::Bool(b)) => ConValue::Bool(a & b),
+        _ => Err(Error::TypeError)?
+    ]
+    BitOr: bitor = [
+        (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
+        (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a | b),
+        (ConValue::Bool(a), ConValue::Bool(b)) => ConValue::Bool(a | b),
+        _ => Err(Error::TypeError)?
+    ]
+    BitXor: bitxor = [
+        (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
+        (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a ^ b),
+        (ConValue::Bool(a), ConValue::Bool(b)) => ConValue::Bool(a ^ b),
+        _ => Err(Error::TypeError)?
+    ]
+    Div: div = [
+        (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
+        (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a.checked_div(b).unwrap_or_else(|| {
+            eprintln!("Warning: Divide by zero in {a} / {b}"); a
+        })),
+        (ConValue::Float(a), ConValue::Float(b)) => ConValue::Float(a / b),
+        _ => Err(Error::TypeError)?
+    ]
+    Mul: mul = [
+        (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
+        (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a.wrapping_mul(b)),
+        (ConValue::Float(a), ConValue::Float(b)) => ConValue::Float(a * b),
+        _ => Err(Error::TypeError)?
+    ]
+    Rem: rem = [
+        (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
+        (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a.checked_rem(b).unwrap_or_else(|| {
+            println!("Warning: Divide by zero in {a} % {b}"); a
+        })),
+        (ConValue::Float(a), ConValue::Float(b)) => ConValue::Float(a % b),
+        _ => Err(Error::TypeError)?
+    ]
+    Shl: shl = [
+        (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
+        (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a.wrapping_shl(b as _)),
+        _ => Err(Error::TypeError)?
+    ]
+    Shr: shr = [
+        (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
+        (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a.wrapping_shr(b as _)),
+        _ => Err(Error::TypeError)?
+    ]
+    Sub: sub = [
+        (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
+        (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a.wrapping_sub(b)),
+        (ConValue::Float(a), ConValue::Float(b)) => ConValue::Float(a - b),
+        _ => Err(Error::TypeError)?
+    ]
+}
+impl std::fmt::Display for ConValue {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            ConValue::Empty => "Empty".fmt(f),
+            ConValue::Int(v) => v.fmt(f),
+            ConValue::Float(v) => v.fmt(f),
+            ConValue::Bool(v) => v.fmt(f),
+            ConValue::Char(v) => v.fmt(f),
+            ConValue::String(v) => v.fmt(f),
+            ConValue::Ref(v) => write!(f, "&{v}"),
+            ConValue::Array(array) => {
+                '['.fmt(f)?;
+                for (idx, element) in array.iter().enumerate() {
+                    if idx > 0 {
+                        ", ".fmt(f)?
+                    }
+                    element.fmt(f)?
+                }
+                ']'.fmt(f)
+            }
+            ConValue::RangeExc(a, b) => write!(f, "{a}..{}", b + 1),
+            ConValue::RangeInc(a, b) => write!(f, "{a}..={b}"),
+            ConValue::Tuple(tuple) => {
+                '('.fmt(f)?;
+                for (idx, element) in tuple.iter().enumerate() {
+                    if idx > 0 {
+                        ", ".fmt(f)?
+                    }
+                    element.fmt(f)?
+                }
+                ')'.fmt(f)
+            }
+            ConValue::Struct(parts) => {
+                let (name, map) = parts.as_ref();
+                use std::fmt::Write;
+                if !name.is_empty() {
+                    write!(f, "{name}: ")?;
+                }
+                let mut f = f.delimit_with("{", "\n}");
+                for (k, v) in map.iter() {
+                    write!(f, "\n{k}: {v},")?;
+                }
+                Ok(())
+            }
+            ConValue::Module(module) => {
+                use std::fmt::Write;
+                let mut f = f.delimit_with("{", "\n}");
+                for (k, v) in module.iter() {
+                    write!(f, "\n{k}: ")?;
+                    match v {
+                        Some(v) => write!(f, "{v},"),
+                        None => write!(f, "_,"),
+                    }?
+                }
+                Ok(())
+            }
+            ConValue::Quote(q) => {
+                write!(f, "`{q}`")
+            }
+            ConValue::Function(func) => {
+                write!(f, "{}", func.decl())
+            }
+            ConValue::Builtin(func) => {
+                write!(f, "{}", func.description())
+            }
+        }
+    }
+}

compiler/cl-interpret/src/env.rs

@@ -0,0 +1,236 @@
+//! Lexical and non-lexical scoping for variables
+
+use crate::builtin::Builtin;
+
+use super::{
+    builtin::{Builtins, Math},
+    convalue::ConValue,
+    error::{Error, IResult},
+    function::Function,
+    Callable, Interpret,
+};
+use cl_ast::{Function as FnDecl, Sym};
+use std::{
+    collections::HashMap,
+    fmt::Display,
+    ops::{Deref, DerefMut},
+    rc::Rc,
+};
+
+type StackFrame = HashMap<Sym, Option<ConValue>>;
+
+/// Implements a nested lexical scope
+#[derive(Clone, Debug)]
+pub struct Environment {
+    builtin: StackFrame,
+    global: Vec<(StackFrame, &'static str)>,
+    frames: Vec<(StackFrame, &'static str)>,
+}
+
+impl Display for Environment {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        for (frame, name) in self
+            .global
+            .iter()
+            .rev()
+            .take(2)
+            .rev()
+            .chain(self.frames.iter())
+        {
+            writeln!(f, "--- {name} ---")?;
+            for (var, val) in frame {
+                write!(f, "{var}: ")?;
+                match val {
+                    Some(value) => writeln!(f, "\t{value}"),
+                    None => writeln!(f, "<undefined>"),
+                }?
+            }
+        }
+        Ok(())
+    }
+}
+impl Default for Environment {
+    fn default() -> Self {
+        Self {
+            builtin: to_hashmap(Builtins.iter().chain(Math.iter())),
+            global: vec![(HashMap::new(), "globals")],
+            frames: vec![],
+        }
+    }
+}
+
+fn to_hashmap(from: impl IntoIterator<Item = &'static Builtin>) -> HashMap<Sym, Option<ConValue>> {
+    from.into_iter()
+        .map(|v| (v.name(), Some(v.into())))
+        .collect()
+}
+
+impl Environment {
+    pub fn new() -> Self {
+        Self::default()
+    }
+    /// Creates an [Environment] with no [builtins](super::builtin)
+    pub fn no_builtins() -> Self {
+        Self {
+            builtin: HashMap::new(),
+            global: vec![(Default::default(), "globals")],
+            frames: vec![],
+        }
+    }
+
+    pub fn builtins(&self) -> &StackFrame {
+        &self.builtin
+    }
+
+    pub fn add_builtin(&mut self, builtin: &'static Builtin) -> &mut Self {
+        self.builtin.insert(builtin.name(), Some(builtin.into()));
+        self
+    }
+
+    pub fn add_builtins(&mut self, builtins: &'static [Builtin]) {
+        for builtin in builtins {
+            self.add_builtin(builtin);
+        }
+    }
+
+    pub fn push_frame(&mut self, name: &'static str, frame: StackFrame) {
+        self.frames.push((frame, name));
+    }
+
+    pub fn pop_frame(&mut self) -> Option<(StackFrame, &'static str)> {
+        self.frames.pop()
+    }
+
+    pub fn eval(&mut self, node: &impl Interpret) -> IResult<ConValue> {
+        node.interpret(self)
+    }
+
+    /// Calls a function inside the interpreter's scope,
+    /// and returns the result
+    pub fn call(&mut self, name: Sym, args: &[ConValue]) -> IResult<ConValue> {
+        // FIXME: Clone to satisfy the borrow checker
+        let function = self.get(name)?.clone();
+        function.call(self, args)
+    }
+    /// Enters a nested scope, returning a [`Frame`] stack-guard.
+    ///
+    /// [`Frame`] implements Deref/DerefMut for [`Environment`].
+    pub fn frame(&mut self, name: &'static str) -> Frame {
+        Frame::new(self, name)
+    }
+    /// Resolves a variable mutably.
+    ///
+    /// Returns a mutable reference to the variable's record, if it exists.
+    pub fn get_mut(&mut self, id: Sym) -> IResult<&mut Option<ConValue>> {
+        for (frame, _) in self.frames.iter_mut().rev() {
+            if let Some(var) = frame.get_mut(&id) {
+                return Ok(var);
+            }
+        }
+        for (frame, _) in self.global.iter_mut().rev() {
+            if let Some(var) = frame.get_mut(&id) {
+                return Ok(var);
+            }
+        }
+        self.builtin.get_mut(&id).ok_or(Error::NotDefined(id))
+    }
+    /// Resolves a variable immutably.
+    ///
+    /// Returns a reference to the variable's contents, if it is defined and initialized.
+    pub fn get(&self, id: Sym) -> IResult<ConValue> {
+        for (frame, _) in self.frames.iter().rev() {
+            match frame.get(&id) {
+                Some(Some(var)) => return Ok(var.clone()),
+                Some(None) => return Err(Error::NotInitialized(id)),
+                _ => (),
+            }
+        }
+        for (frame, _) in self.global.iter().rev() {
+            match frame.get(&id) {
+                Some(Some(var)) => return Ok(var.clone()),
+                Some(None) => return Err(Error::NotInitialized(id)),
+                _ => (),
+            }
+        }
+        self.builtin
+            .get(&id)
+            .cloned()
+            .flatten()
+            .ok_or(Error::NotDefined(id))
+    }
+
+    pub(crate) fn get_local(&self, id: Sym) -> IResult<ConValue> {
+        for (frame, _) in self.frames.iter().rev() {
+            match frame.get(&id) {
+                Some(Some(var)) => return Ok(var.clone()),
+                Some(None) => return Err(Error::NotInitialized(id)),
+                _ => (),
+            }
+        }
+        Err(Error::NotInitialized(id))
+    }
+
+    /// Inserts a new [ConValue] into this [Environment]
+    pub fn insert(&mut self, id: Sym, value: Option<ConValue>) {
+        if let Some((frame, _)) = self.frames.last_mut() {
+            frame.insert(id, value);
+        } else if let Some((frame, _)) = self.global.last_mut() {
+            frame.insert(id, value);
+        }
+    }
+    /// A convenience function for registering a [FnDecl] as a [Function]
+    pub fn insert_fn(&mut self, decl: &FnDecl) {
+        let FnDecl { name, .. } = decl;
+        let (name, function) = (name, Rc::new(Function::new(decl)));
+        if let Some((frame, _)) = self.frames.last_mut() {
+            frame.insert(*name, Some(ConValue::Function(function.clone())));
+        } else if let Some((frame, _)) = self.global.last_mut() {
+            frame.insert(*name, Some(ConValue::Function(function.clone())));
+        }
+        // Tell the function to lift its upvars now, after it's been declared
+        function.lift_upvars(self);
+    }
+}
+
+/// Functions which aid in the implementation of [`Frame`]
+impl Environment {
+    /// Enters a scope, creating a new namespace for variables
+    fn enter(&mut self, name: &'static str) -> &mut Self {
+        self.frames.push((Default::default(), name));
+        self
+    }
+
+    /// Exits the scope, destroying all local variables and
+    /// returning the outer scope, if there is one
+    fn exit(&mut self) -> &mut Self {
+        self.frames.pop();
+        self
+    }
+}
+
+/// Represents a stack frame
+#[derive(Debug)]
+pub struct Frame<'scope> {
+    scope: &'scope mut Environment,
+}
+impl<'scope> Frame<'scope> {
+    fn new(scope: &'scope mut Environment, name: &'static str) -> Self {
+        Self { scope: scope.enter(name) }
+    }
+}
+impl Deref for Frame<'_> {
+    type Target = Environment;
+    fn deref(&self) -> &Self::Target {
+        self.scope
+    }
+}
+impl DerefMut for Frame<'_> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        self.scope
+    }
+}
+impl Drop for Frame<'_> {
+    fn drop(&mut self) {
+        self.scope.exit();
+    }
+}

compiler/cl-interpret/src/error.rs

@@ -0,0 +1,97 @@
+//! The [Error] type represents any error thrown by the [Environment](super::Environment)
+
+use cl_ast::{Pattern, Sym};
+
+use super::convalue::ConValue;
+
+pub type IResult<T> = Result<T, Error>;
+
+/// Represents any error thrown by the [Environment](super::Environment)
+#[derive(Clone, Debug)]
+pub enum Error {
+    /// Propagate a Return value
+    Return(ConValue),
+    /// Propagate a Break value
+    Break(ConValue),
+    /// Break propagated across function bounds
+    BadBreak(ConValue),
+    /// Continue to the next iteration of a loop
+    Continue,
+    /// Underflowed the stack
+    StackUnderflow,
+    /// Exited the last scope
+    ScopeExit,
+    /// Type incompatibility
+    // TODO: store the type information in this error
+    TypeError,
+    /// In clause of For loop didn't yield a Range
+    NotIterable,
+    /// A value could not be indexed
+    NotIndexable,
+    /// An array index went out of bounds
+    OobIndex(usize, usize),
+    /// An expression is not assignable
+    NotAssignable,
+    /// A name was not defined in scope before being used
+    NotDefined(Sym),
+    /// A name was defined but not initialized
+    NotInitialized(Sym),
+    /// A value was called, but is not callable
+    NotCallable(ConValue),
+    /// A function was called with the wrong number of arguments
+    ArgNumber { want: usize, got: usize },
+    /// A pattern failed to match
+    PatFailed(Box<Pattern>),
+    /// Fell through a non-exhaustive match
+    MatchNonexhaustive,
+    /// Error produced by a Builtin
+    BuiltinDebug(String),
+}
+
+impl std::error::Error for Error {}
+impl std::fmt::Display for Error {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Error::Return(value) => write!(f, "return {value}"),
+            Error::Break(value) => write!(f, "break {value}"),
+            Error::BadBreak(value) => write!(f, "rogue break: {value}"),
+            Error::Continue => "continue".fmt(f),
+            Error::StackUnderflow => "Stack underflow".fmt(f),
+            Error::ScopeExit => "Exited the last scope. This is a logic bug.".fmt(f),
+            Error::TypeError => "Incompatible types".fmt(f),
+            Error::NotIterable => "`in` clause of `for` loop did not yield an iterable".fmt(f),
+            Error::NotIndexable => {
+                write!(f, "expression cannot be indexed")
+            }
+            Error::OobIndex(idx, len) => {
+                write!(f, "Index out of bounds: index was {idx}. but len is {len}")
+            }
+            Error::NotAssignable => {
+                write!(f, "expression is not assignable")
+            }
+            Error::NotDefined(value) => {
+                write!(f, "{value} not bound. Did you mean `let {value};`?")
+            }
+            Error::NotInitialized(value) => {
+                write!(f, "{value} bound, but not initialized")
+            }
+            Error::NotCallable(value) => {
+                write!(f, "{value} is not callable.")
+            }
+            Error::ArgNumber { want, got } => {
+                write!(
+                    f,
+                    "Expected {want} argument{}, got {got}",
+                    if *want == 1 { "" } else { "s" }
+                )
+            }
+            Error::PatFailed(pattern) => {
+                write!(f, "Failed to match pattern {pattern}")
+            }
+            Error::MatchNonexhaustive => {
+                write!(f, "Fell through a non-exhaustive match expression!")
+            }
+            Error::BuiltinDebug(s) => write!(f, "DEBUG: {s}"),
+        }
+    }
+}

compiler/cl-interpret/src/function.rs

@@ -0,0 +1,80 @@
+//! Represents a block of code which lives inside the Interpreter
+
+use collect_upvars::collect_upvars;
+
+use super::{Callable, ConValue, Environment, Error, IResult, Interpret};
+use cl_ast::{Function as FnDecl, Param, Sym};
+use std::{
+    cell::{Ref, RefCell},
+    collections::HashMap,
+    rc::Rc,
+};
+
+pub mod collect_upvars;
+
+type Upvars = HashMap<Sym, Option<ConValue>>;
+
+/// Represents a block of code which persists inside the Interpreter
+#[derive(Clone, Debug)]
+pub struct Function {
+    /// Stores the contents of the function declaration
+    decl: Rc<FnDecl>,
+    /// Stores data from the enclosing scopes
+    upvars: RefCell<Upvars>,
+}
+
+impl Function {
+    pub fn new(decl: &FnDecl) -> Self {
+        // let upvars = collect_upvars(decl, env);
+        Self { decl: decl.clone().into(), upvars: Default::default() }
+    }
+    pub fn decl(&self) -> &FnDecl {
+        &self.decl
+    }
+    pub fn upvars(&self) -> Ref<Upvars> {
+        self.upvars.borrow()
+    }
+    pub fn lift_upvars(&self, env: &Environment) {
+        let upvars = collect_upvars(&self.decl, env);
+        if let Ok(mut self_upvars) = self.upvars.try_borrow_mut() {
+            *self_upvars = upvars;
+        }
+    }
+}
+
+impl Callable for Function {
+    fn name(&self) -> Sym {
+        let FnDecl { name, .. } = *self.decl;
+        name
+    }
+    fn call(&self, env: &mut Environment, args: &[ConValue]) -> IResult<ConValue> {
+        let FnDecl { name, bind, body, sign: _ } = &*self.decl;
+
+        // Check arg mapping
+        if args.len() != bind.len() {
+            return Err(Error::ArgNumber { want: bind.len(), got: args.len() });
+        }
+        let Some(body) = body else {
+            return Err(Error::NotDefined(*name));
+        };
+
+        let upvars = self.upvars.take();
+        env.push_frame("upvars", upvars);
+
+        // TODO: completely refactor data storage
+        let mut frame = env.frame("fn args");
+        for (Param { mutability: _, name }, value) in bind.iter().zip(args) {
+            frame.insert(*name, Some(value.clone()));
+        }
+        let res = body.interpret(&mut frame);
+        drop(frame);
+        if let Some((upvars, _)) = env.pop_frame() {
+            self.upvars.replace(upvars);
+        }
+        match res {
+            Err(Error::Return(value)) => Ok(value),
+            Err(Error::Break(value)) => Err(Error::BadBreak(value)),
+            result => result,
+        }
+    }
+}

compiler/cl-interpret/src/function/collect_upvars.rs

@@ -0,0 +1,134 @@
+//! Collects the "Upvars" of a function at the point of its creation, allowing variable capture
+use crate::{convalue::ConValue, env::Environment};
+use cl_ast::{ast_visitor::visit::*, Function, Let, Param, Path, PathPart, Pattern, Sym};
+use std::collections::{HashMap, HashSet};
+
+pub fn collect_upvars(f: &Function, env: &Environment) -> super::Upvars {
+    CollectUpvars::new(env).get_upvars(f)
+}
+
+#[derive(Clone, Debug)]
+pub struct CollectUpvars<'env> {
+    env: &'env Environment,
+    upvars: HashMap<Sym, Option<ConValue>>,
+    blacklist: HashSet<Sym>,
+}
+
+impl<'env> CollectUpvars<'env> {
+    pub fn new(env: &'env Environment) -> Self {
+        Self { upvars: HashMap::new(), blacklist: HashSet::new(), env }
+    }
+    pub fn get_upvars(mut self, f: &cl_ast::Function) -> HashMap<Sym, Option<ConValue>> {
+        self.visit_function(f);
+        self.upvars
+    }
+
+    pub fn add_upvar(&mut self, name: &Sym) {
+        let Self { env, upvars, blacklist } = self;
+        if blacklist.contains(name) || upvars.contains_key(name) {
+            return;
+        }
+        if let Ok(upvar) = env.get_local(*name) {
+            upvars.insert(*name, Some(upvar));
+        }
+    }
+
+    pub fn bind_name(&mut self, name: &Sym) {
+        self.blacklist.insert(*name);
+    }
+}
+
+impl<'a> Visit<'a> for CollectUpvars<'_> {
+    fn visit_block(&mut self, b: &'a cl_ast::Block) {
+        let blacklist = self.blacklist.clone();
+
+        // visit the block
+        let cl_ast::Block { stmts } = b;
+        stmts.iter().for_each(|s| self.visit_stmt(s));
+
+        // restore the blacklist
+        self.blacklist = blacklist;
+    }
+
+    fn visit_let(&mut self, l: &'a cl_ast::Let) {
+        let Let { mutable, name, ty, init } = l;
+        self.visit_mutability(mutable);
+        if let Some(ty) = ty {
+            self.visit_ty(ty);
+        }
+        // visit the initializer, which may use the bound name
+        if let Some(init) = init {
+            self.visit_expr(init)
+        }
+        // a bound name can never be an upvar
+        self.visit_pattern(name);
+    }
+
+    fn visit_function(&mut self, f: &'a cl_ast::Function) {
+        let Function { name: _, sign: _, bind, body } = f;
+        // parameters can never be upvars
+        for Param { mutability: _, name } in bind {
+            self.bind_name(name);
+        }
+        if let Some(body) = body {
+            self.visit_block(body);
+        }
+    }
+
+    fn visit_for(&mut self, f: &'a cl_ast::For) {
+        let cl_ast::For { bind, cond, pass, fail } = f;
+        self.visit_expr(cond);
+        self.visit_else(fail);
+        self.bind_name(bind); // TODO: is bind only bound in the pass block?
+        self.visit_block(pass);
+    }
+
+    fn visit_path(&mut self, p: &'a cl_ast::Path) {
+        // TODO: path resolution in environments
+        let Path { absolute: false, parts } = p else {
+            return;
+        };
+        let [PathPart::Ident(name)] = parts.as_slice() else {
+            return;
+        };
+        self.add_upvar(name);
+    }
+
+    fn visit_fielder(&mut self, f: &'a cl_ast::Fielder) {
+        let cl_ast::Fielder { name, init } = f;
+        if let Some(init) = init {
+            self.visit_expr(init);
+        } else {
+            self.add_upvar(name); // fielder without init grabs from env
+        }
+    }
+
+    fn visit_pattern(&mut self, p: &'a cl_ast::Pattern) {
+        match p {
+            Pattern::Path(path) => {
+                if let [PathPart::Ident(name)] = path.parts.as_slice() {
+                    self.bind_name(name)
+                }
+            }
+            Pattern::Literal(literal) => self.visit_literal(literal),
+            Pattern::Ref(mutability, pattern) => {
+                self.visit_mutability(mutability);
+                self.visit_pattern(pattern);
+            }
+            Pattern::Tuple(patterns) => {
+                patterns.iter().for_each(|p| self.visit_pattern(p));
+            }
+            Pattern::Array(patterns) => {
+                patterns.iter().for_each(|p| self.visit_pattern(p));
+            }
+            Pattern::Struct(path, items) => {
+                self.visit_path(path);
+                items.iter().for_each(|(_name, bind)| {
+                    bind.as_ref().inspect(|bind| {
+                        self.visit_pattern(bind);
+                    });
+                });
+            }
+        }
+    }
+}

