toki: pona

Demonstrates pattern matching

Cargo.toml

@@ -8,14 +8,13 @@ members = [
     "compiler/cl-ast",
     "compiler/cl-parser",
     "compiler/cl-lexer",
-    "compiler/cl-arena",
     "repline",
 ]
 resolver = "2"
 
 [workspace.package]
 repository = "https://git.soft.fish/j/Conlang"
-version = "0.0.7"
+version = "0.0.9"
 authors = ["John Breaux <j@soft.fish>"]
 edition = "2021"
 license = "MIT"

compiler/cl-arena/Cargo.toml

@@ -1,10 +0,0 @@
-[package]
-name = "cl-arena"
-repository.workspace = true
-version.workspace = true
-authors.workspace = true
-edition.workspace = true
-license.workspace = true
-publish.workspace = true
-
-[dependencies]

compiler/cl-arena/src/dropless_arena/tests.rs

@@ -1,42 +0,0 @@
-use super::DroplessArena;
-    extern crate std;
-    use core::alloc::Layout;
-    use std::{prelude::rust_2021::*, vec};
-
-    #[test]
-    fn alloc_raw() {
-        let arena = DroplessArena::new();
-        let bytes = arena.alloc_raw(Layout::for_value(&0u128));
-        let byte2 = arena.alloc_raw(Layout::for_value(&0u128));
-
-        assert_ne!(bytes, byte2);
-    }
-
-    #[test]
-    fn alloc() {
-        let arena = DroplessArena::new();
-        let mut allocations = vec![];
-        for i in 0..0x400 {
-            allocations.push(arena.alloc(i));
-        }
-    }
-
-    #[test]
-    fn alloc_strings() {
-        const KW: &[&str] = &["pub", "mut", "fn", "mod", "conlang", "sidon", "🦈"];
-        let arena = DroplessArena::new();
-        let mut allocations = vec![];
-        for _ in 0..100 {
-            for kw in KW {
-                allocations.push(arena.alloc_str(kw));
-            }
-        }
-    }
-
-    #[test]
-    #[should_panic]
-    fn alloc_zsts() {
-        struct Zst;
-        let arena = DroplessArena::new();
-        arena.alloc(Zst);
-    }

compiler/cl-arena/src/lib.rs

@@ -1,396 +0,0 @@
-//! Typed and dropless arena allocation, paraphrased from [the Rust Compiler's `rustc_arena`](https://github.com/rust-lang/rust/blob/master/compiler/rustc_arena/src/lib.rs). See [LICENSE][1].
-//!
-//! An Arena Allocator is a type of allocator which provides stable locations for allocations within
-//! itself for the entire duration of its lifetime.
-//!
-//! [1]: https://raw.githubusercontent.com/rust-lang/rust/master/LICENSE-MIT
-
-#![feature(dropck_eyepatch, new_uninit, strict_provenance)]
-#![no_std]
-
-extern crate alloc;
-
-pub(crate) mod constants {
-    //! Size constants for arena chunk growth
-    pub(crate) const MIN_CHUNK: usize = 4096;
-    pub(crate) const MAX_CHUNK: usize = 2 * 1024 * 1024;
-}
-
-mod chunk {
-    //! An [ArenaChunk] contains a block of raw memory for use in arena allocators.
-    use alloc::boxed::Box;
-    use core::{
-        mem::{self, MaybeUninit},
-        ptr::{self, NonNull},
-    };
-
-    pub struct ArenaChunk<T> {
-        pub(crate) mem: NonNull<[MaybeUninit<T>]>,
-        pub(crate) filled: usize,
-    }
-
-    impl<T: Sized> ArenaChunk<T> {
-        pub fn new(cap: usize) -> Self {
-            let slice = Box::new_uninit_slice(cap);
-            Self { mem: NonNull::from(Box::leak(slice)), filled: 0 }
-        }
-
-        /// Drops all elements inside self, and resets the filled count to 0
-        ///
-        /// # Safety
-        ///
-        /// The caller must ensure that `self.filled` elements of self are currently initialized
-        pub unsafe fn drop_elements(&mut self) {
-            if mem::needs_drop::<T>() {
-                // Safety: the caller has ensured that `filled` elements are initialized
-                unsafe {
-                    let slice = self.mem.as_mut();
-                    for t in slice[..self.filled].iter_mut() {
-                        t.assume_init_drop();
-                    }
-                }
-                self.filled = 0;
-            }
-        }
-
-        /// Gets a pointer to the start of the arena
-        pub fn start(&mut self) -> *mut T {
-            self.mem.as_ptr() as _
-        }
-
-        /// Gets a pointer to the end of the arena
-        pub fn end(&mut self) -> *mut T {
-            if mem::size_of::<T>() == 0 {
-                ptr::without_provenance_mut(usize::MAX) // pointers to ZSTs must be unique
-            } else {
-                unsafe { self.start().add(self.mem.len()) }
-            }
-        }
-    }
-
-    impl<T> Drop for ArenaChunk<T> {
-        fn drop(&mut self) {
-            let _ = unsafe { Box::from_raw(self.mem.as_ptr()) };
-        }
-    }
-}
-
-pub mod typed_arena {
-    //! A [TypedArena] can hold many instances of a single type, and will properly [Drop] them.
-    #![allow(clippy::mut_from_ref)]
-
-    use crate::{chunk::ArenaChunk, constants::*};
-    use alloc::vec::Vec;
-    use core::{
-        cell::{Cell, RefCell},
-        marker::PhantomData,
-        mem, ptr, slice,
-    };
-
-    /// A [TypedArena] can hold many instances of a single type, and will properly [Drop] them when
-    /// it falls out of scope.
-    pub struct TypedArena<'arena, T> {
-        _lives: PhantomData<&'arena T>,
-        _drops: PhantomData<T>,
-        chunks: RefCell<Vec<ArenaChunk<T>>>,
-        head: Cell<*mut T>,
-        tail: Cell<*mut T>,
-    }
-
-    impl<'arena, T> Default for TypedArena<'arena, T> {
-        fn default() -> Self {
-            Self::new()
-        }
-    }
-
-    impl<'arena, T> TypedArena<'arena, T> {
-        pub const fn new() -> Self {
-            Self {
-                _lives: PhantomData,
-                _drops: PhantomData,
-                chunks: RefCell::new(Vec::new()),
-                head: Cell::new(ptr::null_mut()),
-                tail: Cell::new(ptr::null_mut()),
-            }
-        }
-
-        pub fn alloc(&'arena self, value: T) -> &'arena mut T {
-            if self.head == self.tail {
-                self.grow(1);
-            }
-
-            let out = if mem::size_of::<T>() == 0 {
-                self.head
-                    .set(ptr::without_provenance_mut(self.head.get().addr() + 1));
-                ptr::NonNull::<T>::dangling().as_ptr()
-            } else {
-                let out = self.head.get();
-                self.head.set(unsafe { out.add(1) });
-                out
-            };
-
-            unsafe {
-                ptr::write(out, value);
-                &mut *out
-            }
-        }
-
-        fn can_allocate(&self, len: usize) -> bool {
-            len <= unsafe { self.tail.get().offset_from(self.head.get()) as usize }
-        }
-
-        /// # Panics
-        /// Panics if size_of::<T> == 0 || len == 0
-        #[inline]
-        fn alloc_raw_slice(&self, len: usize) -> *mut T {
-            assert!(mem::size_of::<T>() != 0);
-            assert!(len != 0);
-
-            if !self.can_allocate(len) {
-                self.grow(len)
-            }
-
-            let out = self.head.get();
-
-            unsafe { self.head.set(out.add(len)) };
-            out
-        }
-
-        pub fn alloc_from_iter<I>(&'arena self, iter: I) -> &'arena mut [T]
-        where I: IntoIterator<Item = T> {
-            // Collect them all into a buffer so they're allocated contiguously
-            let mut buf = iter.into_iter().collect::<Vec<_>>();
-            if buf.is_empty() {
-                return &mut [];
-            }
-
-            let len = buf.len();
-            // If T is a ZST, calling alloc_raw_slice will panic
-            let slice = if mem::size_of::<T>() == 0 {
-                self.head
-                    .set(ptr::without_provenance_mut(self.head.get().addr() + len));
-                ptr::NonNull::dangling().as_ptr()
-            } else {
-                self.alloc_raw_slice(len)
-            };
-
-            unsafe {
-                buf.as_ptr().copy_to_nonoverlapping(slice, len);
-                buf.set_len(0);
-                slice::from_raw_parts_mut(slice, len)
-            }
-        }
-
-        #[cold]
-        #[inline(never)]
-        fn grow(&self, len: usize) {
-            let size = mem::size_of::<T>().max(1);
-
-            let mut chunks = self.chunks.borrow_mut();
-
-            let capacity = if let Some(last) = chunks.last_mut() {
-                last.filled = self.get_filled_of_chunk(last);
-                last.mem.len().min(MAX_CHUNK / size) * 2
-            } else {
-                MIN_CHUNK / size
-            }
-            .max(len);
-
-            let mut chunk = ArenaChunk::<T>::new(capacity);
-
-            self.head.set(chunk.start());
-            self.tail.set(chunk.end());
-            chunks.push(chunk);
-        }
-
-        fn get_filled_of_chunk(&self, chunk: &mut ArenaChunk<T>) -> usize {
-            let Self { head: tail, .. } = self;
-            let head = chunk.start();
-            if mem::size_of::<T>() == 0 {
-                tail.get().addr() - head.addr()
-            } else {
-                unsafe { tail.get().offset_from(head) as usize }
-            }
-        }
-    }
-
-    unsafe impl<'arena, T: Send> Send for TypedArena<'arena, T> {}
-
-    unsafe impl<'arena, #[may_dangle] T> Drop for TypedArena<'arena, T> {
-        fn drop(&mut self) {
-            let mut chunks = self.chunks.borrow_mut();
-
-            if let Some(last) = chunks.last_mut() {
-                last.filled = self.get_filled_of_chunk(last);
-                self.tail.set(self.head.get());
-            }
-
-            for chunk in chunks.iter_mut() {
-                unsafe { chunk.drop_elements() }
-            }
-        }
-    }
-
-    #[cfg(test)]
-    mod tests;
-}
-
-pub mod dropless_arena {
-    //! A [DroplessArena] can hold *any* combination of types as long as they don't implement
-    //! [Drop].
-    use crate::{chunk::ArenaChunk, constants::*};
-    use alloc::vec::Vec;
-    use core::{
-        alloc::Layout,
-        cell::{Cell, RefCell},
-        marker::PhantomData,
-        mem, ptr, slice,
-    };
-
-    pub struct DroplessArena<'arena> {
-        _lives: PhantomData<&'arena u8>,
-        chunks: RefCell<Vec<ArenaChunk<u8>>>,
-        head: Cell<*mut u8>,
-        tail: Cell<*mut u8>,
-    }
-
-    impl Default for DroplessArena<'_> {
-        fn default() -> Self {
-            Self::new()
-        }
-    }
-
-    impl<'arena> DroplessArena<'arena> {
-        pub const fn new() -> Self {
-            Self {
-                _lives: PhantomData,
-                chunks: RefCell::new(Vec::new()),
-                head: Cell::new(ptr::null_mut()),
-                tail: Cell::new(ptr::null_mut()),
-            }
-        }
-
-        /// Allocates a `T` in the [DroplessArena], and returns a mutable reference to it.
-        ///
-        /// # Panics
-        /// - Panics if T implements [Drop]
-        /// - Panics if T is zero-sized
-        #[allow(clippy::mut_from_ref)]
-        pub fn alloc<T>(&'arena self, value: T) -> &'arena mut T {
-            assert!(!mem::needs_drop::<T>());
-            assert!(mem::size_of::<T>() != 0);
-
-            let out = self.alloc_raw(Layout::new::<T>()) as *mut T;
-
-            unsafe {
-                ptr::write(out, value);
-                &mut *out
-            }
-        }
-
-        /// Allocates a slice of `T`s`, copied from the given slice, returning a mutable reference
-        /// to it.
-        ///
-        /// # Panics
-        /// - Panics if T implements [Drop]
-        /// - Panics if T is zero-sized
-        /// - Panics if the slice is empty
-        #[allow(clippy::mut_from_ref)]
-        pub fn alloc_slice<T: Copy>(&'arena self, slice: &[T]) -> &'arena mut [T] {
-            assert!(!mem::needs_drop::<T>());
-            assert!(mem::size_of::<T>() != 0);
-            assert!(!slice.is_empty());
-
-            let mem = self.alloc_raw(Layout::for_value::<[T]>(slice)) as *mut T;
-
-            unsafe {
-                mem.copy_from_nonoverlapping(slice.as_ptr(), slice.len());
-                slice::from_raw_parts_mut(mem, slice.len())
-            }
-        }
-
-        /// Allocates a copy of the given [`&str`](str), returning a reference to the allocation.
-        ///
-        /// # Panics
-        /// Panics if the string is empty.
-        pub fn alloc_str(&'arena self, string: &str) -> &'arena str {
-            let slice = self.alloc_slice(string.as_bytes());
-
-            // Safety: This is a clone of the input string, which was valid
-            unsafe { core::str::from_utf8_unchecked(slice) }
-        }
-
-        /// Allocates some [bytes](u8) based on the given [Layout].
-        ///
-        /// # Panics
-        /// Panics if the provided [Layout] has size 0
-        pub fn alloc_raw(&'arena self, layout: Layout) -> *mut u8 {
-            /// Rounds the given size (or pointer value) *up* to the given alignment
-            fn align_up(size: usize, align: usize) -> usize {
-                (size + align - 1) & !(align - 1)
-            }
-            /// Rounds the given size (or pointer value) *down* to the given alignment
-            fn align_down(size: usize, align: usize) -> usize {
-                size & !(align - 1)
-            }
-
-            assert!(layout.size() != 0);
-            loop {
-                let Self { head, tail, .. } = self;
-                let start = head.get().addr();
-                let end = tail.get().addr();
-
-                let align = 8.max(layout.align());
-
-                let bytes = align_up(layout.size(), align);
-
-                if let Some(end) = end.checked_sub(bytes) {
-                    let end = align_down(end, layout.align());
-
-                    if start <= end {
-                        tail.set(tail.get().with_addr(end));
-                        return tail.get();
-                    }
-                }
-
-                self.grow(layout.size());
-            }
-        }
-
-        /// Grows the allocator, doubling the chunk size until it reaches [MAX_CHUNK].
-        #[cold]
-        #[inline(never)]
-        fn grow(&self, len: usize) {
-            let mut chunks = self.chunks.borrow_mut();
-
-            let capacity = if let Some(last) = chunks.last_mut() {
-                last.mem.len().min(MAX_CHUNK / 2) * 2
-            } else {
-                MIN_CHUNK
-            }
-            .max(len);
-
-            let mut chunk = ArenaChunk::<u8>::new(capacity);
-
-            self.head.set(chunk.start());
-            self.tail.set(chunk.end());
-            chunks.push(chunk);
-        }
-
-        /// Checks whether the given slice is allocated in this arena
-        pub fn contains_slice<T>(&self, slice: &[T]) -> bool {
-            let ptr = slice.as_ptr().cast::<u8>().cast_mut();
-            for chunk in self.chunks.borrow_mut().iter_mut() {
-                if chunk.start() <= ptr && ptr <= chunk.end() {
-                    return true;
-                }
-            }
-            false
-        }
-    }
-
-    unsafe impl<'arena> Send for DroplessArena<'arena> {}
-
-    #[cfg(test)]
-    mod tests;
-}

