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AST: merge let, const, static, match_arm into one binder

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John
2025-10-20 00:21:49 -04:00
parent 607615db74
commit 458e95a8ed
3 changed files with 140 additions and 209 deletions
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89
src/ast.rs
View File

@@ -111,14 +111,19 @@ pub enum Ty {
/// let Pat (= Expr)?
/// ``````
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct Let<A: Annotation = Span>(pub Pat, pub Vec<Anno<Expr<A>, A>>);
pub struct Let<A: Annotation = Span>(pub LetKind, pub Pat, pub Vec<Anno<Expr<A>, A>>);
/// A `const` binding (which defines its name before executing)
/// ```ignore
/// const Pat = Expr
/// ```
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct Const<A: Annotation = Span>(pub Pat, pub Anno<Expr<A>, A>);
pub enum LetKind {
/// A `let Pat (= Expr (else Expr)?)?` binding
Let,
/// A `const Pat = Expr` binding
Const,
/// A `static Pat = Expr` binding
Static,
/// A `Pat => Expr` binding
Match,
}
/// A function definition
/// ```ignore
@@ -127,20 +132,6 @@ pub struct Const<A: Annotation = Span>(pub Pat, pub Anno<Expr<A>, A>);
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct Fn<A: Annotation = Span>(pub Option<String>, pub Pat, pub Ty, pub Anno<Expr<A>, A>);
/// A match expression
/// ```ignore
/// match Expr { MatchArm,* }
/// ```
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct Match<A: Annotation = Span>(pub Anno<Expr<A>, A>, pub Vec<MatchArm<A>>);
/// The "arms" of a match expression
/// ```ignore
/// Pat => Expr
/// ```
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct MatchArm<A: Annotation = Span>(pub Pat, pub Anno<Expr<A>, A>);
/// A make (constructor) expression
/// ```ignore
/// Expr { (Ident (: Expr)?),* }
@@ -185,16 +176,12 @@ pub enum Expr<A: Annotation = Span> {
Lit(Literal),
/// let Pat<NoTopAlt> = expr
Let(Box<Let<A>>),
/// `const Pat<NoTopAlt> (= Expr)?` (Basically let rec)
Const(Box<Const<A>>),
/// (struct | enum | type) Pat<NoTopAlt>
Struct(Box<Typedef>),
/// `| Pat<Tuple> | Expr` | `|| Expr` | `fn Ident? (Pat,*) Expr`
Fn(Box<Fn<A>>),
/// Expr { (Ident (: Expr)?),* }
Make(Box<Make<A>>),
/// match Expr { MatchArm,* }
Match(Box<Match<A>>),
/// mod Ty Expr
Mod(Box<Mod<A>>),
/// Op Expr | Expr Op | Expr (Op Expr)+ | Op Expr Expr else Expr
@@ -259,6 +246,7 @@ pub enum Op {
Pub, // pub Expr
Loop, // loop Expr
Match, // match Expr { <Let(Match, ..)>,* }
If, // if Expr Expr (else Expr)?
While, // while Expr Expr (else Expr)?
Break, // break Expr
@@ -339,13 +327,6 @@ impl<T: Display + Annotation, A: Annotation> Display for Anno<T, A> {
}
}
impl<A: Annotation> Display for Const<A> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
let Self(pat, expr) = self;
write!(f, "const {pat} = {expr}")
}
}
impl<A: Annotation> Display for Fn<A> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
@@ -357,21 +338,29 @@ impl<A: Annotation> Display for Fn<A> {
impl<A: Annotation> Display for Let<A> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
let Self(pat, exprs) = self;
let Self(op, pat, exprs) = self;
if let LetKind::Match = op {
return f.delimit(fmt!("{pat} => "), "").list(exprs, ",!? ");
}
match exprs.as_slice() {
[] => write!(f, "let {pat}"),
[value] => write!(f, "let {pat} = {value}"),
[value, fail] => write!(f, "let {pat} = {value} else {fail}"),
other => f.delimit(fmt!("let! {pat} ("), ")").list(other, ", "),
[] => write!(f, "{op} {pat}"),
[value] => write!(f, "{op} {pat} = {value}"),
[value, fail] => write!(f, "{op} {pat} = {value} else {fail}"),
other => f.delimit(fmt!("{op}?! {pat} ("), ")").list(other, ", "),
}
}
}
impl<A: Annotation> Display for Match<A> {
impl Display for LetKind {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
let Self(expr, match_arms) = self;
f.delimit_indented(fmt!("match {expr} {{"), "}")
.list_wrap("\n", match_arms, ",\n", ",\n")
f.write_str(match self {
Self::Let => "let",
Self::Const => "const",
Self::Static => "static",
Self::Match => "| ",
})
}
}
@@ -416,10 +405,8 @@ impl<A: Annotation> Display for Expr<A> {
Self::MetId(id) => write!(f, "`{id}"),
Self::Lit(literal) => literal.fmt(f),
Self::Let(v) => v.fmt(f),
Self::Const(v) => v.fmt(f),
Self::Struct(v) => v.fmt(f),
Self::Make(v) => v.fmt(f),
Self::Match(v) => v.fmt(f),
Self::Mod(v) => v.fmt(f),
Self::Fn(v) => v.fmt(f),
@@ -430,6 +417,12 @@ impl<A: Annotation> Display for Expr<A> {
[cond, pass, fail] => write!(f, "{op}{cond} {pass} else {fail}"),
other => f.delimit(fmt!("({op}, "), ")").list(other, ", "),
},
Self::Op(op @ Op::Match, exprs) => match exprs.as_slice() {
[scrutinee, arms @ ..] => f
.delimit_indented(fmt!("{op}{scrutinee} {{"), "}")
.list_wrap("\n", arms, ",\n", ",\n"),
[] => write!(f, "{op} () {{}}"), // invalid, but whatever.
},
Self::Op(Op::Array, exprs) => f.delimit("[", "]").list(exprs, ", "),
Self::Op(Op::ArRep, exprs) => f.delimit("[", "]").list(exprs, "; "),
Self::Op(Op::Block, exprs) => f
@@ -479,6 +472,7 @@ impl Display for Op {
Op::Call => "",
Op::Pub => "pub ",
Op::Loop => "loop ",
Op::Match => "match ",
Op::If => "if ",
Op::While => "while ",
Op::Break => "break ",
@@ -534,13 +528,6 @@ impl<A: Annotation> Display for MakeArm<A> {
}
}
impl<A: Annotation> Display for MatchArm<A> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
let Self(pat, expr) = self;
write!(f, "{pat} => {expr}")
}
}
impl Display for Pat {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
@@ -550,7 +537,9 @@ impl Display for Pat {
Self::Name(name) => name.fmt(f),
Self::Path(path) => path.fmt(f),
Self::Struct(name, bind) => match bind.as_ref() {
Pat::Op(PatOp::Tuple, parts) => f.delimit(fmt!("{name} {{ "), " }").list(parts, ", "),
Pat::Op(PatOp::Tuple, parts) => {
f.delimit(fmt!("{name} {{ "), " }").list(parts, ", ")
}
other => write!(f, "{name} {{ {other} }}"),
},
Self::TupStruct(name, bind) => write!(f, "{name} {bind}"),