compiler/cl-interpret/src/interpret.rs

@@ -0,0 +1,965 @@
+//! A work-in-progress tree walk interpreter for Conlang
+//!
+//! Currently, major parts of the interpreter are not yet implemented, and major parts will never be
+//! implemented in its current form. Namely, since no [ConValue] has a stable location, it's
+//! meaningless to get a pointer to one, and would be undefined behavior to dereference a pointer to
+//! one in any situation.
+
+use std::{borrow::Borrow, rc::Rc};
+
+use super::*;
+use cl_ast::*;
+use cl_structures::intern::interned::Interned;
+/// A work-in-progress tree walk interpreter for Conlang
+pub trait Interpret {
+    /// Interprets this thing in the given [`Environment`].
+    ///
+    /// Everything returns a value!™
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue>;
+}
+
+impl Interpret for File {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        for item in &self.items {
+            item.interpret(env)?;
+        }
+        Ok(ConValue::Empty)
+    }
+}
+impl Interpret for Item {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        match &self.kind {
+            ItemKind::Alias(item) => item.interpret(env),
+            ItemKind::Const(item) => item.interpret(env),
+            ItemKind::Static(item) => item.interpret(env),
+            ItemKind::Module(item) => item.interpret(env),
+            ItemKind::Function(item) => item.interpret(env),
+            ItemKind::Struct(item) => item.interpret(env),
+            ItemKind::Enum(item) => item.interpret(env),
+            ItemKind::Impl(item) => item.interpret(env),
+            ItemKind::Use(item) => item.interpret(env),
+        }
+    }
+}
+impl Interpret for Alias {
+    fn interpret(&self, _env: &mut Environment) -> IResult<ConValue> {
+        println!("TODO: {self}");
+        Ok(ConValue::Empty)
+    }
+}
+impl Interpret for Const {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Const { name, ty: _, init } = self;
+
+        let init = init.as_ref().interpret(env)?;
+        env.insert(*name, Some(init));
+        Ok(ConValue::Empty)
+    }
+}
+impl Interpret for Static {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Static { mutable: _, name, ty: _, init } = self;
+
+        let init = init.as_ref().interpret(env)?;
+        env.insert(*name, Some(init));
+        Ok(ConValue::Empty)
+    }
+}
+impl Interpret for Module {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Self { name, kind } = self;
+        env.push_frame(Interned::to_ref(name), Default::default());
+        let out = match kind {
+            ModuleKind::Inline(file) => file.interpret(env),
+            ModuleKind::Outline => {
+                eprintln!("Module {name} specified, but not imported.");
+                Ok(ConValue::Empty)
+            }
+        };
+
+        let (frame, _) = env
+            .pop_frame()
+            .expect("Environment frames must be balanced");
+        env.insert(*name, Some(ConValue::Module(frame.into())));
+
+        out
+    }
+}
+impl Interpret for Function {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        // register the function in the current environment
+        env.insert_fn(self);
+        Ok(ConValue::Empty)
+    }
+}
+impl Interpret for Struct {
+    fn interpret(&self, _env: &mut Environment) -> IResult<ConValue> {
+        println!("TODO: {self}");
+        Ok(ConValue::Empty)
+    }
+}
+impl Interpret for Enum {
+    fn interpret(&self, _env: &mut Environment) -> IResult<ConValue> {
+        println!("TODO: {self}");
+        Ok(ConValue::Empty)
+    }
+}
+impl Interpret for Impl {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        println!("TODO: {self}");
+        let Self { target: _, body } = self;
+        body.interpret(env)
+    }
+}
+
+impl Interpret for Use {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Self { absolute: _, tree } = self;
+        tree.interpret(env)
+    }
+}
+
+impl Interpret for UseTree {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        type Bindings = HashMap<Sym, ConValue>;
+        use std::collections::HashMap;
+
+        fn get_bindings(
+            tree: &UseTree,
+            env: &mut Environment,
+            bindings: &mut Bindings,
+        ) -> IResult<()> {
+            match tree {
+                UseTree::Tree(use_trees) => {
+                    for tree in use_trees {
+                        get_bindings(tree, env, bindings)?;
+                    }
+                }
+                UseTree::Path(PathPart::Ident(name), tree) => {
+                    let Ok(ConValue::Module(m)) = env.get(*name) else {
+                        Err(Error::TypeError)?
+                    };
+                    env.push_frame(Interned::to_ref(name), *m);
+                    let out = get_bindings(tree, env, bindings);
+                    env.pop_frame();
+                    return out;
+                }
+                UseTree::Alias(name, alias) => {
+                    bindings.insert(*alias, env.get(*name)?);
+                }
+                UseTree::Name(name) => {
+                    bindings.insert(*name, env.get(*name)?);
+                }
+                UseTree::Glob => {
+                    if let Some((frame, name)) = env.pop_frame() {
+                        for (k, v) in &frame {
+                            if let Some(v) = v {
+                                bindings.insert(*k, v.clone());
+                            }
+                        }
+                        env.push_frame(name, frame);
+                    }
+                }
+                other => {
+                    eprintln!("ERROR: Cannot use {other}");
+                }
+            }
+            Ok(())
+        }
+
+        let mut bindings = Bindings::new();
+        get_bindings(self, env, &mut bindings)?;
+
+        for (name, value) in bindings {
+            env.insert(name, Some(value));
+        }
+
+        Ok(ConValue::Empty)
+    }
+}
+
+impl Interpret for Stmt {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Self { extents: _, kind, semi } = self;
+        let out = match kind {
+            StmtKind::Empty => ConValue::Empty,
+            StmtKind::Item(stmt) => stmt.interpret(env)?,
+            StmtKind::Expr(stmt) => stmt.interpret(env)?,
+        };
+        Ok(match semi {
+            Semi::Terminated => ConValue::Empty,
+            Semi::Unterminated => out,
+        })
+    }
+}
+
+impl Interpret for Expr {
+    #[inline]
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Self { extents: _, kind } = self;
+        kind.interpret(env)
+    }
+}
+
+impl Interpret for ExprKind {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        match self {
+            ExprKind::Empty => Ok(ConValue::Empty),
+            ExprKind::Quote(q) => q.interpret(env),
+            ExprKind::Let(v) => v.interpret(env),
+            ExprKind::Match(v) => v.interpret(env),
+            ExprKind::Assign(v) => v.interpret(env),
+            ExprKind::Modify(v) => v.interpret(env),
+            ExprKind::Binary(v) => v.interpret(env),
+            ExprKind::Unary(v) => v.interpret(env),
+            ExprKind::Cast(v) => v.interpret(env),
+            ExprKind::Member(v) => v.interpret(env),
+            ExprKind::Index(v) => v.interpret(env),
+            ExprKind::Structor(v) => v.interpret(env),
+            ExprKind::Path(v) => v.interpret(env),
+            ExprKind::Literal(v) => v.interpret(env),
+            ExprKind::Array(v) => v.interpret(env),
+            ExprKind::ArrayRep(v) => v.interpret(env),
+            ExprKind::AddrOf(v) => v.interpret(env),
+            ExprKind::Block(v) => v.interpret(env),
+            ExprKind::Group(v) => v.interpret(env),
+            ExprKind::Tuple(v) => v.interpret(env),
+            ExprKind::While(v) => v.interpret(env),
+            ExprKind::If(v) => v.interpret(env),
+            ExprKind::For(v) => v.interpret(env),
+            ExprKind::Break(v) => v.interpret(env),
+            ExprKind::Return(v) => v.interpret(env),
+            ExprKind::Continue => Err(Error::Continue),
+        }
+    }
+}
+
+impl Interpret for Quote {
+    fn interpret(&self, _env: &mut Environment) -> IResult<ConValue> {
+        // TODO: squoosh down into a ConValue?
+        Ok(ConValue::Quote(self.quote.clone()))
+    }
+}
+
+impl Interpret for Let {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Let { mutable: _, name, ty: _, init } = self;
+        match init.as_ref().map(|i| i.interpret(env)).transpose()? {
+            Some(value) => {
+                for (path, value) in assignment::pattern_substitution(name, value)? {
+                    match path.parts.as_slice() {
+                        [PathPart::Ident(name)] => env.insert(*name, Some(value)),
+                        _ => eprintln!("Bad assignment: {path} = {value}"),
+                    }
+                }
+            }
+            None => {
+                for path in assignment::pattern_variables(name) {
+                    match path.parts.as_slice() {
+                        [PathPart::Ident(name)] => env.insert(*name, None),
+                        _ => eprintln!("Bad assignment: {path}"),
+                    }
+                }
+            }
+        }
+        Ok(ConValue::Empty)
+    }
+}
+
+impl Interpret for Match {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Self { scrutinee, arms } = self;
+        let scrutinee = scrutinee.interpret(env)?;
+        'arm: for MatchArm(pat, expr) in arms {
+            if let Ok(substitution) = assignment::pattern_substitution(pat, scrutinee.clone()) {
+                let mut env = env.frame("match");
+                for (path, value) in substitution {
+                    let [PathPart::Ident(name)] = path.parts.as_slice() else {
+                        continue 'arm;
+                    };
+                    env.insert(*name, Some(value));
+                }
+                return expr.interpret(&mut env);
+            }
+        }
+        Err(Error::MatchNonexhaustive)
+    }
+}
+
+mod assignment {
+    /// Pattern matching engine for assignment
+    use super::*;
+    use std::collections::HashMap;
+    type Namespace = HashMap<Sym, Option<ConValue>>;
+
+    /// Gets the path variables in the given Pattern
+    pub fn pattern_variables(pat: &Pattern) -> Vec<&Path> {
+        fn patvars<'p>(set: &mut Vec<&'p Path>, pat: &'p Pattern) {
+            match pat {
+                Pattern::Path(path) if path.is_sinkhole() => {}
+                Pattern::Path(path) => set.push(path),
+                Pattern::Literal(_) => {}
+                Pattern::Ref(_, pattern) => patvars(set, pattern),
+                Pattern::Tuple(patterns) | Pattern::Array(patterns) => {
+                    patterns.iter().for_each(|pat| patvars(set, pat))
+                }
+                Pattern::Struct(_path, items) => {
+                    items.iter().for_each(|(name, pat)| match pat {
+                        Some(pat) => patvars(set, pat),
+                        None => set.push(name),
+                    });
+                }
+            }
+        }
+        let mut set = Vec::new();
+        patvars(&mut set, pat);
+        set
+    }
+
+    /// Appends a substitution to the provided table
+    pub fn append_sub<'pat>(
+        env: &mut HashMap<&'pat Path, ConValue>,
+        pat: &'pat Pattern,
+        value: ConValue,
+    ) -> IResult<()> {
+        match pat {
+            Pattern::Path(path) if path.is_sinkhole() => Ok(()),
+            Pattern::Path(path) => {
+                env.insert(path, value);
+                Ok(())
+            }
+
+            Pattern::Literal(literal) => match (literal, value) {
+                (Literal::Bool(a), ConValue::Bool(b)) => *a == b,
+                (Literal::Char(a), ConValue::Char(b)) => *a == b,
+                (Literal::Int(a), ConValue::Int(b)) => *a as isize == b,
+                (Literal::Float(a), ConValue::Float(b)) => f64::from_bits(*a) == b,
+                (Literal::String(a), ConValue::String(b)) => *a == *b,
+                _ => false,
+            }
+            .then_some(())
+            .ok_or(Error::NotAssignable),
+
+            Pattern::Ref(_, pattern) => match value {
+                ConValue::Ref(value) => append_sub(env, pattern, Rc::unwrap_or_clone(value)),
+                _ => Err(Error::NotAssignable),
+            },
+
+            Pattern::Tuple(patterns) => match value {
+                ConValue::Tuple(values) => {
+                    if patterns.len() != values.len() {
+                        return Err(Error::OobIndex(patterns.len(), values.len()));
+                    };
+                    for (pat, value) in patterns.iter().zip(Vec::from(values).into_iter()) {
+                        append_sub(env, pat, value)?;
+                    }
+                    Ok(())
+                }
+                _ => Err(Error::NotAssignable),
+            },
+
+            Pattern::Array(patterns) => match value {
+                ConValue::Array(values) => {
+                    if patterns.len() != values.len() {
+                        return Err(Error::OobIndex(patterns.len(), values.len()));
+                    };
+                    for (pat, value) in patterns.iter().zip(Vec::from(values).into_iter()) {
+                        append_sub(env, pat, value)?;
+                    }
+                    Ok(())
+                }
+                _ => Err(Error::NotAssignable),
+            },
+
+            Pattern::Struct(_path, patterns) => {
+                let ConValue::Struct(parts) = value else {
+                    return Err(Error::TypeError);
+                };
+                let (_, mut values) = *parts;
+                if values.len() != patterns.len() {
+                    return Err(Error::TypeError);
+                }
+                for (name, pat) in patterns {
+                    let [.., PathPart::Ident(index)] = name.parts.as_slice() else {
+                        Err(Error::TypeError)?
+                    };
+                    let value = values.remove(index).ok_or(Error::TypeError)?;
+                    match pat {
+                        Some(pat) => append_sub(env, pat, value)?,
+                        None => {
+                            env.insert(name, value);
+                        }
+                    }
+                }
+
+                Ok(())
+            }
+        }
+    }
+
+    /// Constructs a substitution from a pattern and a value
+    pub fn pattern_substitution(
+        pat: &Pattern,
+        value: ConValue,
+    ) -> IResult<HashMap<&Path, ConValue>> {
+        let mut substitution = HashMap::new();
+        append_sub(&mut substitution, pat, value)?;
+        Ok(substitution)
+    }
+
+    pub(super) fn pat_assign(env: &mut Environment, pat: &Pattern, value: ConValue) -> IResult<()> {
+        let mut substitution = HashMap::new();
+        append_sub(&mut substitution, pat, value)
+            .map_err(|_| Error::PatFailed(pat.clone().into()))?;
+        for (path, value) in substitution {
+            assign_path(env, path, value)?;
+        }
+        Ok(())
+    }
+
+    pub(super) fn assign(env: &mut Environment, pat: &ExprKind, value: ConValue) -> IResult<()> {
+        if let Ok(pat) = Pattern::try_from(pat.clone()) {
+            return pat_assign(env, &pat, value);
+        }
+        match pat {
+            ExprKind::Member(member) => *addrof_member(env, member)? = value,
+            ExprKind::Index(index) => *addrof_index(env, index)? = value,
+            _ => Err(Error::NotAssignable)?,
+        }
+        Ok(())
+    }
+
+    fn assign_path(env: &mut Environment, path: &Path, value: ConValue) -> IResult<()> {
+        let Ok(addr) = addrof_path(env, &path.parts) else {
+            eprintln!("Cannot assign {value} to path {path}");
+            return Err(Error::NotAssignable);
+        };
+        *addr = Some(value);
+        Ok(())
+    }
+
+    pub(super) fn addrof<'e>(
+        env: &'e mut Environment,
+        pat: &ExprKind,
+    ) -> IResult<&'e mut ConValue> {
+        match pat {
+            ExprKind::Path(path) => addrof_path(env, &path.parts)?
+                .as_mut()
+                .ok_or(Error::NotInitialized("".into())),
+            ExprKind::Member(member) => addrof_member(env, member),
+            ExprKind::Index(index) => addrof_index(env, index),
+            ExprKind::Group(Group { expr }) => addrof(env, expr),
+            ExprKind::AddrOf(AddrOf { mutable: Mutability::Mut, expr }) => addrof(env, expr),
+            _ => Err(Error::TypeError),
+        }
+    }
+
+    pub fn addrof_path<'e>(
+        env: &'e mut Environment,
+        path: &[PathPart],
+    ) -> IResult<&'e mut Option<ConValue>> {
+        match path {
+            [PathPart::Ident(name)] => env.get_mut(*name),
+            [PathPart::Ident(name), rest @ ..] => match env.get_mut(*name)? {
+                Some(ConValue::Module(env)) => addrof_path_within_namespace(env, rest),
+                _ => Err(Error::NotIndexable),
+            },
+            _ => Err(Error::NotAssignable),
+        }
+    }
+
+    fn addrof_member<'e>(env: &'e mut Environment, member: &Member) -> IResult<&'e mut ConValue> {
+        let Member { head, kind } = member;
+        let ExprKind::Path(path) = head.as_ref() else {
+            return Err(Error::TypeError);
+        };
+        let slot = addrof_path(env, &path.parts)?
+            .as_mut()
+            .ok_or(Error::NotAssignable)?;
+        Ok(match (slot, kind) {
+            (ConValue::Struct(s), MemberKind::Struct(id)) => {
+                s.1.get_mut(id).ok_or(Error::NotDefined(*id))?
+            }
+            (ConValue::Tuple(t), MemberKind::Tuple(Literal::Int(id))) => t
+                .get_mut(*id as usize)
+                .ok_or_else(|| Error::NotDefined(id.to_string().into()))?,
+            _ => Err(Error::TypeError)?,
+        })
+    }
+
+    fn addrof_index<'e>(env: &'e mut Environment, index: &Index) -> IResult<&'e mut ConValue> {
+        let Index { head, indices } = index;
+        let indices = indices
+            .iter()
+            .map(|index| index.interpret(env))
+            .collect::<IResult<Vec<_>>>()?;
+        let mut head = addrof(env, head)?;
+        for index in indices {
+            head = match (head, index) {
+                (ConValue::Array(a), ConValue::Int(i)) => {
+                    let a_len = a.len();
+                    a.get_mut(i as usize)
+                        .ok_or(Error::OobIndex(i as usize, a_len))?
+                }
+                _ => Err(Error::NotIndexable)?,
+            }
+        }
+        Ok(head)
+    }
+
+    pub fn addrof_path_within_namespace<'e>(
+        env: &'e mut Namespace,
+        path: &[PathPart],
+    ) -> IResult<&'e mut Option<ConValue>> {
+        match path {
+            [] => Err(Error::NotAssignable),
+            [PathPart::Ident(name)] => env.get_mut(name).ok_or(Error::NotDefined(*name)),
+            [PathPart::Ident(name), rest @ ..] => {
+                match env.get_mut(name).ok_or(Error::NotDefined(*name))? {
+                    Some(ConValue::Module(env)) => addrof_path_within_namespace(env, rest),
+                    _ => Err(Error::NotIndexable),
+                }
+            }
+            [PathPart::SelfKw, rest @ ..] => addrof_path_within_namespace(env, rest),
+            [PathPart::SelfTy, ..] => todo!("calc_address for `Self`"),
+            [PathPart::SuperKw, ..] => todo!("calc_address for `super`"),
+        }
+    }
+}
+
+impl Interpret for Assign {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Assign { parts } = self;
+        let (head, tail) = parts.borrow();
+        let init = tail.interpret(env)?;
+        // Resolve the head pattern
+        assignment::assign(env, head, init).map(|_| ConValue::Empty)
+    }
+}
+impl Interpret for Modify {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Modify { kind: op, parts } = self;
+        let (head, tail) = parts.borrow();
+        // Get the initializer and the tail
+        let init = tail.interpret(env)?;
+        // Resolve the head pattern
+        let target = assignment::addrof(env, head)?;
+
+        match op {
+            ModifyKind::Add => target.add_assign(init),
+            ModifyKind::Sub => target.sub_assign(init),
+            ModifyKind::Mul => target.mul_assign(init),
+            ModifyKind::Div => target.div_assign(init),
+            ModifyKind::Rem => target.rem_assign(init),
+            ModifyKind::And => target.bitand_assign(init),
+            ModifyKind::Or => target.bitor_assign(init),
+            ModifyKind::Xor => target.bitxor_assign(init),
+            ModifyKind::Shl => target.shl_assign(init),
+            ModifyKind::Shr => target.shr_assign(init),
+        }?;
+        Ok(ConValue::Empty)
+    }
+}
+impl Interpret for Binary {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Binary { kind, parts } = self;
+        let (head, tail) = parts.borrow();
+
+        let head = head.interpret(env)?;
+
+        // Short-circuiting ops
+        match kind {
+            BinaryKind::LogAnd => {
+                return if head.truthy()? {
+                    tail.interpret(env)
+                } else {
+                    Ok(head)
+                }; // Short circuiting
+            }
+            BinaryKind::LogOr => {
+                return if !head.truthy()? {
+                    tail.interpret(env)
+                } else {
+                    Ok(head)
+                }; // Short circuiting
+            }
+            BinaryKind::LogXor => {
+                return Ok(ConValue::Bool(
+                    head.truthy()? ^ tail.interpret(env)?.truthy()?,
+                ));
+            }
+            _ => {}
+        }
+        let tail = tail.interpret(env)?;
+        match kind {
+            BinaryKind::Lt => head.lt(&tail),
+            BinaryKind::LtEq => head.lt_eq(&tail),
+            BinaryKind::Equal => head.eq(&tail),
+            BinaryKind::NotEq => head.neq(&tail),
+            BinaryKind::GtEq => head.gt_eq(&tail),
+            BinaryKind::Gt => head.gt(&tail),
+            BinaryKind::RangeExc => head.range_exc(tail),
+            BinaryKind::RangeInc => head.range_inc(tail),
+            BinaryKind::BitAnd => head & tail,
+            BinaryKind::BitOr => head | tail,
+            BinaryKind::BitXor => head ^ tail,
+            BinaryKind::Shl => head << tail,
+            BinaryKind::Shr => head >> tail,
+            BinaryKind::Add => head + tail,
+            BinaryKind::Sub => head - tail,
+            BinaryKind::Mul => head * tail,
+            BinaryKind::Div => head / tail,
+            BinaryKind::Rem => head % tail,
+            BinaryKind::Call => match tail {
+                ConValue::Empty => head.call(env, &[]),
+                ConValue::Tuple(args) => head.call(env, &args),
+                _ => Err(Error::TypeError),
+            },
+            _ => Ok(head),
+        }
+
+        // // Temporarily disabled, to avoid function dispatch overhead while I screw around
+        // // Not like it helped much in the first place!
+        // match kind {
+        //     BinaryKind::Mul => env.call("mul", &[head, tail]),
+        //     BinaryKind::Div => env.call("div", &[head, tail]),
+        //     BinaryKind::Rem => env.call("rem", &[head, tail]),
+        //     BinaryKind::Add => env.call("add", &[head, tail]),
+        //     BinaryKind::Sub => env.call("sub", &[head, tail]),
+        //     BinaryKind::Shl => env.call("shl", &[head, tail]),
+        //     BinaryKind::Shr => env.call("shr", &[head, tail]),
+        //     BinaryKind::BitAnd => env.call("and", &[head, tail]),
+        //     BinaryKind::BitOr => env.call("or", &[head, tail]),
+        //     BinaryKind::BitXor => env.call("xor", &[head, tail]),
+        //     BinaryKind::RangeExc => env.call("range_exc", &[head, tail]),
+        //     BinaryKind::RangeInc => env.call("range_inc", &[head, tail]),
+        //     BinaryKind::Lt => env.call("lt", &[head, tail]),
+        //     BinaryKind::LtEq => env.call("lt_eq", &[head, tail]),
+        //     BinaryKind::Equal => env.call("eq", &[head, tail]),
+        //     BinaryKind::NotEq => env.call("neq", &[head, tail]),
+        //     BinaryKind::GtEq => env.call("gt_eq", &[head, tail]),
+        //     BinaryKind::Gt => env.call("gt", &[head, tail]),
+        //     BinaryKind::Dot => todo!("search within a type's namespace!"),
+        //     BinaryKind::Call => match tail {
+        //         ConValue::Empty => head.call(env, &[]),
+        //         ConValue::Tuple(args) => head.call(env, &args),
+        //         _ => Err(Error::TypeError),
+        //     },
+        //     _ => Ok(head),
+        // }
+    }
+}
+
+impl Interpret for Unary {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Unary { kind, tail } = self;
+        match kind {
+            UnaryKind::Loop => loop {
+                match tail.interpret(env) {
+                    Err(Error::Break(value)) => return Ok(value),
+                    Err(Error::Continue) => continue,
+                    e => e?,
+                };
+            },
+            UnaryKind::Deref => {
+                let operand = tail.interpret(env)?;
+                env.call("deref".into(), &[operand])
+            }
+            UnaryKind::Neg => {
+                let operand = tail.interpret(env)?;
+                env.call("neg".into(), &[operand])
+            }
+            UnaryKind::Not => {
+                let operand = tail.interpret(env)?;
+                env.call("not".into(), &[operand])
+            }
+            UnaryKind::At => {
+                let operand = tail.interpret(env)?;
+                println!("{operand}");
+                Ok(operand)
+            }
+            UnaryKind::Tilde => unimplemented!("Tilde operator"),
+        }
+    }
+}
+
+fn cast(value: ConValue, ty: Sym) -> IResult<ConValue> {
+    let value = match value {
+        ConValue::Empty => 0,
+        ConValue::Int(i) => i as _,
+        ConValue::Bool(b) => b as _,
+        ConValue::Char(c) => c as _,
+        ConValue::Ref(v) => return cast((*v).clone(), ty),
+        // TODO: This, better
+        ConValue::Float(_) if ty.starts_with('f') => return Ok(value),
+        ConValue::Float(f) => f as _,
+        _ => Err(Error::TypeError)?,
+    };
+    Ok(match &*ty {
+        "u8" => ConValue::Int(value as u8 as _),
+        "i8" => ConValue::Int(value as i8 as _),
+        "u16" => ConValue::Int(value as u16 as _),
+        "i16" => ConValue::Int(value as i16 as _),
+        "u32" => ConValue::Int(value as u32 as _),
+        "i32" => ConValue::Int(value as i32 as _),
+        "u64" => ConValue::Int(value),
+        "i64" => ConValue::Int(value),
+        "f32" => ConValue::Float(value as f32 as _),
+        "f64" => ConValue::Float(value as f64 as _),
+        "char" => ConValue::Char(char::from_u32(value as _).unwrap_or('\u{fffd}')),
+        "bool" => ConValue::Bool(value < 0),
+        _ => Err(Error::NotDefined(ty))?,
+    })
+}
+
+impl Interpret for Cast {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Cast { head, ty } = self;
+        let value = head.interpret(env)?;
+        if TyKind::Empty == ty.kind {
+            return Ok(ConValue::Empty);
+        };
+        let TyKind::Path(Path { absolute: false, parts }) = &ty.kind else {
+            Err(Error::TypeError)?
+        };
+        match parts.as_slice() {
+            [PathPart::Ident(ty)] => cast(value, *ty),
+            _ => Err(Error::TypeError),
+        }
+    }
+}
+
+impl Interpret for Member {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Member { head, kind } = self;
+        let head = head.interpret(env)?;
+        match (head, kind) {
+            (ConValue::Tuple(v), MemberKind::Tuple(Literal::Int(id))) => v
+                .get(*id as usize)
+                .cloned()
+                .ok_or(Error::OobIndex(*id as usize, v.len())),
+            (ConValue::Struct(parts), MemberKind::Struct(name)) => {
+                parts.1.get(name).cloned().ok_or(Error::NotDefined(*name))
+            }
+            (ConValue::Struct(parts), MemberKind::Call(name, args)) => {
+                let mut values = vec![];
+                for arg in &args.exprs {
+                    values.push(arg.interpret(env)?);
+                }
+                (parts.1)
+                    .get(name)
+                    .cloned()
+                    .ok_or(Error::NotDefined(*name))?
+                    .call(env, &values)
+            }
+            (head, MemberKind::Call(name, args)) => {
+                let mut values = vec![head];
+                for arg in &args.exprs {
+                    values.push(arg.interpret(env)?);
+                }
+                env.call(*name, &values)
+            }
+            _ => Err(Error::TypeError)?,
+        }
+    }
+}
+impl Interpret for Index {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Self { head, indices } = self;
+        let mut head = head.interpret(env)?;
+        for index in indices {
+            head = head.index(&index.interpret(env)?)?;
+        }
+        Ok(head)
+    }
+}
+impl Interpret for Structor {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Self { to: Path { absolute: _, parts }, init } = self;
+        use std::collections::HashMap;
+
+        let name = match parts.last() {
+            Some(PathPart::Ident(name)) => *name,
+            Some(PathPart::SelfKw) => "self".into(),
+            Some(PathPart::SelfTy) => "Self".into(),
+            Some(PathPart::SuperKw) => "super".into(),
+            None => "".into(),
+        };
+
+        let mut map = HashMap::new();
+        for Fielder { name, init } in init {
+            let value = match init {
+                Some(init) => init.interpret(env)?,
+                None => env.get(*name)?,
+            };
+            map.insert(*name, value);
+        }
+        Ok(ConValue::Struct(Box::new((name, map))))
+    }
+}
+
+impl Interpret for Path {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Self { absolute: _, parts } = self;
+
+        assignment::addrof_path(env, parts)
+            .cloned()
+            .transpose()
+            .ok_or_else(|| Error::NotInitialized(format!("{self}").into()))?
+    }
+}
+impl Interpret for Literal {
+    fn interpret(&self, _env: &mut Environment) -> IResult<ConValue> {
+        Ok(match self {
+            Literal::String(value) => ConValue::from(value.as_str()),
+            Literal::Char(value) => ConValue::Char(*value),
+            Literal::Bool(value) => ConValue::Bool(*value),
+            Literal::Float(value) => ConValue::Float(f64::from_bits(*value)),
+            Literal::Int(value) => ConValue::Int(*value as _),
+        })
+    }
+}
+impl Interpret for Array {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Self { values } = self;
+        let mut out = vec![];
+        for expr in values {
+            out.push(expr.interpret(env)?)
+        }
+        Ok(ConValue::Array(out.into()))
+    }
+}
+impl Interpret for ArrayRep {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Self { value, repeat } = self;
+        let repeat = match repeat.interpret(env)? {
+            ConValue::Int(v) => v,
+            _ => Err(Error::TypeError)?,
+        };
+        let value = value.interpret(env)?;
+        Ok(ConValue::Array(vec![value; repeat as usize].into()))
+    }
+}
+impl Interpret for AddrOf {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Self { mutable: _, expr } = self;
+        match expr.as_ref() {
+            ExprKind::Index(_) => todo!("AddrOf array index"),
+            ExprKind::Path(_) => todo!("Path traversal in addrof"),
+            _ => Ok(ConValue::Ref(Rc::new(expr.interpret(env)?))),
+        }
+    }
+}
+impl Interpret for Block {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Self { stmts } = self;
+        let mut env = env.frame("block");
+        let mut out = ConValue::Empty;
+        for stmt in stmts {
+            out = stmt.interpret(&mut env)?;
+        }
+        Ok(out)
+    }
+}
+impl Interpret for Group {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Self { expr } = self;
+        expr.interpret(env)
+    }
+}
+impl Interpret for Tuple {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Self { exprs } = self;
+        Ok(ConValue::Tuple(
+            exprs
+                .iter()
+                .try_fold(vec![], |mut out, element| {
+                    out.push(element.interpret(env)?);
+                    Ok(out)
+                })?
+                .into(),
+        ))
+    }
+}
+impl Interpret for While {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Self { cond, pass, fail } = self;
+        loop {
+            if cond.interpret(env)?.truthy()? {
+                match pass.interpret(env) {
+                    Err(Error::Break(value)) => return Ok(value),
+                    Err(Error::Continue) => continue,
+                    e => e?,
+                };
+            } else {
+                break fail.interpret(env);
+            }
+        }
+    }
+}
+impl Interpret for If {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Self { cond, pass, fail } = self;
+        if cond.interpret(env)?.truthy()? {
+            pass.interpret(env)
+        } else {
+            fail.interpret(env)
+        }
+    }
+}
+impl Interpret for For {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Self { bind: name, cond, pass, fail } = self;
+        let cond = cond.interpret(env)?;
+        // TODO: A better iterator model
+        let mut bounds: Box<dyn Iterator<Item = ConValue>> = match &cond {
+            &ConValue::RangeExc(a, b) => Box::new((a..b).map(ConValue::Int)),
+            &ConValue::RangeInc(a, b) => Box::new((a..=b).map(ConValue::Int)),
+            ConValue::Array(a) => Box::new(a.iter().cloned()),
+            ConValue::String(s) => Box::new(s.chars().map(ConValue::Char)),
+            _ => Err(Error::TypeError)?,
+        };
+        loop {
+            let mut env = env.frame("loop variable");
+            if let Some(loop_var) = bounds.next() {
+                env.insert(*name, Some(loop_var));
+                match pass.interpret(&mut env) {
+                    Err(Error::Break(value)) => return Ok(value),
+                    Err(Error::Continue) => continue,
+                    result => result?,
+                };
+            } else {
+                break fail.interpret(&mut env);
+            }
+        }
+    }
+}
+impl Interpret for Else {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Self { body } = self;
+        match body {
+            Some(body) => body.interpret(env),
+            None => Ok(ConValue::Empty),
+        }
+    }
+}
+impl Interpret for Return {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Self { body } = self;
+        Err(Error::Return(
+            body.as_ref()
+                .map(|body| body.interpret(env))
+                .unwrap_or(Ok(ConValue::Empty))?,
+        ))
+    }
+}
+impl Interpret for Break {
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
+        let Self { body } = self;
+        Err(Error::Break(
+            body.as_ref()
+                .map(|body| body.interpret(env))
+                .unwrap_or(Ok(ConValue::Empty))?,
+        ))
+    }
+}

compiler/cl-interpret/src/lib.rs

@@ -0,0 +1,33 @@
+//! Walks a Conlang AST, interpreting it as a program.
+#![warn(clippy::all)]
+#![feature(decl_macro)]
+
+use cl_ast::Sym;
+use convalue::ConValue;
+use env::Environment;
+use error::{Error, IResult};
+use interpret::Interpret;
+
+/// Callable types can be called from within a Conlang program
+pub trait Callable: std::fmt::Debug {
+    /// Calls this [Callable] in the provided [Environment], with [ConValue] args  \
+    /// The Callable is responsible for checking the argument count and validating types
+    fn call(&self, interpreter: &mut Environment, args: &[ConValue]) -> IResult<ConValue>;
+    /// Returns the common name of this identifier.
+    fn name(&self) -> Sym;
+}
+
+pub mod convalue;
+
+pub mod interpret;
+
+pub mod function;
+
+pub mod builtin;
+
+pub mod env;
+
+pub mod error;
+
+#[cfg(test)]
+mod tests;

compiler/cl-interpret/src/tests.rs

@@ -1,5 +1,5 @@
 #![allow(unused_imports)]
-use crate::{env::Environment, temp_type_impl::ConValue, Interpret};
+use crate::{convalue::ConValue, env::Environment, Interpret};
 use cl_ast::*;
 use cl_lexer::Lexer;
 use cl_parser::Parser;
@@ -48,6 +48,7 @@ mod macros {
     //! ```
     #![allow(unused_macros)]
     use crate::IResult;
+    use cl_parser::parser::Parse;
 
     use super::*;
 
@@ -63,14 +64,14 @@ mod macros {
     ///
     /// Returns a `Result<`[`File`]`, ParseError>`
     pub macro file($($t:tt)*) {
-        Parser::new(Lexer::new(stringify!( $($t)* ))).file()
+        File::parse(&mut Parser::new(Lexer::new(stringify!( $($t)* ))))
     }
 
     /// Stringifies, lexes, and parses everything you give to it
     ///
     /// Returns a `Result<`[`Block`]`, ParseError>`
     pub macro block($($t:tt)*) {
-        Parser::new(Lexer::new(stringify!({ $($t)* }))).block()
+        Block::parse(&mut Parser::new(Lexer::new(stringify!({ $($t)* }))))
     }
 
     /// Evaluates a block of code in the given environment
@@ -127,7 +128,7 @@ mod macros {
     }
 
     pub macro env_ne($env:ident.$var:ident, $expr:expr) {{
-        let evaluated = $env.get(stringify!($var))
+        let evaluated = $env.get(stringify!($var).into())
             .expect(stringify!($var should be defined and initialized));
         if !conv_cmp!(neq, evaluated, $expr) {
             panic!("assertion {} ({evaluated}) != {} failed.", stringify!($var), stringify!($expr))
@@ -135,7 +136,7 @@ mod macros {
     }}
 
     pub macro env_eq($env:ident.$var:ident, $expr:expr) {{
-        let evaluated = $env.get(stringify!($var))
+        let evaluated = $env.get(stringify!($var).into())
             .expect(stringify!($var should be defined and initialized));
         if !conv_cmp!(eq, evaluated, $expr) {
             panic!("assertion {} ({evaluated}) == {} failed.", stringify!($var), stringify!($expr))
@@ -177,6 +178,45 @@ mod let_declarations {
         env_eq!(env.x, 10);
         env_eq!(env.y, 10);
     }
+
+    #[test]
+    fn let_destructuring_tuple() {
+        let mut env = Environment::new();
+        assert_eval!(env,
+            let (x, y) = (10, 20);
+        );
+
+        env_eq!(env.x, 10);
+        env_eq!(env.y, 20);
+    }
+
+    #[test]
+    fn let_destructuring_array() {
+        let mut env = Environment::new();
+        assert_eval!(env,
+            let [x, y] = [10, 20];
+        );
+
+        env_eq!(env.x, 10);
+        env_eq!(env.y, 20);
+    }
+
+    #[test]
+    fn let_destructuring_nested() {
+        let mut env = Environment::new();
+        assert_eval!(env,
+            let (x, [one, two, three], (a, b, c))
+              = ('x', [1, 2, 3], ('a', 'b', 'c'));
+        );
+
+        env_eq!(env.x, 'x');
+        env_eq!(env.one, 1);
+        env_eq!(env.two, 2);
+        env_eq!(env.three, 3);
+        env_eq!(env.a, 'a');
+        env_eq!(env.b, 'b');
+        env_eq!(env.c, 'c');
+    }
 }
 
 mod fn_declarations {
@@ -187,10 +227,10 @@ mod fn_declarations {
         assert_eval!(env, fn empty_fn() {});
         // TODO: true equality for functions
         assert_eq!(
-            "fn empty_fn () {\n    \n}",
+            "fn empty_fn () {}",
             format!(
                 "{}",
-                env.get("empty_fn")
+                env.get("empty_fn".into())
                     .expect(stringify!(empty_fn should be defined and initialized))
             )
         )
@@ -436,16 +476,17 @@ mod operators {
         env_eq!(env.y, 10);
         env_eq!(env.z, 10);
     }
-    #[test]
-    #[should_panic]
-    fn assignment_accounts_for_type() {
-        let mut env = Default::default();
-        assert_eval!(env,
-            let x = "a string";
-            let y = 0xdeadbeef;
-            y = x; // should crash: type error
-        );
-    }
+    // Test is disabled, since new assignment system intentionally does not care.
+    // #[test]
+    // #[should_panic]
+    // fn assignment_accounts_for_type() {
+    //     let mut env = Default::default();
+    //     assert_eval!(env,
+    //         let x = "a string";
+    //         let y = 0xdeadbeef;
+    //         y = x; // should crash: type error
+    //     );
+    // }
     #[test]
     fn precedence() {
         let mut env = Default::default();
@@ -468,6 +509,56 @@ mod operators {
     }
 }
 