compiler/cl-arena/src/typed_arena/tests.rs

@@ -1,61 +0,0 @@
-use super::TypedArena;
-    extern crate std;
-    use std::{prelude::rust_2021::*, print, vec};
-    #[test]
-    fn pushing_to_arena() {
-        let arena = TypedArena::new();
-        let foo = arena.alloc("foo");
-        let bar = arena.alloc("bar");
-        let baz = arena.alloc("baz");
-
-        assert_eq!("foo", *foo);
-        assert_eq!("bar", *bar);
-        assert_eq!("baz", *baz);
-    }
-
-    #[test]
-    fn pushing_vecs_to_arena() {
-        let arena = TypedArena::new();
-
-        let foo = arena.alloc(vec!["foo"]);
-        let bar = arena.alloc(vec!["bar"]);
-        let baz = arena.alloc(vec!["baz"]);
-
-        assert_eq!("foo", foo[0]);
-        assert_eq!("bar", bar[0]);
-        assert_eq!("baz", baz[0]);
-    }
-
-    #[test]
-    fn pushing_zsts() {
-        struct ZeroSized;
-        impl Drop for ZeroSized {
-            fn drop(&mut self) {
-                print!("")
-            }
-        }
-
-        let arena = TypedArena::new();
-
-        for _ in 0..0x100 {
-            arena.alloc(ZeroSized);
-        }
-    }
-
-    #[test]
-    fn pushing_nodrop_zsts() {
-        struct ZeroSized;
-        let arena = TypedArena::new();
-
-        for _ in 0..0x1000 {
-            arena.alloc(ZeroSized);
-        }
-    }
-    #[test]
-    fn resize() {
-        let arena = TypedArena::new();
-
-        for _ in 0..0x780 {
-            arena.alloc(0u128);
-        }
-    }

compiler/cl-ast/src/ast.rs

@@ -8,6 +8,7 @@
 //!   - [Assign], [Modify], [Binary], and [Unary] expressions
 //!   - [ModifyKind], [BinaryKind], and [UnaryKind] operators
 //! - [Ty] and [TyKind]: Type qualifiers
+//! - [Pattern]: Pattern matching operators
 //! - [Path]: Path expressions
 use cl_structures::{intern::interned::Interned, span::*};
 
@@ -36,6 +37,7 @@ pub enum Literal {
     Bool(bool),
     Char(char),
     Int(u128),
+    Float(u64),
     String(String),
 }
 
@@ -79,7 +81,6 @@ pub struct Item {
 /// What kind of [Item] is this?
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub enum ItemKind {
-    // TODO: Import declaration ("use") item
     // TODO: Trait declaration ("trait") item?
     /// A [module](Module)
     Module(Module),
@@ -346,8 +347,12 @@ pub enum ExprKind {
     /// 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`])\+
@@ -395,15 +400,43 @@ pub enum ExprKind {
     Continue,
 }
 
+/// 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: Sym,
+    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 {
@@ -486,6 +519,7 @@ pub enum UnaryKind {
     Tilde,
 }
 
+/// A cast expression: [`Expr`] `as` [`Ty`]
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Cast {
     pub head: Box<ExprKind>,
@@ -545,7 +579,6 @@ pub struct ArrayRep {
 /// An address-of expression: `&` `mut`? [`Expr`]
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct AddrOf {
-    pub count: usize,
     pub mutable: Mutability,
     pub expr: Box<ExprKind>,
 }

compiler/cl-ast/src/ast_impl.rs

@@ -9,8 +9,24 @@ mod display {
     use std::{
         borrow::Borrow,
         fmt::{Display, Write},
+        io::IsTerminal,
     };
 
+    fn keyword(d: impl Display, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        if std::io::stdout().is_terminal() {
+            write!(f, "\x1b[31m{d}\x1b[0m")
+        } else {
+            d.fmt(f)
+        }
+    }
+    fn ident(d: impl Display, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        if std::io::stdout().is_terminal() {
+            write!(f, "\x1b[95m{d}\x1b[0m")
+        } else {
+            d.fmt(f)
+        }
+    }
+
     fn separate<I: Display, W: Write>(
         iterable: impl IntoIterator<Item = I>,
         sep: &'static str,
@@ -30,7 +46,7 @@ mod display {
         fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
             match self {
                 Mutability::Not => Ok(()),
-                Mutability::Mut => "mut ".fmt(f),
+                Mutability::Mut => keyword("ante ", f),
             }
         }
     }
@@ -39,18 +55,28 @@ mod display {
         fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
             match self {
                 Visibility::Private => Ok(()),
-                Visibility::Public => "pub ".fmt(f),
+                Visibility::Public => keyword("lukin ", f),
             }
         }
     }
 
     impl Display for Literal {
         fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            match self {
+            fn fmt(this: &Literal, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-                Literal::Bool(v) => v.fmt(f),
+                match this {
-                Literal::Char(v) => write!(f, "'{}'", v.escape_debug()),
+                    Literal::Bool(v) => v.fmt(f),
-                Literal::Int(v) => v.fmt(f),
+                    Literal::Char(v) => write!(f, "'{}'", v.escape_debug()),
-                Literal::String(v) => write!(f, "\"{}\"", v.escape_debug()),
+                    Literal::Int(v) => v.fmt(f),
+                    Literal::Float(v) => write!(f, "{:?}", f64::from_bits(*v)),
+                    Literal::String(v) => write!(f, "\"{}\"", v.escape_debug()),
+                }
+            }
+            if std::io::stdout().is_terminal() {
+                write!(f, "\x1b[94m")?;
+                fmt(self, f)?;
+                write!(f, "\x1b[0m")
+            } else {
+                fmt(self, f)
             }
         }
     }
@@ -76,7 +102,8 @@ mod display {
     impl Display for Meta {
         fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
             let Self { name, kind } = self;
-            write!(f, "{name}{kind}")
+            ident(name, f)?;
+            write!(f, "{kind}")
         }
     }
 
@@ -118,9 +145,10 @@ mod display {
     impl Display for Alias {
         fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
             let Self { to, from } = self;
+            keyword("ijo", f)?;
             match from {
-                Some(from) => write!(f, "type {to} = {from};"),
+                Some(from) => write!(f, " {to} = {from};"),
-                None => write!(f, "type {to};"),
+                None => write!(f, " {to};"),
             }
         }
     }
@@ -128,21 +156,28 @@ mod display {
     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}")
+            keyword("kiwen ", f)?;
+            ident(name, f)?;
+            write!(f, ": {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}")
+            keyword("mute", f)?;
+            write!(f, " {mutable}")?;
+            ident(name, f)?;
+            write!(f, ": {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}")
+            keyword("selo ", f)?;
+            ident(name, f)?;
+            write!(f, "{kind}")
         }
     }
 
@@ -171,7 +206,10 @@ mod display {
             };
 
             debug_assert_eq!(bind.len(), types.len());
-            write!(f, "fn {name} ")?;
+            keyword("nasin", f)?;
+            " ".fmt(f)?;
+            ident(name, f)?;
+            " ".fmt(f)?;
             {
                 let mut f = f.delimit(INLINE_PARENS);
                 for (idx, (arg, ty)) in bind.iter().zip(types.iter()).enumerate() {
@@ -194,14 +232,17 @@ mod display {
     impl Display for Param {
         fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
             let Self { mutability, name } = self;
-            write!(f, "{mutability}{name}")
+            write!(f, "{mutability}")?;
+            ident(name, f)
         }
     }
 
     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}")
+            keyword("lipu ", f)?;
+            ident(name, f)?;
+            write!(f, "{kind}")
         }
     }
 