+mod control_flow {
+    use super::*;
+
+    #[test]
+    fn if_evaluates_pass_block_on_true() {
+        let mut env = Default::default();
+        assert_eval!(env,
+            let evaluated = if true { "pass" } else { "fail" }
+        );
+        env_eq!(env.evaluated, "pass");
+    }
+
+    #[test]
+    fn if_evaluates_fail_block_on_false() {
+        let mut env = Default::default();
+        assert_eval!(env,
+            let evaluated = if false { "pass" } else { "fail" }
+        );
+        env_eq!(env.evaluated, "fail");
+    }
+
+    #[test]
+    fn match_evaluates_in_order() {
+        let mut env = Default::default();
+        assert_eval!(env,
+            let x = '\u{1f988}';
+            let passed = match x {
+                '\u{1f988}' => true,
+                _ => false,
+            };
+        );
+        env_eq!(env.passed, true);
+    }
+
+    #[test]
+    fn match_sinkoles_underscore_patterns() {
+        let mut env = Default::default();
+        assert_eval!(env,
+            let x = '\u{1f988}';
+            let passed = match x {
+                _ => true,
+                '\u{1f988}' => false,
+            };
+        );
+        env_eq!(env.passed, true);
+    }
+
+    //TODO: test other control flow constructs like loops, while-else, etc.
+}
+
 #[allow(dead_code)]
 fn test_template() {
     let mut env = Default::default();

compiler/cl-lexer/src/lib.rs

@@ -23,7 +23,7 @@ pub mod lexer_iter {
     pub struct LexerIter<'t> {
         lexer: Lexer<'t>,
     }
-    impl<'t> Iterator for LexerIter<'t> {
+    impl Iterator for LexerIter<'_> {
         type Item = LResult<Token>;
         fn next(&mut self) -> Option<Self::Item> {
             match self.lexer.scan() {
@@ -97,33 +97,33 @@ impl<'t> Lexer<'t> {
     /// Scans through the text, searching for the next [Token]
     pub fn scan(&mut self) -> LResult<Token> {
         match self.skip_whitespace().peek()? {
-            '{' => self.consume()?.produce_op(Punct::LCurly),
-            '}' => self.consume()?.produce_op(Punct::RCurly),
-            '[' => self.consume()?.produce_op(Punct::LBrack),
-            ']' => self.consume()?.produce_op(Punct::RBrack),
-            '(' => self.consume()?.produce_op(Punct::LParen),
-            ')' => self.consume()?.produce_op(Punct::RParen),
+            '{' => self.consume()?.produce_op(Kind::LCurly),
+            '}' => self.consume()?.produce_op(Kind::RCurly),
+            '[' => self.consume()?.produce_op(Kind::LBrack),
+            ']' => self.consume()?.produce_op(Kind::RBrack),
+            '(' => self.consume()?.produce_op(Kind::LParen),
+            ')' => self.consume()?.produce_op(Kind::RParen),
             '&' => self.consume()?.amp(),
-            '@' => self.consume()?.produce_op(Punct::At),
-            '\\' => self.consume()?.produce_op(Punct::Backslash),
+            '@' => self.consume()?.produce_op(Kind::At),
+            '\\' => self.consume()?.produce_op(Kind::Backslash),
             '!' => self.consume()?.bang(),
             '|' => self.consume()?.bar(),
             ':' => self.consume()?.colon(),
-            ',' => self.consume()?.produce_op(Punct::Comma),
+            ',' => self.consume()?.produce_op(Kind::Comma),
             '.' => self.consume()?.dot(),
             '=' => self.consume()?.equal(),
-            '`' => self.consume()?.produce_op(Punct::Grave),
+            '`' => self.consume()?.produce_op(Kind::Grave),
             '>' => self.consume()?.greater(),
             '#' => self.consume()?.hash(),
             '<' => self.consume()?.less(),
             '-' => self.consume()?.minus(),
             '+' => self.consume()?.plus(),
-            '?' => self.consume()?.produce_op(Punct::Question),
+            '?' => self.consume()?.produce_op(Kind::Question),
             '%' => self.consume()?.rem(),
-            ';' => self.consume()?.produce_op(Punct::Semi),
+            ';' => self.consume()?.produce_op(Kind::Semi),
             '/' => self.consume()?.slash(),
             '*' => self.consume()?.star(),
-            '~' => self.consume()?.produce_op(Punct::Tilde),
+            '~' => self.consume()?.produce_op(Kind::Tilde),
             '^' => self.consume()?.xor(),
             '0' => self.consume()?.int_with_base(),
             '1'..='9' => self.digits::<10>(),
@@ -157,14 +157,14 @@ impl<'t> Lexer<'t> {
             .copied()
             .ok_or(Error::end_of_file(self.line(), self.col()))
     }
-    fn produce(&mut self, kind: TokenKind, data: impl Into<TokenData>) -> LResult<Token> {
+    fn produce(&mut self, kind: Kind, data: impl Into<TokenData>) -> LResult<Token> {
         let loc = self.start_loc;
         self.start_loc = self.current_loc;
         self.start = self.current;
         Ok(Token::new(kind, data, loc.0, loc.1))
     }
-    fn produce_op(&mut self, kind: Punct) -> LResult<Token> {
-        self.produce(TokenKind::Punct(kind), ())
+    fn produce_op(&mut self, kind: Kind) -> LResult<Token> {
+        self.produce(kind, ())
     }
     fn skip_whitespace(&mut self) -> &mut Self {
         while let Ok(c) = self.peek() {
@@ -192,145 +192,154 @@ impl<'t> Lexer<'t> {
     }
 }
 /// Digraphs and trigraphs
-impl<'t> Lexer<'t> {
+impl Lexer<'_> {
     fn amp(&mut self) -> LResult<Token> {
         match self.peek() {
-            Ok('&') => self.consume()?.produce_op(Punct::AmpAmp),
-            Ok('=') => self.consume()?.produce_op(Punct::AmpEq),
-            _ => self.produce_op(Punct::Amp),
+            Ok('&') => self.consume()?.produce_op(Kind::AmpAmp),
+            Ok('=') => self.consume()?.produce_op(Kind::AmpEq),
+            _ => self.produce_op(Kind::Amp),
         }
     }
     fn bang(&mut self) -> LResult<Token> {
         match self.peek() {
-            Ok('!') => self.consume()?.produce_op(Punct::BangBang),
-            Ok('=') => self.consume()?.produce_op(Punct::BangEq),
-            _ => self.produce_op(Punct::Bang),
+            Ok('!') => self.consume()?.produce_op(Kind::BangBang),
+            Ok('=') => self.consume()?.produce_op(Kind::BangEq),
+            _ => self.produce_op(Kind::Bang),
         }
     }
     fn bar(&mut self) -> LResult<Token> {
         match self.peek() {
-            Ok('|') => self.consume()?.produce_op(Punct::BarBar),
-            Ok('=') => self.consume()?.produce_op(Punct::BarEq),
-            _ => self.produce_op(Punct::Bar),
+            Ok('|') => self.consume()?.produce_op(Kind::BarBar),
+            Ok('=') => self.consume()?.produce_op(Kind::BarEq),
+            _ => self.produce_op(Kind::Bar),
         }
     }
     fn colon(&mut self) -> LResult<Token> {
         match self.peek() {
-            Ok(':') => self.consume()?.produce_op(Punct::ColonColon),
-            _ => self.produce_op(Punct::Colon),
+            Ok(':') => self.consume()?.produce_op(Kind::ColonColon),
+            _ => self.produce_op(Kind::Colon),
         }
     }
     fn dot(&mut self) -> LResult<Token> {
         match self.peek() {
             Ok('.') => {
                 if let Ok('=') = self.consume()?.peek() {
-                    self.consume()?.produce_op(Punct::DotDotEq)
+                    self.consume()?.produce_op(Kind::DotDotEq)
                 } else {
-                    self.produce_op(Punct::DotDot)
+                    self.produce_op(Kind::DotDot)
                 }
             }
-            _ => self.produce_op(Punct::Dot),
+            _ => self.produce_op(Kind::Dot),
         }
     }
     fn equal(&mut self) -> LResult<Token> {
         match self.peek() {
-            Ok('=') => self.consume()?.produce_op(Punct::EqEq),
-            Ok('>') => self.consume()?.produce_op(Punct::FatArrow),
-            _ => self.produce_op(Punct::Eq),
+            Ok('=') => self.consume()?.produce_op(Kind::EqEq),
+            Ok('>') => self.consume()?.produce_op(Kind::FatArrow),
+            _ => self.produce_op(Kind::Eq),
         }
     }
     fn greater(&mut self) -> LResult<Token> {
         match self.peek() {
-            Ok('=') => self.consume()?.produce_op(Punct::GtEq),
+            Ok('=') => self.consume()?.produce_op(Kind::GtEq),
             Ok('>') => {
                 if let Ok('=') = self.consume()?.peek() {
-                    self.consume()?.produce_op(Punct::GtGtEq)
+                    self.consume()?.produce_op(Kind::GtGtEq)
                 } else {
-                    self.produce_op(Punct::GtGt)
+                    self.produce_op(Kind::GtGt)
                 }
             }
-            _ => self.produce_op(Punct::Gt),
+            _ => self.produce_op(Kind::Gt),
         }
     }
     fn hash(&mut self) -> LResult<Token> {
         match self.peek() {
-            Ok('!') => self.consume()?.produce_op(Punct::HashBang),
-            _ => self.produce_op(Punct::Hash),
+            Ok('!') => self.consume()?.hashbang(),
+            _ => self.produce_op(Kind::Hash),
+        }
+    }
+    fn hashbang(&mut self) -> LResult<Token> {
+        match self.peek() {
+            Ok('/' | '\'') => self.line_comment(),
+            _ => self.produce_op(Kind::HashBang),
         }
     }
     fn less(&mut self) -> LResult<Token> {
         match self.peek() {
-            Ok('=') => self.consume()?.produce_op(Punct::LtEq),
+            Ok('=') => self.consume()?.produce_op(Kind::LtEq),
             Ok('<') => {
                 if let Ok('=') = self.consume()?.peek() {
-                    self.consume()?.produce_op(Punct::LtLtEq)
+                    self.consume()?.produce_op(Kind::LtLtEq)
                 } else {
-                    self.produce_op(Punct::LtLt)
+                    self.produce_op(Kind::LtLt)
                 }
             }
-            _ => self.produce_op(Punct::Lt),
+            _ => self.produce_op(Kind::Lt),
         }
     }
     fn minus(&mut self) -> LResult<Token> {
         match self.peek() {
-            Ok('=') => self.consume()?.produce_op(Punct::MinusEq),
-            Ok('>') => self.consume()?.produce_op(Punct::Arrow),
-            _ => self.produce_op(Punct::Minus),
+            Ok('=') => self.consume()?.produce_op(Kind::MinusEq),
+            Ok('>') => self.consume()?.produce_op(Kind::Arrow),
+            _ => self.produce_op(Kind::Minus),
         }
     }
     fn plus(&mut self) -> LResult<Token> {
         match self.peek() {
-            Ok('=') => self.consume()?.produce_op(Punct::PlusEq),
-            _ => self.produce_op(Punct::Plus),
+            Ok('=') => self.consume()?.produce_op(Kind::PlusEq),
+            _ => self.produce_op(Kind::Plus),
         }
     }
     fn rem(&mut self) -> LResult<Token> {
         match self.peek() {
-            Ok('=') => self.consume()?.produce_op(Punct::RemEq),
-            _ => self.produce_op(Punct::Rem),
+            Ok('=') => self.consume()?.produce_op(Kind::RemEq),
+            _ => self.produce_op(Kind::Rem),
         }
     }
     fn slash(&mut self) -> LResult<Token> {
         match self.peek() {
-            Ok('=') => self.consume()?.produce_op(Punct::SlashEq),
+            Ok('=') => self.consume()?.produce_op(Kind::SlashEq),
             Ok('/') => self.consume()?.line_comment(),
             Ok('*') => self.consume()?.block_comment(),
-            _ => self.produce_op(Punct::Slash),
+            _ => self.produce_op(Kind::Slash),
         }
     }
     fn star(&mut self) -> LResult<Token> {
         match self.peek() {
-            Ok('=') => self.consume()?.produce_op(Punct::StarEq),
-            _ => self.produce_op(Punct::Star),
+            Ok('=') => self.consume()?.produce_op(Kind::StarEq),
+            _ => self.produce_op(Kind::Star),
         }
     }
     fn xor(&mut self) -> LResult<Token> {
         match self.peek() {
-            Ok('=') => self.consume()?.produce_op(Punct::XorEq),
-            Ok('^') => self.consume()?.produce_op(Punct::XorXor),
-            _ => self.produce_op(Punct::Xor),
+            Ok('=') => self.consume()?.produce_op(Kind::XorEq),
+            Ok('^') => self.consume()?.produce_op(Kind::XorXor),
+            _ => self.produce_op(Kind::Xor),
         }
     }
 }
 /// Comments
-impl<'t> Lexer<'t> {
+impl Lexer<'_> {
     fn line_comment(&mut self) -> LResult<Token> {
+        let mut comment = String::new();
         while Ok('\n') != self.peek() {
-            self.consume()?;
+            comment.push(self.next()?);
         }
-        self.produce(Kind::Comment, ())
+        self.produce(Kind::Comment, comment)
     }
     fn block_comment(&mut self) -> LResult<Token> {
+        let mut comment = String::new();
         while let Ok(c) = self.next() {
-            if '*' == c && Ok('/') == self.next() {
+            if '*' == c && Ok('/') == self.peek() {
                 break;
             }
+            comment.push(c);
         }
-        self.produce(Kind::Comment, ())
+        self.consume()?.produce(Kind::Comment, comment)
     }
 }
 /// Identifiers
-impl<'t> Lexer<'t> {
+impl Lexer<'_> {
     fn identifier(&mut self) -> LResult<Token> {
         let mut out = String::from(self.xid_start()?);
         while let Ok(c) = self.xid_continue() {
@@ -362,23 +371,39 @@ impl<'t> Lexer<'t> {
     }
 }
 /// Integers
-impl<'t> Lexer<'t> {
+impl Lexer<'_> {
     fn int_with_base(&mut self) -> LResult<Token> {
         match self.peek() {
             Ok('x') => self.consume()?.digits::<16>(),
             Ok('d') => self.consume()?.digits::<10>(),
             Ok('o') => self.consume()?.digits::<8>(),
             Ok('b') => self.consume()?.digits::<2>(),
-            Ok('0'..='9') => self.digits::<10>(),
+            Ok('0'..='9' | '.') => self.digits::<10>(),
             _ => self.produce(Kind::Literal, 0),
         }
     }
     fn digits<const B: u32>(&mut self) -> LResult<Token> {
-        let mut value = self.digit::<B>()? as u128;
+        let mut value = 0;
         while let Ok(true) = self.peek().as_ref().map(char::is_ascii_alphanumeric) {
             value = value * B as u128 + self.digit::<B>()? as u128;
         }
-        self.produce(Kind::Literal, value)
+        // TODO: find a better way to handle floats in the tokenizer
+        match self.peek() {
+            Ok('.') => {
+                // FIXME: hack: 0.. is not [0.0, '.']
+                if let Ok('.') = self.clone().consume()?.next() {
+                    return self.produce(Kind::Literal, value);
+                }
+                let mut float = format!("{value}.");
+                self.consume()?;
+                while let Ok(true) = self.peek().as_ref().map(char::is_ascii_digit) {
+                    float.push(self.iter.next().unwrap_or_default());
+                }
+                let float = f64::from_str(&float).expect("must be parsable as float");
+                self.produce(Kind::Literal, float)
+            }
+            _ => self.produce(Kind::Literal, value),
+        }
     }
     fn digit<const B: u32>(&mut self) -> LResult<u32> {
         let digit = self.peek()?;
@@ -389,7 +414,7 @@ impl<'t> Lexer<'t> {
     }
 }
 /// Strings and characters
-impl<'t> Lexer<'t> {
+impl Lexer<'_> {
     fn string(&mut self) -> LResult<Token> {
         let mut value = String::new();
         while '"'

compiler/cl-lexer/src/tests.rs

@@ -110,7 +110,7 @@ mod string {
 }
 mod punct {
     macro op($op:ident) {
-        TokenKind::Punct(Punct::$op)
+        TokenKind::$op
     }
 
     use super::*;

compiler/cl-parser/src/error.rs

@@ -22,14 +22,15 @@ pub enum ErrorKind {
     UnmatchedCurlyBraces,
     UnmatchedSquareBrackets,
     Unexpected(TokenKind),
-    Expected {
+    ExpectedToken {
         want: TokenKind,
         got: TokenKind,
     },
-    /// No rules matched
-    Nothing,
+    ExpectedParsing {
+        want: Parsing,
+    },
     /// Indicates unfinished code
-    Todo,
+    Todo(&'static str),
 }
 impl From<LexError> for ErrorKind {
     fn from(value: LexError) -> Self {
@@ -43,14 +44,18 @@ impl From<LexError> for ErrorKind {
 /// Compactly represents the stage of parsing an [Error] originated in
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum Parsing {
+    Mutability,
+    Visibility,
+    Identifier,
+    Literal,
+
     File,
 
     Attrs,
     Meta,
+    MetaKind,
 
     Item,
-    Visibility,
-    Mutability,
     ItemKind,
     Alias,
     Const,
@@ -67,13 +72,21 @@ pub enum Parsing {
     Variant,
     VariantKind,
     Impl,
+    ImplKind,
+    Use,
+    UseTree,
 
     Ty,
     TyKind,
+    TySlice,
+    TyArray,
     TyTuple,
     TyRef,
     TyFn,
 
+    Path,
+    PathPart,
+
     Stmt,
     StmtKind,
     Let,
@@ -86,19 +99,19 @@ pub enum Parsing {
     BinaryKind,
     Unary,
     UnaryKind,
+    Cast,
     Index,
+    Structor,
+    Fielder,
     Call,
     Member,
-    PathExpr,
-    PathPart,
-    Identifier,
-    Literal,
     Array,
     ArrayRep,
     AddrOf,
     Block,
     Group,
     Tuple,
+    Loop,
     While,
     If,
     For,
@@ -106,6 +119,10 @@ pub enum Parsing {
     Break,
     Return,
     Continue,
+
+    Pattern,
+    Match,
+    MatchArm,
 }
 
 impl Display for Error {
@@ -113,7 +130,7 @@ impl Display for Error {
         let Self { reason, while_parsing, loc } = self;
         match reason {
             // TODO entries are debug-printed
-            ErrorKind::Todo => write!(f, "{loc} {reason} {while_parsing:?}"),
+            ErrorKind::Todo(_) => write!(f, "{loc} {reason} {while_parsing:?}"),
             // lexical errors print their own higher-resolution loc info
             ErrorKind::Lexical(e) => write!(f, "{e} (while parsing {while_parsing})"),
             _ => write!(f, "{loc} {reason} while parsing {while_parsing}"),
@@ -129,25 +146,26 @@ impl Display for ErrorKind {
             ErrorKind::UnmatchedCurlyBraces => write!(f, "Unmatched curly braces"),
             ErrorKind::UnmatchedSquareBrackets => write!(f, "Unmatched square brackets"),
             ErrorKind::Unexpected(t) => write!(f, "Encountered unexpected token `{t}`"),
-            ErrorKind::Expected { want: e, got: g } => {
-                write!(f, "Expected `{e}`, got `{g}`")
-            }
-            ErrorKind::Nothing => write!(f, "Nothing found"),
-            ErrorKind::Todo => write!(f, "TODO:"),
+            ErrorKind::ExpectedToken { want: e, got: g } => write!(f, "Expected `{e}`, got `{g}`"),
+            ErrorKind::ExpectedParsing { want } => write!(f, "Expected {want}"),
+            ErrorKind::Todo(unfinished) => write!(f, "TODO: {unfinished}"),
         }
     }
 }
 impl Display for Parsing {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
+            Parsing::Visibility => "a visibility qualifier",
+            Parsing::Mutability => "a mutability qualifier",
+            Parsing::Identifier => "an identifier",
+            Parsing::Literal => "a literal",
+
             Parsing::File => "a file",
 
             Parsing::Attrs => "an attribute-set",
             Parsing::Meta => "an attribute",
-
+            Parsing::MetaKind => "an attribute's arguments",
             Parsing::Item => "an item",
-            Parsing::Visibility => "a visibility qualifier",
-            Parsing::Mutability => "a mutability qualifier",
             Parsing::ItemKind => "an item",
             Parsing::Alias => "a type alias",
             Parsing::Const => "a const item",
@@ -164,13 +182,21 @@ impl Display for Parsing {
             Parsing::Variant => "an enum variant",
             Parsing::VariantKind => "an enum variant",
             Parsing::Impl => "an impl block",
+            Parsing::ImplKind => "the target of an impl block",
+            Parsing::Use => "a use item",
+            Parsing::UseTree => "a use-tree",
 
             Parsing::Ty => "a type",
             Parsing::TyKind => "a type",
+            Parsing::TySlice => "a slice type",
+            Parsing::TyArray => "an array type",
             Parsing::TyTuple => "a tuple of types",
             Parsing::TyRef => "a reference type",
             Parsing::TyFn => "a function pointer type",
 
+            Parsing::Path => "a path",
+            Parsing::PathPart => "a path component",
+
             Parsing::Stmt => "a statement",
             Parsing::StmtKind => "a statement",
             Parsing::Let => "a local variable declaration",
@@ -183,19 +209,19 @@ impl Display for Parsing {
             Parsing::BinaryKind => "a binary operator",
             Parsing::Unary => "a unary expression",
             Parsing::UnaryKind => "a unary operator",
+            Parsing::Cast => "an `as`-casting expression",
             Parsing::Index => "an indexing expression",
+            Parsing::Structor => "a struct constructor expression",
+            Parsing::Fielder => "a struct field expression",
             Parsing::Call => "a call expression",
             Parsing::Member => "a member access expression",
-            Parsing::PathExpr => "a path",
-            Parsing::PathPart => "a path component",
-            Parsing::Identifier => "an identifier",
-            Parsing::Literal => "a literal",
             Parsing::Array => "an array",
             Parsing::ArrayRep => "an array of form [k;N]",
             Parsing::AddrOf => "a borrow op",
             Parsing::Block => "a block",
             Parsing::Group => "a grouped expression",
             Parsing::Tuple => "a tuple",
+            Parsing::Loop => "an unconditional loop expression",
             Parsing::While => "a while expression",
             Parsing::If => "an if expression",
             Parsing::For => "a for expression",
@@ -203,6 +229,10 @@ impl Display for Parsing {
             Parsing::Break => "a break expression",
             Parsing::Return => "a return expression",
             Parsing::Continue => "a continue expression",
+
+            Parsing::Pattern => "a pattern",
+            Parsing::Match => "a match expression",
+            Parsing::MatchArm => "a match arm",
         }
         .fmt(f)
     }

compiler/cl-parser/src/inliner.rs

@@ -0,0 +1,98 @@
+//! The [ModuleInliner] reads files described in the module structure of the
+
+use crate::Parser;
+use cl_ast::{ast_visitor::Fold, *};
+use cl_lexer::Lexer;
+use std::path::{Path, PathBuf};
+
+pub type IoErrs = Vec<(PathBuf, std::io::Error)>;
+pub type ParseErrs = Vec<(PathBuf, crate::error::Error)>;
+
+pub struct ModuleInliner {
+    path: PathBuf,
+    io_errs: IoErrs,
+    parse_errs: ParseErrs,
+}
+
+impl ModuleInliner {
+    /// Creates a new [ModuleInliner]
+    pub fn new(root: impl AsRef<Path>) -> Self {
+        Self {
+            path: root.as_ref().to_path_buf(),
+            io_errs: Default::default(),
+            parse_errs: Default::default(),
+        }
+    }
+
+    /// Returns true when the [ModuleInliner] has errors to report
+    pub fn has_errors(&self) -> bool {
+        !(self.io_errs.is_empty() && self.parse_errs.is_empty())
+    }
+
+    /// Returns the [IO Errors](IoErrs) and [parse Errors](ParseErrs)
+    pub fn into_errs(self) -> Option<(IoErrs, ParseErrs)> {
+        self.has_errors().then_some((self.io_errs, self.parse_errs))
+    }
+
+    /// Traverses a [File], attempting to inline all submodules.
+    ///
+    /// This is a simple wrapper around [ModuleInliner::fold_file()] and
+    /// [ModuleInliner::into_errs()]
+    pub fn inline(mut self, file: File) -> Result<File, (File, IoErrs, ParseErrs)> {
+        let file = self.fold_file(file);
+
+        match self.into_errs() {
+            Some((io, parse)) => Err((file, io, parse)),
+            None => Ok(file),
+        }
+    }
+
+    /// Records an [I/O error](std::io::Error) for later
+    fn handle_io_error(&mut self, error: std::io::Error) -> ModuleKind {
+        self.io_errs.push((self.path.clone(), error));
+        ModuleKind::Outline
+    }
+
+    /// Records a [parse error](crate::error::Error) for later
+    fn handle_parse_error(&mut self, error: crate::error::Error) -> ModuleKind {
+        self.parse_errs.push((self.path.clone(), error));
+        ModuleKind::Outline
+    }
+}
+
+impl Fold for ModuleInliner {
+    /// Traverses down the module tree, entering ever nested directories
+    fn fold_module(&mut self, m: Module) -> Module {
+        let Module { name, kind } = m;
+        self.path.push(&*name); // cd ./name
+
+        let kind = self.fold_module_kind(kind);
+
+        self.path.pop(); // cd ..
+        Module { name, kind }
+    }
+
+    /// Attempts to read and parse a file for every module in the tree
+    fn fold_module_kind(&mut self, m: ModuleKind) -> ModuleKind {
+        if let ModuleKind::Inline(f) = m {
+            return ModuleKind::Inline(self.fold_file(f));
+        }
+        // cd path/mod.cl
+        self.path.set_extension("cl");
+
+        let file = match std::fs::read_to_string(&self.path) {
+            Err(error) => return self.handle_io_error(error),
+            Ok(file) => file,
+        };
+
+        let kind = match Parser::new(Lexer::new(&file)).parse() {
+            Err(e) => return self.handle_parse_error(e),
+            Ok(file) => ModuleKind::Inline(file),
+        };
+        // cd path/mod
+        self.path.set_extension("");
+
+        // The newly loaded module may need further inlining
+        self.fold_module_kind(kind)
+    }
+}

compiler/cl-parser/src/lib.rs

@@ -14,3 +14,5 @@ use cl_token::*;
 pub mod error;
 
 pub mod parser;
+
+pub mod inliner;

compiler/cl-parser/src/parser/prec.rs

@@ -0,0 +1,381 @@
+//! Parses an [ExprKind] using a modified pratt parser
+//!
+//! See also: [Expr::parse], [ExprKind::parse]
+//!
+//! Implementer's note: [ExprKind::parse] is the public API for parsing [ExprKind]s.
+//! Do not call it from within this function.
+
+use super::{Parse, *};
+
+/// Parses an [ExprKind]
+pub fn exprkind(p: &mut Parser, power: u8) -> PResult<ExprKind> {
+    let parsing = Parsing::ExprKind;
+
+    // Prefix expressions
+    let mut head = match p.peek_kind(Parsing::Unary)? {
+        literal_like!() => Literal::parse(p)?.into(),
+        path_like!() => exprkind_pathlike(p)?,
+        TokenKind::Amp | TokenKind::AmpAmp => AddrOf::parse(p)?.into(),
+        TokenKind::Grave => Quote::parse(p)?.into(),
+        TokenKind::LCurly => Block::parse(p)?.into(),
+        TokenKind::LBrack => exprkind_arraylike(p)?,
+        TokenKind::LParen => exprkind_tuplelike(p)?,
+        TokenKind::Let => Let::parse(p)?.into(),
+        TokenKind::Match => Match::parse(p)?.into(),
+        TokenKind::While => ExprKind::While(While::parse(p)?),
+        TokenKind::If => ExprKind::If(If::parse(p)?),
+        TokenKind::For => ExprKind::For(For::parse(p)?),
+        TokenKind::Break => ExprKind::Break(Break::parse(p)?),
+        TokenKind::Return => ExprKind::Return(Return::parse(p)?),
+        TokenKind::Continue => {
+            p.consume_peeked();
+            ExprKind::Continue
+        }
+
+        op => {
+            let (kind, prec) = from_prefix(op).ok_or_else(|| p.error(Unexpected(op), parsing))?;
+            let ((), after) = prec.prefix().expect("should have a precedence");
+            p.consume_peeked();
+            Unary { kind, tail: exprkind(p, after)?.into() }.into()
+        }
+    };
+
+    fn from_postfix(op: TokenKind) -> Option<Precedence> {
+        Some(match op {
+            TokenKind::LBrack => Precedence::Index,
+            TokenKind::LParen => Precedence::Call,
+            TokenKind::Dot => Precedence::Member,
+            _ => None?,
+        })
+    }
+
+    while let Ok(op) = p.peek_kind(parsing) {
+        // Postfix expressions
+        if let Some((before, ())) = from_postfix(op).and_then(Precedence::postfix) {
+            if before < power {
+                break;
+            }
+            p.consume_peeked();
+
+            head = match op {
+                TokenKind::LBrack => {
+                    let indices =
+                        sep(Expr::parse, TokenKind::Comma, TokenKind::RBrack, parsing)(p)?;
+                    p.match_type(TokenKind::RBrack, parsing)?;
+                    ExprKind::Index(Index { head: head.into(), indices })
+                }
+                TokenKind::LParen => {
+                    let exprs = sep(Expr::parse, TokenKind::Comma, TokenKind::RParen, parsing)(p)?;
+                    p.match_type(TokenKind::RParen, parsing)?;
+                    Binary { kind: BinaryKind::Call, parts: (head, Tuple { exprs }.into()).into() }
+                        .into()
+                }
+                TokenKind::Dot => {
+                    let kind = MemberKind::parse(p)?;
+                    Member { head: Box::new(head), kind }.into()
+                }
+                _ => Err(p.error(Unexpected(op), parsing))?,
+            };
+            continue;
+        }
+        // infix expressions
+        if let Some((kind, prec)) = from_infix(op) {
+            let (before, after) = prec.infix().expect("should have a precedence");
+            if before < power {
+                break;
+            }
+            p.consume_peeked();
+
+            let tail = exprkind(p, after)?;
+            head = Binary { kind, parts: (head, tail).into() }.into();
+            continue;
+        }
+
+        if let Some((kind, prec)) = from_modify(op) {
+            let (before, after) = prec.infix().expect("should have a precedence");
+            if before < power {
+                break;
+            }
+            p.consume_peeked();
+
+            let tail = exprkind(p, after)?;
+            head = Modify { kind, parts: (head, tail).into() }.into();
+            continue;
+        }
+
+        if let TokenKind::Eq = op {
+            let (before, after) = Precedence::Assign
+                .infix()
+                .expect("should have a precedence");
+            if before < power {
+                break;
+            }
+            p.consume_peeked();
+
+            let tail = exprkind(p, after)?;
+            head = Assign { parts: (head, tail).into() }.into();
+            continue;
+        }
+
+        if let TokenKind::As = op {
+            let before = Precedence::Cast.level();
+            if before < power {
+                break;
+            }
+            p.consume_peeked();
+
+            let ty = Ty::parse(p)?;
+            head = Cast { head: head.into(), ty }.into();
+            continue;
+        }
+
+        break;
+    }
+
+    Ok(head)
+}
+
+/// [Array] = '[' ([Expr] ',')* [Expr]? ']'
+///
+/// Array and ArrayRef are ambiguous until the second token,
+/// so they can't be independent subexpressions
+fn exprkind_arraylike(p: &mut Parser) -> PResult<ExprKind> {
+    const P: Parsing = Parsing::Array;
+    const START: TokenKind = TokenKind::LBrack;
+    const END: TokenKind = TokenKind::RBrack;
+
+    p.match_type(START, P)?;
+    let out = match p.peek_kind(P)? {
+        END => Array { values: vec![] }.into(),
+        _ => exprkind_array_rep(p)?,
+    };
+    p.match_type(END, P)?;
+    Ok(out)
+}
+
+/// [ArrayRep] = `[` [Expr] `;` [Expr] `]`
+fn exprkind_array_rep(p: &mut Parser) -> PResult<ExprKind> {
+    const P: Parsing = Parsing::Array;
+    const END: TokenKind = TokenKind::RBrack;
+
+    let first = Expr::parse(p)?;
+    Ok(match p.peek_kind(P)? {
+        TokenKind::Semi => ArrayRep {
+            value: first.kind.into(),
+            repeat: {
+                p.consume_peeked();
+                Box::new(exprkind(p, 0)?)
+            },
+        }
+        .into(),
+        TokenKind::RBrack => Array { values: vec![first] }.into(),
+        TokenKind::Comma => Array {
+            values: {
+                p.consume_peeked();
+                let mut out = vec![first];
+                out.extend(sep(Expr::parse, TokenKind::Comma, END, P)(p)?);
+                out
+            },
+        }
+        .into(),
+        ty => Err(p.error(Unexpected(ty), P))?,
+    })
+}
+
+/// [Group] = `(`([Empty](ExprKind::Empty)|[Expr]|[Tuple])`)`
+///
+/// [ExprKind::Empty] and [Group] are special cases of [Tuple]
+fn exprkind_tuplelike(p: &mut Parser) -> PResult<ExprKind> {
+    p.match_type(TokenKind::LParen, Parsing::Group)?;
+    let out = match p.peek_kind(Parsing::Group)? {
+        TokenKind::RParen => Ok(ExprKind::Empty),
+        _ => exprkind_group(p),
+    };
+    p.match_type(TokenKind::RParen, Parsing::Group)?;
+    out
+}
+
+/// [Group] = `(`([Empty](ExprKind::Empty)|[Expr]|[Tuple])`)`
+fn exprkind_group(p: &mut Parser) -> PResult<ExprKind> {
+    let first = Expr::parse(p)?;
+    match p.peek_kind(Parsing::Group)? {
+        TokenKind::Comma => {
+            let mut exprs = vec![first];
+            p.consume_peeked();
+            while TokenKind::RParen != p.peek_kind(Parsing::Tuple)? {
+                exprs.push(Expr::parse(p)?);
+                match p.peek_kind(Parsing::Tuple)? {
+                    TokenKind::Comma => p.consume_peeked(),
+                    _ => break,
+                };
+            }
+            Ok(Tuple { exprs }.into())
+        }
+        _ => Ok(Group { expr: first.kind.into() }.into()),
+    }
+}
+
+/// Parses an expression beginning with a [Path] (i.e. [Path] or [Structor])
+fn exprkind_pathlike(p: &mut Parser) -> PResult<ExprKind> {
+    let head = Path::parse(p)?;
+    Ok(match p.match_type(TokenKind::Colon, Parsing::Path) {
+        Ok(_) => ExprKind::Structor(structor_body(p, head)?),
+        Err(_) => ExprKind::Path(head),
+    })
+}
+
+/// [Structor]Body = `{` ([Fielder] `,`)* [Fielder]? `}`
+fn structor_body(p: &mut Parser, to: Path) -> PResult<Structor> {
+    let init = delim(
+        sep(
+            Fielder::parse,
+            TokenKind::Comma,
+            CURLIES.1,
+            Parsing::Structor,
+        ),
+        CURLIES,
+        Parsing::Structor,
+    )(p)?;
+
+    Ok(Structor { to, init })
+}
+
+/// Precedence provides a total ordering among operators
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub enum Precedence {
+    Assign,
+    Logic,
+    Compare,
+    Range,
+    Bitwise,
+    Shift,
+    Factor,
+    Term,
+    Unary,
+    Index,
+    Cast,
+    Member, // left-associative
+    Call,
+    Highest,
+}
+
+impl Precedence {
+    #[inline]
+    pub const fn level(self) -> u8 {
+        (self as u8) << 1
+    }
+
+    pub fn prefix(self) -> Option<((), u8)> {
+        match self {
+            Self::Assign => Some(((), self.level())),
+            Self::Unary => Some(((), self.level())),
+            _ => None,
+        }
+    }
+
+    pub fn infix(self) -> Option<(u8, u8)> {
+        let level = self.level();
+        match self {
+            Self::Unary => None,
+            Self::Assign => Some((level + 1, level)),
+            _ => Some((level, level + 1)),
+        }
+    }
+
+    pub fn postfix(self) -> Option<(u8, ())> {
+        match self {
+            Self::Index | Self::Call | Self::Member => Some((self.level(), ())),
+            _ => None,
+        }
+    }
+}
+
+impl From<ModifyKind> for Precedence {
+    fn from(_value: ModifyKind) -> Self {
+        Precedence::Assign
+    }
+}
+
+impl From<BinaryKind> for Precedence {
+    fn from(value: BinaryKind) -> Self {
+        use BinaryKind as Op;
+        match value {
+            Op::Call => Precedence::Call,
+            Op::Mul | Op::Div | Op::Rem => Precedence::Term,
+            Op::Add | Op::Sub => Precedence::Factor,
+            Op::Shl | Op::Shr => Precedence::Shift,
+            Op::BitAnd | Op::BitOr | Op::BitXor => Precedence::Bitwise,
+            Op::LogAnd | Op::LogOr | Op::LogXor => Precedence::Logic,
+            Op::RangeExc | Op::RangeInc => Precedence::Range,
+            Op::Lt | Op::LtEq | Op::Equal | Op::NotEq | Op::GtEq | Op::Gt => Precedence::Compare,
+        }
+    }
+}
+
+impl From<UnaryKind> for Precedence {
+    fn from(value: UnaryKind) -> Self {
+        use UnaryKind as Op;
+        match value {
+            Op::Loop => Precedence::Assign,
+            Op::Deref | Op::Neg | Op::Not | Op::At | Op::Tilde => Precedence::Unary,
+        }
+    }
+}
+
+/// Creates helper functions for turning TokenKinds into AST operators
+macro operator($($name:ident ($takes:ident => $returns:ident) {$($t:ident => $p:ident),*$(,)?};)*) {$(
+    pub fn $name (value: $takes) -> Option<($returns, Precedence)> {
+        match value {
+            $($takes::$t => Some(($returns::$p, Precedence::from($returns::$p))),)*
+            _ => None?,
+        }
+    })*
+}
+
+operator! {
+    from_prefix (TokenKind => UnaryKind) {
+        Loop => Loop,
+        Star => Deref,
+        Minus => Neg,
+        Bang => Not,
+        At => At,
+        Tilde => Tilde,
+    };
+
+    from_modify(TokenKind => ModifyKind) {
+        AmpEq => And,
+        BarEq => Or,
+        XorEq => Xor,
+        LtLtEq => Shl,
+        GtGtEq => Shr,
+        PlusEq => Add,
+        MinusEq => Sub,
+        StarEq => Mul,
+        SlashEq => Div,
+        RemEq => Rem,
+    };
+
+    from_infix (TokenKind => BinaryKind) {
+        Lt => Lt,
+        LtEq => LtEq,
+        EqEq => Equal,
+        BangEq => NotEq,
+        GtEq => GtEq,
+        Gt => Gt,
+        DotDot => RangeExc,
+        DotDotEq => RangeInc,
+        AmpAmp => LogAnd,
+        BarBar => LogOr,
+        XorXor => LogXor,
+        Amp => BitAnd,
+        Bar => BitOr,
+        Xor => BitXor,
+        LtLt => Shl,
+        GtGt => Shr,
+        Plus => Add,
+        Minus => Sub,
+        Star => Mul,
+        Slash => Div,
+        Rem => Rem,
+    };
+}

compiler/cl-repl/Cargo.toml

@@ -15,9 +15,5 @@ cl-lexer = { path = "../cl-lexer" }
 cl-token = { path = "../cl-token" }
 cl-parser = { path = "../cl-parser" }
 cl-interpret = { path = "../cl-interpret" }
-crossterm = "0.27.0"
-argh = "0.1.12"
-
-[dev-dependencies]
-cl-structures = { path = "../cl-structures" }
-cl-typeck = { path = "../cl-typeck" }
+repline = { path = "../../repline" }
+argwerk = "0.20.4"

compiler/cl-repl/examples/yaml.rs

@@ -1,8 +1,9 @@
 //! Pretty prints a conlang AST in yaml
 
+use cl_ast::Stmt;
 use cl_lexer::Lexer;
 use cl_parser::Parser;
-use cl_repl::repline::{error::Error as RlError, Repline};
+use repline::{error::Error as RlError, Repline};
 use std::error::Error;
 
 fn main() -> Result<(), Box<dyn Error>> {
@@ -19,7 +20,7 @@ fn main() -> Result<(), Box<dyn Error>> {
         };
 
         let mut parser = Parser::new(Lexer::new(&line));
-        let code = match parser.stmt() {
+        let code = match parser.parse::<Stmt>() {
             Ok(code) => {
                 rl.accept();
                 code
@@ -119,19 +120,19 @@ pub mod yamler {
         }
     }
 