@@ -218,14 +259,18 @@ mod display {
     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}")
+            write!(f, "{vis}")?;
+            ident(name, f)?;
+            write!(f, ": {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}")
+            keyword("kulupu ", f)?;
+            ident(name, f)?;
+            write!(f, "{kind}")
         }
     }
 
@@ -241,7 +286,8 @@ mod display {
     impl Display for Variant {
         fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
             let Self { name, kind } = self;
-            write!(f, "{name}{kind}")
+            ident(name, f)?;
+            write!(f, "{kind}")
         }
     }
 
@@ -259,7 +305,8 @@ mod display {
     impl Display for Impl {
         fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
             let Self { target, body } = self;
-            write!(f, "impl {target} ")?;
+            keyword("insa", f)?;
+            write!(f, " {target} ")?;
             write!(f.delimit(BRACES), "{body}")
         }
     }
@@ -269,7 +316,9 @@ mod display {
             match self {
                 ImplKind::Type(t) => t.fmt(f),
                 ImplKind::Trait { impl_trait, for_type } => {
-                    write!(f, "{impl_trait} for {for_type}")
+                    write!(f, "{impl_trait} ")?;
+                    keyword("ale", f)?;
+                    write!(f, " {for_type}")
                 }
             }
         }
@@ -278,7 +327,8 @@ mod display {
     impl Display for Use {
         fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
             let Self { absolute, tree } = self;
-            f.write_str(if *absolute { "use ::" } else { "use " })?;
+            keyword("jo", f)?;
+            f.write_str(if *absolute { " ::" } else { " " })?;
             write!(f, "{tree};")
         }
     }
@@ -288,8 +338,12 @@ mod display {
             match self {
                 UseTree::Tree(tree) => separate(tree, ", ")(f.delimit(INLINE_BRACES)),
                 UseTree::Path(path, rest) => write!(f, "{path}::{rest}"),
-                UseTree::Alias(path, name) => write!(f, "{path} as {name}"),
+                UseTree::Alias(path, name) => {
-                UseTree::Name(name) => write!(f, "{name}"),
+                    write!(f, "{path} ")?;
+                    keyword("sama ", f)?;
+                    ident(name, f)
+                }
+                UseTree::Name(name) => ident(name, f),
                 UseTree::Glob => write!(f, "*"),
             }
         }
@@ -349,7 +403,8 @@ mod display {
     impl Display for TyFn {
         fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
             let Self { args, rety } = self;
-            write!(f, "fn {args}")?;
+            keyword("nasin", f)?;
+            write!(f, " {args}")?;
             match rety {
                 Some(v) => write!(f, " -> {v}"),
                 None => Ok(()),
@@ -370,10 +425,10 @@ mod display {
     impl Display for PathPart {
         fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
             match self {
-                PathPart::SuperKw => "super".fmt(f),
+                PathPart::SuperKw => keyword("mama", f),
-                PathPart::SelfKw => "self".fmt(f),
+                PathPart::SelfKw => keyword("mi", f),
-                PathPart::SelfTy => "Self".fmt(f),
+                PathPart::SelfTy => keyword("Mi", f),
-                PathPart::Ident(id) => id.fmt(f),
+                PathPart::Ident(id) => ident(id, f),
             }
         }
     }
@@ -414,7 +469,9 @@ mod display {
         fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
             match self {
                 ExprKind::Empty => "()".fmt(f),
+                ExprKind::Quote(v) => v.fmt(f),
                 ExprKind::Let(v) => v.fmt(f),
+                ExprKind::Match(v) => v.fmt(f),
                 ExprKind::Assign(v) => v.fmt(f),
                 ExprKind::Modify(v) => v.fmt(f),
                 ExprKind::Binary(v) => v.fmt(f),
@@ -436,15 +493,25 @@ mod display {
                 ExprKind::For(v) => v.fmt(f),
                 ExprKind::Break(v) => v.fmt(f),
                 ExprKind::Return(v) => v.fmt(f),
-                ExprKind::Continue => "continue".fmt(f),
+                ExprKind::Continue => keyword("tama", f),
             }
         }
     }
 
+    impl Display for Quote {
+        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+            let Self { quote } = self;
+            write!(f, "`{quote}`")
+        }
+    }
+
     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}")?;
+            keyword("poki", f)?;
+            write!(f, " {mutable}")?;
+            ident(name, f)?;
+
             if let Some(value) = ty {
                 write!(f, ": {value}")?;
             }
@@ -455,6 +522,48 @@ mod display {
         }
     }
 
+    impl Display for Pattern {
+        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+            match self {
+                Pattern::Path(path) => path.fmt(f),
+                Pattern::Literal(literal) => literal.fmt(f),
+                Pattern::Ref(mutability, pattern) => write!(f, "&{mutability}{pattern}"),
+                Pattern::Tuple(patterns) => separate(patterns, ", ")(f.delimit(INLINE_PARENS)),
+                Pattern::Array(patterns) => separate(patterns, ", ")(f.delimit(INLINE_SQUARE)),
+                Pattern::Struct(path, items) => {
+                    write!(f, "{path}: ")?;
+                    let f = &mut f.delimit(BRACES);
+                    for (idx, (name, item)) in items.iter().enumerate() {
+                        if idx != 0 {
+                            f.write_str(",\n")?;
+                        }
+                        write!(f, "{name}")?;
+                        if let Some(pattern) = item {
+                            write!(f, ": {pattern}")?
+                        }
+                    }
+                    Ok(())
+                }
+            }
+        }
+    }
+
+    impl Display for Match {
+        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+            let Self { scrutinee, arms } = self;
+            keyword("seme", f)?;
+            write!(f, " {scrutinee} ")?;
+            separate(arms, ",\n")(f.delimit(BRACES))
+        }
+    }
+
+    impl Display for MatchArm {
+        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+            let Self(pat, expr) = self;
+            write!(f, "{pat} => {expr}")
+        }
+    }
+
     impl Display for Assign {
         fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
             let Self { parts } = self;
@@ -538,7 +647,7 @@ mod display {
     impl Display for UnaryKind {
         fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
             match self {
-                UnaryKind::Loop => "loop ",
+                UnaryKind::Loop => return keyword("awen ", f),
                 UnaryKind::Deref => "*",
                 UnaryKind::Neg => "-",
                 UnaryKind::Not => "!",
@@ -552,7 +661,9 @@ mod display {
     impl Display for Cast {
         fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
             let Self { head, ty } = self;
-            write!(f, "{head} as {ty}")
+            write!(f, "{head} ")?;
+            keyword("sama", f)?;
+            write!(f, " {ty}")
         }
     }
 
@@ -566,9 +677,12 @@ mod display {
     impl Display for MemberKind {
         fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
             match self {
-                MemberKind::Call(name, args) => write!(f, "{name}{args}"),
+                MemberKind::Call(name, args) => {
-                MemberKind::Struct(name) => write!(f, "{name}"),
+                    ident(name, f)?;
-                MemberKind::Tuple(name) => write!(f, "{name}"),
+                    separate(&args.exprs, ", ")(f.delimit(INLINE_PARENS))
+                }
+                MemberKind::Struct(name) => ident(name, f),
+                MemberKind::Tuple(name) => ident(name, f),
             }
         }
     }
@@ -592,7 +706,7 @@ mod display {
     impl Display for Fielder {
         fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
             let Self { name, init } = self;
-            write!(f, "{name}")?;
+            ident(name, f)?;
             if let Some(init) = init {
                 write!(f, ": {init}")?;
             }
@@ -615,11 +729,8 @@ mod display {
 
     impl Display for AddrOf {
         fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            let Self { count, mutable, expr } = self;
+            let Self { mutable, expr } = self;
-            for _ in 0..*count {
+            write!(f, "&{mutable}{expr}")
-                f.write_char('&')?;
-            }
-            write!(f, "{mutable}{expr}")
         }
     }
 
@@ -655,28 +766,35 @@ mod display {
     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}")
+            write!(f, "lawa {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}")
+            keyword("tan", f)?;
+            write!(f, " {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}")
+            keyword("ale", f)?;
+            write!(f, " {bind} ")?;
+            keyword("lon", f)?;
+            write!(f, " {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}"),
+                Some(body) => {
+                    keyword(" taso", f)?;
+                    write!(f, " {body}")
+                }
                 _ => Ok(()),
             }
         }
@@ -684,7 +802,7 @@ mod display {
 
     impl Display for Break {
         fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            write!(f, "break")?;
+            keyword("pana", f)?;
             match &self.body {
                 Some(body) => write!(f, " {body}"),
                 _ => Ok(()),
@@ -694,7 +812,7 @@ mod display {
 
     impl Display for Return {
         fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            write!(f, "return")?;
+            keyword("pini", f)?;
             match &self.body {
                 Some(body) => write!(f, " {body}"),
                 _ => Ok(()),
@@ -766,6 +884,8 @@ mod convert {
         }
         impl From for ExprKind {
             Let => ExprKind::Let,
+            Quote => ExprKind::Quote,
+            Match => ExprKind::Match,
             Assign => ExprKind::Assign,
             Modify => ExprKind::Modify,
             Binary => ExprKind::Binary,
@@ -805,6 +925,50 @@ mod convert {
             Self { body: Some(value.into()) }
         }
     }
+
+    impl TryFrom<ExprKind> for Pattern {
+        type Error = ExprKind;
+
+        /// Performs the conversion. On failure, returns the *first* non-pattern subexpression.
+        fn try_from(value: ExprKind) -> Result<Self, Self::Error> {
+            Ok(match value {
+                ExprKind::Literal(literal) => Pattern::Literal(literal),
+                ExprKind::Path(path) => Pattern::Path(path),
+                ExprKind::Empty => Pattern::Tuple(vec![]),
+                ExprKind::Group(Group { expr }) => Pattern::Tuple(vec![Pattern::try_from(*expr)?]),
+                ExprKind::Tuple(Tuple { exprs }) => Pattern::Tuple(
+                    exprs
+                        .into_iter()
+                        .map(|e| Pattern::try_from(e.kind))
+                        .collect::<Result<_, _>>()?,
+                ),
+                ExprKind::AddrOf(AddrOf { mutable, expr }) => {
+                    Pattern::Ref(mutable, Box::new(Pattern::try_from(*expr)?))
+                }
+                ExprKind::Array(Array { values }) => Pattern::Array(
+                    values
+                        .into_iter()
+                        .map(|e| Pattern::try_from(e.kind))
+                        .collect::<Result<_, _>>()?,
+                ),
+                // ExprKind::Index(index) => todo!(),
+                // ExprKind::Member(member) => todo!(),
+                ExprKind::Structor(Structor { to, init }) => {
+                    let fields = init
+                        .into_iter()
+                        .map(|Fielder { name, init }| {
+                            Ok((
+                                name.into(),
+                                init.map(|i| Pattern::try_from(i.kind)).transpose()?,
+                            ))
+                        })
+                        .collect::<Result<_, Self::Error>>()?;
+                    Pattern::Struct(to, fields)
+                }
+                err => Err(err)?,
+            })
+        }
+    }
 }
 
 mod path {
@@ -830,10 +994,26 @@ mod path {
                 self
             }
         }
+
+        /// Checks whether this path refers to the sinkhole identifier, `_`
+        pub fn is_sinkhole(&self) -> bool {
+            if let [PathPart::Ident(id)] = self.parts.as_slice() {
+                if let "_" = Sym::to_ref(id) {
+                    return true;
+                }
+            }
+            false
+        }
     }
     impl PathPart {
         pub fn from_sym(ident: Sym) -> Self {
             Self::Ident(ident)
         }
     }
+
+    impl From<Sym> for Path {
+        fn from(value: Sym) -> Self {
+            Self { parts: vec![PathPart::Ident(value)], absolute: false }
+        }
+    }
 }