-    impl<'y> Deref for Section<'y> {
+    impl Deref for Section<'_> {
         type Target = Yamler;
         fn deref(&self) -> &Self::Target {
             self.yamler
         }
     }
-    impl<'y> DerefMut for Section<'y> {
+    impl DerefMut for Section<'_> {
         fn deref_mut(&mut self) -> &mut Self::Target {
             self.yamler
         }
     }
 
-    impl<'y> Drop for Section<'y> {
+    impl Drop for Section<'_> {
         fn drop(&mut self) {
             let Self { yamler } = self;
             yamler.decrease();
@@ -207,6 +208,7 @@ pub mod yamlify {
                 ItemKind::Struct(f) => y.yaml(f),
                 ItemKind::Enum(f) => y.yaml(f),
                 ItemKind::Impl(f) => y.yaml(f),
+                ItemKind::Use(f) => y.yaml(f),
             };
         }
     }
@@ -247,12 +249,12 @@ pub mod yamlify {
     }
     impl Yamlify for Function {
         fn yaml(&self, y: &mut Yamler) {
-            let Self { name, args, body, rety } = self;
+            let Self { name, sign, bind, body } = self;
             y.key("Function")
                 .pair("name", name)
-                .pair("args", args)
-                .pair("body", body)
-                .pair("rety", rety);
+                .pair("sign", sign)
+                .pair("bind", bind)
+                .pair("body", body);
         }
     }
     impl Yamlify for Struct {
@@ -312,6 +314,33 @@ pub mod yamlify {
             y.key("Impl").pair("target", target).pair("body", body);
         }
     }
+    impl Yamlify for ImplKind {
+        fn yaml(&self, y: &mut Yamler) {
+            match self {
+                ImplKind::Type(t) => y.value(t),
+                ImplKind::Trait { impl_trait, for_type } => {
+                    y.pair("trait", impl_trait).pair("for_type", for_type)
+                }
+            };
+        }
+    }
+    impl Yamlify for Use {
+        fn yaml(&self, y: &mut Yamler) {
+            let Self { absolute, tree } = self;
+            y.key("Use").pair("absolute", absolute).yaml(tree);
+        }
+    }
+    impl Yamlify for UseTree {
+        fn yaml(&self, y: &mut Yamler) {
+            match self {
+                UseTree::Tree(trees) => y.pair("trees", trees),
+                UseTree::Path(path, tree) => y.pair("path", path).pair("tree", tree),
+                UseTree::Alias(from, to) => y.pair("from", from).pair("to", to),
+                UseTree::Name(name) => y.pair("name", name),
+                UseTree::Glob => y.value("Glob"),
+            };
+        }
+    }
     impl Yamlify for Block {
         fn yaml(&self, y: &mut Yamler) {
             let Self { stmts } = self;
@@ -335,22 +364,11 @@ pub mod yamlify {
         fn yaml(&self, y: &mut Yamler) {
             match self {
                 StmtKind::Empty => y,
-                StmtKind::Local(s) => y.yaml(s),
                 StmtKind::Item(s) => y.yaml(s),
                 StmtKind::Expr(s) => y.yaml(s),
             };
         }
     }
-    impl Yamlify for Let {
-        fn yaml(&self, y: &mut Yamler) {
-            let Self { mutable, name, ty, init } = self;
-            y.key("Let")
-                .pair("name", name)
-                .yaml(mutable)
-                .pair("ty", ty)
-                .pair("init", init);
-        }
-    }
     impl Yamlify for Expr {
         fn yaml(&self, y: &mut Yamler) {
             let Self { extents: _, kind } = self;
@@ -360,10 +378,17 @@ pub mod yamlify {
     impl Yamlify for ExprKind {
         fn yaml(&self, y: &mut Yamler) {
             match self {
+                ExprKind::Quote(k) => k.yaml(y),
+                ExprKind::Let(k) => k.yaml(y),
+                ExprKind::Match(k) => k.yaml(y),
                 ExprKind::Assign(k) => k.yaml(y),
+                ExprKind::Modify(k) => k.yaml(y),
                 ExprKind::Binary(k) => k.yaml(y),
                 ExprKind::Unary(k) => k.yaml(y),
+                ExprKind::Cast(k) => k.yaml(y),
+                ExprKind::Member(k) => k.yaml(y),
                 ExprKind::Index(k) => k.yaml(y),
+                ExprKind::Structor(k) => k.yaml(y),
                 ExprKind::Path(k) => k.yaml(y),
                 ExprKind::Literal(k) => k.yaml(y),
                 ExprKind::Array(k) => k.yaml(y),
@@ -378,20 +403,84 @@ pub mod yamlify {
                 ExprKind::For(k) => k.yaml(y),
                 ExprKind::Break(k) => k.yaml(y),
                 ExprKind::Return(k) => k.yaml(y),
-                ExprKind::Continue(k) => k.yaml(y),
+                ExprKind::Continue => {
+                    y.key("Continue");
                 }
             }
         }
+    }
+    impl Yamlify for Quote {
+        fn yaml(&self, y: &mut Yamler) {
+            y.key("Quote").value(self);
+        }
+    }
+    impl Yamlify for Let {
+        fn yaml(&self, y: &mut Yamler) {
+            let Self { mutable, name, ty, init } = self;
+            y.key("Let")
+                .pair("name", name)
+                .yaml(mutable)
+                .pair("ty", ty)
+                .pair("init", init);
+        }
+    }
+
+    impl Yamlify for Pattern {
+        fn yaml(&self, y: &mut Yamler) {
+            match self {
+                Pattern::Path(path) => y.value(path),
+                Pattern::Literal(literal) => y.value(literal),
+                Pattern::Ref(mutability, pattern) => {
+                    y.pair("mutability", mutability).pair("subpattern", pattern)
+                }
+                Pattern::Tuple(patterns) => y.key("Tuple").yaml(patterns),
+                Pattern::Array(patterns) => y.key("Array").yaml(patterns),
+                Pattern::Struct(path, items) => {
+                    {
+                        let mut y = y.key("Struct");
+                        y.pair("name", path);
+                        for (name, item) in items {
+                            y.pair(name, item);
+                        }
+                    }
+                    y
+                }
+            };
+        }
+    }
+    impl Yamlify for Match {
+        fn yaml(&self, y: &mut Yamler) {
+            let Self { scrutinee, arms } = self;
+            y.key("Match")
+                .pair("scrutinee", scrutinee)
+                .pair("arms", arms);
+        }
+    }
+
+    impl Yamlify for MatchArm {
+        fn yaml(&self, y: &mut Yamler) {
+            let Self(pat, expr) = self;
+            y.pair("pat", pat).pair("expr", expr);
+        }
+    }
     impl Yamlify for Assign {
         fn yaml(&self, y: &mut Yamler) {
-            let Self { kind, parts } = self;
+            let Self { parts } = self;
             y.key("Assign")
+                .pair("head", &parts.0)
+                .pair("tail", &parts.1);
+        }
+    }
+    impl Yamlify for Modify {
+        fn yaml(&self, y: &mut Yamler) {
+            let Self { kind, parts } = self;
+            y.key("Modify")
                 .pair("kind", kind)
                 .pair("head", &parts.0)
                 .pair("tail", &parts.1);
         }
     }
-    impl Yamlify for AssignKind {
+    impl Yamlify for ModifyKind {
         fn yaml(&self, y: &mut Yamler) {
             y.value(self);
         }
@@ -421,6 +510,27 @@ pub mod yamlify {
             y.value(self);
         }
     }
+    impl Yamlify for Cast {
+        fn yaml(&self, y: &mut Yamler) {
+            let Self { head, ty } = self;
+            y.key("Cast").pair("head", head).pair("ty", ty);
+        }
+    }
+    impl Yamlify for Member {
+        fn yaml(&self, y: &mut Yamler) {
+            let Self { head, kind } = self;
+            y.key("Member").pair("head", head).pair("kind", kind);
+        }
+    }
+    impl Yamlify for MemberKind {
+        fn yaml(&self, y: &mut Yamler) {
+            match self {
+                MemberKind::Call(id, args) => y.pair("id", id).pair("args", args),
+                MemberKind::Struct(id) => y.pair("id", id),
+                MemberKind::Tuple(id) => y.pair("id", id),
+            };
+        }
+    }
     impl Yamlify for Tuple {
         fn yaml(&self, y: &mut Yamler) {
             let Self { exprs } = self;
@@ -433,6 +543,18 @@ pub mod yamlify {
             y.key("Index").pair("head", head).list(indices);
         }
     }
+    impl Yamlify for Structor {
+        fn yaml(&self, y: &mut Yamler) {
+            let Self { to, init } = self;
+            y.key("Structor").pair("to", to).list(init);
+        }
+    }
+    impl Yamlify for Fielder {
+        fn yaml(&self, y: &mut Yamler) {
+            let Self { name, init } = self;
+            y.key("Fielder").pair("name", name).pair("init", init);
+        }
+    }
     impl Yamlify for Array {
         fn yaml(&self, y: &mut Yamler) {
             let Self { values } = self;
@@ -449,11 +571,8 @@ pub mod yamlify {
     }
     impl Yamlify for AddrOf {
         fn yaml(&self, y: &mut Yamler) {
-            let Self { count, mutable, expr } = self;
-            y.key("AddrOf")
-                .yaml(mutable)
-                .pair("count", count)
-                .pair("expr", expr);
+            let Self { mutable, expr } = self;
+            y.key("AddrOf").yaml(mutable).pair("expr", expr);
         }
     }
     impl Yamlify for Group {
@@ -468,7 +587,7 @@ pub mod yamlify {
             y.key("While")
                 .pair("cond", cond)
                 .pair("pass", pass)
-                .pair("fail", fail);
+                .yaml(fail);
         }
     }
     impl Yamlify for Else {
@@ -505,29 +624,20 @@ pub mod yamlify {
             y.key("Return").yaml(body);
         }
     }
-    impl Yamlify for Continue {
-        fn yaml(&self, y: &mut Yamler) {
-            y.key("Continue");
-        }
-    }
     impl Yamlify for Literal {
         fn yaml(&self, y: &mut Yamler) {
             y.value(format_args!("\"{self}\""));
         }
     }
-    impl Yamlify for Identifier {
+    impl Yamlify for Sym {
         fn yaml(&self, y: &mut Yamler) {
-            let Self(name) = self;
-            y.value(name);
+            y.value(self);
         }
     }
     impl Yamlify for Param {
         fn yaml(&self, y: &mut Yamler) {
-            let Self { mutability, name, ty } = self;
-            y.key("Param")
-                .yaml(mutability)
-                .pair("name", name)
-                .pair("ty", ty);
+            let Self { mutability, name } = self;
+            y.key("Param").yaml(mutability).pair("name", name);
         }
     }
     impl Yamlify for Ty {
@@ -541,11 +651,12 @@ pub mod yamlify {
             match self {
                 TyKind::Never => y.value("Never"),
                 TyKind::Empty => y.value("Empty"),
-                TyKind::SelfTy => y.value("Self"),
                 TyKind::Path(t) => y.yaml(t),
                 TyKind::Tuple(t) => y.yaml(t),
                 TyKind::Ref(t) => y.yaml(t),
                 TyKind::Fn(t) => y.yaml(t),
+                TyKind::Slice(_) => todo!(),
+                TyKind::Array(_) => todo!(),
             };
         }
     }
@@ -566,10 +677,23 @@ pub mod yamlify {
             match self {
                 PathPart::SuperKw => y.value("super"),
                 PathPart::SelfKw => y.value("self"),
+                PathPart::SelfTy => y.value("Self"),
                 PathPart::Ident(i) => y.yaml(i),
             };
         }
     }
+    impl Yamlify for TyArray {
+        fn yaml(&self, y: &mut Yamler) {
+            let Self { ty, count } = self;
+            y.key("TyArray").pair("ty", ty).pair("count", count);
+        }
+    }
+    impl Yamlify for TySlice {
+        fn yaml(&self, y: &mut Yamler) {
+            let Self { ty } = self;
+            y.key("TyArray").pair("ty", ty);
+        }
+    }
     impl Yamlify for TyTuple {
         fn yaml(&self, y: &mut Yamler) {
             let Self { types } = self;
@@ -581,8 +705,11 @@ pub mod yamlify {
     }
     impl Yamlify for TyRef {
         fn yaml(&self, y: &mut Yamler) {
-            let Self { count, to } = self;
-            y.key("TyRef").pair("count", count).pair("to", to);
+            let Self { count, mutable, to } = self;
+            y.key("TyRef")
+                .pair("count", count)
+                .yaml(mutable)
+                .pair("to", to);
         }
     }
     impl Yamlify for TyFn {

compiler/cl-repl/src/ansi.rs

@@ -0,0 +1,14 @@
+//! ANSI escape sequences
+
+pub const RED: &str = "\x1b[31m";
+pub const GREEN: &str = "\x1b[32m"; // the color of type checker mode
+pub const CYAN: &str = "\x1b[36m";
+pub const BRIGHT_GREEN: &str = "\x1b[92m";
+pub const BRIGHT_BLUE: &str = "\x1b[94m";
+pub const BRIGHT_MAGENTA: &str = "\x1b[95m";
+pub const BRIGHT_CYAN: &str = "\x1b[96m";
+pub const RESET: &str = "\x1b[0m";
+pub const OUTPUT: &str = "\x1b[38;5;117m";
+
+pub const CLEAR_LINES: &str = "\x1b[G\x1b[J";
+pub const CLEAR_ALL: &str = "\x1b[H\x1b[2J";

compiler/cl-repl/src/args.rs

@@ -0,0 +1,69 @@
+//! Handles argument parsing (currently using the [argwerk] crate)
+
+use std::{io::IsTerminal, path::PathBuf, str::FromStr};
+
+argwerk::define! {
+    ///
+    ///The Conlang prototype debug interface
+    #[usage = "conlang [<file>] [-I <include...>] [-m <mode>] [-r <repl>]"]
+    #[derive(Clone, PartialEq, Eq, PartialOrd, Ord)]
+    pub struct Args {
+        pub file: Option<PathBuf>,
+        pub include: Vec<PathBuf>,
+        pub mode: Mode,
+        pub repl: bool = is_terminal(),
+    }
+
+    ///files to include
+    ["-I" | "--include", path] => {
+        include.push(path.into());
+    }
+    ///the CLI operating mode (`f`mt | `l`ex | `r`un)
+    ["-m" | "--mode", flr] => {
+        mode = flr.parse()?;
+    }
+    ///whether to start the repl (`true` or `false`)
+    ["-r" | "--repl", bool] => {
+        repl = bool.parse()?;
+    }
+    ///display usage information
+    ["-h" | "--help"] => {
+        println!("{}", Args::help());
+        if true { std::process::exit(0); }
+    }
+    ///the main source file
+    [#[option] path] if file.is_none() => {
+        file = path.map(Into::into);
+    }
+
+    [path] if file.is_some() => {
+        include.push(path.into());
+    }
+}
+
+/// gets whether stdin AND stdout are a terminal, for pipelining
+pub fn is_terminal() -> bool {
+    std::io::stdin().is_terminal() && std::io::stdout().is_terminal()
+}
+
+/// The CLI's operating mode
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, PartialOrd, Ord)]
+pub enum Mode {
+    #[default]
+    Menu,
+    Lex,
+    Fmt,
+    Run,
+}
+
+impl FromStr for Mode {
+    type Err = &'static str;
+    fn from_str(s: &str) -> Result<Self, &'static str> {
+        Ok(match s {
+            "f" | "fmt" | "p" | "pretty" => Mode::Fmt,
+            "l" | "lex" | "tokenize" | "token" => Mode::Lex,
+            "r" | "run" => Mode::Run,
+            _ => Err("Recognized modes are: 'r' \"run\", 'f' \"fmt\", 'l' \"lex\"")?,
+        })
+    }
+}

compiler/cl-repl/src/bin/conlang.rs

@@ -0,0 +1,5 @@
+use cl_repl::{args, cli::run};
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    run(args::Args::args()?)
+}

compiler/cl-repl/src/cli.rs

@@ -0,0 +1,126 @@
+//! Implement's the command line interface
+use crate::{
+    args::{Args, Mode},
+    ctx::Context,
+    menu,
+    tools::print_token,
+};
+use cl_ast::File;
+use cl_interpret::{builtin::builtins, convalue::ConValue, env::Environment, interpret::Interpret};
+use cl_lexer::Lexer;
+use cl_parser::Parser;
+use std::{error::Error, path::Path};
+
+/// Run the command line interface
+pub fn run(args: Args) -> Result<(), Box<dyn Error>> {
+    let Args { file, include, mode, repl } = args;
+
+    let mut env = Environment::new();
+
+    env.add_builtins(&builtins! {
+        /// Clears the screen
+        fn clear() {
+            menu::clear();
+            Ok(ConValue::Empty)
+        }
+        /// Evaluates a quoted expression
+        fn eval(ConValue::Quote(quote)) @env {
+            env.eval(quote.as_ref())
+        }
+        /// Executes a file
+        fn import(ConValue::String(path)) @env {
+            load_file(env, &**path).or(Ok(ConValue::Empty))
+        }
+
+        /// Gets a line of input from stdin
+        fn get_line() {
+            match repline::Repline::new("", "", "").read() {
+                Ok(line) => Ok(ConValue::String(line.into())),
+                Err(e) => Ok(ConValue::String(e.to_string().into())),
+            }
+        }
+    });
+
+    for path in include {
+        load_file(&mut env, path)?;
+    }
+
+    if repl {
+        if let Some(file) = file {
+            load_file(&mut env, file)?;
+        }
+        let mut ctx = Context::with_env(env);
+        match mode {
+            Mode::Menu => menu::main_menu(&mut ctx)?,
+            Mode::Lex => menu::lex(&mut ctx)?,
+            Mode::Fmt => menu::fmt(&mut ctx)?,
+            Mode::Run => menu::run(&mut ctx)?,
+        }
+    } else {
+        let code = match &file {
+            Some(file) => std::fs::read_to_string(file)?,
+            None => std::io::read_to_string(std::io::stdin())?,
+        };
+
+        match mode {
+            Mode::Lex => lex_code(&code, file),
+            Mode::Fmt => fmt_code(&code),
+            Mode::Run | Mode::Menu => run_code(&code, &mut env),
+        }?;
+    }
+    Ok(())
+}
+
+fn load_file(env: &mut Environment, path: impl AsRef<Path>) -> Result<ConValue, Box<dyn Error>> {
+    let inliner =
+        cl_parser::inliner::ModuleInliner::new(path.as_ref().parent().unwrap_or(Path::new("")));
+    let file = std::fs::read_to_string(path)?;
+    let code = Parser::new(Lexer::new(&file)).parse()?;
+    let code = match inliner.inline(code) {
+        Ok(a) => a,
+        Err((code, io_errs, parse_errs)) => {
+            for (file, err) in io_errs {
+                eprintln!("{}:{err}", file.display());
+            }
+            for (file, err) in parse_errs {
+                eprintln!("{}:{err}", file.display());
+            }
+            code
+        }
+    };
+    Ok(env.eval(&code)?)
+}
+
+fn lex_code(code: &str, path: Option<impl AsRef<Path>>) -> Result<(), Box<dyn Error>> {
+    for token in Lexer::new(code) {
+        if let Some(path) = &path {
+            print!("{}:", path.as_ref().display());
+        }
+        match token {
+            Ok(token) => print_token(&token),
+            Err(e) => println!("{e}"),
+        }
+    }
+    Ok(())
+}
+
+fn fmt_code(code: &str) -> Result<(), Box<dyn Error>> {
+    let code = Parser::new(Lexer::new(code)).parse::<File>()?;
+    println!("{code}");
+    Ok(())
+}
+
+fn run_code(code: &str, env: &mut Environment) -> Result<(), Box<dyn Error>> {
+    let code = Parser::new(Lexer::new(code)).parse::<File>()?;
+    match code.interpret(env)? {
+        ConValue::Empty => {}
+        ret => println!("{ret}"),
+    }
+    if env.get("main".into()).is_ok() {
+        match env.call("main".into(), &[])? {
+            ConValue::Empty => {}
+            ret => println!("{ret}"),
+        }
+    }
+    Ok(())
+}

compiler/cl-repl/src/ctx.rs

@@ -0,0 +1,24 @@
+use cl_interpret::{convalue::ConValue, env::Environment, error::IResult, interpret::Interpret};
+
+#[derive(Clone, Debug)]
+pub struct Context {
+    pub env: Environment,
+}
+
+impl Context {
+    pub fn new() -> Self {
+        Self { env: Environment::new() }
+    }
+    pub fn with_env(env: Environment) -> Self {
+        Self { env }
+    }
+    pub fn run(&mut self, code: &impl Interpret) -> IResult<ConValue> {
+        code.interpret(&mut self.env)
+    }
+}
+
+impl Default for Context {
+    fn default() -> Self {
+        Self::new()
+    }
+}

compiler/cl-repl/src/lib.rs

@@ -0,0 +1,11 @@
+//! The Conlang REPL, based on [repline]
+//! 
+//! Uses [argwerk] for argument parsing.
+#![warn(clippy::all)]
+
+pub mod ansi;
+pub mod args;
+pub mod cli;
+pub mod ctx;
+pub mod menu;
+pub mod tools;

compiler/cl-repl/src/menu.rs

@@ -0,0 +1,87 @@
+use crate::{ansi, ctx};
+use cl_ast::Stmt;
+use cl_interpret::convalue::ConValue;
+use cl_lexer::Lexer;
+use cl_parser::Parser;
+use repline::{error::ReplResult, prebaked::*};
+
+pub fn clear() {
+    print!("{}", ansi::CLEAR_ALL);
+    banner()
+}
+
+pub fn banner() {
+    println!("--- conlang v{} 💪🦈 ---", env!("CARGO_PKG_VERSION"))
+}
+
+/// Presents a selection interface to the user
+pub fn main_menu(ctx: &mut ctx::Context) -> ReplResult<()> {
+    banner();
+    run(ctx)?;
+    read_and(ansi::GREEN, "mu>", " ?>", |line| {
+        match line.trim() {
+            "clear" => clear(),
+            "l" | "lex" => lex(ctx)?,
+            "f" | "fmt" => fmt(ctx)?,
+            "r" | "run" => run(ctx)?,
+            "q" | "quit" => return Ok(Response::Break),
+            "h" | "help" => println!(
+                "Valid commands
+    lex     (l): Spin up a lexer, and lex some lines
+    fmt     (f): Format the input
+    run     (r): Enter the REPL, and evaluate some statements
+    help    (h): Print this list
+    quit    (q): Exit the program"
+            ),
+            _ => Err("Unknown command. Type \"help\" for help")?,
+        }
+        Ok(Response::Accept)
+    })
+}
+
+pub fn run(ctx: &mut ctx::Context) -> ReplResult<()> {
+    use cl_ast::ast_visitor::Fold;
+    use cl_parser::inliner::ModuleInliner;
+
+    read_and(ansi::CYAN, "cl>", " ?>", |line| {
+        if line.trim().is_empty() {
+            return Ok(Response::Deny);
+        }
+        let code = Parser::new(Lexer::new(line)).parse::<Stmt>()?;
+        let code = ModuleInliner::new(".").fold_stmt(code);
+
+        print!("{}", ansi::OUTPUT);
+        match ctx.run(&code) {
+            Ok(ConValue::Empty) => print!("{}", ansi::RESET),
+            Ok(v) => println!("{}{v}", ansi::RESET),
+            Err(e) => println!("{}! > {e}{}", ansi::RED, ansi::RESET),
+        }
+        Ok(Response::Accept)
+    })
+}
+
+pub fn lex(_ctx: &mut ctx::Context) -> ReplResult<()> {
+    read_and(ansi::BRIGHT_BLUE, "lx>", " ?>", |line| {
+        for token in Lexer::new(line) {
+            match token {
+                Ok(token) => crate::tools::print_token(&token),
+                Err(e) => eprintln!("! > {}{e}{}", ansi::RED, ansi::RESET),
+            }
+        }
+
+        Ok(Response::Accept)
+    })
+}
+
+pub fn fmt(_ctx: &mut ctx::Context) -> ReplResult<()> {
+    read_and(ansi::BRIGHT_MAGENTA, "cl>", " ?>", |line| {
+        let mut p = Parser::new(Lexer::new(line));
+
+        match p.parse::<Stmt>() {
+            Ok(code) => println!("{}{code}{}", ansi::OUTPUT, ansi::RESET),
+            Err(e) => Err(e)?,
+        }
+
+        Ok(Response::Accept)
+    })
+}

compiler/cl-repl/src/tools.rs

@@ -0,0 +1,11 @@
+use cl_token::Token;
+/// Prints a token in the particular way [cl-repl](crate) does
+pub fn print_token(t: &Token) {
+    println!(
+        "{:02}:{:02}: {:#19} │{}│",
+        t.line(),
+        t.col(),
+        t.ty(),
+        t.data(),
+    )
+}

compiler/cl-structures/Cargo.toml

@@ -8,3 +8,4 @@ license.workspace = true
 publish.workspace = true
 
 [dependencies]
+cl-arena = { version = "0", registry = "soft-fish" }

compiler/cl-structures/src/index_map.rs

@@ -0,0 +1,217 @@
+//! Trivially-copyable, easily comparable typed [indices](MapIndex),
+//! and an [IndexMap] to contain them.
+//!
+//! # Examples
+//!
+//! ```rust
+//! # use cl_structures::index_map::*;
+//! // first, create a new MapIndex type (this ensures type safety)
+//! make_index! {
+//!     Number
+//! }
+//!
+//! // then, create a map with that type
+//! let mut numbers: IndexMap<Number, i32> = IndexMap::new();
+//! let first = numbers.insert(1);
+//! let second = numbers.insert(2);
+//! let third = numbers.insert(3);
+//!
+//! // You can access elements immutably with `get`
+//! assert_eq!(Some(&3), numbers.get(third));
+//! assert_eq!(Some(&2), numbers.get(second));
+//! // or by indexing
+//! assert_eq!(1, numbers[first]);
+//!
+//! // Or mutably
+//! *numbers.get_mut(first).unwrap() = 100000;
+//!
+//! assert_eq!(Some(&100000), numbers.get(first));
+//! ```
+
+/// Creates newtype indices over [`usize`] for use as [IndexMap] keys.
+///
+/// Generated key types implement [Clone], [Copy],
+/// [Debug](core::fmt::Debug), [PartialEq], [Eq], [PartialOrd], [Ord], [Hash](core::hash::Hash),
+/// and [MapIndex].
+#[macro_export]
+macro_rules! make_index {($($(#[$meta:meta])* $name:ident),*$(,)?) => {$(
+    $(#[$meta])*
+    #[repr(transparent)]
+    #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+    pub struct $name(usize);
+
+    impl $crate::index_map::MapIndex for $name {
+        #[doc = concat!("Constructs a [`", stringify!($name), "`] from a [`usize`] without checking bounds.\n")]
+        /// The provided value should be within the bounds of its associated container
+        #[inline]
+        fn from_usize(value: usize) -> Self {
+            Self(value)
+        }
+        #[inline]
+        fn get(&self) -> usize {
+            self.0
+        }
+    }
+
+    impl From< $name > for usize {
+        fn from(value: $name) -> Self {
+            value.0
+        }
+    }
+)*}}
+
+use self::iter::MapIndexIter;
+use core::slice::GetManyMutError;
+use std::ops::{Index, IndexMut};
+
+pub use make_index;
+
+/// An index into a [IndexMap]. For full type-safety,
+/// there should be a unique [MapIndex] for each [IndexMap].
+pub trait MapIndex: std::fmt::Debug {
+    /// Constructs an [`MapIndex`] from a [`usize`] without checking bounds.
+    ///
+    /// The provided value should be within the bounds of its associated container.
+    fn from_usize(value: usize) -> Self;
+    /// Gets the index of the [`MapIndex`] by value
+    fn get(&self) -> usize;
+}
+
+/// It's an array. Lmao.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct IndexMap<K: MapIndex, V> {
+    map: Vec<V>,
+    id_type: std::marker::PhantomData<K>,
+}
+
+impl<V, K: MapIndex> IndexMap<K, V> {
+    /// Constructs an empty IndexMap.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Gets a reference to the value in slot `index`.
+    pub fn get(&self, index: K) -> Option<&V> {
+        self.map.get(index.get())
+    }
+
+    /// Gets a mutable reference to the value in slot `index`.
+    pub fn get_mut(&mut self, index: K) -> Option<&mut V> {
+        self.map.get_mut(index.get())
+    }
+
+    /// Returns mutable references to many indices at once.
+    ///
+    /// Returns an error if any index is out of bounds, or if the same index was passed twice.
+    pub fn get_many_mut<const N: usize>(
+        &mut self,
+        indices: [K; N],
+    ) -> Result<[&mut V; N], GetManyMutError> {
+        self.map.get_many_mut(indices.map(|id| id.get()))
+    }
+
+    /// Returns an iterator over the IndexMap.
+    pub fn values(&self) -> impl Iterator<Item = &V> {
+        self.map.iter()
+    }
+
+    /// Returns an iterator that allows modifying each value.
+    pub fn values_mut(&mut self) -> impl Iterator<Item = &mut V> {
+        self.map.iter_mut()
+    }
+
+    /// Returns an iterator over all keys in the IndexMap.
+    pub fn keys(&self) -> iter::MapIndexIter<K> {
+        // Safety: IndexMap currently has map.len() entries, and data cannot be removed
+        MapIndexIter::new(0..self.map.len())
+    }
+
+    /// Constructs an [ID](MapIndex) from a [usize], if it's within bounds
+    #[doc(hidden)]
+    pub fn try_key_from(&self, value: usize) -> Option<K> {
+        (value < self.map.len()).then(|| K::from_usize(value))
+    }
+
+    /// Inserts a new item into the IndexMap, returning the key associated with it.
+    pub fn insert(&mut self, value: V) -> K {
+        let id = self.map.len();
+        self.map.push(value);
+
+        // Safety: value was pushed to `self.map[id]`
+        K::from_usize(id)
+    }
+
+    /// Replaces a value in the IndexMap, returning the old value.
+    pub fn replace(&mut self, key: K, value: V) -> V {
+        std::mem::replace(&mut self[key], value)
+    }
+}
+
+impl<K: MapIndex, V> Default for IndexMap<K, V> {
+    fn default() -> Self {
+        Self { map: vec![], id_type: std::marker::PhantomData }
+    }
+}
+
+impl<K: MapIndex, V> Index<K> for IndexMap<K, V> {
+    type Output = V;
+
+    fn index(&self, index: K) -> &Self::Output {
+        match self.map.get(index.get()) {
+            None => panic!("Index {:?} out of bounds in IndexMap!", index),
+            Some(value) => value,
+        }
+    }
+}
+
+impl<K: MapIndex, V> IndexMut<K> for IndexMap<K, V> {
+    fn index_mut(&mut self, index: K) -> &mut Self::Output {
+        match self.map.get_mut(index.get()) {
+            None => panic!("Index {:?} out of bounds in IndexMap!", index),
+            Some(value) => value,
+        }
+    }
+}
+
+mod iter {
+    //! Iterators for [IndexMap](super::IndexMap)
+    use super::MapIndex;
+    use std::{marker::PhantomData, ops::Range};
+
+    /// Iterates over the keys of an [IndexMap](super::IndexMap), independently of the map.
+    ///
+    /// This is guaranteed to never overrun the length of the map, but is *NOT* guaranteed
+    /// to iterate over all elements of the map if the map is extended during iteration.
+    #[derive(Clone, Debug, PartialEq, Eq, Hash)]
+    pub struct MapIndexIter<K: MapIndex> {
+        range: Range<usize>,
+        _id: PhantomData<K>,
+    }
+
+    impl<K: MapIndex> MapIndexIter<K> {
+        /// Creates a new [MapIndexIter] producing the given [MapIndex]
+        pub(super) fn new(range: Range<usize>) -> Self {
+            Self { range, _id: PhantomData }
+        }
+    }
+
+    impl<ID: MapIndex> Iterator for MapIndexIter<ID> {
+        type Item = ID;
+
+        fn next(&mut self) -> Option<Self::Item> {
+            Some(ID::from_usize(self.range.next()?))
+        }
+        fn size_hint(&self) -> (usize, Option<usize>) {
+            self.range.size_hint()
+        }
+    }
+
+    impl<ID: MapIndex> DoubleEndedIterator for MapIndexIter<ID> {
+        fn next_back(&mut self) -> Option<Self::Item> {
+            // Safety: see above
+            Some(ID::from_usize(self.range.next_back()?))
+        }
+    }
+
+    impl<ID: MapIndex> ExactSizeIterator for MapIndexIter<ID> {}
+}