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

@@ -37,6 +37,9 @@ pub trait Fold {
     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
     }
@@ -226,15 +229,6 @@ pub trait Fold {
     fn fold_semi(&mut self, s: Semi) -> Semi {
         s
     }
-    fn fold_let(&mut self, l: Let) -> Let {
-        let Let { mutable, name, ty, init } = l;
-        Let {
-            mutable: self.fold_mutability(mutable),
-            name: self.fold_sym(name),
-            ty: ty.map(|t| Box::new(self.fold_ty(*t))),
-            init: init.map(|e| Box::new(self.fold_expr(*e))),
-        }
-    }
     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) }
@@ -242,6 +236,56 @@ pub trait Fold {
     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;
@@ -319,9 +363,8 @@ pub trait Fold {
         }
     }
     fn fold_addrof(&mut self, a: AddrOf) -> AddrOf {
-        let AddrOf { count, mutable, expr } = a;
+        let AddrOf { mutable, expr } = a;
         AddrOf {
-            count,
             mutable: self.fold_mutability(mutable),
             expr: Box::new(self.fold_expr_kind(*expr)),
         }
@@ -384,6 +427,7 @@ pub fn or_fold_literal<F: Fold + ?Sized>(folder: &mut F, lit: Literal) -> Litera
         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)),
     }
 }
@@ -526,7 +570,9 @@ pub fn or_fold_stmt_kind<F: Fold + ?Sized>(folder: &mut F, kind: StmtKind) -> St
 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)),

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

@@ -23,6 +23,7 @@ pub trait Visit<'a>: Sized {
     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;
@@ -191,17 +192,6 @@ pub trait Visit<'a>: Sized {
         or_visit_stmt_kind(self, kind)
     }
     fn visit_semi(&mut self, _s: &'a Semi) {}
-    fn visit_let(&mut self, l: &'a Let) {
-        let Let { mutable, name, ty, init } = l;
-        self.visit_mutability(mutable);
-        self.visit_sym(name);
-        if let Some(ty) = ty {
-            self.visit_ty(ty);
-        }
-        if let Some(init) = init {
-            self.visit_expr(init)
-        }
-    }
     fn visit_expr(&mut self, e: &'a Expr) {
         let Expr { extents, kind } = e;
         self.visit_span(extents);
@@ -210,6 +200,55 @@ pub trait Visit<'a>: Sized {
     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();
@@ -278,7 +317,7 @@ pub trait Visit<'a>: Sized {
         self.visit_expr_kind(repeat);
     }
     fn visit_addrof(&mut self, a: &'a AddrOf) {
-        let AddrOf { count: _, mutable, expr } = a;
+        let AddrOf { mutable, expr } = a;
         self.visit_mutability(mutable);
         self.visit_expr_kind(expr);
     }
@@ -339,6 +378,7 @@ pub fn or_visit_literal<'a, V: Visit<'a>>(visitor: &mut V, l: &'a Literal) {
         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),
     }
 }
@@ -450,7 +490,9 @@ pub fn or_visit_stmt_kind<'a, V: Visit<'a>>(visitor: &mut V, kind: &'a StmtKind)
 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),

compiler/cl-ast/src/format.rs

@@ -21,7 +21,7 @@ pub struct Indent<'f, F: Write + ?Sized> {
     f: &'f mut F,
 }
 
-impl<'f, F: Write + ?Sized> Write for Indent<'f, 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)?;
@@ -45,14 +45,14 @@ impl<'f, F: Write + ?Sized> Delimit<'f, F> {
         Self { f, delim }
     }
 }
-impl<'f, F: Write + ?Sized> Drop for Delimit<'f, F> {
+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, F: Write + ?Sized> Write for Delimit<'f, F> {
+impl<F: Write + ?Sized> Write for Delimit<'_, F> {
     fn write_str(&mut self, s: &str) -> std::fmt::Result {
         self.f.write_str(s)
     }

compiler/cl-ast/src/lib.rs

@@ -8,6 +8,7 @@
 //!   - [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)]

compiler/cl-interpret/src/builtin.rs

@@ -1,81 +1,192 @@
-//! Implementations of built-in functions
+#![allow(non_upper_case_globals)]
 
-use super::{
+use crate::{
     convalue::ConValue,
     env::Environment,
     error::{Error, IResult},
-    BuiltIn, Callable,
 };
-use cl_ast::Sym;
 use std::{
     io::{stdout, Write},
-    rc::Rc,
     slice,
 };
 
-builtins! {
+/// A function built into the interpreter.
-    const MISC;
+#[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
-    pub fn format<_, args> () -> IResult<ConValue> {
+    fn fmt(args @ ..) {
         use std::fmt::Write;
         let mut out = String::new();
-        for arg in args {
+        if let Err(e) = args.iter().try_for_each(|arg| write!(out, "{arg}")) {
-            write!(out, "{arg}").ok();
+            eprintln!("{e}");
         }
-        Ok(ConValue::String(out.into()))
+        Ok(out)
     }
 
-    /// Unstable variadic print function
+    /// Prints the arguments in-order, with no separators
-    pub fn print<_, args> () -> IResult<ConValue> {
+    fn print(args @ ..) {
         let mut out = stdout().lock();
-        for arg in args {
+        args.iter().try_for_each(|arg| write!(out, "{arg}") ).ok();
-            write!(out, "{arg}").ok();
+        Ok(())
-        }
-        Ok(ConValue::Empty)
     }
 
-    /// Unstable variadic println function
+    /// Prints the arguments in-order, followed by a newline
-    pub fn println<_, args> () -> IResult<ConValue> {
+    fn println(args @ ..) {
         let mut out = stdout().lock();
-        for arg in args {
+        args.iter().try_for_each(|arg| write!(out, "{arg}") ).ok();
-            write!(out, "{arg}").ok();
-        }
         writeln!(out).ok();
-        Ok(ConValue::Empty)
+        Ok(())
     }
 
-    /// Prints the [Debug](std::fmt::Debug) version of the input values
+    /// Debug-prints the argument, returning a copy
-    pub fn dbg<_, args> () -> IResult<ConValue> {
+    fn dbg(arg) {
+        println!("{arg:?}");
+        Ok(arg.clone())
+    }
+
+    /// Debug-prints the argument
+    fn dbgp(args @ ..) {
         let mut out = stdout().lock();
-        for arg in args {
+        args.iter().try_for_each(|arg| writeln!(out, "{arg:#?}") ).ok();
-            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(args.into())
+        Ok(())
     }
 
-    /// Dumps info from the environment
+    /// Returns the length of the input list as a [ConValue::Int]
-    pub fn dump<env, _>() -> IResult<ConValue> {
+    fn len(list) @env {
-        println!("{}", *env);
+        Ok(match list {
-        Ok(ConValue::Empty)
-    }
-
-    pub fn len<env, _>(list) -> IResult<ConValue> {
-        Ok(ConValue::Int(match list {
             ConValue::Empty => 0,
             ConValue::String(s) => s.chars().count() as _,
-            ConValue::Ref(r) => return len.call(env, slice::from_ref(r.as_ref())),
+            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)?,
-        }))
+        })
     }
-}
+
-builtins! {
+    fn dump_symbols() {
-    const BINARY;
+        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`
-    pub fn mul(lhs, rhs) -> IResult<ConValue> {
+    fn mul(lhs, rhs) {
         Ok(match (lhs, rhs) {
             (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
             (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a * b),
@@ -84,7 +195,7 @@ builtins! {
     }
 
     /// Division `a / b`
-    pub fn div(lhs, rhs) -> IResult<ConValue> {
+    fn div(lhs, rhs) {
         Ok(match (lhs, rhs){
             (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
             (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a / b),
@@ -93,7 +204,7 @@ builtins! {
     }
 
     /// Remainder `a % b`
-    pub fn rem(lhs, rhs) -> IResult<ConValue> {
+    fn rem(lhs, rhs) {
         Ok(match (lhs, rhs) {
             (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
             (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a % b),
@@ -102,7 +213,7 @@ builtins! {
     }
 
     /// Addition `a + b`
-    pub fn add(lhs, rhs) -> IResult<ConValue> {
+    fn add(lhs, rhs) {
         Ok(match (lhs, rhs) {
             (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
             (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a + b),
@@ -112,7 +223,7 @@ builtins! {
     }
 
     /// Subtraction `a - b`
-    pub fn sub(lhs, rhs) -> IResult<ConValue> {
+    fn sub(lhs, rhs) {
         Ok(match (lhs, rhs) {
             (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
             (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a - b),
@@ -121,7 +232,7 @@ builtins! {
     }
 
     /// Shift Left `a << b`
-    pub fn shl(lhs, rhs) -> IResult<ConValue> {
+    fn shl(lhs, rhs) {
         Ok(match (lhs, rhs) {
             (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
             (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a << b),
@@ -130,7 +241,7 @@ builtins! {
     }
 
     /// Shift Right `a >> b`
-    pub fn shr(lhs, rhs) -> IResult<ConValue> {
+    fn shr(lhs, rhs) {
         Ok(match (lhs, rhs) {
             (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
             (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a >> b),
@@ -139,7 +250,7 @@ builtins! {
     }
 
     /// Bitwise And `a & b`
-    pub fn and(lhs, rhs) -> IResult<ConValue> {
+    fn and(lhs, rhs) {
         Ok(match (lhs, rhs) {
             (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
             (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a & b),
@@ -149,7 +260,7 @@ builtins! {
     }
 
     /// Bitwise Or `a | b`
-    pub fn or(lhs, rhs) -> IResult<ConValue> {
+    fn or(lhs, rhs) {
         Ok(match (lhs, rhs) {
             (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
             (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a | b),
@@ -159,7 +270,7 @@ builtins! {
     }
 
     /// Bitwise Exclusive Or `a ^ b`
-    pub fn xor(lhs, rhs) -> IResult<ConValue> {
+    fn xor(lhs, rhs) {
         Ok(match (lhs, rhs) {
             (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
             (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a ^ b),
@@ -168,67 +279,34 @@ builtins! {
         })
     }
 
-    /// 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> {
+    fn range_exc(from, to) {
-        let (&ConValue::Int(lhs), &ConValue::Int(rhs)) = (lhs, rhs) else {
+        let (&ConValue::Int(from), &ConValue::Int(to)) = (from, to) else {
             Err(Error::TypeError)?
         };
-        Ok(ConValue::RangeExc(lhs, rhs.saturating_sub(1)))
+        Ok(ConValue::RangeExc(from, to))
     }
 
     /// Inclusive Range `a..=b`
-    pub fn range_inc(lhs, rhs) -> IResult<ConValue> {
+    fn range_inc(from, to) {
-        let (&ConValue::Int(lhs), &ConValue::Int(rhs)) = (lhs, rhs) else {
+        let (&ConValue::Int(from), &ConValue::Int(to)) = (from, to) else {
             Err(Error::TypeError)?
         };
-        Ok(ConValue::RangeInc(lhs, rhs))
+        Ok(ConValue::RangeInc(from, to))
     }
-}
+
-builtins! {
-    const UNARY;
     /// Negates the ConValue
-    pub fn neg(tail) -> IResult<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
-    pub fn not(tail) -> IResult<ConValue> {
+    fn not(tail) {
         Ok(match tail {
             ConValue::Empty => ConValue::Empty,
             ConValue::Int(v) => ConValue::Int(!v),
@@ -237,62 +315,23 @@ builtins! {
         })
     }
 