compiler/cl-structures/src/intern.rs

@@ -0,0 +1,315 @@
+//! Interners for [strings](string_interner) and arbitrary [types](typed_interner).
+//!
+//! An object is [Interned][1] if it is allocated within one of the interners
+//! in this module. [Interned][1] values have referential equality semantics, and
+//! [Deref](std::ops::Deref) to the value within their respective intern pool.
+//!
+//! This means, of course, that the same value interned in two different pools will be
+//! considered *not equal* by [Eq] and [Hash](std::hash::Hash).
+//!
+//! [1]: interned::Interned
+
+pub mod interned {
+    //! An [Interned] reference asserts its wrapped value has referential equality.
+    use super::string_interner::StringInterner;
+    use std::{
+        fmt::{Debug, Display},
+        hash::Hash,
+        ops::Deref,
+    };
+
+    /// An [Interned] value is one that is *referentially comparable*.
+    /// That is, the interned value is unique in memory, simplifying
+    /// its equality and hashing implementation.
+    ///
+    /// Comparing [Interned] values via [PartialOrd] or [Ord] will still
+    /// dereference to the wrapped pointers, and as such, may produce
+    /// results inconsistent with [PartialEq] or [Eq].
+    #[repr(transparent)]
+    pub struct Interned<'a, T: ?Sized> {
+        value: &'a T,
+    }
+
+    impl<'a, T: ?Sized> Interned<'a, T> {
+        /// Gets the internal value as a pointer
+        pub fn as_ptr(interned: &Self) -> *const T {
+            interned.value
+        }
+
+        /// Gets the internal value as a reference with the interner's lifetime
+        pub fn to_ref(interned: &Self) -> &'a T {
+            interned.value
+        }
+    }
+
+    impl<T: ?Sized + Debug> Debug for Interned<'_, T> {
+        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+            f.debug_struct("Interned")
+                .field("value", &self.value)
+                .finish()
+        }
+    }
+    impl<'a, T: ?Sized> Interned<'a, T> {
+        pub(super) fn new(value: &'a T) -> Self {
+            Self { value }
+        }
+    }
+    impl<T: ?Sized> Deref for Interned<'_, T> {
+        type Target = T;
+        fn deref(&self) -> &Self::Target {
+            self.value
+        }
+    }
+    impl<T: ?Sized> Copy for Interned<'_, T> {}
+    impl<T: ?Sized> Clone for Interned<'_, T> {
+        fn clone(&self) -> Self {
+            *self
+        }
+    }
+    // TODO: These implementations are subtly incorrect, as they do not line up with `eq`
+    // impl<'a, T: ?Sized + PartialOrd> PartialOrd for Interned<'a, T> {
+    //     fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
+    //         match self == other {
+    //             true => Some(std::cmp::Ordering::Equal),
+    //             false => self.value.partial_cmp(other.value),
+    //         }
+    //     }
+    // }
+    // impl<'a, T: ?Sized + Ord> Ord for Interned<'a, T> {
+    //     fn cmp(&self, other: &Self) -> std::cmp::Ordering {
+    //         match self == other {
+    //             true => std::cmp::Ordering::Equal,
+    //             false => self.value.cmp(other.value),
+    //         }
+    //     }
+    // }
+
+    impl<T: ?Sized> Eq for Interned<'_, T> {}
+    impl<T: ?Sized> PartialEq for Interned<'_, T> {
+        fn eq(&self, other: &Self) -> bool {
+            std::ptr::eq(self.value, other.value)
+        }
+    }
+    impl<T: ?Sized> Hash for Interned<'_, T> {
+        fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+            Self::as_ptr(self).hash(state)
+        }
+    }
+    impl<T: ?Sized + Display> Display for Interned<'_, T> {
+        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+            self.value.fmt(f)
+        }
+    }
+
+    impl<T: AsRef<str>> From<T> for Interned<'static, str> {
+        /// Types which implement [`AsRef<str>`] will be stored in the global [StringInterner]
+        fn from(value: T) -> Self {
+            from_str(value.as_ref())
+        }
+    }
+    fn from_str(value: &str) -> Interned<'static, str> {
+        let global_interner = StringInterner::global();
+        global_interner.get_or_insert(value)
+    }
+}
+
+pub mod string_interner {
+    //! A [StringInterner] hands out [Interned] copies of each unique string given to it.
+
+    use super::interned::Interned;
+    use cl_arena::dropless_arena::DroplessArena;
+    use std::{
+        collections::HashSet,
+        sync::{OnceLock, RwLock},
+    };
+
+    /// A string interner hands out [Interned] copies of each unique string given to it.
+    #[derive(Default)]
+    pub struct StringInterner<'a> {
+        arena: DroplessArena<'a>,
+        keys: RwLock<HashSet<&'a str>>,
+    }
+
+    impl StringInterner<'static> {
+        /// Gets a reference to a global string interner whose [Interned] strings are `'static`
+        pub fn global() -> &'static Self {
+            static GLOBAL_INTERNER: OnceLock<StringInterner<'static>> = OnceLock::new();
+
+            // SAFETY: The RwLock within the interner's `keys` protects the arena
+            // from being modified concurrently.
+            GLOBAL_INTERNER.get_or_init(|| StringInterner {
+                arena: DroplessArena::new(),
+                keys: Default::default(),
+            })
+        }
+    }
+
+    impl<'a> StringInterner<'a> {
+        /// Creates a new [StringInterner] backed by the provided [DroplessArena]
+        pub fn new(arena: DroplessArena<'a>) -> Self {
+            Self { arena, keys: RwLock::new(HashSet::new()) }
+        }
+
+        /// Returns an [Interned] copy of the given string,
+        /// allocating a new one if it doesn't already exist.
+        ///
+        /// # Blocks
+        /// This function blocks when the interner is held by another thread.
+        pub fn get_or_insert(&'a self, value: &str) -> Interned<'a, str> {
+            let Self { arena, keys } = self;
+
+            // Safety: Holding this write guard for the entire duration of this
+            // function enforces a safety invariant. See StringInterner::global.
+            let mut keys = keys.write().expect("should not be poisoned");
+
+            Interned::new(match keys.get(value) {
+                Some(value) => value,
+                None => {
+                    let value = match value {
+                        "" => "", // Arena will panic if passed an empty string
+                        _ => arena.alloc_str(value),
+                    };
+                    keys.insert(value);
+                    value
+                }
+            })
+        }
+        /// Gets a reference to the interned copy of the given value, if it exists
+        /// # Blocks
+        /// This function blocks when the interner is held by another thread.
+        pub fn get(&'a self, value: &str) -> Option<Interned<'a, str>> {
+            let keys = self.keys.read().expect("should not be poisoned");
+            keys.get(value).copied().map(Interned::new)
+        }
+    }
+
+    impl std::fmt::Debug for StringInterner<'_> {
+        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+            f.debug_struct("Interner")
+                .field("keys", &self.keys)
+                .finish()
+        }
+    }
+
+    impl std::fmt::Display for StringInterner<'_> {
+        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+            let Ok(keys) = self.keys.read() else {
+                return write!(f, "Could not lock StringInterner key map.");
+            };
+            let mut keys: Vec<_> = keys.iter().collect();
+            keys.sort();
+
+            writeln!(f, "Keys:")?;
+            for (idx, key) in keys.iter().enumerate() {
+                writeln!(f, "{idx}:\t\"{key}\"")?
+            }
+            writeln!(f, "Count: {}", keys.len())?;
+
+            Ok(())
+        }
+    }
+
+    // # Safety:
+    // This is fine because StringInterner::get_or_insert(v) holds a RwLock
+    // for its entire duration, and doesn't touch the non-(Send+Sync) arena
+    // unless the lock is held by a write guard.
+    unsafe impl Send for StringInterner<'_> {}
+    unsafe impl Sync for StringInterner<'_> {}
+
+    #[cfg(test)]
+    mod tests {
+        use super::StringInterner;
+
+        macro_rules! ptr_eq {
+        ($a: expr, $b: expr $(, $($t:tt)*)?) => {
+            assert_eq!(std::ptr::addr_of!($a), std::ptr::addr_of!($b) $(, $($t)*)?)
+        };
+    }
+        macro_rules! ptr_ne {
+        ($a: expr, $b: expr $(, $($t:tt)*)?) => {
+            assert_ne!(std::ptr::addr_of!($a), std::ptr::addr_of!($b) $(, $($t)*)?)
+        };
+    }
+
+        #[test]
+        fn empties_is_unique() {
+            let interner = StringInterner::global();
+            let empty = interner.get_or_insert("");
+            let empty2 = interner.get_or_insert("");
+            ptr_eq!(*empty, *empty2);
+        }
+        #[test]
+        fn non_empty_is_unique() {
+            let interner = StringInterner::global();
+            let nonempty1 = interner.get_or_insert("not empty!");
+            let nonempty2 = interner.get_or_insert("not empty!");
+            let different = interner.get_or_insert("different!");
+            ptr_eq!(*nonempty1, *nonempty2);
+            ptr_ne!(*nonempty1, *different);
+        }
+    }
+}
+
+pub mod typed_interner {
+    //! A [TypedInterner] hands out [Interned] references for arbitrary types.
+    //!
+    //! Note: It is a *logic error* to modify the returned reference via interior mutability
+    //! in a way that changes the values produced by [Eq] and [Hash].
+    //!
+    //! See the standard library [HashSet] for more details.
+    use super::interned::Interned;
+    use cl_arena::typed_arena::TypedArena;
+    use std::{collections::HashSet, hash::Hash, sync::RwLock};
+
+    /// A [TypedInterner] hands out [Interned] references for arbitrary types.
+    ///
+    /// See the [module-level documentation](self) for more information.
+    #[derive(Default)]
+    pub struct TypedInterner<'a, T: Eq + Hash> {
+        arena: TypedArena<'a, T>,
+        keys: RwLock<HashSet<&'a T>>,
+    }
+
+    impl<'a, T: Eq + Hash> TypedInterner<'a, T> {
+        /// Creates a new [TypedInterner] backed by the provided [TypedArena]
+        pub fn new(arena: TypedArena<'a, T>) -> Self {
+            Self { arena, keys: RwLock::new(HashSet::new()) }
+        }
+
+        /// Converts the given value into an [Interned] value.
+        ///
+        /// # Blocks
+        /// This function blocks when the interner is held by another thread.
+        pub fn get_or_insert(&'a self, value: T) -> Interned<'a, T> {
+            let Self { arena, keys } = self;
+
+            // Safety: Locking the keyset for the entire duration of this function
+            // enforces a safety invariant when the interner is stored in a global.
+            let mut keys = keys.write().expect("should not be poisoned");
+
+            Interned::new(match keys.get(&value) {
+                Some(value) => value,
+                None => {
+                    let value = arena.alloc(value);
+                    keys.insert(value);
+                    value
+                }
+            })
+        }
+        /// Returns the [Interned] copy of the given value, if one already exists
+        ///
+        /// # Blocks
+        /// This function blocks when the interner is being written to by another thread.
+        pub fn get(&self, value: &T) -> Option<Interned<'a, T>> {
+            let keys = self.keys.read().expect("should not be poisoned");
+            keys.get(value).copied().map(Interned::new)
+        }
+    }
+
+    /// # Safety
+    /// This should be safe because references yielded by
+    /// [get_or_insert](TypedInterner::get_or_insert) are unique, and the function uses
+    /// the [RwLock] around the [HashSet] to ensure mutual exclusion
+    unsafe impl<'a, T: Eq + Hash + Send> Send for TypedInterner<'a, T> where &'a T: Send {}
+    unsafe impl<T: Eq + Hash + Send + Sync> Sync for TypedInterner<'_, T> {}
+}

compiler/cl-structures/src/lib.rs

@@ -0,0 +1,24 @@
+//! # Universally useful structures
+//! - [Span](struct@span::Span): Stores a start and end [Loc](struct@span::Loc)
+//! - [Loc](struct@span::Loc): Stores the index in a stream
+//! - [TypedInterner][ti] & [StringInterner][si]: Provies stable, unique allocations
+//! - [Stack](stack::Stack): Contiguous collections with constant capacity
+//! - [IndexMap][im]: A map from [map indices][mi] to values
+//!
+//! [ti]: intern::typed_interner::TypedInterner
+//! [si]: intern::string_interner::StringInterner
+//! [im]: index_map::IndexMap
+//! [mi]: index_map::MapIndex
+#![warn(clippy::all)]
+#![feature(dropck_eyepatch, decl_macro, get_many_mut)]
+#![deny(unsafe_op_in_unsafe_fn)]
+
+pub mod intern;
+
+pub mod span;
+
+pub mod tree;
+
+pub mod stack;
+
+pub mod index_map;

compiler/cl-structures/src/span.rs

@@ -8,24 +8,33 @@ pub struct Span {
     pub head: Loc,
     pub tail: Loc,
 }
-pub fn Span(head: Loc, tail: Loc) -> Span {
+pub const fn Span(head: Loc, tail: Loc) -> Span {
     Span { head, tail }
 }
 
+impl Span {
+    pub const fn dummy() -> Self {
+        Span { head: Loc::dummy(), tail: Loc::dummy() }
+    }
+}
+
 /// Stores a read-only (line, column) location in a token stream
 #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct Loc {
     line: u32,
     col: u32,
 }
-pub fn Loc(line: u32, col: u32) -> Loc {
+pub const fn Loc(line: u32, col: u32) -> Loc {
     Loc { line, col }
 }
 impl Loc {
-    pub fn line(self) -> u32 {
+    pub const fn dummy() -> Self {
+        Loc { line: 0, col: 0 }
+    }
+    pub const fn line(self) -> u32 {
         self.line
     }
-    pub fn col(self) -> u32 {
+    pub const fn col(self) -> u32 {
         self.col
     }
 }

compiler/cl-structures/src/stack.rs

@@ -164,9 +164,11 @@ unsafe impl<#[may_dangle] T, const N: usize> Drop for Stack<T, N> {
     #[inline]
     fn drop(&mut self) {
         // Safety: We have ensured that all elements in the list are
+        if std::mem::needs_drop::<T>() {
             unsafe { core::ptr::drop_in_place(self.as_mut_slice()) };
         }
     }
+}
 
 impl<T, const N: usize> Extend<T> for Stack<T, N> {
     fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I) {
@@ -617,7 +619,6 @@ mod tests {
         assert_eq!(std::mem::size_of::<usize>(), std::mem::size_of_val(&v))
     }
     #[test]
-    #[cfg_attr(debug_assertions, ignore = "calls ().drop() usize::MAX times")]
     fn from_usize_max_zst_array() {
         let mut v = Stack::from([(); usize::MAX]);
         assert_eq!(v.len(), usize::MAX);

compiler/cl-token/src/lib.rs

@@ -10,4 +10,4 @@ pub mod token_type;
 
 pub use token::Token;
 pub use token_data::TokenData;
-pub use token_type::{Punct, TokenKind};
+pub use token_type::TokenKind;

compiler/cl-token/src/token_type.rs

@@ -0,0 +1,235 @@
+//! Stores a [Token's](super::Token) lexical information
+use std::{fmt::Display, str::FromStr};
+
+/// Stores a [Token's](super::Token) lexical information
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub enum TokenKind {
+    /// Invalid sequence
+    Invalid,
+    /// Any kind of comment
+    Comment,
+    /// Any tokenizable literal (See [TokenData](super::TokenData))
+    Literal,
+    /// A non-keyword identifier
+    Identifier,
+    // A keyword
+    As,       // as
+    Break,    // "break"
+    Cl,       // "cl"
+    Const,    // "const"
+    Continue, // "continue"
+    Else,     // "else"
+    Enum,     // "enum"
+    False,    // "false"
+    Fn,       // "fn"
+    For,      // "for"
+    If,       // "if"
+    Impl,     // "impl"
+    In,       // "in"
+    Let,      // "let"
+    Loop,     // "loop"
+    Match,    // "match"
+    Mod,      // "mod"
+    Mut,      // "mut"
+    Pub,      // "pub"
+    Return,   // "return"
+    SelfKw,   // "self"
+    SelfTy,   // "Self"
+    Static,   // "static"
+    Struct,   // "struct"
+    Super,    // "super"
+    True,     // "true"
+    Type,     // "type"
+    Use,      // "use"
+    While,    // "while"
+    // Delimiter or punctuation
+    LCurly,     // {
+    RCurly,     // }
+    LBrack,     // [
+    RBrack,     // ]
+    LParen,     // (
+    RParen,     // )
+    Amp,        // &
+    AmpAmp,     // &&
+    AmpEq,      // &=
+    Arrow,      // ->
+    At,         // @
+    Backslash,  // \
+    Bang,       // !
+    BangBang,   // !!
+    BangEq,     // !=
+    Bar,        // |
+    BarBar,     // ||
+    BarEq,      // |=
+    Colon,      // :
+    ColonColon, // ::
+    Comma,      // ,
+    Dot,        // .
+    DotDot,     // ..
+    DotDotEq,   // ..=
+    Eq,         // =
+    EqEq,       // ==
+    FatArrow,   // =>
+    Grave,      // `
+    Gt,         // >
+    GtEq,       // >=
+    GtGt,       // >>
+    GtGtEq,     // >>=
+    Hash,       // #
+    HashBang,   // #!
+    Lt,         // <
+    LtEq,       // <=
+    LtLt,       // <<
+    LtLtEq,     // <<=
+    Minus,      // -
+    MinusEq,    // -=
+    Plus,       // +
+    PlusEq,     // +=
+    Question,   // ?
+    Rem,        // %
+    RemEq,      // %=
+    Semi,       // ;
+    Slash,      // /
+    SlashEq,    // /=
+    Star,       // *
+    StarEq,     // *=
+    Tilde,      // ~
+    Xor,        // ^
+    XorEq,      // ^=
+    XorXor,     // ^^
+}
+
+impl Display for TokenKind {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            TokenKind::Invalid => "invalid".fmt(f),
+            TokenKind::Comment => "comment".fmt(f),
+            TokenKind::Literal => "literal".fmt(f),
+            TokenKind::Identifier => "identifier".fmt(f),
+
+            TokenKind::As => "sama".fmt(f),
+            TokenKind::Break => "pana".fmt(f),
+            TokenKind::Cl => "la".fmt(f),
+            TokenKind::Const => "kiwen".fmt(f),
+            TokenKind::Continue => "tawa".fmt(f),
+            TokenKind::Else => "taso".fmt(f),
+            TokenKind::Enum => "kulupu".fmt(f),
+            TokenKind::False => "ike".fmt(f),
+            TokenKind::Fn => "nasin".fmt(f),
+            TokenKind::For => "ale".fmt(f),
+            TokenKind::If => "tan".fmt(f),
+            TokenKind::Impl => "insa".fmt(f),
+            TokenKind::In => "lon".fmt(f),
+            TokenKind::Let => "poki".fmt(f),
+            TokenKind::Loop => "awen".fmt(f),
+            TokenKind::Match => "seme".fmt(f),
+            TokenKind::Mod => "selo".fmt(f),
+            TokenKind::Mut => "ante".fmt(f),
+            TokenKind::Pub => "lukin".fmt(f),
+            TokenKind::Return => "pini".fmt(f),
+            TokenKind::SelfKw => "mi".fmt(f),
+            TokenKind::SelfTy => "Mi".fmt(f),
+            TokenKind::Static => "mute".fmt(f),
+            TokenKind::Struct => "lipu".fmt(f),
+            TokenKind::Super => "mama".fmt(f),
+            TokenKind::True => "pona".fmt(f),
+            TokenKind::Type => "ijo".fmt(f),
+            TokenKind::Use => "jo".fmt(f),
+            TokenKind::While => "lawa".fmt(f),
+
+            TokenKind::LCurly => "{".fmt(f),
+            TokenKind::RCurly => "}".fmt(f),
+            TokenKind::LBrack => "[".fmt(f),
+            TokenKind::RBrack => "]".fmt(f),
+            TokenKind::LParen => "(".fmt(f),
+            TokenKind::RParen => ")".fmt(f),
+            TokenKind::Amp => "&".fmt(f),
+            TokenKind::AmpAmp => "&&".fmt(f),
+            TokenKind::AmpEq => "&=".fmt(f),
+            TokenKind::Arrow => "->".fmt(f),
+            TokenKind::At => "@".fmt(f),
+            TokenKind::Backslash => "\\".fmt(f),
+            TokenKind::Bang => "!".fmt(f),
+            TokenKind::BangBang => "!!".fmt(f),
+            TokenKind::BangEq => "!=".fmt(f),
+            TokenKind::Bar => "|".fmt(f),
+            TokenKind::BarBar => "||".fmt(f),
+            TokenKind::BarEq => "|=".fmt(f),
+            TokenKind::Colon => ":".fmt(f),
+            TokenKind::ColonColon => "::".fmt(f),
+            TokenKind::Comma => ",".fmt(f),
+            TokenKind::Dot => ".".fmt(f),
+            TokenKind::DotDot => "..".fmt(f),
+            TokenKind::DotDotEq => "..=".fmt(f),
+            TokenKind::Eq => "=".fmt(f),
+            TokenKind::EqEq => "==".fmt(f),
+            TokenKind::FatArrow => "=>".fmt(f),
+            TokenKind::Grave => "`".fmt(f),
+            TokenKind::Gt => ">".fmt(f),
+            TokenKind::GtEq => ">=".fmt(f),
+            TokenKind::GtGt => ">>".fmt(f),
+            TokenKind::GtGtEq => ">>=".fmt(f),
+            TokenKind::Hash => "#".fmt(f),
+            TokenKind::HashBang => "#!".fmt(f),
+            TokenKind::Lt => "<".fmt(f),
+            TokenKind::LtEq => "<=".fmt(f),
+            TokenKind::LtLt => "<<".fmt(f),
+            TokenKind::LtLtEq => "<<=".fmt(f),
+            TokenKind::Minus => "-".fmt(f),
+            TokenKind::MinusEq => "-=".fmt(f),
+            TokenKind::Plus => "+".fmt(f),
+            TokenKind::PlusEq => "+=".fmt(f),
+            TokenKind::Question => "?".fmt(f),
+            TokenKind::Rem => "%".fmt(f),
+            TokenKind::RemEq => "%=".fmt(f),
+            TokenKind::Semi => ";".fmt(f),
+            TokenKind::Slash => "/".fmt(f),
+            TokenKind::SlashEq => "/=".fmt(f),
+            TokenKind::Star => "*".fmt(f),
+            TokenKind::StarEq => "*=".fmt(f),
+            TokenKind::Tilde => "~".fmt(f),
+            TokenKind::Xor => "^".fmt(f),
+            TokenKind::XorEq => "^=".fmt(f),
+            TokenKind::XorXor => "^^".fmt(f),
+        }
+    }
+}
+impl FromStr for TokenKind {
+    /// [FromStr] can only fail when an identifier isn't a keyword
+    type Err = ();
+    /// Parses a string s to return a Keyword
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Ok(match s {
+            "as" | "sama" => Self::As,
+            "break" | "pana" => Self::Break,
+            "cl" | "la" => Self::Cl,
+            "const" | "kiwen" => Self::Const,
+            "continue" | "tawa" => Self::Continue,
+            "else" | "taso" => Self::Else,
+            "enum" | "kulupu" => Self::Enum,
+            "false" | "ike" => Self::False,
+            "fn" | "nasin" => Self::Fn,
+            "for" | "ale" => Self::For,
+            "if" | "tan" => Self::If,
+            "impl" | "insa" => Self::Impl,
+            "in" | "lon" => Self::In,
+            "let" | "poki" => Self::Let,
+            "loop" | "awen" => Self::Loop,
+            "match" | "seme" => Self::Match,
+            "mod" | "selo" => Self::Mod,
+            "mut" | "ante" => Self::Mut,
+            "pub" | "lukin" => Self::Pub,
+            "return" | "pini" => Self::Return,
+            "self" | "mi" => Self::SelfKw,
+            "Self" | "Mi" => Self::SelfTy,
+            "static" | "mute" => Self::Static,
+            "struct" | "lipu" => Self::Struct,
+            "super" | "mama" => Self::Super,
+            "true" | "pona" => Self::True,
+            "type" | "ijo" => Self::Type,
+            "use" | "jo" => Self::Use,
+            "while" | "lawa" => Self::While,
+            _ => Err(())?,
+        })
+    }
+}

compiler/cl-typeck/Cargo.toml

@@ -10,3 +10,8 @@ publish.workspace = true
 [dependencies]
 cl-ast = { path = "../cl-ast" }
 cl-structures = { path = "../cl-structures" }
+
+[dev-dependencies]
+repline = { path = "../../repline" }
+cl-lexer = { path = "../cl-lexer" }
+cl-parser = { path = "../cl-parser" }

compiler/cl-typeck/examples/typeck.rs

@@ -0,0 +1,328 @@
+use cl_typeck::{entry::Entry, stage::*, table::Table, type_expression::TypeExpression};
+
+use cl_ast::{
+    ast_visitor::{Fold, Visit},
+    desugar::*,
+    Stmt, Ty,
+};
+use cl_lexer::Lexer;
+use cl_parser::{inliner::ModuleInliner, Parser};
+use cl_structures::intern::string_interner::StringInterner;
+use repline::{error::Error as RlError, prebaked::*};
+use std::{
+    error::Error,
+    path::{self, PathBuf},
+    sync::LazyLock,
+};
+
+// Path to display in standard library errors
+const STDLIB_DISPLAY_PATH: &str = "stdlib/lib.cl";
+// Statically included standard library
+const PREAMBLE: &str = r"
+pub mod std;
+pub use std::preamble::*;
+";
+
+// Colors
+const C_MAIN: &str = C_LISTING;
+const C_RESV: &str = "\x1b[35m";
+const C_CODE: &str = "\x1b[36m";
+const C_BYID: &str = "\x1b[95m";
+const C_ERROR: &str = "\x1b[31m";
+const C_LISTING: &str = "\x1b[38;5;117m";
+
+fn main() -> Result<(), Box<dyn Error>> {
+    let mut prj = Table::default();
+
+    let mut parser = Parser::new(Lexer::new(PREAMBLE));
+    let code = match parser.parse() {
+        Ok(code) => code,
+        Err(e) => {
+            eprintln!("{STDLIB_DISPLAY_PATH}:{e}");
+            Err(e)?
+        }
+    };
+    // This code is special - it gets loaded from a hard-coded project directory (for now)
+    let code = inline_modules(code, concat!(env!("CARGO_MANIFEST_DIR"), "/../../stdlib"));
+    Populator::new(&mut prj).visit_file(interned(code));
+
+    main_menu(&mut prj)?;
+    Ok(())
+}
+
+fn main_menu(prj: &mut Table) -> Result<(), RlError> {
+    banner();
+    read_and(C_MAIN, "mu>", "? >", |line| {
+        match line.trim() {
+            "c" | "code" => enter_code(prj)?,
+            "clear" => clear()?,
+            "d" | "desugar" => live_desugar()?,
+            "e" | "exit" => return Ok(Response::Break),
+            "f" | "file" => import_files(prj)?,
+            "i" | "id" => get_by_id(prj)?,
+            "l" | "list" => list_types(prj),
+            "q" | "query" => query_type_expression(prj)?,
+            "r" | "resolve" => resolve_all(prj)?,
+            "s" | "strings" => print_strings(),
+            "h" | "help" | "" => {
+                println!(
+                    "Valid commands are:
+    clear      : Clear the screen
+    code    (c): Enter code to type-check
+    desugar (d): WIP: Test the experimental desugaring passes
+    file    (f): Load files from disk
+    id      (i): Get a type by its type ID
+    list    (l): List all known types
+    query   (q): Query the type system
+    resolve (r): Perform type resolution
+    help    (h): Print this list
+    exit    (e): Exit the program"
+                );
+                return Ok(Response::Deny);
+            }
+            _ => Err(r#"Invalid command. Type "help" to see the list of valid commands."#)?,
+        }
+        Ok(Response::Accept)
+    })
+}
+
+fn enter_code(prj: &mut Table) -> Result<(), RlError> {
+    read_and(C_CODE, "cl>", "? >", |line| {
+        if line.trim().is_empty() {
+            return Ok(Response::Break);
+        }
+        let code = Parser::new(Lexer::new(line)).parse()?;
+        let code = inline_modules(code, "");
+        let code = WhileElseDesugar.fold_file(code);
+
+        Populator::new(prj).visit_file(interned(code));
+        Ok(Response::Accept)
+    })
+}
+
+fn live_desugar() -> Result<(), RlError> {
+    read_and(C_RESV, "se>", "? >", |line| {
+        let code = Parser::new(Lexer::new(line)).parse::<Stmt>()?;
+        println!("Raw, as parsed:\n{C_LISTING}{code}\x1b[0m");
+
+        let code = SquashGroups.fold_stmt(code);
+        println!("SquashGroups\n{C_LISTING}{code}\x1b[0m");
+
+        let code = WhileElseDesugar.fold_stmt(code);
+        println!("WhileElseDesugar\n{C_LISTING}{code}\x1b[0m");
+
+        let code = NormalizePaths::new().fold_stmt(code);
+        println!("NormalizePaths\n{C_LISTING}{code}\x1b[0m");
+
+        Ok(Response::Accept)
+    })
+}
+
+fn print_strings() {
+    println!("{}", StringInterner::global());
+}
+
+fn query_type_expression(prj: &mut Table) -> Result<(), RlError> {
+    read_and(C_RESV, "ty>", "? >", |line| {
+        if line.trim().is_empty() {
+            return Ok(Response::Break);
+        }
+        // parse it as a path, and convert the path into a borrowed path
+        let ty: Ty = Parser::new(Lexer::new(line)).parse()?;
+        let id = ty.evaluate(prj, prj.root())?;
+        pretty_handle(id.to_entry(prj))?;
+        Ok(Response::Accept)
+    })
+}
+
+fn get_by_id(prj: &mut Table) -> Result<(), RlError> {
+    use cl_parser::parser::Parse;
+    use cl_structures::index_map::MapIndex;
+    use cl_typeck::handle::Handle;
+    read_and(C_BYID, "id>", "? >", |line| {
+        if line.trim().is_empty() {
+            return Ok(Response::Break);
+        }
+        let mut parser = Parser::new(Lexer::new(line));
+        let def_id = match Parse::parse(&mut parser)? {
+            cl_ast::Literal::Int(int) => int as _,
+            other => Err(format!("Expected integer, got {other}"))?,
+        };
+        let mut path = parser.parse::<cl_ast::Path>().unwrap_or_default();
+        path.absolute = false;
+
+        let handle = Handle::from_usize(def_id).to_entry(prj);
+
+        print!("  > {{{C_LISTING}{handle}\x1b[0m}}");
+        if !path.parts.is_empty() {
+            print!("::{path}")
+        }
+        println!();
+
+        let Some(entry) = handle.nav(&path.parts) else {
+            Err("No results.")?
+        };
+
+        pretty_handle(entry)?;
+
+        Ok(Response::Accept)
+    })
+}
+
+fn resolve_all(table: &mut Table) -> Result<(), Box<dyn Error>> {
+    for (id, error) in import(table) {
+        eprintln!("{error} in {} ({id})", id.to_entry(table))
+    }
+    for handle in table.handle_iter() {
+        if let Err(error) = handle.to_entry_mut(table).categorize() {
+            eprintln!("{error}");
+        }
+    }
+
+    for handle in implement(table) {
+        eprintln!("Unable to reparent {} ({handle})", handle.to_entry(table))
+    }
+
+    println!("...Resolved!");
+    Ok(())
+}
+
+fn list_types(table: &mut Table) {
+    for handle in table.debug_entry_iter() {
+        let id = handle.id();
+        let kind = handle.kind().unwrap();
+        let name = handle.name().unwrap_or("".into());
+        println!("{id:3}: {name:16}| {kind}: {handle}");
+    }
+}
+
+fn import_files(table: &mut Table) -> Result<(), RlError> {
+    read_and(C_RESV, "fi>", "? >", |line| {
+        let line = line.trim();
+        if line.is_empty() {
+            return Ok(Response::Break);
+        }
+        let Ok(file) = std::fs::read_to_string(line) else {
+            for file in std::fs::read_dir(line)? {
+                println!("{}", file?.path().display())
+            }
+            return Ok(Response::Accept);
+        };
+
+        let mut parser = Parser::new(Lexer::new(&file));
+        let code = match parser.parse() {
+            Ok(code) => inline_modules(code, PathBuf::from(line).parent().unwrap_or("".as_ref())),
+            Err(e) => {
+                eprintln!("{C_ERROR}{line}:{e}\x1b[0m");
+                return Ok(Response::Deny);
+            }
+        };
+
+        Populator::new(table).visit_file(interned(code));
+
+        println!("...Imported!");
+        Ok(Response::Accept)
+    })
+}
+
+fn pretty_handle(entry: Entry) -> Result<(), std::io::Error> {
+    use std::io::Write;
+    let mut out = std::io::stdout().lock();
+    let Some(kind) = entry.kind() else {
+        return writeln!(out, "{entry}");
+    };
+    write!(out, "{C_LISTING}{kind}")?;
+
+    if let Some(name) = entry.name() {
+        write!(out, " {name}")?;
+    }
+    writeln!(out, "\x1b[0m ({}): {entry}", entry.id())?;
+
+    if let Some(parent) = entry.parent() {
+        writeln!(
+            out,
+            "- {C_LISTING}Parent\x1b[0m: {parent} ({})",
+            parent.id()
+        )?;
+    }
+
+    if let Some(span) = entry.span() {
+        writeln!(
+            out,
+            "- {C_LISTING}Span:\x1b[0m ({}, {})",
+            span.head, span.tail
+        )?;
+    }
+
+    match entry.meta() {
+        Some(meta) if !meta.is_empty() => {
+            writeln!(out, "- {C_LISTING}Meta:\x1b[0m")?;
+            for meta in meta {
+                writeln!(out, "  - {meta}")?;
+            }
+        }
+        _ => {}
+    }
+
+    if let Some(children) = entry.children() {
+        writeln!(out, "- {C_LISTING}Children:\x1b[0m")?;
+        for (name, child) in children {
+            writeln!(
+                out,
+                "  - {C_LISTING}{name}\x1b[0m ({child}): {}",
+                entry.with_id(*child)
+            )?
+        }
+    }
+
+    if let Some(imports) = entry.imports() {
+        writeln!(out, "- {C_LISTING}Imports:\x1b[0m")?;
+        for (name, child) in imports {
+            writeln!(
+                out,
+                "  - {C_LISTING}{name}\x1b[0m ({child}): {}",
+                entry.with_id(*child)
+            )?
+        }
+    }
+
+    Ok(())
+}
+
+fn inline_modules(code: cl_ast::File, path: impl AsRef<path::Path>) -> cl_ast::File {
+    match ModuleInliner::new(path).inline(code) {
+        Err((code, io, parse)) => {
+            for (file, error) in io {
+                eprintln!("{}:{error}", file.display());
+            }
+            for (file, error) in parse {
+                eprintln!("{}:{error}", file.display());
+            }
+            code
+        }
+        Ok(code) => code,
+    }
+}
+
+fn clear() -> Result<(), Box<dyn Error>> {
+    println!("\x1b[H\x1b[2J");
+    banner();
+    Ok(())
+}
+
+fn banner() {
+    println!(
+        "--- {} v{} 💪🦈 ---",
+        env!("CARGO_BIN_NAME"),
+        env!("CARGO_PKG_VERSION"),
+    );
+}
+
+/// Interns a [File](cl_ast::File), returning a static reference to it.
+fn interned(file: cl_ast::File) -> &'static cl_ast::File {
+    use cl_structures::intern::{interned::Interned, typed_interner::TypedInterner};
+    static INTERNER: LazyLock<TypedInterner<'static, cl_ast::File>> =
+        LazyLock::new(Default::default);
+
+    Interned::to_ref(&INTERNER.get_or_insert(file))
+}