-    pub fn deref(tail) -> IResult<ConValue> {
+    /// 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(),
         })
     }
-}
+];
-
-/// 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)?;)?
-                $body
-            }
-            fn name(&self) -> Sym { stringify!($name).into() }
-        }
-    )*
-}
-
-/// 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)
-    }
-}

compiler/cl-interpret/src/convalue.rs

@@ -1,14 +1,14 @@
 //! Values in the dynamically typed AST interpreter.
 //!
 //! The most permanent fix is a temporary one.
-use cl_ast::Sym;
+use cl_ast::{format::FmtAdapter, ExprKind, Sym};
 
 use super::{
+    builtin::Builtin,
     error::{Error, IResult},
-    function::Function,
+    function::Function, Callable, Environment,
-    BuiltIn, Callable, Environment,
 };
-use std::{ops::*, rc::Rc};
+use std::{collections::HashMap, ops::*, rc::Rc};
 
 type Integer = isize;
 
@@ -20,6 +20,8 @@ pub enum ConValue {
     Empty,
     /// An integer
     Int(Integer),
+    /// A floating point number
+    Float(f64),
     /// A boolean
     Bool(bool),
     /// A unicode character
@@ -29,18 +31,25 @@ pub enum ConValue {
     /// A reference
     Ref(Rc<ConValue>),
     /// An Array
-    Array(Rc<[ConValue]>),
+    Array(Box<[ConValue]>),
     /// A tuple
-    Tuple(Rc<[ConValue]>),
+    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(Function),
+    Function(Rc<Function>),
     /// A built-in function
-    BuiltIn(&'static dyn BuiltIn),
+    Builtin(&'static Builtin),
 }
+
 impl ConValue {
     /// Gets whether the current value is true or false
     pub fn truthy(&self) -> IResult<bool> {
@@ -53,7 +62,7 @@ impl ConValue {
         let (Self::Int(a), Self::Int(b)) = (self, other) else {
             Err(Error::TypeError)?
         };
-        Ok(Self::RangeExc(a, b.saturating_sub(1)))
+        Ok(Self::RangeExc(a, b))
     }
     pub fn range_inc(self, other: Self) -> IResult<Self> {
         let (Self::Int(a), Self::Int(b)) = (self, other) else {
@@ -104,14 +113,14 @@ impl Callable for ConValue {
     fn name(&self) -> Sym {
         match self {
             ConValue::Function(func) => func.name(),
-            ConValue::BuiltIn(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),
+            Self::Builtin(func) => func.call(interpreter, args),
             _ => Err(Error::NotCallable(self.clone())),
         }
     }
@@ -124,6 +133,7 @@ macro cmp ($($fn:ident: $empty:literal, $op:tt);*$(;)?) {$(
         match (self, other) {
             (Self::Empty, Self::Empty) => Ok(Self::Bool($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)),
@@ -150,15 +160,17 @@ impl From<&Sym> for ConValue {
 }
 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 dyn BuiltIn => ConValue::BuiltIn,
+    &'static Builtin => ConValue::Builtin,
 }
 impl From<()> for ConValue {
     fn from(_: ()) -> Self {
@@ -189,7 +201,8 @@ ops! {
     Add: add = [
         (ConValue::Empty, ConValue::Empty) => ConValue::Empty,
         (ConValue::Int(a), ConValue::Int(b)) => ConValue::Int(a.wrapping_add(b)),
-        (ConValue::String(a), ConValue::String(b)) => (a.to_string() + &b.to_string()).into(),
+        (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())
@@ -219,18 +232,21 @@ ops! {
         (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(|| {
-            eprintln!("Warning: Divide by zero in {a} % {b}"); a
+            println!("Warning: Divide by zero in {a} % {b}"); a
         })),
+        (ConValue::Float(a), ConValue::Float(b)) => ConValue::Float(a % b),
         _ => Err(Error::TypeError)?
     ]
     Shl: shl = [
@@ -246,6 +262,7 @@ ops! {
     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)?
     ]
 }
@@ -254,6 +271,7 @@ impl std::fmt::Display for ConValue {
         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),
@@ -280,10 +298,37 @@ impl std::fmt::Display for ConValue {
                 }
                 ')'.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) => {
+            ConValue::Builtin(func) => {
                 write!(f, "{}", func.description())
             }
         }

compiler/cl-interpret/src/env.rs

@@ -1,16 +1,20 @@
 //! Lexical and non-lexical scoping for variables
+
+use crate::builtin::Builtin;
+
 use super::{
-    builtin::{BINARY, MISC, RANGE, UNARY},
+    builtin::{Builtins, Math},
     convalue::ConValue,
     error::{Error, IResult},
     function::Function,
-    BuiltIn, Callable, Interpret,
+    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>>;
@@ -18,12 +22,21 @@ 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.frames.iter().rev() {
+        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}: ")?;
@@ -39,18 +52,17 @@ impl Display for Environment {
 impl Default for Environment {
     fn default() -> Self {
         Self {
-            frames: vec![
+            builtin: to_hashmap(Builtins.iter().chain(Math.iter())),
-                (to_hashmap(RANGE), "range ops"),
+            global: vec![(HashMap::new(), "globals")],
-                (to_hashmap(UNARY), "unary ops"),
+            frames: vec![],
-                (to_hashmap(BINARY), "binary ops"),
-                (to_hashmap(MISC), "builtins"),
-                (HashMap::new(), "globals"),
-            ],
         }
     }
 }
-fn to_hashmap(from: &[&'static dyn BuiltIn]) -> HashMap<Sym, Option<ConValue>> {
+
-    from.iter().map(|&v| (v.name(), Some(v.into()))).collect()
+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 {
@@ -58,8 +70,35 @@ impl Environment {
         Self::default()
     }
     /// Creates an [Environment] with no [builtins](super::builtin)
-    pub fn no_builtins(name: &'static str) -> Self {
+    pub fn no_builtins() -> Self {
-        Self { frames: vec![(Default::default(), name)] }
+        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> {
@@ -88,7 +127,12 @@ impl Environment {
                 return Ok(var);
             }
         }
-        Err(Error::NotDefined(id))
+        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.
     ///
@@ -101,21 +145,50 @@ impl Environment {
                 _ => (),
             }
         }
-        Err(Error::NotDefined(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, Some(Function::new(decl).into()));
+        let (name, function) = (name, Rc::new(Function::new(decl)));
         if let Some((frame, _)) = self.frames.last_mut() {
-            frame.insert(*name, function);
+            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);
     }
 }
 
@@ -130,9 +203,7 @@ impl Environment {
     /// 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.frames.pop();
-        }
         self
     }
 }
@@ -147,18 +218,18 @@ impl<'scope> Frame<'scope> {
         Self { scope: scope.enter(name) }
     }
 }
-impl<'scope> Deref for Frame<'scope> {
+impl Deref for Frame<'_> {
     type Target = Environment;
     fn deref(&self) -> &Self::Target {
         self.scope
     }
 }
-impl<'scope> DerefMut for Frame<'scope> {
+impl DerefMut for Frame<'_> {
     fn deref_mut(&mut self) -> &mut Self::Target {
         self.scope
     }
 }
-impl<'scope> Drop for Frame<'scope> {
+impl Drop for Frame<'_> {
     fn drop(&mut self) {
         self.scope.exit();
     }

compiler/cl-interpret/src/error.rs

@@ -1,6 +1,6 @@
 //! The [Error] type represents any error thrown by the [Environment](super::Environment)
 
-use cl_ast::Sym;
+use cl_ast::{Pattern, Sym};
 
 use super::convalue::ConValue;
 
@@ -39,11 +39,13 @@ pub enum Error {
     /// A value was called, but is not callable
     NotCallable(ConValue),
     /// A function was called with the wrong number of arguments
-    ArgNumber {
+    ArgNumber { want: usize, got: usize },
-        want: usize,
+    /// A pattern failed to match
-        got: usize,
+    PatFailed(Box<Pattern>),
-    },
+    /// Fell through a non-exhaustive match
-    Outlined(Sym),
+    MatchNonexhaustive,
+    /// Error produced by a Builtin
+    BuiltinDebug(String),
 }
 
 impl std::error::Error for Error {}
@@ -83,9 +85,13 @@ impl std::fmt::Display for Error {
                     if *want == 1 { "" } else { "s" }
                 )
             }
-            Error::Outlined(name) => {
+            Error::PatFailed(pattern) => {
-                write!(f, "Module {name} specified, but not imported.")
+                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

@@ -1,24 +1,45 @@
 //! 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::rc::Rc;
+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 the enclosing scope of the function
+    /// Stores data from the enclosing scopes
-    // env: Box<Environment>,
+    upvars: RefCell<Upvars>,
 }
 
 impl Function {
     pub fn new(decl: &FnDecl) -> Self {
-        Self { decl: decl.clone().into() }
+        // 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 {
@@ -28,6 +49,7 @@ impl Callable for Function {
     }
     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() });
@@ -35,12 +57,21 @@ impl Callable for Function {
         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()));
         }
-        match body.interpret(&mut frame) {
+        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

@@ -9,6 +9,7 @@ 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`].
@@ -36,7 +37,7 @@ impl Interpret for Item {
             ItemKind::Struct(item) => item.interpret(env),
             ItemKind::Enum(item) => item.interpret(env),
             ItemKind::Impl(item) => item.interpret(env),
-            ItemKind::Use(_) => todo!("namespaces and imports in the interpreter"),
+            ItemKind::Use(item) => item.interpret(env),
         }
     }
 }
@@ -67,11 +68,21 @@ impl Interpret for Static {
 impl Interpret for Module {
     fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
         let Self { name, kind } = self;
-        // TODO: Enter this module's namespace
+        env.push_frame(Interned::to_ref(name), Default::default());
-        match kind {
+        let out = match kind {
             ModuleKind::Inline(file) => file.interpret(env),
-            ModuleKind::Outline => Err(Error::Outlined(*name)),
+            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 {
@@ -100,6 +111,73 @@ impl Interpret for Impl {
         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;
@@ -114,14 +192,7 @@ impl Interpret for Stmt {
         })
     }
 }
-impl Interpret for Let {
+
-    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        let Let { mutable: _, 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> {
@@ -129,11 +200,14 @@ impl Interpret for Expr {
         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),
@@ -160,25 +234,296 @@ impl Interpret for ExprKind {
     }
 }
 
-fn evaluate_place_expr<'e>(
+impl Interpret for Quote {
-    env: &'e mut Environment,
+    fn interpret(&self, _env: &mut Environment) -> IResult<ConValue> {
-    expr: &ExprKind,
+        // TODO: squoosh down into a ConValue?
-) -> IResult<(&'e mut Option<ConValue>, Sym)> {
+        Ok(ConValue::Quote(self.quote.clone()))
-    match expr {
+    }
-        ExprKind::Path(Path { parts, .. }) if parts.len() == 1 => {
+}
-            match parts.last().expect("parts should not be empty") {
+
-                PathPart::SuperKw => Err(Error::NotAssignable),
+impl Interpret for Let {
-                PathPart::SelfKw => todo!("Assignment to `self`"),
+    fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-                PathPart::SelfTy => todo!("What does it mean to assign to capital-S Self?"),
+        let Let { mutable: _, name, ty: _, init } = self;
-                PathPart::Ident(s) => env.get_mut(*s).map(|v| (v, *s)),
+        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}"),
+                    }
+                }
             }
         }
-        ExprKind::Index(_) => todo!("Assignment to an index operation"),
+        Ok(ConValue::Empty)
-        ExprKind::Path(_) => todo!("Path expression resolution (IMPORTANT)"),
+    }
-        ExprKind::Empty | ExprKind::Group(_) | ExprKind::Tuple(_) => {
+}
-            todo!("Pattern Destructuring?")
+
+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`"),
         }
-        _ => Err(Error::NotAssignable),
     }
 }
 
@@ -188,17 +533,7 @@ impl Interpret for Assign {
         let (head, tail) = parts.borrow();
         let init = tail.interpret(env)?;
         // Resolve the head pattern
-        let target = evaluate_place_expr(env, head)?;
+        assignment::assign(env, head, init).map(|_| ConValue::Empty)
-        use std::mem::discriminant as variant;
-        // runtime typecheck
-        match target.0 {
-            Some(value) if variant(value) == variant(&init) => {
-                *value = init;
-            }
-            value @ None => *value = Some(init),
-            _ => Err(Error::TypeError)?,
-        }
-        Ok(ConValue::Empty)
     }
 }
 impl Interpret for Modify {
@@ -208,10 +543,7 @@ impl Interpret for Modify {
         // Get the initializer and the tail
         let init = tail.interpret(env)?;
         // Resolve the head pattern
-        let target = evaluate_place_expr(env, head)?;
+        let target = assignment::addrof(env, head)?;
-        let (Some(target), _) = target else {
-            return Err(Error::NotInitialized(target.1));
-        };
 
         match op {
             ModifyKind::Add => target.add_assign(init),
@@ -358,6 +690,9 @@ fn cast(value: ConValue, ty: Sym) -> IResult<ConValue> {
         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 {
@@ -369,6 +704,8 @@ fn cast(value: ConValue, ty: Sym) -> IResult<ConValue> {
         "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))?,
@@ -401,6 +738,20 @@ impl Interpret for Member {
                 .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 {
@@ -424,22 +775,37 @@ impl Interpret for Index {
 }
 impl Interpret for Structor {
     fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        todo!("struct construction in {env}")
+        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;
 
-        if parts.len() == 1 {
+        assignment::addrof_path(env, parts)
-            match parts.last().expect("parts should not be empty") {
+            .cloned()
-                PathPart::SuperKw | PathPart::SelfKw => todo!("Path navigation"),
+            .transpose()
-                PathPart::SelfTy => todo!("Path navigation to Self"),
+            .ok_or_else(|| Error::NotInitialized(format!("{self}").into()))?
-                PathPart::Ident(name) => env.get(*name),
-            }
-        } else {
-            todo!("Path navigation!")
-        }
     }
 }
 impl Interpret for Literal {
@@ -448,7 +814,7 @@ impl Interpret for Literal {
             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::Float(value) => ConValue::Float(f64::from_bits(*value)),
             Literal::Int(value) => ConValue::Int(*value as _),
         })
     }
@@ -476,13 +842,9 @@ impl Interpret for ArrayRep {
 }
 impl Interpret for AddrOf {
     fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
-        let Self { count: _, mutable: _, expr } = self;
+        let Self { mutable: _, expr } = self;
         match expr.as_ref() {
             ExprKind::Index(_) => todo!("AddrOf array index"),
-            // ExprKind::Path(Path { absolute: false, parts }) => match parts.as_slice() {
-            //     [PathPart::Ident(id)] => env.get_ref(id),
-            //     _ => todo!("Path traversal in addrof"),
-            // },
             ExprKind::Path(_) => todo!("Path traversal in addrof"),
             _ => Ok(ConValue::Ref(Rc::new(expr.interpret(env)?))),
         }
@@ -548,16 +910,19 @@ impl Interpret for If {
 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 = match cond.interpret(env)? {
+        let mut bounds: Box<dyn Iterator<Item = ConValue>> = match &cond {
-            ConValue::RangeExc(a, b) => a..=b,
+            &ConValue::RangeExc(a, b) => Box::new((a..b).map(ConValue::Int)),
-            ConValue::RangeInc(a, b) => a..=b,
+            &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.into()));
+                env.insert(*name, Some(loop_var));
                 match pass.interpret(&mut env) {
                     Err(Error::Break(value)) => return Ok(value),
                     Err(Error::Continue) => continue,

compiler/cl-interpret/src/lib.rs

@@ -17,11 +17,6 @@ pub trait Callable: std::fmt::Debug {
     fn name(&self) -> Sym;
 }
 
-/// [BuiltIn]s are [Callable]s with bespoke definitions
-pub trait BuiltIn: std::fmt::Debug + Callable {
-    fn description(&self) -> &str;
-}
-
 pub mod convalue;
 
 pub mod interpret;

compiler/cl-interpret/src/tests.rs

@@ -1,5 +1,5 @@
 #![allow(unused_imports)]
-use crate::{env::Environment, convalue::ConValue, Interpret};
+use crate::{convalue::ConValue, env::Environment, Interpret};
 use cl_ast::*;
 use cl_lexer::Lexer;
 use cl_parser::Parser;
@@ -178,6 +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 {
@@ -188,7 +227,7 @@ 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".into())
@@ -437,16 +476,17 @@ mod operators {
         env_eq!(env.y, 10);
         env_eq!(env.z, 10);
     }
-    #[test]
+    // Test is disabled, since new assignment system intentionally does not care.
-    #[should_panic]
+    // #[test]
-    fn assignment_accounts_for_type() {
+    // #[should_panic]
-        let mut env = Default::default();
+    // fn assignment_accounts_for_type() {
-        assert_eval!(env,
+    //     let mut env = Default::default();
-            let x = "a string";
+    //     assert_eval!(env,
-            let y = 0xdeadbeef;
+    //         let x = "a string";
-            y = x; // should crash: type error
+    //         let y = 0xdeadbeef;
-        );
+    //         y = x; // should crash: type error
-    }
+    //     );
+    // }
     #[test]
     fn precedence() {
         let mut env = Default::default();
@@ -469,6 +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() {
@@ -192,7 +192,7 @@ 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(Kind::AmpAmp),
@@ -319,7 +319,7 @@ impl<'t> Lexer<'t> {
     }
 }
 /// Comments
-impl<'t> Lexer<'t> {
+impl Lexer<'_> {
     fn line_comment(&mut self) -> LResult<Token> {
         let mut comment = String::new();
         while Ok('\n') != self.peek() {
@@ -339,7 +339,7 @@ impl<'t> Lexer<'t> {
     }
 }
 /// 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() {
@@ -371,23 +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()?;
@@ -398,7 +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-parser/src/error.rs

@@ -119,6 +119,10 @@ pub enum Parsing {
     Break,
     Return,
     Continue,
+
+    Pattern,
+    Match,
+    MatchArm,
 }
 
 impl Display for Error {
@@ -225,6 +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/parser.rs

@@ -245,7 +245,7 @@ impl Parse<'_> for Literal {
             TokenData::String(v) => Literal::String(v),
             TokenData::Character(v) => Literal::Char(v),
             TokenData::Integer(v) => Literal::Int(v),
-            TokenData::Float(v) => todo!("Literal::Float({v})"),
+            TokenData::Float(v) => Literal::Float(v.to_bits()),
             _ => panic!("Expected token data for {ty:?}"),
         })
     }
@@ -681,7 +681,11 @@ impl Parse<'_> for UseTree {
                     let PathPart::Ident(name) = name else {
                         Err(p.error(ErrorKind::ExpectedParsing { want: Parsing::Identifier }, P))?
                     };
-                    UseTree::Name(name)
+                    if p.match_type(TokenKind::As, P).is_ok() {
+                        UseTree::Alias(name, p.parse()?)
+                    } else {
+                        UseTree::Name(name)
+                    }
                 }
             }
             t => Err(p.error(Unexpected(t), Parsing::UseTree))?,
@@ -900,12 +904,24 @@ impl Parse<'_> for ExprKind {
     }
 }
 
+impl Parse<'_> for Quote {
+    fn parse(p: &mut Parser<'_>) -> PResult<Self> {
+        let quote = delim(
+            ExprKind::parse,
+            (TokenKind::Grave, TokenKind::Grave),
+            Parsing::ExprKind,
+        )(p)?
+        .into();
+        Ok(Quote { quote })
+    }
+}
+
 impl Parse<'_> for Let {
     fn parse(p: &mut Parser) -> PResult<Let> {
         p.consume_peeked();
         Ok(Let {
             mutable: Mutability::parse(p)?,
-            name: Sym::parse(p)?,
+            name: Pattern::parse(p)?,
             ty: if p.match_type(TokenKind::Colon, Parsing::Let).is_ok() {
                 Some(Ty::parse(p)?.into())
             } else {
@@ -962,16 +978,24 @@ impl Parse<'_> for AddrOf {
     /// [AddrOf] = (`&`|`&&`)* [Expr]
     fn parse(p: &mut Parser) -> PResult<AddrOf> {
         const P: Parsing = Parsing::AddrOf;
-        let mut count = 0;
+        match p.peek_kind(P)? {
-        loop {
+            TokenKind::Amp => {
-            count += match p.peek_kind(P)? {
+                p.consume_peeked();
-                TokenKind::Amp => 1,
+                Ok(AddrOf { mutable: Mutability::parse(p)?, expr: ExprKind::parse(p)?.into() })
-                TokenKind::AmpAmp => 2,
+            }
-                _ => break,
+            TokenKind::AmpAmp => {
-            };
+                p.consume_peeked();
-            p.consume_peeked();
+                Ok(AddrOf {
+                    mutable: Mutability::Not,
+                    expr: ExprKind::AddrOf(AddrOf {
+                        mutable: Mutability::parse(p)?,
+                        expr: ExprKind::parse(p)?.into(),
+                    })
+                    .into(),
+                })
+            }
+            got => Err(p.error(ExpectedToken { want: TokenKind::Amp, got }, P)),
         }
-        Ok(AddrOf { count, mutable: Mutability::parse(p)?, expr: ExprKind::parse(p)?.into() })
     }
 }
 
@@ -1055,6 +1079,38 @@ impl Parse<'_> for Return {
     }
 }
 
+impl Parse<'_> for Pattern {
+    fn parse(p: &mut Parser<'_>) -> PResult<Self> {
+        let value = prec::exprkind(p, prec::Precedence::Highest.level())?;
+        Pattern::try_from(value)
+            .map_err(|_| p.error(ExpectedParsing { want: Parsing::Pattern }, Parsing::Pattern))
+    }
+}
+
+impl Parse<'_> for Match {
+    /// [Match] = `match` [Expr] `{` [MatchArm],* `}`
+    fn parse(p: &mut Parser<'_>) -> PResult<Self> {
+        p.match_type(TokenKind::Match, Parsing::Match)?;
+        let scrutinee = Expr::parse(p)?.into();
+        let arms = delim(
+            sep(MatchArm::parse, TokenKind::Comma, CURLIES.1, Parsing::Match),
+            CURLIES,
+            Parsing::Match,
+        )(p)?;
+        Ok(Match { scrutinee, arms })
+    }
+}
+
+impl Parse<'_> for MatchArm {
+    /// [MatchArm] = [Pattern] `=>` [Expr]
+    fn parse(p: &mut Parser<'_>) -> PResult<Self> {
+        let pat = Pattern::parse(p)?;
+        p.match_type(TokenKind::FatArrow, Parsing::MatchArm)?;
+        let expr = Expr::parse(p)?;
+        Ok(MatchArm(pat, expr))
+    }
+}
+
 /// ret_body = (*unconsumed* `;` | [Expr])
 fn ret_body(p: &mut Parser, while_parsing: Parsing) -> PResult<Option<Box<Expr>>> {
     Ok(match p.peek_kind(while_parsing)? {