compiler/cl-typeck/src/entry.rs

@@ -0,0 +1,184 @@
+//! An [Entry] is an accessor for [nodes](Handle) in a [Table].
+//!
+//! There are two kinds of entry:
+//! - [Entry]: Provides getters for an entry's fields, and an implementation of
+//!   [Display](std::fmt::Display)
+//! - [EntryMut]: Provides setters for an entry's fields, and an [`as_ref`](EntryMut::as_ref) method
+//!   to demote to an [Entry].
+
+use std::collections::HashMap;
+
+use cl_ast::{Meta, PathPart, Sym};
+use cl_structures::span::Span;
+
+use crate::{
+    handle::Handle,
+    source::Source,
+    stage::categorize as cat,
+    table::{NodeKind, Table},
+    type_expression::{self as tex, TypeExpression},
+    type_kind::TypeKind,
+};
+
+mod display;
+
+impl Handle {
+    pub const fn to_entry<'t, 'a>(self, table: &'t Table<'a>) -> Entry<'t, 'a> {
+        Entry { id: self, table }
+    }
+    pub fn to_entry_mut<'t, 'a>(self, table: &'t mut Table<'a>) -> EntryMut<'t, 'a> {
+        EntryMut { id: self, table }
+    }
+}
+
+#[derive(Debug)]
+pub struct Entry<'t, 'a> {
+    table: &'t Table<'a>,
+    id: Handle,
+}
+
+impl<'t, 'a> Entry<'t, 'a> {
+    pub const fn new(table: &'t Table<'a>, id: Handle) -> Self {
+        Self { table, id }
+    }
+
+    pub const fn id(&self) -> Handle {
+        self.id
+    }
+
+    pub fn inner(&self) -> &Table<'a> {
+        self.table
+    }
+
+    pub const fn with_id(&self, id: Handle) -> Entry<'_, 'a> {
+        Self { table: self.table, id }
+    }
+
+    pub fn nav(&self, path: &[PathPart]) -> Option<Entry<'_, 'a>> {
+        Some(Entry { id: self.table.nav(self.id, path)?, table: self.table })
+    }
+
+    pub const fn root(&self) -> Handle {
+        self.table.root()
+    }
+
+    pub fn kind(&self) -> Option<&NodeKind> {
+        self.table.kind(self.id)
+    }
+
+    pub fn parent(&self) -> Option<Entry<'_, 'a>> {
+        Some(Entry { id: *self.table.parent(self.id)?, ..*self })
+    }
+
+    pub fn children(&self) -> Option<&HashMap<Sym, Handle>> {
+        self.table.children(self.id)
+    }
+
+    pub fn imports(&self) -> Option<&HashMap<Sym, Handle>> {
+        self.table.imports(self.id)
+    }
+
+    pub fn ty(&self) -> Option<&TypeKind> {
+        self.table.ty(self.id)
+    }
+
+    pub fn span(&self) -> Option<&Span> {
+        self.table.span(self.id)
+    }
+
+    pub fn meta(&self) -> Option<&'a [Meta]> {
+        self.table.meta(self.id)
+    }
+
+    pub fn source(&self) -> Option<&Source<'a>> {
+        self.table.source(self.id)
+    }
+
+    pub fn impl_target(&self) -> Option<Entry<'_, 'a>> {
+        Some(Entry { id: self.table.impl_target(self.id)?, ..*self })
+    }
+
+    pub fn selfty(&self) -> Option<Entry<'_, 'a>> {
+        Some(Entry { id: self.table.selfty(self.id)?, ..*self })
+    }
+
+    pub fn name(&self) -> Option<Sym> {
+        self.table.name(self.id)
+    }
+}
+
+#[derive(Debug)]
+pub struct EntryMut<'t, 'a> {
+    table: &'t mut Table<'a>,
+    id: Handle,
+}
+
+impl<'t, 'a> EntryMut<'t, 'a> {
+    pub fn new(table: &'t mut Table<'a>, id: Handle) -> Self {
+        Self { table, id }
+    }
+
+    pub fn as_ref(&self) -> Entry<'_, 'a> {
+        Entry { table: self.table, id: self.id }
+    }
+
+    pub const fn id(&self) -> Handle {
+        self.id
+    }
+
+    /// Evaluates a [TypeExpression] in this entry's context
+    pub fn evaluate<Out>(&mut self, ty: &impl TypeExpression<Out>) -> Result<Out, tex::Error> {
+        let Self { table, id } = self;
+        ty.evaluate(table, *id)
+    }
+
+    pub fn categorize(&mut self) -> Result<(), cat::Error> {
+        cat::categorize(self.table, self.id)
+    }
+
+    /// Constructs a new Handle with the provided parent [Handle]
+    pub fn with_id(&mut self, parent: Handle) -> EntryMut<'_, 'a> {
+        EntryMut { table: self.table, id: parent }
+    }
+
+    pub fn nav(&mut self, path: &[PathPart]) -> Option<EntryMut<'_, 'a>> {
+        Some(EntryMut { id: self.table.nav(self.id, path)?, table: self.table })
+    }
+
+    pub fn new_entry(&mut self, kind: NodeKind) -> EntryMut<'_, 'a> {
+        let id = self.table.new_entry(self.id, kind);
+        self.with_id(id)
+    }
+
+    pub fn add_child(&mut self, name: Sym, child: Handle) -> Option<Handle> {
+        self.table.add_child(self.id, name, child)
+    }
+
+    pub fn set_ty(&mut self, kind: TypeKind) -> Option<TypeKind> {
+        self.table.set_ty(self.id, kind)
+    }
+
+    pub fn set_span(&mut self, span: Span) -> Option<Span> {
+        self.table.set_span(self.id, span)
+    }
+
+    pub fn set_meta(&mut self, meta: &'a [Meta]) -> Option<&'a [Meta]> {
+        self.table.set_meta(self.id, meta)
+    }
+
+    pub fn set_source(&mut self, source: Source<'a>) -> Option<Source<'a>> {
+        self.table.set_source(self.id, source)
+    }
+
+    pub fn set_impl_target(&mut self, target: Handle) -> Option<Handle> {
+        self.table.set_impl_target(self.id, target)
+    }
+
+    pub fn mark_use_item(&mut self) {
+        self.table.mark_use_item(self.id)
+    }
+
+    pub fn mark_impl_item(&mut self) {
+        self.table.mark_impl_item(self.id)
+    }
+}

compiler/cl-typeck/src/entry/display.rs

@@ -0,0 +1,100 @@
+use super::*;
+use crate::{format_utils::*, type_kind::Adt};
+use std::fmt::{self, Write};
+
+/// Printing the name of a named type stops infinite recursion
+fn write_name_or(h: Entry, f: &mut impl Write) -> fmt::Result {
+    match h.name() {
+        Some(name) => write!(f, "{name}"),
+        None => write!(f, "{h}"),
+    }
+}
+
+impl fmt::Display for Entry<'_, '_> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let Some(&kind) = self.kind() else {
+            return write!(f, "<invalid type: {}>", self.id);
+        };
+
+        if let Some(ty) = self.ty() {
+            match ty {
+                TypeKind::Instance(id) => write!(f, "{}", self.with_id(*id)),
+                TypeKind::Intrinsic(kind) => write!(f, "{kind}"),
+                TypeKind::Adt(adt) => write_adt(adt, self, f),
+                &TypeKind::Ref(id) => {
+                    f.write_str("&")?;
+                    let h_id = self.with_id(id);
+                    write_name_or(h_id, f)
+                }
+                TypeKind::Slice(id) => {
+                    write_name_or(self.with_id(*id), &mut f.delimit_with("[", "]"))
+                }
+                &TypeKind::Array(t, cnt) => {
+                    let mut f = f.delimit_with("[", "]");
+                    write_name_or(self.with_id(t), &mut f)?;
+                    write!(f, "; {cnt}")
+                }
+                TypeKind::Tuple(ids) => {
+                    let mut f = f.delimit_with("(", ")");
+                    for (index, &id) in ids.iter().enumerate() {
+                        if index > 0 {
+                            write!(f, ", ")?;
+                        }
+                        write_name_or(self.with_id(id), &mut f)?;
+                    }
+                    Ok(())
+                }
+                TypeKind::FnSig { args, rety } => {
+                    write!(f, "fn {} -> ", self.with_id(*args))?;
+                    write_name_or(self.with_id(*rety), f)
+                }
+                TypeKind::Empty => write!(f, "()"),
+                TypeKind::Never => write!(f, "!"),
+                TypeKind::Module => write!(f, "module?"),
+            }
+        } else {
+            write!(f, "{kind}")
+        }
+    }
+}
+
+fn write_adt(adt: &Adt, h: &Entry, f: &mut impl Write) -> fmt::Result {
+    match adt {
+        Adt::Enum(variants) => {
+            let mut variants = variants.iter();
+            separate(", ", || {
+                variants.next().map(|(name, def)| {
+                    move |f: &mut Delimit<_>| match def {
+                        Some(def) => {
+                            write!(f, "{name}: ")?;
+                            write_name_or(h.with_id(*def), f)
+                        }
+                        None => write!(f, "{name}"),
+                    }
+                })
+            })(f.delimit_with("enum {", "}"))
+        }
+        Adt::Struct(members) => {
+            let mut members = members.iter();
+            separate(", ", || {
+                let (name, vis, id) = members.next()?;
+                Some(move |f: &mut Delimit<_>| {
+                    write!(f, "{vis}{name}: ")?;
+                    write_name_or(h.with_id(*id), f)
+                })
+            })(f.delimit_with("struct {", "}"))
+        }
+        Adt::TupleStruct(members) => {
+            let mut members = members.iter();
+            separate(", ", || {
+                let (vis, def) = members.next()?;
+                Some(move |f: &mut Delimit<_>| {
+                    write!(f, "{vis}")?;
+                    write_name_or(h.with_id(*def), f)
+                })
+            })(f.delimit_with("struct (", ")"))
+        }
+        Adt::UnitStruct => write!(f, "struct"),
+        Adt::Union(_) => todo!("Display union types"),
+    }
+}

compiler/cl-typeck/src/format_utils.rs

@@ -0,0 +1,23 @@
+pub use cl_ast::format::*;
+use std::{fmt, iter};
+
+/// Separates the items yielded by iterating the provided function
+pub const fn separate<'f, 's, Item, F, W>(
+    sep: &'s str,
+    t: F,
+) -> impl FnOnce(W) -> fmt::Result + 's
+where
+    Item: FnMut(&mut W) -> fmt::Result,
+    F: FnMut() -> Option<Item> + 's,
+    W: fmt::Write,
+{
+    move |mut f| {
+        for (idx, mut disp) in iter::from_fn(t).enumerate() {
+            if idx > 0 {
+                f.write_str(sep)?;
+            }
+            disp(&mut f)?;
+        }
+        Ok(())
+    }
+}

compiler/cl-typeck/src/handle.rs

@@ -0,0 +1,15 @@
+//! A [Handle] uniquely represents an entry in the [Table](crate::table::Table)
+
+use cl_structures::index_map::*;
+
+// define the index types
+make_index! {
+    /// Uniquely represents an entry in the [Table](crate::table::Table)
+    Handle,
+}
+
+impl std::fmt::Display for Handle {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.0.fmt(f)
+    }
+}

compiler/cl-typeck/src/lib.rs

@@ -0,0 +1,74 @@
+//! # The Conlang Type Checker
+//!
+//! As a statically typed language, Conlang requires a robust type checker to enforce correctness.
+//!
+//! This crate is a major work-in-progress.
+//!
+//! # The [Table](table::Table)™
+//! A directed graph of nodes and their dependencies.
+//!
+//! Contains [item definitions](handle) and [type expression](type_expression) information.
+//!
+//! *Every* item is itself a module, and can contain arbitrarily nested items
+//! as part of the item graph
+//!
+//! The table, additionally, has some queues for use in external algorithms,
+//! detailed in the [stage] module.
+//!
+//! # Namespaces
+//! Each item in the graph is given its own namespace, which is further separated into
+//! two distinct parts:
+//! - Children of an item are direct descendents (i.e. their `parent` is a handle to the item)
+//! - Imports of an item are indirect descendents created by `use` or `impl` directives. They are
+//!   shadowed by Children with the same name.
+//!
+//! # Order of operations:
+//! For order-of-operations information, see the [stage] module.
+#![warn(clippy::all)]
+
+pub(crate) mod format_utils;
+
+pub mod table;
+
+pub mod handle;
+
+pub mod entry;
+
+pub mod source;
+
+pub mod type_kind;
+
+pub mod type_expression;
+
+pub mod stage {
+    //! Type collection, evaluation, checking, and inference passes.
+    //!
+    //! # Order of operations
+    //! 1. [mod@populate]: Populate the graph with nodes for every named item.
+    //! 2. [mod@import]: Import the `use` nodes discovered in [Stage 1](populate).
+    //! 3. [mod@categorize]: Categorize the nodes according to textual type information.
+    //!    - Creates anonymous types (`fn(T) -> U`, `&T`, `[T]`, etc.) as necessary to fill in the
+    //!      type graph
+    //!    - Creates a new struct type for every enum struct-variant.
+    //! 4. [mod@implement]: Import members of implementation modules into types.
+
+    pub use populate::Populator;
+    /// Stage 1: Populate the graph with nodes.
+    pub mod populate;
+
+    pub use import::import;
+    /// Stage 2: Import the `use` nodes discovered in Stage 1.
+    pub mod import;
+
+    pub use categorize::categorize;
+    /// Stage 3: Categorize the nodes according to textual type information.
+    pub mod categorize;
+
+    pub use implement::implement;
+    /// Stage 4: Import members of `impl` blocks into their corresponding types.
+    pub mod implement;
+
+    // TODO: Make type inference stage 5
+    // TODO: Use the type information stored in the [table]
+    pub mod infer;
+}

compiler/cl-typeck/src/source.rs

@@ -0,0 +1,87 @@
+//! Holds the [Source] of a definition in the AST
+
+use cl_ast::ast::*;
+use std::fmt;
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub enum Source<'a> {
+    Root,
+    Module(&'a Module),
+    Alias(&'a Alias),
+    Enum(&'a Enum),
+    Variant(&'a Variant),
+    Struct(&'a Struct),
+    Const(&'a Const),
+    Static(&'a Static),
+    Function(&'a Function),
+    Local(&'a Let),
+    Impl(&'a Impl),
+    Use(&'a Use),
+    Ty(&'a TyKind),
+}
+
+impl Source<'_> {
+    pub fn name(&self) -> Option<Sym> {
+        match self {
+            Source::Root => None,
+            Source::Module(v) => Some(v.name),
+            Source::Alias(v) => Some(v.to),
+            Source::Enum(v) => Some(v.name),
+            Source::Variant(v) => Some(v.name),
+            Source::Struct(v) => Some(v.name),
+            Source::Const(v) => Some(v.name),
+            Source::Static(v) => Some(v.name),
+            Source::Function(v) => Some(v.name),
+            Source::Local(_) => None,
+            Source::Impl(_) | Source::Use(_) | Source::Ty(_) => None,
+        }
+    }
+
+    /// Returns `true` if this [Source] defines a named value
+    pub fn is_named_value(&self) -> bool {
+        matches!(self, Self::Const(_) | Self::Static(_) | Self::Function(_))
+    }
+
+    /// Returns `true` if this [Source] defines a named type
+    pub fn is_named_type(&self) -> bool {
+        matches!(
+            self,
+            Self::Module(_) | Self::Alias(_) | Self::Enum(_) | Self::Struct(_)
+        )
+    }
+
+    /// Returns `true` if this [Source] refers to a [Ty] with no name
+    pub fn is_anon_type(&self) -> bool {
+        matches!(self, Self::Ty(_))
+    }
+
+    /// Returns `true` if this [Source] refers to an [Impl] block
+    pub fn is_impl(&self) -> bool {
+        matches!(self, Self::Impl(_))
+    }
+
+    /// Returns `true` if this [Source] refers to a [Use] import
+    pub fn is_use_import(&self) -> bool {
+        matches!(self, Self::Use(_))
+    }
+}
+
+impl fmt::Display for Source<'_> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::Root => "🌳 root 🌳".fmt(f),
+            Self::Module(arg0) => arg0.fmt(f),
+            Self::Alias(arg0) => arg0.fmt(f),
+            Self::Enum(arg0) => arg0.fmt(f),
+            Self::Variant(arg0) => arg0.fmt(f),
+            Self::Struct(arg0) => arg0.fmt(f),
+            Self::Const(arg0) => arg0.fmt(f),
+            Self::Static(arg0) => arg0.fmt(f),
+            Self::Function(arg0) => arg0.fmt(f),
+            Self::Impl(arg0) => arg0.fmt(f),
+            Self::Use(arg0) => arg0.fmt(f),
+            Self::Ty(arg0) => arg0.fmt(f),
+            Self::Local(arg0) => arg0.fmt(f),
+        }
+    }
+}

compiler/cl-typeck/src/stage/categorize.rs

@@ -0,0 +1,229 @@
+//! Categorizes an entry in a table according to its embedded type information
+
+use crate::{
+    handle::Handle,
+    source::Source,
+    table::{NodeKind, Table},
+    type_expression::{Error as TypeEval, TypeExpression},
+    type_kind::{Adt, TypeKind},
+};
+use cl_ast::*;
+
+/// Ensures a type entry exists for the provided handle in the table
+pub fn categorize(table: &mut Table, node: Handle) -> CatResult<()> {
+    if let Some(meta) = table.meta(node) {
+        for meta @ Meta { name, kind } in meta {
+            if let ("intrinsic", MetaKind::Equals(Literal::String(s))) = (&**name, kind) {
+                let kind =
+                    TypeKind::Intrinsic(s.parse().map_err(|_| Error::BadMeta(meta.clone()))?);
+                table.set_ty(node, kind);
+                return Ok(());
+            }
+        }
+    }
+
+    let Some(source) = table.source(node) else {
+        return Ok(());
+    };
+
+    match source {
+        Source::Root => Ok(()),
+        Source::Module(_) => Ok(()),
+        Source::Alias(a) => cat_alias(table, node, a),
+        Source::Enum(e) => cat_enum(table, node, e),
+        Source::Variant(_) => Ok(()),
+        Source::Struct(s) => cat_struct(table, node, s),
+        Source::Const(c) => cat_const(table, node, c),
+        Source::Static(s) => cat_static(table, node, s),
+        Source::Function(f) => cat_function(table, node, f),
+        Source::Local(l) => cat_local(table, node, l),
+        Source::Impl(i) => cat_impl(table, node, i),
+        Source::Use(_) => Ok(()),
+        Source::Ty(ty) => ty
+            .evaluate(table, node)
+            .map_err(|e| Error::TypeEval(e, " while categorizing a type"))
+            .map(drop),
+    }
+}
+
+fn parent(table: &Table, node: Handle) -> Handle {
+    table.parent(node).copied().unwrap_or(node)
+}
+
+fn cat_alias(table: &mut Table, node: Handle, a: &Alias) -> CatResult<()> {
+    let parent = parent(table, node);
+    let kind = match &a.from {
+        Some(ty) => TypeKind::Instance(
+            ty.evaluate(table, parent)
+                .map_err(|e| Error::TypeEval(e, " while categorizing an alias"))?,
+        ),
+        None => TypeKind::Empty,
+    };
+    table.set_ty(node, kind);
+
+    Ok(())
+}
+
+fn cat_struct(table: &mut Table, node: Handle, s: &Struct) -> CatResult<()> {
+    let parent = parent(table, node);
+    let Struct { name: _, kind } = s;
+    let kind = match kind {
+        StructKind::Empty => TypeKind::Adt(Adt::UnitStruct),
+        StructKind::Tuple(types) => {
+            let mut out = vec![];
+            for ty in types {
+                out.push((Visibility::Public, ty.evaluate(table, parent)?))
+            }
+            TypeKind::Adt(Adt::TupleStruct(out))
+        }
+        StructKind::Struct(members) => {
+            let mut out = vec![];
+            for m in members {
+                out.push(cat_member(table, node, m)?)
+            }
+            TypeKind::Adt(Adt::Struct(out))
+        }
+    };
+
+    table.set_ty(node, kind);
+    Ok(())
+}
+
+fn cat_member(
+    table: &mut Table,
+    node: Handle,
+    m: &StructMember,
+) -> CatResult<(Sym, Visibility, Handle)> {
+    let StructMember { vis, name, ty } = m;
+    Ok((*name, *vis, ty.evaluate(table, node)?))
+}
+
+fn cat_enum<'a>(table: &mut Table<'a>, node: Handle, e: &'a Enum) -> CatResult<()> {
+    let Enum { name: _, kind } = e;
+    let kind = match kind {
+        EnumKind::NoVariants => TypeKind::Adt(Adt::Enum(vec![])),
+        EnumKind::Variants(variants) => {
+            let mut out_vars = vec![];
+            for v in variants {
+                out_vars.push(cat_variant(table, node, v)?)
+            }
+            TypeKind::Adt(Adt::Enum(out_vars))
+        }
+    };
+
+    table.set_ty(node, kind);
+    Ok(())
+}
+
+fn cat_variant<'a>(
+    table: &mut Table<'a>,
+    node: Handle,
+    v: &'a Variant,
+) -> CatResult<(Sym, Option<Handle>)> {
+    let parent = parent(table, node);
+    let Variant { name, kind } = v;
+    match kind {
+        VariantKind::Plain => Ok((*name, None)),
+        VariantKind::CLike(c) => todo!("enum-variant constant {c}"),
+        VariantKind::Tuple(ty) => {
+            let ty = ty
+                .evaluate(table, parent)
+                .map_err(|e| Error::TypeEval(e, " while categorizing a variant"))?;
+            Ok((*name, Some(ty)))
+        }
+        VariantKind::Struct(members) => {
+            let mut out = vec![];
+            for m in members {
+                out.push(cat_member(table, node, m)?)
+            }
+            let kind = TypeKind::Adt(Adt::Struct(out));
+
+            let mut h = node.to_entry_mut(table);
+            let mut variant = h.new_entry(NodeKind::Type);
+            variant.set_source(Source::Variant(v));
+            variant.set_ty(kind);
+            Ok((*name, Some(variant.id())))
+        }
+    }
+}
+
+fn cat_const(table: &mut Table, node: Handle, c: &Const) -> CatResult<()> {
+    let parent = parent(table, node);
+    let kind = TypeKind::Instance(
+        c.ty.evaluate(table, parent)
+            .map_err(|e| Error::TypeEval(e, " while categorizing a const"))?,
+    );
+    table.set_ty(node, kind);
+    Ok(())
+}
+
+fn cat_static(table: &mut Table, node: Handle, s: &Static) -> CatResult<()> {
+    let parent = parent(table, node);
+    let kind = TypeKind::Instance(
+        s.ty.evaluate(table, parent)
+            .map_err(|e| Error::TypeEval(e, " while categorizing a static"))?,
+    );
+    table.set_ty(node, kind);
+    Ok(())
+}
+
+fn cat_function(table: &mut Table, node: Handle, f: &Function) -> CatResult<()> {
+    let parent = parent(table, node);
+    let kind = TypeKind::Instance(
+        f.sign
+            .evaluate(table, parent)
+            .map_err(|e| Error::TypeEval(e, " while categorizing a function"))?,
+    );
+    table.set_ty(node, kind);
+    Ok(())
+}
+
+fn cat_local(table: &mut Table, node: Handle, l: &Let) -> CatResult<()> {
+    let parent = parent(table, node);
+    if let Some(ty) = &l.ty {
+        let kind = ty
+            .evaluate(table, parent)
+            .map_err(|e| Error::TypeEval(e, " while categorizing a let binding"))?;
+        table.set_ty(node, TypeKind::Instance(kind));
+    }
+    Ok(())
+}
+
+fn cat_impl(table: &mut Table, node: Handle, i: &Impl) -> CatResult<()> {
+    let parent = parent(table, node);
+    let Impl { target, body: _ } = i;
+    let target = match target {
+        ImplKind::Type(t) => t.evaluate(table, parent),
+        ImplKind::Trait { impl_trait: _, for_type: t } => t.evaluate(table, parent),
+    }?;
+
+    table.set_impl_target(node, target);
+    Ok(())
+}
+
+type CatResult<T> = Result<T, Error>;
+
+#[derive(Clone, Debug)]
+pub enum Error {
+    BadMeta(Meta),
+    Recursive(Handle),
+    TypeEval(TypeEval, &'static str),
+}
+
+impl From<TypeEval> for Error {
+    fn from(value: TypeEval) -> Self {
+        Error::TypeEval(value, "")
+    }
+}
+
+impl std::fmt::Display for Error {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Error::BadMeta(meta) => write!(f, "Unknown meta attribute: #[{meta}]"),
+            Error::Recursive(id) => {
+                write!(f, "Encountered recursive type without indirection: {id}")
+            }
+            Error::TypeEval(e, during) => write!(f, "{e}{during}"),
+        }
+    }
+}

compiler/cl-typeck/src/stage/implement.rs

@@ -0,0 +1,23 @@
+use crate::{handle::Handle, table::Table};
+
+pub fn implement(table: &mut Table) -> Vec<Handle> {
+    let pending = std::mem::take(&mut table.impls);
+    let mut errors = vec![];
+    for node in pending {
+        if let Err(e) = impl_one(table, node) {
+            errors.push(e);
+        }
+    }
+    errors
+}
+
+pub fn impl_one(table: &mut Table, node: Handle) -> Result<(), Handle> {
+    let Some(target) = table.impl_target(node) else {
+        Err(node)?
+    };
+    let Table { children, imports, .. } = table;
+    if let Some(children) = children.get(&node) {
+        imports.entry(target).or_default().extend(children);
+    }
+    Ok(())
+}

compiler/cl-typeck/src/stage/import.rs

@@ -0,0 +1,158 @@
+//! An algorithm for importing external nodes
+
+use crate::{
+    handle::Handle,
+    source::Source,
+    table::{NodeKind, Table},
+};
+use cl_ast::{PathPart, Sym, Use, UseTree};
+use core::slice;
+use std::{collections::HashSet, mem};
+
+type Seen = HashSet<Handle>;
+
+pub fn import<'a>(table: &mut Table<'a>) -> Vec<(Handle, Error<'a>)> {
+    let pending = mem::take(&mut table.uses);
+
+    let mut seen = Seen::new();
+    let mut failed = vec![];
+    for import in pending {
+        let Err(e) = import_one(table, import, &mut seen) else {
+            continue;
+        };
+        if let Error::NotFound(_, _) = e {
+            table.mark_use_item(import)
+        }
+        failed.push((import, e));
+    }
+    failed
+}
+
+fn import_one<'a>(table: &mut Table<'a>, item: Handle, seen: &mut Seen) -> UseResult<'a, ()> {
+    if !seen.insert(item) {
+        return Ok(());
+    }
+
+    let Some(NodeKind::Use) = table.kind(item) else {
+        Err(Error::ItsNoUse)?
+    };
+    let Some(&dst) = table.parent(item) else {
+        Err(Error::NoParents)?
+    };
+    let Some(code) = table.source(item) else {
+        Err(Error::NoSource)?
+    };
+    let &Source::Use(tree) = code else {
+        Err(Error::BadSource(*code))?
+    };
+    let Use { absolute, tree } = tree;
+
+    import_tree(
+        table,
+        if !absolute { dst } else { table.root() },
+        dst,
+        tree,
+        seen,
+    )
+}
+
+fn import_tree<'a>(
+    table: &mut Table<'a>,
+    src: Handle,
+    dst: Handle,
+    tree: &UseTree,
+    seen: &mut Seen,
+) -> UseResult<'a, ()> {
+    match tree {
+        UseTree::Tree(trees) => trees
+            .iter()
+            .try_for_each(|tree| import_tree(table, src, dst, tree, seen)),
+        UseTree::Path(part, rest) => {
+            let source = table
+                .nav(src, slice::from_ref(part))
+                .ok_or_else(|| Error::NotFound(src, part.clone()))?;
+            import_tree(table, source, dst, rest, seen)
+        }
+        UseTree::Alias(src_name, dst_name) => {
+            import_name(table, src, src_name, dst, dst_name, seen)
+        }
+        UseTree::Name(src_name) => import_name(table, src, src_name, dst, src_name, seen),
+        UseTree::Glob => import_glob(table, src, dst, seen),
+    }
+}
+
+fn import_glob<'a>(
+    table: &mut Table<'a>,
+    src: Handle,
+    dst: Handle,
+    seen: &mut Seen,
+) -> UseResult<'a, ()> {
+    let Table { children, imports, .. } = table;
+
+    if let Some(c) = children.get(&src) {
+        imports.entry(dst).or_default().extend(c)
+    }
+
+    import_deps(table, src, seen)?;
+
+    let Table { imports, .. } = table;
+
+    // Importing imports requires some extra work, since we can't `get_many_mut`
+    if let Some(i) = imports.get(&src) {
+        let uses: Vec<_> = i.iter().map(|(&k, &v)| (k, v)).collect();
+        imports.entry(dst).or_default().extend(uses);
+    }
+
+    Ok(())
+}
+
+fn import_name<'a>(
+    table: &mut Table<'a>,
+    src: Handle,
+    src_name: &Sym,
+    dst: Handle,
+    dst_name: &Sym,
+    seen: &mut Seen,
+) -> UseResult<'a, ()> {
+    import_deps(table, src, seen)?;
+    match table.get_by_sym(src, src_name) {
+        // TODO: check for new imports clobbering existing imports
+        Some(src_id) => table.add_import(dst, *dst_name, src_id),
+        None => Err(Error::NotFound(src, PathPart::Ident(*src_name)))?,
+    };
+    Ok(())
+}
+
+/// Imports the dependencies of this node
+fn import_deps<'a>(table: &mut Table<'a>, node: Handle, seen: &mut Seen) -> UseResult<'a, ()> {
+    if let Some(items) = table.use_items.get(&node) {
+        let out = items.clone();
+        for item in out {
+            import_one(table, item, seen)?;
+        }
+    }
+    Ok(())
+}
+
+pub type UseResult<'a, T> = Result<T, Error<'a>>;
+
+#[derive(Debug)]
+pub enum Error<'a> {
+    ItsNoUse,
+    NoParents,
+    NoSource,
+    BadSource(Source<'a>),
+    NotFound(Handle, PathPart),
+}
+
+impl std::fmt::Display for Error<'_> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Error::ItsNoUse => write!(f, "Entry is not use"),
+            Error::NoParents => write!(f, "Entry has no parents"),
+            Error::NoSource => write!(f, "Entry has no source"),
+            Error::BadSource(s) => write!(f, "Entry incorrectly marked as use item: {s}"),
+            Error::NotFound(id, part) => write!(f, "Could not traverse {id}::{part}"),
+        }
+    }
+}

compiler/cl-typeck/src/stage/infer.rs

@@ -0,0 +1,248 @@
+//! Implements type unification, used by the Hindley-Milner type inference algorithm
+//!
+//! Inspired by [rust-hindley-milner][1] and [hindley-milner-python][2]
+//!
+//! [1]: https://github.com/tcr/rust-hindley-milner/
+//! [2]: https://github.com/rob-smallshire/hindley-milner-python
+
+use cl_ast::Sym;
+use core::fmt;
+use std::{cell::RefCell, rc::Rc};
+
+/*
+    Types in Conlang:
+    - Never type: !
+      - type !
+      - for<A> ! -> A
+    - Primitive types: bool, i32, (), ...
+      - type bool; ...
+    - Reference types: &T, *T
+      - for<T> type ref<T>; for<T> type ptr<T>
+    - Slice type:      [T]
+      - for<T> type slice<T>
+    - Array type:      [T;usize]
+      - for<T> type array<T, instanceof<usize>>
+    - Tuple type:      (T, ...Z)
+      - for<T, ..> type tuple<T, ..>    // on a per-case basis!
+    - Funct type:      fn Tuple -> R
+      - for<T, R> type T -> R           // on a per-case basis!
+*/
+
+/// A refcounted [Type]
+pub type RcType = Rc<Type>;
+
+#[derive(Debug, PartialEq, Eq)]
+pub struct Variable {
+    pub instance: RefCell<Option<RcType>>,
+}
+
+#[derive(Debug, PartialEq, Eq)]
+pub struct Operator {
+    name: Sym,
+    types: RefCell<Vec<RcType>>,
+}
+
+/// A [Type::Variable] or [Type::Operator]:
+/// - A [Type::Variable] can be either bound or unbound (instance: Some(_) | None)
+/// - A [Type::Operator] has a name (used to identify the operator) and a list of types.
+///
+/// A type which contains unbound variables is considered "generic" (see
+/// [`Type::is_generic()`]).
+#[derive(Debug, PartialEq, Eq)]
+pub enum Type {
+    Variable(Variable),
+    Operator(Operator),
+}
+
+impl Type {
+    /// Creates a new unbound [type variable](Type::Variable)
+    pub fn new_var() -> RcType {
+        Rc::new(Self::Variable(Variable { instance: RefCell::new(None) }))
+    }
+    /// Creates a variable that is a new instance of another [Type]
+    pub fn new_inst(of: &RcType) -> RcType {
+        Rc::new(Self::Variable(Variable {
+            instance: RefCell::new(Some(of.clone())),
+        }))
+    }
+    /// Creates a new [type operator](Type::Operator)
+    pub fn new_op(name: Sym, types: &[RcType]) -> RcType {
+        Rc::new(Self::Operator(Operator {
+            name,
+            types: RefCell::new(types.to_vec()),
+        }))
+    }
+    /// Creates a new [type operator](Type::Operator) representing a lambda
+    pub fn new_fn(takes: &RcType, returns: &RcType) -> RcType {
+        Self::new_op("fn".into(), &[takes.clone(), returns.clone()])
+    }
+    /// Creates a new [type operator](Type::Operator) representing a primitive type
+    pub fn new_prim(name: Sym) -> RcType {
+        Self::new_op(name, &[])
+    }
+    /// Creates a new [type operator](Type::Operator) representing a tuple
+    pub fn new_tuple(members: &[RcType]) -> RcType {
+        Self::new_op("tuple".into(), members)
+    }
+
+    /// Sets this type variable to be an instance `of` the other
+    /// # Panics
+    /// Panics if `self` is not a type variable
+    pub fn set_instance(self: &RcType, of: &RcType) {
+        match self.as_ref() {
+            Type::Operator(_) => unimplemented!("Cannot set instance of a type operator"),
+            Type::Variable(Variable { instance }) => *instance.borrow_mut() = Some(of.clone()),
+        }
+    }
+    /// Checks whether there are any unbound type variables in this type.
+    /// ```rust
+    /// # use cl_typeck::stage::infer::*;
+    /// let bool = Type::new_op("bool".into(), &[]);
+    /// let true_v = Type::new_inst(&bool);
+    /// let unbound = Type::new_var();
+    /// let id_fun = Type::new_fn(&unbound, &unbound);
+    /// let truthy = Type::new_fn(&unbound, &bool);
+    /// assert!(!bool.is_generic());   // bool contains no unbound type variables
+    /// assert!(!true_v.is_generic()); // true_v is bound to `bool`
+    /// assert!(unbound.is_generic()); // unbound is an unbound type variable
+    /// assert!(id_fun.is_generic());  // id_fun is a function with unbound type variables
+    /// assert!(truthy.is_generic());  // truthy is a function with one unbound type variable
+    /// ```
+    pub fn is_generic(self: &RcType) -> bool {
+        match self.as_ref() {
+            Type::Variable(Variable { instance }) => match instance.borrow().as_ref() {
+                // base case: self is an unbound type variable (instance is none)
+                None => true,
+                // Variable is bound to a type which may be generic
+                Some(instance) => instance.is_generic(),
+            },
+            Type::Operator(Operator { types, .. }) => {
+                // Operator may have generic args
+                types.borrow().iter().any(Self::is_generic)
+            }
+        }
+    }
+    /// Makes a deep copy of a type expression.
+    ///
+    /// Bound variables are shared, unbound variables are duplicated.
+    pub fn deep_clone(self: &RcType) -> RcType {
+        // If there aren't any unbound variables, it's fine to clone the entire expression
+        if !self.is_generic() {
+            return self.clone();
+        }
+        // There are unbound type variables, so we make a new one
+        match self.as_ref() {
+            Type::Variable { .. } => Self::new_var(),
+            Type::Operator(Operator { name, types }) => Self::new_op(
+                *name,
+                &types
+                    .borrow()
+                    .iter()
+                    .map(Self::deep_clone)
+                    .collect::<Vec<_>>(),
+            ),
+        }
+    }
+    /// Returns the defining instance of `self`,
+    /// collapsing type instances along the way.
+    /// # May panic
+    /// Panics if this type variable's instance field is already borrowed.
+    /// # Examples
+    /// ```rust
+    /// # use cl_typeck::stage::infer::*;
+    /// let t_bool = Type::new_op("bool".into(), &[]);
+    /// let t_nest = Type::new_inst(&Type::new_inst(&Type::new_inst(&t_bool)));
+    /// let pruned = t_nest.prune();
+    /// assert_eq!(pruned, t_bool);
+    /// assert_eq!(t_nest, Type::new_inst(&t_bool));
+    /// ```
+    pub fn prune(self: &RcType) -> RcType {
+        if let Type::Variable(Variable { instance }) = self.as_ref() {
+            if let Some(old_inst) = instance.borrow_mut().as_mut() {
+                let new_inst = old_inst.prune(); // get defining instance
+                *old_inst = new_inst.clone(); // collapse
+                return new_inst;
+            }
+        }
+        self.clone()
+    }
+
+    /// Checks whether a type expression occurs in another type expression
+    ///
+    /// # Note:
+    /// - Since the test uses strict equality, `self` should be pruned prior to testing.
+    /// - The test is *not guaranteed to terminate* for recursive types.
+    pub fn occurs_in(self: &RcType, other: &RcType) -> bool {
+        if self == other {
+            return true;
+        }
+        match other.as_ref() {
+            Type::Variable(Variable { instance }) => match instance.borrow().as_ref() {
+                Some(t) => self.occurs_in(t),
+                None => false,
+            },
+            Type::Operator(Operator { types, .. }) => {
+                // Note: this might panic.
+                // Think about whether it panics for only recursive types?
+                types.borrow().iter().any(|other| self.occurs_in(other))
+            }
+        }
+    }
+
+    /// Unifies two type expressions, propagating changes via interior mutability
+    pub fn unify(self: &RcType, other: &RcType) -> Result<(), InferenceError> {
+        let (a, b) = (self.prune(), other.prune()); // trim the hedges
+        match (a.as_ref(), b.as_ref()) {
+            (Type::Variable { .. }, _) if !a.occurs_in(&b) => a.set_instance(&b),
+            (Type::Variable { .. }, _) => Err(InferenceError::Recursive(a, b))?,
+            (Type::Operator { .. }, Type::Variable { .. }) => b.unify(&a)?,
+            (
+                Type::Operator(Operator { name: a_name, types: a_types }),
+                Type::Operator(Operator { name: b_name, types: b_types }),
+            ) => {
+                let (a_types, b_types) = (a_types.borrow(), b_types.borrow());
+                if a_name != b_name || a_types.len() != b_types.len() {
+                    Err(InferenceError::Mismatch(a.clone(), b.clone()))?
+                }
+                for (a, b) in a_types.iter().zip(b_types.iter()) {
+                    a.unify(b)?
+                }
+            }
+        }
+        Ok(())
+    }
+}
+
+impl fmt::Display for Type {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Type::Variable(Variable { instance }) => match instance.borrow().as_ref() {
+                Some(instance) => write!(f, "{instance}"),
+                None => write!(f, "_"),
+            },
+            Type::Operator(Operator { name, types }) => {
+                write!(f, "({name}")?;
+                for ty in types.borrow().iter() {
+                    write!(f, " {ty}")?;
+                }
+                f.write_str(")")
+            }
+        }
+    }
+}
+
+/// An error produced during type inference
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub enum InferenceError {
+    Mismatch(RcType, RcType),
+    Recursive(RcType, RcType),
+}
+
+impl fmt::Display for InferenceError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            InferenceError::Mismatch(a, b) => write!(f, "Type mismatch: {a:?} != {b:?}"),
+            InferenceError::Recursive(_, _) => write!(f, "Recursive type!"),
+        }
+    }
+}

compiler/cl-typeck/src/stage/populate.rs

@@ -0,0 +1,167 @@
+//! The [Populator] populates entries in the sym table, including span info
+use crate::{
+    entry::EntryMut,
+    handle::Handle,
+    source::Source,
+    table::{NodeKind, Table},
+};
+use cl_ast::{ast_visitor::Visit, ItemKind, Sym};
+
+#[derive(Debug)]
+pub struct Populator<'t, 'a> {
+    inner: EntryMut<'t, 'a>,
+    name: Option<Sym>, // this is a hack to get around the Visitor interface
+}
+
+impl<'t, 'a> Populator<'t, 'a> {
+    pub fn new(table: &'t mut Table<'a>) -> Self {
+        Self { inner: table.root_entry_mut(), name: None }
+    }
+    /// Constructs a new Populator with the provided parent Handle
+    pub fn with_id(&mut self, parent: Handle) -> Populator<'_, 'a> {
+        Populator { inner: self.inner.with_id(parent), name: None }
+    }
+
+    pub fn new_entry(&mut self, kind: NodeKind) -> Populator<'_, 'a> {
+        Populator { inner: self.inner.new_entry(kind), name: None }
+    }
+
+    pub fn set_name(&mut self, name: Sym) {
+        self.name = Some(name);
+    }
+}
+
+impl<'a> Visit<'a> for Populator<'_, 'a> {
+    fn visit_item(&mut self, i: &'a cl_ast::Item) {
+        let cl_ast::Item { extents, attrs, vis, kind } = i;
+        // TODO: this, better, better.
+        let entry_kind = match kind {
+            ItemKind::Alias(_) => NodeKind::Type,
+            ItemKind::Enum(_) => NodeKind::Type,
+            ItemKind::Struct(_) => NodeKind::Type,
+
+            ItemKind::Const(_) => NodeKind::Const,
+            ItemKind::Static(_) => NodeKind::Static,
+            ItemKind::Function(_) => NodeKind::Function,
+
+            ItemKind::Module(_) => NodeKind::Module,
+            ItemKind::Impl(_) => NodeKind::Impl,
+            ItemKind::Use(_) => NodeKind::Use,
+        };
+
+        let mut entry = self.new_entry(entry_kind);
+        entry.inner.set_span(*extents);
+        entry.inner.set_meta(&attrs.meta);
+
+        entry.visit_span(extents);
+        entry.visit_attrs(attrs);
+        entry.visit_visibility(vis);
+        entry.visit_item_kind(kind);
+
+        if let (Some(name), child) = (entry.name, entry.inner.id()) {
+            self.inner.add_child(name, child);
+        }
+    }
+
+    fn visit_alias(&mut self, a: &'a cl_ast::Alias) {
+        let cl_ast::Alias { to, from } = a;
+        self.inner.set_source(Source::Alias(a));
+        self.set_name(*to);
+
+        if let Some(t) = from {
+            self.visit_ty(t)
+        }
+    }
+
+    fn visit_const(&mut self, c: &'a cl_ast::Const) {
+        let cl_ast::Const { name, ty, init } = c;
+        self.inner.set_source(Source::Const(c));
+        self.set_name(*name);
+
+        self.visit_ty(ty);
+        self.visit_expr(init);
+    }
+
+    fn visit_static(&mut self, s: &'a cl_ast::Static) {
+        let cl_ast::Static { mutable, name, ty, init } = s;
+        self.inner.set_source(Source::Static(s));
+        self.set_name(*name);
+
+        self.visit_mutability(mutable);
+        self.visit_ty(ty);
+        self.visit_expr(init);
+    }
+
+    fn visit_module(&mut self, m: &'a cl_ast::Module) {
+        let cl_ast::Module { name, kind } = m;
+        self.inner.set_source(Source::Module(m));
+        self.set_name(*name);
+
+        self.visit_module_kind(kind);
+    }
+
+    fn visit_function(&mut self, f: &'a cl_ast::Function) {
+        let cl_ast::Function { name, sign, bind, body } = f;
+        self.inner.set_source(Source::Function(f));
+        self.set_name(*name);
+
+        self.visit_ty_fn(sign);
+        bind.iter().for_each(|p| self.visit_param(p));
+        if let Some(b) = body {
+            self.visit_block(b)
+        }
+    }
+
+    fn visit_struct(&mut self, s: &'a cl_ast::Struct) {
+        let cl_ast::Struct { name, kind } = s;
+        self.inner.set_source(Source::Struct(s));
+        self.set_name(*name);
+
+        self.visit_struct_kind(kind);
+    }
+
+    fn visit_enum(&mut self, e: &'a cl_ast::Enum) {
+        let cl_ast::Enum { name, kind } = e;
+        self.inner.set_source(Source::Enum(e));
+        self.set_name(*name);
+
+        self.visit_enum_kind(kind);
+    }
+
+    fn visit_impl(&mut self, i: &'a cl_ast::Impl) {
+        let cl_ast::Impl { target, body } = i;
+        self.inner.set_source(Source::Impl(i));
+        self.inner.mark_impl_item();
+
+        self.visit_impl_kind(target);
+        self.visit_file(body);
+    }
+
+    fn visit_use(&mut self, u: &'a cl_ast::Use) {
+        let cl_ast::Use { absolute: _, tree } = u;
+        self.inner.set_source(Source::Use(u));
+        self.inner.mark_use_item();
+
+        self.visit_use_tree(tree);
+    }
+
+    fn visit_let(&mut self, l: &'a cl_ast::Let) {
+        let cl_ast::Let { mutable, name: _, ty, init } = l;
+        let mut entry = self.new_entry(NodeKind::Local);
+
+        entry.inner.set_source(Source::Local(l));
+        // entry.set_name(*name);
+
+        entry.visit_mutability(mutable);
+        if let Some(ty) = ty {
+            entry.visit_ty(ty);
+        }
+        if let Some(init) = init {
+            entry.visit_expr(init)
+        }
+
+        // let child = entry.inner.id();
+        // self.inner.add_child(*name, child);
+        todo!("Pattern destructuring in cl-typeck")
+    }
+}

compiler/cl-typeck/src/table.rs

@@ -0,0 +1,308 @@
+//! The [Table] is a monolithic data structure representing everything the type checker
+//! knows about a program.
+//!
+//! Individual nodes in the table can be queried using the [Entry] API ([Table::entry])
+//! or modified using the [EntryMut] API ([Table::entry_mut]).
+//!
+//! # Contents of a "node"
+//! Always present:
+//! - [NodeKind]: Determines how this node will be treated during the [stages](crate::stage) of
+//!   compilation
+//! - [Parent node](Handle): Arranges this node in the hierarchical graph structure
+//!
+//! Populated as needed:
+//! - Children: An associative array of [names](Sym) to child nodes in the graph. Child nodes are
+//!   arranged in a *strict* tree structure, with no back edges
+//! - Imports: An associative array of [names](Sym) to other nodes in the graph. Not all import
+//!   nodes are back edges, but all back edges *must be* import nodes.
+//! - [Types](TypeKind): Contains type information populated through type checking and inference.
+//!   Nodes with unpopulated types may be considered type variables in the future.
+//! - [Spans][span]: Positional information from the source text. See [cl_structures::span].
+//! - [Metas](Meta): Metadata decorators. These may have an effect throughout the compiler.
+//! - [Sources](Source): Pointers back into the AST, for future analysis.
+//! - Impl Targets: Sparse mapping of `impl` nodes to their corresponding targets.
+//! - etc.
+//!
+//! [span]: struct@Span
+
+use crate::{
+    entry::{Entry, EntryMut},
+    handle::Handle,
+    source::Source,
+    type_kind::TypeKind,
+};
+use cl_ast::{Meta, PathPart, Sym};
+use cl_structures::{index_map::IndexMap, span::Span};
+use std::collections::HashMap;
+
+// TODO: Cycle detection external to this module
+
+/// The table is a monolithic data structure representing everything the type checker
+/// knows about a program.
+///
+/// See [module documentation](self).
+#[derive(Debug)]
+pub struct Table<'a> {
+    root: Handle,
+    /// This is the source of truth for handles
+    kinds: IndexMap<Handle, NodeKind>,
+    parents: IndexMap<Handle, Handle>,
+    pub(crate) children: HashMap<Handle, HashMap<Sym, Handle>>,
+    pub(crate) imports: HashMap<Handle, HashMap<Sym, Handle>>,
+    pub(crate) use_items: HashMap<Handle, Vec<Handle>>,
+    types: HashMap<Handle, TypeKind>,
+    spans: HashMap<Handle, Span>,
+    metas: HashMap<Handle, &'a [Meta]>,
+    sources: HashMap<Handle, Source<'a>>,
+    // code: HashMap<Handle, BasicBlock>, // TODO: lower sources
+    impl_targets: HashMap<Handle, Handle>,
+    anon_types: HashMap<TypeKind, Handle>,
+
+    // --- Queues for algorithms ---
+    pub(crate) impls: Vec<Handle>,
+    pub(crate) uses: Vec<Handle>,
+}
+
+impl<'a> Table<'a> {
+    pub fn new() -> Self {
+        let mut kinds = IndexMap::new();
+        let mut parents = IndexMap::new();
+        let root = kinds.insert(NodeKind::Root);
+        assert_eq!(root, parents.insert(root));
+
+        Self {
+            root,
+            kinds,
+            parents,
+            children: HashMap::new(),
+            imports: HashMap::new(),
+            use_items: HashMap::new(),
+            types: HashMap::new(),
+            spans: HashMap::new(),
+            metas: HashMap::new(),
+            sources: HashMap::new(),
+            impl_targets: HashMap::new(),
+            anon_types: HashMap::new(),
+            impls: Vec::new(),
+            uses: Vec::new(),
+        }
+    }
+
+    pub fn entry(&self, handle: Handle) -> Entry<'_, 'a> {
+        handle.to_entry(self)
+    }
+
+    pub fn entry_mut(&mut self, handle: Handle) -> EntryMut<'_, 'a> {
+        handle.to_entry_mut(self)
+    }
+
+    pub fn new_entry(&mut self, parent: Handle, kind: NodeKind) -> Handle {
+        let entry = self.kinds.insert(kind);
+        assert_eq!(entry, self.parents.insert(parent));
+        entry
+    }
+
+    pub fn add_child(&mut self, parent: Handle, name: Sym, child: Handle) -> Option<Handle> {
+        self.children.entry(parent).or_default().insert(name, child)
+    }
+
+    pub fn add_import(&mut self, parent: Handle, name: Sym, import: Handle) -> Option<Handle> {
+        self.imports.entry(parent).or_default().insert(name, import)
+    }
+
+    pub fn mark_use_item(&mut self, item: Handle) {
+        let parent = self.parents[item];
+        self.use_items.entry(parent).or_default().push(item);
+        self.uses.push(item);
+    }
+
+    pub fn mark_impl_item(&mut self, item: Handle) {
+        self.impls.push(item);
+    }
+
+    pub fn handle_iter(&mut self) -> impl Iterator<Item = Handle> {
+        self.kinds.keys()
+    }
+
+    /// Returns handles to all nodes sequentially by [Entry]
+    pub fn debug_entry_iter(&self) -> impl Iterator<Item = Entry<'_, 'a>> {
+        self.kinds.keys().map(|key| key.to_entry(self))
+    }
+
+    /// Gets the [Handle] of an anonymous type with the provided [TypeKind].
+    /// If not already present, a new one is created.
+    pub(crate) fn anon_type(&mut self, kind: TypeKind) -> Handle {
+        if let Some(id) = self.anon_types.get(&kind) {
+            return *id;
+        }
+        let entry = self.new_entry(self.root, NodeKind::Type);
+        // Anonymous types require a bijective map (anon_types => Def => types)
+        self.types.insert(entry, kind.clone());
+        self.anon_types.insert(kind, entry);
+        entry
+    }
+
+    pub const fn root_entry(&self) -> Entry<'_, 'a> {
+        self.root.to_entry(self)
+    }
+
+    pub fn root_entry_mut(&mut self) -> crate::entry::EntryMut<'_, 'a> {
+        self.root.to_entry_mut(self)
+    }
+
+    // --- inherent properties ---
+
+    pub const fn root(&self) -> Handle {
+        self.root
+    }
+
+    pub fn kind(&self, node: Handle) -> Option<&NodeKind> {
+        self.kinds.get(node)
+    }
+
+    pub fn parent(&self, node: Handle) -> Option<&Handle> {
+        self.parents.get(node)
+    }
+
+    pub fn children(&self, node: Handle) -> Option<&HashMap<Sym, Handle>> {
+        self.children.get(&node)
+    }
+
+    pub fn imports(&self, node: Handle) -> Option<&HashMap<Sym, Handle>> {
+        self.imports.get(&node)
+    }
+
+    pub fn ty(&self, node: Handle) -> Option<&TypeKind> {
+        self.types.get(&node)
+    }
+
+    pub fn span(&self, node: Handle) -> Option<&Span> {
+        self.spans.get(&node)
+    }
+
+    pub fn meta(&self, node: Handle) -> Option<&'a [Meta]> {
+        self.metas.get(&node).copied()
+    }
+
+    pub fn source(&self, node: Handle) -> Option<&Source<'a>> {
+        self.sources.get(&node)
+    }
+
+    pub fn impl_target(&self, node: Handle) -> Option<Handle> {
+        self.impl_targets.get(&node).copied()
+    }
+
+    pub fn set_ty(&mut self, node: Handle, kind: TypeKind) -> Option<TypeKind> {
+        self.types.insert(node, kind)
+    }
+
+    pub fn set_span(&mut self, node: Handle, span: Span) -> Option<Span> {
+        self.spans.insert(node, span)
+    }
+
+    pub fn set_meta(&mut self, node: Handle, meta: &'a [Meta]) -> Option<&'a [Meta]> {
+        self.metas.insert(node, meta)
+    }
+
+    pub fn set_source(&mut self, node: Handle, source: Source<'a>) -> Option<Source<'a>> {
+        self.sources.insert(node, source)
+    }
+
+    pub fn set_impl_target(&mut self, node: Handle, target: Handle) -> Option<Handle> {
+        self.impl_targets.insert(node, target)
+    }
+
+    // --- derived properties ---
+
+    /// Gets a handle to the local `Self` type, if one exists
+    pub fn selfty(&self, node: Handle) -> Option<Handle> {
+        match self.kinds.get(node)? {
+            NodeKind::Root | NodeKind::Use => None,
+            NodeKind::Type => Some(node),
+            NodeKind::Impl => self.impl_target(node),
+            _ => self.selfty(*self.parent(node)?),
+        }
+    }
+
+    pub fn name(&self, node: Handle) -> Option<Sym> {
+        self.source(node).and_then(|s| s.name())
+    }
+
+    pub fn is_transparent(&self, node: Handle) -> bool {
+        !matches!(
+            self.kind(node),
+            None | Some(NodeKind::Root | NodeKind::Module)
+        )
+    }
+
+    pub fn get_child(&self, node: Handle, name: &Sym) -> Option<Handle> {
+        self.children.get(&node).and_then(|c| c.get(name)).copied()
+    }
+
+    pub fn get_import(&self, node: Handle, name: &Sym) -> Option<Handle> {
+        self.imports.get(&node).and_then(|i| i.get(name)).copied()
+    }
+
+    pub fn get_by_sym(&self, node: Handle, name: &Sym) -> Option<Handle> {
+        self.get_child(node, name)
+            .or_else(|| self.get_import(node, name))
+            .or_else(|| {
+                self.is_transparent(node)
+                    .then(|| {
+                        self.parent(node)
+                            .and_then(|node| self.get_by_sym(*node, name))
+                    })
+                    .flatten()
+            })
+    }
+
+    /// Does path traversal relative to the provided `node`.
+    pub fn nav(&self, node: Handle, path: &[PathPart]) -> Option<Handle> {
+        match path {
+            [PathPart::SuperKw, rest @ ..] => self.nav(*self.parent(node)?, rest),
+            [PathPart::SelfKw, rest @ ..] => self.nav(node, rest),
+            [PathPart::SelfTy, rest @ ..] => self.nav(self.selfty(node)?, rest),
+            [PathPart::Ident(name), rest @ ..] => self.nav(self.get_by_sym(node, name)?, rest),
+            [] => Some(node),
+        }
+    }
+}
+
+impl Default for Table<'_> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+#[derive(Clone, Copy, Debug)]
+pub enum NodeKind {
+    Root,
+    Module,
+    Type,
+    Const,
+    Static,
+    Function,
+    Local,
+    Impl,
+    Use,
+}
+
+mod display {
+    use super::*;
+    use std::fmt;
+    impl fmt::Display for NodeKind {
+        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+            match self {
+                NodeKind::Root => write!(f, "root"),
+                NodeKind::Module => write!(f, "mod"),
+                NodeKind::Type => write!(f, "type"),
+                NodeKind::Const => write!(f, "const"),
+                NodeKind::Static => write!(f, "static"),
+                NodeKind::Function => write!(f, "fn"),
+                NodeKind::Local => write!(f, "local"),
+                NodeKind::Use => write!(f, "use"),
+                NodeKind::Impl => write!(f, "impl"),
+            }
+        }
+    }
+}

compiler/cl-typeck/src/type_expression.rs

@@ -0,0 +1,131 @@
+//! A [TypeExpression] is a [syntactic](cl_ast) representation of a [TypeKind], and is used to
+//! construct type bindings in a [Table]'s typing context.
+
+use crate::{handle::Handle, table::Table, type_kind::TypeKind};
+use cl_ast::{PathPart, Ty, TyArray, TyFn, TyKind, TyRef, TySlice, TyTuple};
+
+#[derive(Clone, Debug, PartialEq, Eq)] // TODO: impl Display and Error
+pub enum Error {
+    BadPath { parent: Handle, path: Vec<PathPart> },
+}
+
+impl std::error::Error for Error {}
+impl std::fmt::Display for Error {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Error::BadPath { parent, path } => {
+                write!(f, "No item at path {parent}")?;
+                for part in path {
+                    write!(f, "::{part}")?;
+                }
+            }
+        }
+        Ok(())
+    }
+}
+
+/// A [TypeExpression] is a syntactic representation of a [TypeKind], and is used to construct
+/// type bindings in a [Table]'s typing context.
+pub trait TypeExpression<Out = Handle> {
+    /// Evaluates a type expression, recursively creating intermediate bindings.
+    fn evaluate(&self, table: &mut Table, node: Handle) -> Result<Out, Error>;
+}
+
+impl TypeExpression for Ty {
+    fn evaluate(&self, table: &mut Table, node: Handle) -> Result<Handle, Error> {
+        self.kind.evaluate(table, node)
+    }
+}
+
+impl TypeExpression for TyKind {
+    fn evaluate(&self, table: &mut Table, node: Handle) -> Result<Handle, Error> {
+        match self {
+            TyKind::Never => Ok(table.anon_type(TypeKind::Never)),
+            TyKind::Empty => Ok(table.anon_type(TypeKind::Empty)),
+            TyKind::Path(p) => p.evaluate(table, node),
+            TyKind::Array(a) => a.evaluate(table, node),
+            TyKind::Slice(s) => s.evaluate(table, node),
+            TyKind::Tuple(t) => t.evaluate(table, node),
+            TyKind::Ref(r) => r.evaluate(table, node),
+            TyKind::Fn(f) => f.evaluate(table, node),
+        }
+    }
+}
+
+impl TypeExpression for cl_ast::Path {
+    fn evaluate(&self, table: &mut Table, node: Handle) -> Result<Handle, Error> {
+        let Self { absolute, parts } = self;
+        parts.evaluate(table, if *absolute { table.root() } else { node })
+    }
+}
+
+impl TypeExpression for [PathPart] {
+    fn evaluate(&self, table: &mut Table, node: Handle) -> Result<Handle, Error> {
+        table
+            .nav(node, self)
+            .ok_or_else(|| Error::BadPath { parent: node, path: self.to_owned() })
+    }
+}
+
+impl TypeExpression for TyArray {
+    fn evaluate(&self, table: &mut Table, node: Handle) -> Result<Handle, Error> {
+        let Self { ty, count } = self;
+        let kind = TypeKind::Array(ty.evaluate(table, node)?, *count);
+        Ok(table.anon_type(kind))
+    }
+}
+
+impl TypeExpression for TySlice {
+    fn evaluate(&self, table: &mut Table, node: Handle) -> Result<Handle, Error> {
+        let Self { ty } = self;
+        let kind = TypeKind::Slice(ty.evaluate(table, node)?);
+        Ok(table.anon_type(kind))
+    }
+}
+
+impl TypeExpression for TyTuple {
+    fn evaluate(&self, table: &mut Table, node: Handle) -> Result<Handle, Error> {
+        let Self { types } = self;
+        let kind = match types.len() {
+            0 => TypeKind::Empty,
+            _ => TypeKind::Tuple(types.evaluate(table, node)?),
+        };
+        Ok(table.anon_type(kind))
+    }
+}
+
+impl TypeExpression for TyRef {
+    fn evaluate(&self, table: &mut Table, node: Handle) -> Result<Handle, Error> {
+        let Self { mutable: _, count, to } = self;
+        let mut t = to.evaluate(table, node)?;
+        for _ in 0..*count {
+            let kind = TypeKind::Ref(t);
+            t = table.anon_type(kind)
+        }
+        Ok(t)
+    }
+}
+
+impl TypeExpression for TyFn {
+    fn evaluate(&self, table: &mut Table, node: Handle) -> Result<Handle, Error> {
+        let Self { args, rety } = self;
+        let kind = TypeKind::FnSig {
+            args: args.evaluate(table, node)?,
+            rety: match rety {
+                Some(ty) => ty.evaluate(table, node)?,
+                None => TyKind::Empty.evaluate(table, node)?,
+            },
+        };
+        Ok(table.anon_type(kind))
+    }
+}
+
+impl<T: TypeExpression<U>, U> TypeExpression<Vec<U>> for [T] {
+    fn evaluate(&self, table: &mut Table, node: Handle) -> Result<Vec<U>, Error> {
+        let mut out = Vec::with_capacity(self.len());
+        for te in self {
+            out.push(te.evaluate(table, node)?) // try_collect is unstable
+        }
+        Ok(out)
+    }
+}