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

@@ -16,10 +16,12 @@ pub fn exprkind(p: &mut Parser, power: u8) -> PResult<ExprKind> {
         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)?),
@@ -31,8 +33,7 @@ pub fn exprkind(p: &mut Parser, power: u8) -> PResult<ExprKind> {
         }
 
         op => {
-            let (kind, prec) =
+            let (kind, prec) = from_prefix(op).ok_or_else(|| p.error(Unexpected(op), parsing))?;
-                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()
@@ -64,14 +65,10 @@ pub fn exprkind(p: &mut Parser, power: u8) -> PResult<ExprKind> {
                     ExprKind::Index(Index { head: head.into(), indices })
                 }
                 TokenKind::LParen => {
-                    let exprs =
+                    let exprs = sep(Expr::parse, TokenKind::Comma, TokenKind::RParen, parsing)(p)?;
-                        sep(Expr::parse, TokenKind::Comma, TokenKind::RParen, parsing)(p)?;
                     p.match_type(TokenKind::RParen, parsing)?;
-                    Binary {
+                    Binary { kind: BinaryKind::Call, parts: (head, Tuple { exprs }.into()).into() }
-                        kind: BinaryKind::Call,
+                        .into()
-                        parts: (head, Tuple { exprs }.into()).into(),
-                    }
-                    .into()
                 }
                 TokenKind::Dot => {
                     let kind = MemberKind::parse(p)?;
@@ -247,9 +244,9 @@ fn structor_body(p: &mut Parser, to: Path) -> PResult<Structor> {
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
 pub enum Precedence {
     Assign,
+    Logic,
     Compare,
     Range,
-    Logic,
     Bitwise,
     Shift,
     Factor,
@@ -259,6 +256,7 @@ pub enum Precedence {
     Cast,
     Member, // left-associative
     Call,
+    Highest,
 }
 
 impl Precedence {
@@ -309,9 +307,7 @@ impl From<BinaryKind> for Precedence {
             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 => {
+            Op::Lt | Op::LtEq | Op::Equal | Op::NotEq | Op::GtEq | Op::Gt => Precedence::Compare,
-                Precedence::Compare
-            }
         }
     }
 }

compiler/cl-repl/examples/yaml.rs

@@ -120,19 +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();
@@ -369,16 +369,6 @@ pub mod yamlify {
             };
         }
     }
-    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;
@@ -388,7 +378,9 @@ 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),
@@ -417,6 +409,60 @@ pub mod yamlify {
             }
         }
     }
+    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 { parts } = self;
@@ -525,11 +571,8 @@ pub mod yamlify {
     }
     impl Yamlify for AddrOf {
         fn yaml(&self, y: &mut Yamler) {
-            let Self { count, mutable, expr } = self;
+            let Self { mutable, expr } = self;
-            y.key("AddrOf")
+            y.key("AddrOf").yaml(mutable).pair("expr", expr);
-                .pair("count", count)
-                .yaml(mutable)
-                .pair("expr", expr);
         }
     }
     impl Yamlify for Group {

compiler/cl-repl/src/cli.rs

@@ -6,7 +6,7 @@ use crate::{
     tools::print_token,
 };
 use cl_ast::File;
-use cl_interpret::{convalue::ConValue, env::Environment, interpret::Interpret};
+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};
@@ -16,6 +16,31 @@ 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)?;
     }

compiler/cl-repl/src/ctx.rs

@@ -1,6 +1,4 @@
-use cl_interpret::{
+use cl_interpret::{convalue::ConValue, env::Environment, error::IResult, interpret::Interpret};
-    env::Environment, error::IResult, interpret::Interpret, convalue::ConValue,
-};
 
 #[derive(Clone, Debug)]
 pub struct Context {

compiler/cl-repl/src/menu.rs

@@ -1,11 +1,12 @@
 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::*};
 
-fn clear() {
+pub fn clear() {
-    println!("{}", ansi::CLEAR_ALL);
+    print!("{}", ansi::CLEAR_ALL);
     banner()
 }
 
@@ -43,11 +44,15 @@ pub fn run(ctx: &mut ctx::Context) -> ReplResult<()> {
     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),
         }

compiler/cl-structures/Cargo.toml

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

compiler/cl-structures/src/index_map.rs

@@ -106,7 +106,7 @@ impl<V, K: MapIndex> IndexMap<K, V> {
     pub fn get_many_mut<const N: usize>(
         &mut self,
         indices: [K; N],
-    ) -> Result<[&mut V; N], GetManyMutError<N>> {
+    ) -> Result<[&mut V; N], GetManyMutError> {
         self.map.get_many_mut(indices.map(|id| id.get()))
     }
 

compiler/cl-structures/src/intern.rs

@@ -35,9 +35,14 @@ pub mod interned {
         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<'a, T: ?Sized + Debug> Debug for Interned<'a, T> {
+    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)
@@ -49,14 +54,14 @@ pub mod interned {
             Self { value }
         }
     }
-    impl<'a, T: ?Sized> Deref for Interned<'a, T> {
+    impl<T: ?Sized> Deref for Interned<'_, T> {
         type Target = T;
         fn deref(&self) -> &Self::Target {
             self.value
         }
     }
-    impl<'a, T: ?Sized> Copy for Interned<'a, T> {}
+    impl<T: ?Sized> Copy for Interned<'_, T> {}
-    impl<'a, T: ?Sized> Clone for Interned<'a, T> {
+    impl<T: ?Sized> Clone for Interned<'_, T> {
         fn clone(&self) -> Self {
             *self
         }
@@ -79,13 +84,13 @@ pub mod interned {
     //     }
     // }
 
-    impl<'a, T: ?Sized> Eq for Interned<'a, T> {}
+    impl<T: ?Sized> Eq for Interned<'_, T> {}
-    impl<'a, T: ?Sized> PartialEq for Interned<'a, T> {
+    impl<T: ?Sized> PartialEq for Interned<'_, T> {
         fn eq(&self, other: &Self) -> bool {
             std::ptr::eq(self.value, other.value)
         }
     }
-    impl<'a, T: ?Sized> Hash for Interned<'a, T> {
+    impl<T: ?Sized> Hash for Interned<'_, T> {
         fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
             Self::as_ptr(self).hash(state)
         }
@@ -119,6 +124,7 @@ pub mod string_interner {
     };
 
     /// 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>>,
@@ -207,8 +213,8 @@ pub mod string_interner {
     // 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<'a> Send for StringInterner<'a> {}
+    unsafe impl Send for StringInterner<'_> {}
-    unsafe impl<'a> Sync for StringInterner<'a> {}
+    unsafe impl Sync for StringInterner<'_> {}
 
     #[cfg(test)]
     mod tests {
@@ -258,6 +264,7 @@ pub mod typed_interner {
     /// 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>>,
@@ -304,5 +311,5 @@ pub mod typed_interner {
     /// [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<'a, T: Eq + Hash + Send + Sync> Sync for TypedInterner<'a, T> {}
+    unsafe impl<T: Eq + Hash + Send + Sync> Sync for TypedInterner<'_, T> {}
 }

compiler/cl-token/src/token_type.rs

@@ -28,6 +28,7 @@ pub enum TokenKind {
     In,       // "in"
     Let,      // "let"
     Loop,     // "loop"
+    Match,    // "match"
     Mod,      // "mod"
     Mut,      // "mut"
     Pub,      // "pub"
@@ -106,34 +107,35 @@ impl Display for TokenKind {
             TokenKind::Literal => "literal".fmt(f),
             TokenKind::Identifier => "identifier".fmt(f),
 
-            TokenKind::As => "as".fmt(f),
+            TokenKind::As => "sama".fmt(f),
-            TokenKind::Break => "break".fmt(f),
+            TokenKind::Break => "pana".fmt(f),
-            TokenKind::Cl => "cl".fmt(f),
+            TokenKind::Cl => "la".fmt(f),
-            TokenKind::Const => "const".fmt(f),
+            TokenKind::Const => "kiwen".fmt(f),
-            TokenKind::Continue => "continue".fmt(f),
+            TokenKind::Continue => "tawa".fmt(f),
-            TokenKind::Else => "else".fmt(f),
+            TokenKind::Else => "taso".fmt(f),
-            TokenKind::Enum => "enum".fmt(f),
+            TokenKind::Enum => "kulupu".fmt(f),
-            TokenKind::False => "false".fmt(f),
+            TokenKind::False => "ike".fmt(f),
-            TokenKind::Fn => "fn".fmt(f),
+            TokenKind::Fn => "nasin".fmt(f),
-            TokenKind::For => "for".fmt(f),
+            TokenKind::For => "ale".fmt(f),
-            TokenKind::If => "if".fmt(f),
+            TokenKind::If => "tan".fmt(f),
-            TokenKind::Impl => "impl".fmt(f),
+            TokenKind::Impl => "insa".fmt(f),
-            TokenKind::In => "in".fmt(f),
+            TokenKind::In => "lon".fmt(f),
-            TokenKind::Let => "let".fmt(f),
+            TokenKind::Let => "poki".fmt(f),
-            TokenKind::Loop => "loop".fmt(f),
+            TokenKind::Loop => "awen".fmt(f),
-            TokenKind::Mod => "mod".fmt(f),
+            TokenKind::Match => "seme".fmt(f),
-            TokenKind::Mut => "mut".fmt(f),
+            TokenKind::Mod => "selo".fmt(f),
-            TokenKind::Pub => "pub".fmt(f),
+            TokenKind::Mut => "ante".fmt(f),
-            TokenKind::Return => "return".fmt(f),
+            TokenKind::Pub => "lukin".fmt(f),
-            TokenKind::SelfKw => "self".fmt(f),
+            TokenKind::Return => "pini".fmt(f),
-            TokenKind::SelfTy => "Self".fmt(f),
+            TokenKind::SelfKw => "mi".fmt(f),
-            TokenKind::Static => "static".fmt(f),
+            TokenKind::SelfTy => "Mi".fmt(f),
-            TokenKind::Struct => "struct".fmt(f),
+            TokenKind::Static => "mute".fmt(f),
-            TokenKind::Super => "super".fmt(f),
+            TokenKind::Struct => "lipu".fmt(f),
-            TokenKind::True => "true".fmt(f),
+            TokenKind::Super => "mama".fmt(f),
-            TokenKind::Type => "type".fmt(f),
+            TokenKind::True => "pona".fmt(f),
-            TokenKind::Use => "use".fmt(f),
+            TokenKind::Type => "ijo".fmt(f),
-            TokenKind::While => "while".fmt(f),
+            TokenKind::Use => "jo".fmt(f),
+            TokenKind::While => "lawa".fmt(f),
 