compiler/cl-typeck/src/type_kind.rs

@@ -0,0 +1,97 @@
+//! A [TypeKind] is a node in the [Table](crate::table::Table)'s type graph
+
+use crate::handle::Handle;
+use cl_ast::{Sym, Visibility};
+use std::{fmt::Debug, str::FromStr};
+
+mod display;
+
+/// A [TypeKind] represents an item
+/// (a component of a [Table](crate::table::Table))
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub enum TypeKind {
+    /// An alias for an already-defined type
+    Instance(Handle),
+    /// A primitive type, built-in to the compiler
+    Intrinsic(Intrinsic),
+    /// A user-defined aromatic data type
+    Adt(Adt),
+    /// A reference to an already-defined type: &T
+    Ref(Handle),
+    /// A contiguous view of dynamically sized memory
+    Slice(Handle),
+    /// A contiguous view of statically sized memory
+    Array(Handle, usize),
+    /// A tuple of existing types
+    Tuple(Vec<Handle>),
+    /// A function which accepts multiple inputs and produces an output
+    FnSig { args: Handle, rety: Handle },
+    /// The unit type
+    Empty,
+    /// The never type
+    Never,
+    /// An untyped module
+    Module,
+}
+
+/// A user-defined Aromatic Data Type
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub enum Adt {
+    /// A union-like enum type
+    Enum(Vec<(Sym, Option<Handle>)>),
+
+    /// A structural product type with named members
+    Struct(Vec<(Sym, Visibility, Handle)>),
+    /// A structural product type with unnamed members
+    TupleStruct(Vec<(Visibility, Handle)>),
+    /// A structural product type of neither named nor unnamed members
+    UnitStruct,
+
+    /// A choose your own undefined behavior type
+    /// TODO: should unions be a language feature?
+    Union(Vec<(Sym, Handle)>),
+}
+
+/// The set of compiler-intrinsic types.
+/// These primitive types have native implementations of the basic operations.
+#[rustfmt::skip]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub enum Intrinsic {
+    I8, I16, I32, I64, I128, Isize, // Signed integers
+    U8, U16, U32, U64, U128, Usize, // Unsigned integers
+    F8, F16, F32, F64, F128, Fsize, // Floating point numbers
+    Bool,                           // boolean value
+    Char,                           // Unicode codepoint
+}
+
+// Author's note: the fsize type is a meme
+
+impl FromStr for Intrinsic {
+    type Err = ();
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Ok(match s {
+            "i8" => Intrinsic::I8,
+            "i16" => Intrinsic::I16,
+            "i32" => Intrinsic::I32,
+            "i64" => Intrinsic::I64,
+            "i128" => Intrinsic::I128,
+            "isize" => Intrinsic::Isize,
+            "u8" => Intrinsic::U8,
+            "u16" => Intrinsic::U16,
+            "u32" => Intrinsic::U32,
+            "u64" => Intrinsic::U64,
+            "u128" => Intrinsic::U128,
+            "usize" => Intrinsic::Usize,
+            "f8" => Intrinsic::F8,
+            "f16" => Intrinsic::F16,
+            "f32" => Intrinsic::F32,
+            "f64" => Intrinsic::F64,
+            "f128" => Intrinsic::F128,
+            "fsize" => Intrinsic::Fsize,
+            "bool" => Intrinsic::Bool,
+            "char" => Intrinsic::Char,
+            _ => Err(())?,
+        })
+    }
+}

compiler/cl-typeck/src/type_kind/display.rs

@@ -0,0 +1,96 @@
+//! [Display] implementations for [TypeKind], [Adt], and [Intrinsic]
+
+use super::{Adt, Intrinsic, TypeKind};
+use crate::format_utils::*;
+use cl_ast::format::FmtAdapter;
+use std::fmt::{self, Display, Write};
+
+impl Display for TypeKind {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            TypeKind::Instance(def) => write!(f, "alias to #{def}"),
+            TypeKind::Intrinsic(i) => i.fmt(f),
+            TypeKind::Adt(a) => a.fmt(f),
+            TypeKind::Ref(def) => write!(f, "&{def}"),
+            TypeKind::Slice(def) => write!(f, "slice [#{def}]"),
+            TypeKind::Array(def, size) => write!(f, "array [#{def}; {size}]"),
+            TypeKind::Tuple(defs) => {
+                let mut defs = defs.iter();
+                separate(", ", || {
+                    let def = defs.next()?;
+                    Some(move |f: &mut Delimit<_>| write!(f, "#{def}"))
+                })(f.delimit_with("tuple (", ")"))
+            }
+            TypeKind::FnSig { args, rety } => write!(f, "fn (#{args}) -> #{rety}"),
+            TypeKind::Empty => f.write_str("()"),
+            TypeKind::Never => f.write_str("!"),
+            TypeKind::Module => f.write_str("mod"),
+        }
+    }
+}
+
+impl Display for Adt {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Adt::Enum(variants) => {
+                let mut variants = variants.iter();
+                separate(", ", || {
+                    let (name, def) = variants.next()?;
+                    Some(move |f: &mut Delimit<_>| match def {
+                        Some(def) => write!(f, "{name}: #{def}"),
+                        None => write!(f, "{name}"),
+                    })
+                })(f.delimit_with("enum {", "}"))
+            }
+            Adt::Struct(members) => {
+                let mut members = members.iter();
+                separate(", ", || {
+                    let (name, vis, def) = members.next()?;
+                    Some(move |f: &mut Delimit<_>| write!(f, "{vis}{name}: #{def}"))
+                })(f.delimit_with("struct {", "}"))
+            }
+            Adt::TupleStruct(members) => {
+                let mut members = members.iter();
+                separate(", ", || {
+                    let (vis, def) = members.next()?;
+                    Some(move |f: &mut Delimit<_>| write!(f, "{vis}#{def}"))
+                })(f.delimit_with("struct (", ")"))
+            }
+            Adt::UnitStruct => write!(f, "struct"),
+            Adt::Union(variants) => {
+                let mut variants = variants.iter();
+                separate(", ", || {
+                    let (name, def) = variants.next()?;
+                    Some(move |f: &mut Delimit<_>| write!(f, "{name}: #{def}"))
+                })(f.delimit_with("union {", "}"))
+            }
+        }
+    }
+}
+
+impl Display for Intrinsic {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Intrinsic::I8 => f.write_str("i8"),
+            Intrinsic::I16 => f.write_str("i16"),
+            Intrinsic::I32 => f.write_str("i32"),
+            Intrinsic::I64 => f.write_str("i64"),
+            Intrinsic::I128 => f.write_str("i128"),
+            Intrinsic::Isize => f.write_str("isize"),
+            Intrinsic::U8 => f.write_str("u8"),
+            Intrinsic::U16 => f.write_str("u16"),
+            Intrinsic::U32 => f.write_str("u32"),
+            Intrinsic::U64 => f.write_str("u64"),
+            Intrinsic::U128 => f.write_str("u128"),
+            Intrinsic::Usize => f.write_str("usize"),
+            Intrinsic::F8 => f.write_str("f8"),
+            Intrinsic::F16 => f.write_str("f16"),
+            Intrinsic::F32 => f.write_str("f32"),
+            Intrinsic::F64 => f.write_str("f64"),
+            Intrinsic::F128 => f.write_str("f128"),
+            Intrinsic::Fsize => f.write_str("fsize"),
+            Intrinsic::Bool => f.write_str("bool"),
+            Intrinsic::Char => f.write_str("char"),
+        }
+    }
+}

grammar.ebnf

@@ -15,7 +15,7 @@ Meta        = Identifier ('=' Literal | '(' (Literal ',')* Literal? ')')? ;
 Item        = Attrs Visibility ItemKind ;
 ItemKind    = Const    | Static | Module 
             | Function | Struct | Enum 
-            | Alias    | Impl ;
+            | Alias    | Impl   | Use ;
 
 
 (* item *)
@@ -45,20 +45,26 @@ Alias       = "type" Identifier ('=' Ty)? ';' ;
 Impl        = "impl" Path '{' Item* '}' ;
 (* TODO: Impl Trait for Target*)
 
+Use         = "use" '::'? UseTree ';' ;
+UseTree     = '*' | '{' (UseTree ',')* UseTree? '}'
+            | PathPart ('::' UseTree | "as" Identifier)? ;
 
 (* type *)
-Ty          = Never | Empty | Path | TyTuple | TyRef | TyFn ;
+Ty          = Never | Empty | Path | TyArray | TySlice | TyTuple | TyRef | TyFn ;
 Never       = '!' ;
 Empty       = '(' ')' ;
 TyTuple     = '(' (Ty ',')* Ty? ')' ;
+TyArray     = '[' Ty ';' INTEGER ']' ;
+TySlice     = '[' Ty ']' ;
 TyRef       = Amps* Path ;
 Amps        = '&' | '&&' ;
 TyFn        = "fn" TyTuple ('->' Ty)? ;
 
 
 (* path *)
-Path        = '::'? PathPart ('::' PathPart)* ;
-PathPart    = "super" | "self" | Identifier ;
+Path        = PathPart ('::' PathPart)*
+            | '::' (PathPart ('::' PathPart)*)? ;
+PathPart    = "super" | "self" | "Self" | Identifier ;
 Identifier  = IDENTIFIER ;
 
 
@@ -78,7 +84,8 @@ Bool        = "true" | "false" ;
 
 Expr        = Assign ;
 
-Assign      = Path (AssignKind  Assign ) | Compare ;
+Assign      = Path (AssignKind  Assign ) | Modify ;
+Modify      = Path (ModifyKind  Assign ) | Compare ;
 
 (* Binary      = Compare | Range | Logic | Bitwise | Shift | Factor | Term ; *)
 Compare     = Range    (CompareOp Range  )* ;
@@ -89,21 +96,27 @@ Shift       = Factor   (ShiftOp   Factor )* ;
 Factor      = Term     (FactorOp  Term   )* ;
 Term        = Unary    (TermOp    Unary  )* ;
 
-Unary       = (UnaryKind)* Member ;
+Unary       = (UnaryKind)* Cast ;
 
-Member      = Call ('.' Call)* ;
+Cast        = Member ("as" Ty)? ;
+
+Member      = Call (Access)* ;
+Access      = '.' (Identifier ('(' Tuple? ')')? | Literal) ;
 
 Call        = Index  ('(' Tuple? ')')* ;
 
 Index       = Primary ('[' Indices ']')* ;
 Indices     = (Expr ',')* Expr? ;
 
-Primary     = Literal | Path  | Array | ArrayRep | AddrOf 
-            | Block   | Group 
-            | If      | While | For   | Break    | Return | Continue;
+Primary     = Literal | PathLike | Array | ArrayRep | AddrOf | Block  | Group
+            | Loop    | If       | While | For      | Break  | Return | Continue;
 
 Literal     = STRING | CHARACTER | FLOAT | INTEGER | Bool ;
 
+PathLike    = Path | Structor ;
+Structor    = Path ':' '{' (Fielder ',')* Fielder? '}' ;
+Fielder     = Identifier ('=' Expr)? ;
+
 Array       = '[' (Expr ',')* Expr? ']' ;
 ArrayRep    = '[' Expr ';' Expr ']' ;
 
@@ -114,6 +127,7 @@ Block       = '{' Stmt* '}';
 Group       = Empty | '(' (Expr | Tuple) ')' ;
 Tuple       = (Expr ',')* Expr? ;
 
+Loop        = "loop"  Block ;
 While       = "while" Expr Block Else ;
 If          = "if"    Expr Block Else ;
 For         = "for"   Identifier "in" Expr Block Else ;
@@ -122,7 +136,8 @@ Break       = "break"  Expr ;
 Return      = "return" Expr ;
 Continue    = "continue" ;
 
-AssignKind  =  '=' | '+=' | '-=' | '*=' | '/=' | '&=' | '|=' | '^=' |'<<=' |'>>=' ;
+AssignKind  =  '=' ;
+ModifyKind  = '+=' | '-=' | '*=' | '/=' | '&=' | '|=' | '^=' |'<<=' |'>>=' ;
 
 CompareOp   =  '<' | '<=' | '==' | '!=' | '>=' | '>' ;
 RangeOp     = '..' | '..=' ;

readme.md

@@ -1,8 +1,7 @@
 # Conlang: Expression-Oriented Programming Language
 This project began out of a desire to merge Rust-style control flow expressions 
 with Python's fun for-else/while-else syntax. I fully intend to devote my spare time
-to conlang for the forseeable future, and I livestream development on Twitch for one 
-Friday each month.
+to conlang for the forseeable future.
 
 ## Immediate Goals:
 - [x] Decide on a minimal set of keywords and operators to support
@@ -20,10 +19,11 @@ Friday each month.
 ## Short Goals:
 - [x] `for` loops and `while` loops can be used on the trailing side of an assignment
 - [x] Tree-walk interpreter for prototyping and debugging
-- [ ] Data structures and sum-type enums
+- [x] Data structures and sum-type enums
 - [ ] Expression type-checker
-- [ ] Trait/Interface system
+- [ ] Pattern destructuring, to take advantage of sum-type enums
 - [ ] Three-address bytecode VM for standard library development
+- [ ] Trait/Interface system
 
 ## Long Goals:
 - [ ] Minimize the number of kinds of statements

repline/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "repline"
+repository.workspace = true
+version.workspace = true
+authors.workspace = true
+edition.workspace = true
+license.workspace = true
+publish.workspace = true
+
+[dependencies]
+crossterm = { version = "0.27.0", default-features = false }

repline/examples/repl_float.rs

@@ -0,0 +1,17 @@
+//! Demonstrates the use of [read_and()]:
+//! 
+//! The provided closure:
+//! 1. Takes a line of input (a [String])
+//! 2. Performs some calculation (using [FromStr])
+//! 3. Returns a [Result] containing a [Response] or an [Err]
+
+use repline::{prebaked::read_and, Response};
+use std::{error::Error, str::FromStr};
+
+fn main() -> Result<(), Box<dyn Error>> {
+    read_and("\x1b[33m", "  >", " ?>", |line| {
+        println!("-> {:?}", f64::from_str(line.trim())?);
+        Ok(Response::Accept)
+    })?;
+    Ok(())
+}

repline/src/editor.rs

@@ -0,0 +1,324 @@
+//! The [Editor] is a multi-line buffer of [`char`]s which operates on an ANSI-compatible terminal.
+
+use crossterm::{cursor::*, execute, queue, style::*, terminal::*};
+use std::{collections::VecDeque, fmt::Display, io::Write};
+
+use super::error::{Error, ReplResult};
+
+fn is_newline(c: &char) -> bool {
+    *c == '\n'
+}
+
+fn write_chars<'a, W: Write>(
+    c: impl IntoIterator<Item = &'a char>,
+    w: &mut W,
+) -> std::io::Result<()> {
+    for c in c {
+        write!(w, "{c}")?;
+    }
+    Ok(())
+}
+
+/// A multi-line editor which operates on an un-cleared ANSI terminal.
+#[derive(Clone, Debug)]
+pub struct Editor<'a> {
+    head: VecDeque<char>,
+    tail: VecDeque<char>,
+
+    pub color: &'a str,
+    begin: &'a str,
+    again: &'a str,
+}
+
+impl<'a> Editor<'a> {
+    /// Constructs a new Editor with the provided prompt color, begin prompt, and again prompt.
+    pub fn new(color: &'a str, begin: &'a str, again: &'a str) -> Self {
+        Self { head: Default::default(), tail: Default::default(), color, begin, again }
+    }
+
+    /// Returns an iterator over characters in the editor.
+    pub fn iter(&self) -> impl Iterator<Item = &char> {
+        let Self { head, tail, .. } = self;
+        head.iter().chain(tail.iter())
+    }
+
+    /// Moves up to the first line of the editor, and clears the screen.
+    ///
+    /// This assumes the screen hasn't moved since the last draw.
+    pub fn undraw<W: Write>(&self, w: &mut W) -> ReplResult<()> {
+        let Self { head, .. } = self;
+        match head.iter().copied().filter(is_newline).count() {
+            0 => write!(w, "\x1b[0G"),
+            lines => write!(w, "\x1b[{}F", lines),
+        }?;
+        queue!(w, Clear(ClearType::FromCursorDown))?;
+        // write!(w, "\x1b[0J")?;
+        Ok(())
+    }
+
+    /// Redraws the entire editor
+    pub fn redraw<W: Write>(&self, w: &mut W) -> ReplResult<()> {
+        let Self { head, tail, color, begin, again } = self;
+        write!(w, "{color}{begin}\x1b[0m ")?;
+        // draw head
+        for c in head {
+            match c {
+                '\n' => write!(w, "\r\n{color}{again}\x1b[0m "),
+                _ => w.write_all({ *c as u32 }.to_le_bytes().as_slice()),
+            }?
+        }
+        // save cursor
+        execute!(w, SavePosition)?;
+        // draw tail
+        for c in tail {
+            match c {
+                '\n' => write!(w, "\r\n{color}{again}\x1b[0m "),
+                _ => write!(w, "{c}"),
+            }?
+        }
+        // restore cursor
+        execute!(w, RestorePosition)?;
+        Ok(())
+    }
+
+    /// Prints a context-sensitive prompt (either `begin` if this is the first line,
+    /// or `again` for subsequent lines)
+    pub fn prompt<W: Write>(&self, w: &mut W) -> ReplResult<()> {
+        let Self { head, color, begin, again, .. } = self;
+        queue!(
+            w,
+            MoveToColumn(0),
+            Print(color),
+            Print(if head.is_empty() { begin } else { again }),
+            ResetColor,
+            Print(' '),
+        )?;
+        Ok(())
+    }
+
+    /// Prints the characters before the cursor on the current line.
+    pub fn print_head<W: Write>(&self, w: &mut W) -> ReplResult<()> {
+        self.prompt(w)?;
+        write_chars(
+            self.head.iter().skip(
+                self.head
+                    .iter()
+                    .rposition(is_newline)
+                    .unwrap_or(self.head.len())
+                    + 1,
+            ),
+            w,
+        )?;
+        Ok(())
+    }
+
+    /// Prints the characters after the cursor on the current line.
+    pub fn print_tail<W: Write>(&self, w: &mut W) -> ReplResult<()> {
+        let Self { tail, .. } = self;
+        queue!(w, SavePosition, Clear(ClearType::UntilNewLine))?;
+        write_chars(tail.iter().take_while(|&c| !is_newline(c)), w)?;
+        queue!(w, RestorePosition)?;
+        Ok(())
+    }
+
+    /// Writes a character at the cursor, shifting the text around as necessary.
+    pub fn push<W: Write>(&mut self, c: char, w: &mut W) -> ReplResult<()> {
+        // Tail optimization: if the tail is empty,
+        //we don't have to undraw and redraw on newline
+        if self.tail.is_empty() {
+            self.head.push_back(c);
+            match c {
+                '\n' => {
+                    write!(w, "\r\n")?;
+                    self.print_head(w)?;
+                }
+                c => {
+                    queue!(w, Print(c))?;
+                }
+            };
+            return Ok(());
+        }
+
+        if '\n' == c {
+            self.undraw(w)?;
+        }
+        self.head.push_back(c);
+        match c {
+            '\n' => self.redraw(w)?,
+            _ => {
+                write!(w, "{c}")?;
+                self.print_tail(w)?;
+            }
+        }
+        Ok(())
+    }
+
+    /// Erases a character at the cursor, shifting the text around as necessary.
+    pub fn pop<W: Write>(&mut self, w: &mut W) -> ReplResult<Option<char>> {
+        if let Some('\n') = self.head.back() {
+            self.undraw(w)?;
+        }
+        let c = self.head.pop_back();
+        // if the character was a newline, we need to go back a line
+        match c {
+            Some('\n') => self.redraw(w)?,
+            Some(_) => {
+                // go back a char
+                queue!(w, MoveLeft(1), Print(' '), MoveLeft(1))?;
+                self.print_tail(w)?;
+            }
+            None => {}
+        }
+        Ok(c)
+    }
+
+    /// Writes characters into the editor at the location of the cursor.
+    pub fn extend<T: IntoIterator<Item = char>, W: Write>(
+        &mut self,
+        iter: T,
+        w: &mut W,
+    ) -> ReplResult<()> {
+        for c in iter {
+            self.push(c, w)?;
+        }
+        Ok(())
+    }
+
+    /// Sets the editor to the contents of a string, placing the cursor at the end.
+    pub fn restore(&mut self, s: &str) {
+        self.clear();
+        self.head.extend(s.chars())
+    }
+
+    /// Clears the editor, removing all characters.
+    pub fn clear(&mut self) {
+        self.head.clear();
+        self.tail.clear();
+    }
+
+    /// Pops the character after the cursor, redrawing if necessary
+    pub fn delete<W: Write>(&mut self, w: &mut W) -> ReplResult<char> {
+        match self.tail.front() {
+            Some('\n') => {
+                self.undraw(w)?;
+                let out = self.tail.pop_front();
+                self.redraw(w)?;
+                out
+            }
+            _ => {
+                let out = self.tail.pop_front();
+                self.print_tail(w)?;
+                out
+            }
+        }
+        .ok_or(Error::EndOfInput)
+    }
+
+    /// Erases a word from the buffer, where a word is any non-whitespace characters
+    /// preceded by a single whitespace character
+    pub fn erase_word<W: Write>(&mut self, w: &mut W) -> ReplResult<()> {
+        while self.pop(w)?.filter(|c| !c.is_whitespace()).is_some() {}
+        Ok(())
+    }
+
+    /// Returns the number of characters in the buffer
+    pub fn len(&self) -> usize {
+        self.head.len() + self.tail.len()
+    }
+
+    /// Returns true if the buffer is empty.
+    pub fn is_empty(&self) -> bool {
+        self.head.is_empty() && self.tail.is_empty()
+    }
+
+    /// Returns true if the buffer ends with a given pattern
+    pub fn ends_with(&self, iter: impl DoubleEndedIterator<Item = char>) -> bool {
+        let mut iter = iter.rev();
+        let mut head = self.head.iter().rev();
+        loop {
+            match (iter.next(), head.next()) {
+                (None, _) => break true,
+                (Some(_), None) => break false,
+                (Some(a), Some(b)) if a != *b => break false,
+                (Some(_), Some(_)) => continue,
+            }
+        }
+    }
+
+    /// Moves the cursor back `steps` steps
+    pub fn cursor_back<W: Write>(&mut self, steps: usize, w: &mut W) -> ReplResult<()> {
+        for _ in 0..steps {
+            if let Some('\n') = self.head.back() {
+                self.undraw(w)?;
+            }
+            let Some(c) = self.head.pop_back() else {
+                return Ok(());
+            };
+            self.tail.push_front(c);
+            match c {
+                '\n' => self.redraw(w)?,
+                _ => queue!(w, MoveLeft(1))?,
+            }
+        }
+        Ok(())
+    }
+
+    /// Moves the cursor forward `steps` steps
+    pub fn cursor_forward<W: Write>(&mut self, steps: usize, w: &mut W) -> ReplResult<()> {
+        for _ in 0..steps {
+            if let Some('\n') = self.tail.front() {
+                self.undraw(w)?
+            }
+            let Some(c) = self.tail.pop_front() else {
+                return Ok(());
+            };
+            self.head.push_back(c);
+            match c {
+                '\n' => self.redraw(w)?,
+                _ => queue!(w, MoveRight(1))?,
+            }
+        }
+        Ok(())
+    }
+
+    /// Moves the cursor to the beginning of the current line
+    pub fn home<W: Write>(&mut self, w: &mut W) -> ReplResult<()> {
+        loop {
+            match self.head.back() {
+                Some('\n') | None => break Ok(()),
+                Some(_) => self.cursor_back(1, w)?,
+            }
+        }
+    }
+
+    /// Moves the cursor to the end of the current line
+    pub fn end<W: Write>(&mut self, w: &mut W) -> ReplResult<()> {
+        loop {
+            match self.tail.front() {
+                Some('\n') | None => break Ok(()),
+                Some(_) => self.cursor_forward(1, w)?,
+            }
+        }
+    }
+}
+
+impl<'e> IntoIterator for &'e Editor<'_> {
+    type Item = &'e char;
+    type IntoIter = std::iter::Chain<
+        std::collections::vec_deque::Iter<'e, char>,
+        std::collections::vec_deque::Iter<'e, char>,
+    >;
+    fn into_iter(self) -> Self::IntoIter {
+        self.head.iter().chain(self.tail.iter())
+    }
+}
+
+impl Display for Editor<'_> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        use std::fmt::Write;
+        for c in self.iter() {
+            f.write_char(*c)?;
+        }
+        Ok(())
+    }
+}

repline/src/error.rs

@@ -0,0 +1,42 @@
+use crate::iter::chars::BadUnicode;
+
+/// Result type for Repline
+pub type ReplResult<T> = std::result::Result<T, Error>;
+/// Borrowed error (does not implement [Error](std::error::Error)!)
+#[derive(Debug)]
+pub enum Error {
+    /// User broke with Ctrl+C
+    CtrlC(String),
+    /// User broke with Ctrl+D
+    CtrlD(String),
+    /// Invalid unicode codepoint
+    BadUnicode(u32),
+    /// Error came from [std::io]
+    IoFailure(std::io::Error),
+    /// End of input
+    EndOfInput,
+}
+
+impl std::error::Error for Error {}
+impl std::fmt::Display for Error {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Error::CtrlC(_) => write!(f, "Ctrl+C"),
+            Error::CtrlD(_) => write!(f, "Ctrl+D"),
+            Error::BadUnicode(u) => write!(f, "\\u{{{u:x}}} is not a valid unicode codepoint"),
+            Error::IoFailure(s) => write!(f, "{s}"),
+            Error::EndOfInput => write!(f, "End of input"),
+        }
+    }
+}
+impl From<std::io::Error> for Error {
+    fn from(value: std::io::Error) -> Self {
+        Self::IoFailure(value)
+    }
+}
+impl From<BadUnicode> for Error {
+    fn from(value: BadUnicode) -> Self {
+        let BadUnicode(code) = value;
+        Self::BadUnicode(code)
+    }
+}

repline/src/iter.rs

@@ -0,0 +1,68 @@
+//! Shmancy iterator adapters
+
+pub use chars::Chars;
+pub use flatten::Flatten;
+
+pub mod chars {
+    //! Converts an <code>[Iterator]<Item = [u8]></code> into an
+    //! <code>[Iterator]<Item = [Result]<[char], [BadUnicode]>></code>
+
+    /// Invalid unicode codepoint found when iterating over [Chars]
+    #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+    pub struct BadUnicode(pub u32);
+    impl std::error::Error for BadUnicode {}
+    impl std::fmt::Display for BadUnicode {
+        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+            let Self(code) = self;
+            write!(f, "Bad unicode: {code}")
+        }
+    }
+
+    /// Converts an <code>[Iterator]<Item = [u8]></code> into an
+    /// <code>[Iterator]<Item = [char]></code>
+    #[derive(Clone, Debug)]
+    pub struct Chars<I: Iterator<Item = u8>>(pub I);
+    impl<I: Iterator<Item = u8>> Iterator for Chars<I> {
+        type Item = Result<char, BadUnicode>;
+        fn next(&mut self) -> Option<Self::Item> {
+            let Self(bytes) = self;
+            let start = bytes.next()? as u32;
+            let (mut out, count) = match start {
+                start if start & 0x80 == 0x00 => (start, 0), // ASCII valid range
+                start if start & 0xe0 == 0xc0 => (start & 0x1f, 1), // 1 continuation byte
+                start if start & 0xf0 == 0xe0 => (start & 0x0f, 2), // 2 continuation bytes
+                start if start & 0xf8 == 0xf0 => (start & 0x07, 3), // 3 continuation bytes
+                _ => return None,
+            };
+            for _ in 0..count {
+                let cont = bytes.next()? as u32;
+                if cont & 0xc0 != 0x80 {
+                    return None;
+                }
+                out = (out << 6) | (cont & 0x3f);
+            }
+            Some(char::from_u32(out).ok_or(BadUnicode(out)))
+        }
+    }
+}
+pub mod flatten {
+    //! Flattens an [Iterator] returning [`Result<T, E>`](Result) or [`Option<T>`](Option)
+    //! into a *non-[FusedIterator](std::iter::FusedIterator)* over `T`
+
+    /// Flattens an [Iterator] returning [`Result<T, E>`](Result) or [`Option<T>`](Option)
+    /// into a *non-[FusedIterator](std::iter::FusedIterator)* over `T`
+    #[derive(Clone, Debug)]
+    pub struct Flatten<T, I: Iterator<Item = T>>(pub I);
+    impl<T, E, I: Iterator<Item = Result<T, E>>> Iterator for Flatten<Result<T, E>, I> {
+        type Item = T;
+        fn next(&mut self) -> Option<Self::Item> {
+            self.0.next()?.ok()
+        }
+    }
+    impl<T, I: Iterator<Item = Option<T>>> Iterator for Flatten<Option<T>, I> {
+        type Item = T;
+        fn next(&mut self) -> Option<Self::Item> {
+            self.0.next()?
+        }
+    }
+}

repline/src/lib.rs

@@ -0,0 +1,13 @@
+//! A small pseudo-multiline editing library
+
+mod editor;
+mod iter;
+mod raw;
+
+pub mod error;
+pub mod prebaked;
+pub mod repline;
+
+pub use error::Error;
+pub use prebaked::{read_and, Response};
+pub use repline::Repline;

repline/src/prebaked.rs

@@ -0,0 +1,56 @@
+//! Here's a menu I prepared earlier!
+//!
+//! Constructs a [Repline] and repeatedly runs the provided closure on the input strings,
+//! obeying the closure's [Response].
+
+use std::error::Error;
+
+use crate::{error::Error as RlError, repline::Repline};
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+/// Control codes for the [prebaked menu](read_and)
+pub enum Response {
+    /// Accept the line, and save it to history
+    Accept,
+    /// Reject the line, and clear the buffer
+    Deny,
+    /// End the loop
+    Break,
+    /// Gather more input and try again
+    Continue,
+}
+
+/// Implements a basic menu loop using an embedded [Repline].
+///
+/// Repeatedly runs the provided closure on the input strings,
+/// obeying the closure's [Response].
+///
+/// Captures and displays all user [Error]s.
+///
+/// # Keybinds
+/// - `Ctrl+C` exits the loop
+/// - `Ctrl+D` clears the input, but *runs the closure* with the old input
+pub fn read_and<F>(color: &str, begin: &str, again: &str, mut f: F) -> Result<(), RlError>
+where F: FnMut(&str) -> Result<Response, Box<dyn Error>> {
+    let mut rl = Repline::new(color, begin, again);
+    loop {
+        let line = match rl.read() {
+            Err(RlError::CtrlC(_)) => break,
+            Err(RlError::CtrlD(line)) => {
+                rl.deny();
+                line
+            }
+            Ok(line) => line,
+            Err(e) => Err(e)?,
+        };
+        print!("\x1b[G\x1b[J");
+        match f(&line) {
+            Ok(Response::Accept) => rl.accept(),
+            Ok(Response::Deny) => rl.deny(),
+            Ok(Response::Break) => break,
+            Ok(Response::Continue) => continue,
+            Err(e) => print!("\x1b[40G\x1b[A\x1bJ\x1b[91m{e}\x1b[0m\x1b[B"),
+        }
+    }
+    Ok(())
+}

repline/src/raw.rs

@@ -0,0 +1,21 @@
+//! Sets the terminal to [`raw`] mode for the duration of the returned object's lifetime.
+
+/// Sets the terminal to raw mode for the duration of the returned object's lifetime.
+pub fn raw() -> impl Drop {
+    Raw::default()
+}
+struct Raw();
+impl Default for Raw {
+    fn default() -> Self {
+        std::thread::yield_now();
+        crossterm::terminal::enable_raw_mode()
+            .expect("should be able to transition into raw mode");
+        Raw()
+    }
+}
+impl Drop for Raw {
+    fn drop(&mut self) {
+        crossterm::terminal::disable_raw_mode()
+            .expect("should be able to transition out of raw mode");
+    }
+}