             TokenKind::LCurly => "{".fmt(f),
             TokenKind::RCurly => "}".fmt(f),
@@ -198,34 +200,35 @@ impl FromStr for TokenKind {
     /// Parses a string s to return a Keyword
     fn from_str(s: &str) -> Result<Self, Self::Err> {
         Ok(match s {
-            "as" => Self::As,
+            "as" | "sama" => Self::As,
-            "break" => Self::Break,
+            "break" | "pana" => Self::Break,
-            "cl" => Self::Cl,
+            "cl" | "la" => Self::Cl,
-            "const" => Self::Const,
+            "const" | "kiwen" => Self::Const,
-            "continue" => Self::Continue,
+            "continue" | "tawa" => Self::Continue,
-            "else" => Self::Else,
+            "else" | "taso" => Self::Else,
-            "enum" => Self::Enum,
+            "enum" | "kulupu" => Self::Enum,
-            "false" => Self::False,
+            "false" | "ike" => Self::False,
-            "fn" => Self::Fn,
+            "fn" | "nasin" => Self::Fn,
-            "for" => Self::For,
+            "for" | "ale" => Self::For,
-            "if" => Self::If,
+            "if" | "tan" => Self::If,
-            "impl" => Self::Impl,
+            "impl" | "insa" => Self::Impl,
-            "in" => Self::In,
+            "in" | "lon" => Self::In,
-            "let" => Self::Let,
+            "let" | "poki" => Self::Let,
-            "loop" => Self::Loop,
+            "loop" | "awen" => Self::Loop,
-            "mod" => Self::Mod,
+            "match" | "seme" => Self::Match,
-            "mut" => Self::Mut,
+            "mod" | "selo" => Self::Mod,
-            "pub" => Self::Pub,
+            "mut" | "ante" => Self::Mut,
-            "return" => Self::Return,
+            "pub" | "lukin" => Self::Pub,
-            "self" => Self::SelfKw,
+            "return" | "pini" => Self::Return,
-            "Self" => Self::SelfTy,
+            "self" | "mi" => Self::SelfKw,
-            "static" => Self::Static,
+            "Self" | "Mi" => Self::SelfTy,
-            "struct" => Self::Struct,
+            "static" | "mute" => Self::Static,
-            "super" => Self::Super,
+            "struct" | "lipu" => Self::Struct,
-            "true" => Self::True,
+            "super" | "mama" => Self::Super,
-            "type" => Self::Type,
+            "true" | "pona" => Self::True,
-            "use" => Self::Use,
+            "type" | "ijo" => Self::Type,
-            "while" => Self::While,
+            "use" | "jo" => Self::Use,
+            "while" | "lawa" => Self::While,
             _ => Err(())?,
         })
     }

compiler/cl-typeck/examples/typeck.rs

@@ -1,4 +1,3 @@
-use cl_structures::intern::string_interner::StringInterner;
 use cl_typeck::{entry::Entry, stage::*, table::Table, type_expression::TypeExpression};
 
 use cl_ast::{
@@ -8,10 +7,12 @@ use cl_ast::{
 };
 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
@@ -30,11 +31,6 @@ const C_BYID: &str = "\x1b[95m";
 const C_ERROR: &str = "\x1b[31m";
 const C_LISTING: &str = "\x1b[38;5;117m";
 
-/// A home for immutable intermediate ASTs
-///
-/// TODO: remove this.
-static mut TREES: TreeManager = TreeManager::new();
-
 fn main() -> Result<(), Box<dyn Error>> {
     let mut prj = Table::default();
 
@@ -48,7 +44,7 @@ fn main() -> Result<(), Box<dyn Error>> {
     };
     // 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(unsafe { TREES.push(code) });
+    Populator::new(&mut prj).visit_file(interned(code));
 
     main_menu(&mut prj)?;
     Ok(())
@@ -98,8 +94,8 @@ fn enter_code(prj: &mut Table) -> Result<(), RlError> {
         let code = Parser::new(Lexer::new(line)).parse()?;
         let code = inline_modules(code, "");
         let code = WhileElseDesugar.fold_file(code);
-        // Safety: this is totally unsafe
+
-        Populator::new(prj).visit_file(unsafe { TREES.push(code) });
+        Populator::new(prj).visit_file(interned(code));
         Ok(Response::Accept)
     })
 }
@@ -222,7 +218,7 @@ fn import_files(table: &mut Table) -> Result<(), RlError> {
             }
         };
 
-        Populator::new(table).visit_file(unsafe { TREES.push(code) });
+        Populator::new(table).visit_file(interned(code));
 
         println!("...Imported!");
         Ok(Response::Accept)
@@ -322,18 +318,11 @@ fn banner() {
     );
 }
 
-/// Keeps leaked references to past ASTs, for posterity:tm:
+/// Interns a [File](cl_ast::File), returning a static reference to it.
-struct TreeManager {
+fn interned(file: cl_ast::File) -> &'static cl_ast::File {
-    trees: Vec<&'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);
 
-impl TreeManager {
+    Interned::to_ref(&INTERNER.get_or_insert(file))
-    const fn new() -> Self {
-        Self { trees: vec![] }
-    }
-    fn push(&mut self, tree: cl_ast::File) -> &'static cl_ast::File {
-        let ptr = Box::leak(Box::new(tree));
-        self.trees.push(ptr);
-        ptr
-    }
 }

compiler/cl-typeck/src/source.rs

@@ -20,7 +20,7 @@ pub enum Source<'a> {
     Ty(&'a TyKind),
 }
 
-impl<'a> Source<'a> {
+impl Source<'_> {
     pub fn name(&self) -> Option<Sym> {
         match self {
             Source::Root => None,
@@ -32,7 +32,7 @@ impl<'a> Source<'a> {
             Source::Const(v) => Some(v.name),
             Source::Static(v) => Some(v.name),
             Source::Function(v) => Some(v.name),
-            Source::Local(l) => Some(l.name),
+            Source::Local(_) => None,
             Source::Impl(_) | Source::Use(_) | Source::Ty(_) => None,
         }
     }

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

@@ -146,11 +146,11 @@ impl<'a> Visit<'a> for Populator<'_, 'a> {
     }
 
     fn visit_let(&mut self, l: &'a cl_ast::Let) {
-        let cl_ast::Let { mutable, name, ty, init } = l;
+        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.set_name(*name);
 
         entry.visit_mutability(mutable);
         if let Some(ty) = ty {
@@ -160,7 +160,8 @@ impl<'a> Visit<'a> for Populator<'_, 'a> {
             entry.visit_expr(init)
         }
 
-        let child = entry.inner.id();
+        // let child = entry.inner.id();
-        self.inner.add_child(*name, child);
+        // self.inner.add_child(*name, child);
+        todo!("Pattern destructuring in cl-typeck")
     }
 }

compiler/cl-typeck/src/table.rs

@@ -268,7 +268,7 @@ impl<'a> Table<'a> {
     }
 }
 
-impl<'a> Default for Table<'a> {
+impl Default for Table<'_> {
     fn default() -> Self {
         Self::new()
     }

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

@@ -302,7 +302,7 @@ impl<'a> Editor<'a> {
     }
 }
 
-impl<'a, 'e> IntoIterator for &'e Editor<'a> {
+impl<'e> IntoIterator for &'e Editor<'_> {
     type Item = &'e char;
     type IntoIter = std::iter::Chain<
         std::collections::vec_deque::Iter<'e, char>,
@@ -313,7 +313,7 @@ impl<'a, 'e> IntoIterator for &'e Editor<'a> {
     }
 }
 
-impl<'a> Display for Editor<'a> {
+impl Display for Editor<'_> {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         use std::fmt::Write;
         for c in self.iter() {

repline/src/iter.rs

@@ -39,7 +39,7 @@ pub mod chars {
                 if cont & 0xc0 != 0x80 {
                     return None;
                 }
-                out = out << 6 | (cont & 0x3f);
+                out = (out << 6) | (cont & 0x3f);
             }
             Some(char::from_u32(out).ok_or(BadUnicode(out)))
         }

sample-code/hello.tp

@@ -0,0 +1,5 @@
+
+// The main function
+nasin wan () {
+    toki_linja("mi toki ale a!")
+}

sample-code/hex.cl

@@ -1,5 +1,6 @@
 //! Formats numbers in hexadecimal, octal, or binary
 mod math;
+use math::{min, count_leading_zeroes};
 
 fn as_digit(n: u32) -> char {
     (if n > 9 {

sample-code/letter_frequency.cl

@@ -0,0 +1,44 @@
+#!/usr/bin/env -S conlang -r false
+// Showcases `get_line` behavior by sorting stdin
+
+fn in_range(this: Ord, min: Ord, max: Ord) -> bool {
+    min < this && this < max
+}
+
+fn frequency(s: str) -> [i32; 128] {
+    let letters = [0;128];
+    for letter in s {
+        if (letter).in_range(' ', letters.len() as char) {
+            letters[(letter as i32)] += 1;
+        }
+    }
+    letters
+}
+
+fn plot_freq(freq: [i32; 128]) -> str {
+    let buf = "";
+    for idx in 0..len(freq) {
+        for n in 0..(freq[idx]) {
+            buf += idx as char;
+        }
+    }
+    buf
+}
+
+const msg: str ="letter_frequency.cl
+Computes the frequency of ascii characters in a block of text, and prints it bucket-sorted.
+Press Ctrl+D to quit.";
+
+fn main () {
+    println(msg)
+    let lines = "";
+    loop {
+        let line = get_line();
+        if line == "" { break() }
+        lines += line;
+    }
+
+    let freq = frequency(lines)
+    let plot = plot_freq(freq)
+    println(plot)
+}

sample-code/match_test.cl

@@ -0,0 +1,18 @@
+//! This is a Conlang library demonstrating `match`
+
+struct Student {
+    name: str,
+    age: i32,
+}
+
+fn Student (name: str, age: i32) -> Student {
+    Student: { name, age }
+}
+
+fn match_test(student: Student) {
+    match student {
+        Student: { name: "shark", age } => println("Found a shark of ", age, " year(s)"),
+        Student: { name, age: 22 } => println("Found a 22-year-old named ", name),
+        Student: { name, age } => println("Found someone named ", name, " of ", age, " year(s)"),
+    }
+}

sample-code/pona.tp

@@ -0,0 +1,10 @@
+//! toki!
+
+nasin toki_pona(nimi: linja) -> linja {
+    seme nimi {
+        "a" => "PARTICLE: Emphasis or emotion",
+        _ => "",
+    }
+}
+
+kiwen main: nasin(Linja) -> Linja = toki_pona;

sample-code/sqrt.cl

@@ -0,0 +1,56 @@
+#!/usr/bin/env conlang-run
+//! Square root approximation, and example applications
+
+/// A really small nonzero number
+const EPSILON: f64 = 8.8541878188 / 1000000000000.0;
+
+/// Calcuates the absolute value of a number
+fn f64_abs(n: f64) -> f64 {
+    let n = n as f64
+    if n < (0.0) { -n } else { n }
+}
+
+/// Square root approximation using Newton's method
+fn sqrt(n: f64) -> f64 {
+    let n = n as f64
+    if n < 0.0 {
+        return 0.0 / 0.0 // TODO: NaN constant
+    }
+    if n == 0.0 {
+        return 0.0
+    }
+
+    let z = n
+    loop {
+        let adj = (z * z - n) / (2.0 * z)
+        z -= adj
+        if adj.f64_abs() < EPSILON {
+            break z;
+        }
+    }
+}
+
+/// Pythagorean theorem: a² + b² = c²
+fn pythag(a: f64, b: f64) -> f64 {
+    sqrt(a * a + b * b)
+}
+
+/// Quadratic formula: (-b ± √(b² - 4ac)) / 2a
+fn quadratic(a: f64, b: f64, c: f64) -> (f64, f64) {
+    let a = a as f64; let b = b as f64; let c = c as f64;
+    (
+        (-b + sqrt(b * b - 4.0 * a * c)) / 2.0 * a,
+        (-b - sqrt(b * b - 4.0 * a * c)) / 2.0 * a,
+    )
+}
+
+fn main() {
+    for i in 0..10 {
+        println("sqrt(",i,") ≅ ",sqrt(i as f64))
+    }
+    println("\nPythagorean Theorem")
+    println("Hypotenuse of ⊿(5, 12): ", pythag(5.0, 12.0))
+
+    println("\nQuadratic formula")
+    println("Roots of 10x² + 4x - 1: ", quadratic(10.0, 40, -1.0))
+}