52
src/ast/macro_matcher.rs
View File

@@ -78,19 +78,6 @@ impl<M: Match<A> + Annotation, A: Annotation> Match<A> for Anno<M, A> {
}
}
impl<A: Annotation> Match<A> for Const<A> {
fn recurse(sub: &mut Subst<A>, pat: &Self, expr: &Self) -> bool {
let (Self(pat_pat, pat_expr), Self(expr_pat, expr_expr)) = (pat, expr);
Match::recurse(sub, pat_pat, expr_pat) && Match::recurse(sub, pat_expr, expr_expr)
}
fn apply(&mut self, sub: &Subst<A>) {
let Self(pat, expr) = self;
pat.apply(sub);
expr.apply(sub);
}
}
impl<A: Annotation> Match<A> for Fn<A> {
fn recurse(sub: &mut Subst<A>, pat: &Self, expr: &Self) -> bool {
let (
@@ -111,25 +98,14 @@ impl<A: Annotation> Match<A> for Fn<A> {
impl<A: Annotation> Match<A> for Let<A> {
fn recurse(sub: &mut Subst<A>, pat: &Self, expr: &Self) -> bool {
let (Self(pat_pat, pat_expr), Self(expr_pat, expr_expr)) = (pat, expr);
Match::recurse(sub, pat_pat, expr_pat) && Match::recurse(sub, pat_expr, expr_expr)
let (Self(pat_kind, pat_pat, pat_expr), Self(expr_kind, expr_pat, expr_expr)) = (pat, expr);
pat_kind == expr_kind
&& Match::recurse(sub, pat_pat, expr_pat)
&& Match::recurse(sub, pat_expr, expr_expr)
}
fn apply(&mut self, sub: &Subst<A>) {
let Self(pat, expr) = self;
pat.apply(sub);
expr.apply(sub);
}
}
impl<A: Annotation> Match<A> for crate::ast::Match<A> {
fn recurse(sub: &mut Subst<A>, pat: &Self, expr: &Self) -> bool {
let (Self(pat_expr, pat_arms), Self(expr_expr, expr_arms)) = (pat, expr);
Match::recurse(sub, pat_expr, expr_expr) && Match::recurse(sub, pat_arms, expr_arms)
}
fn apply(&mut self, sub: &Subst<A>) {
let Self(pat, expr) = self;
let Self(_, pat, expr) = self;
pat.apply(sub);
expr.apply(sub);
}
@@ -185,14 +161,10 @@ impl<A: Annotation> Match<A> for Expr<A> {
(Expr::Lit(_), _) => false,
(Expr::Let(pat), Expr::Let(expr)) => Match::recurse(sub, pat, expr),
(Expr::Let(..), _) => false,
(Expr::Const(pat), Expr::Const(expr)) => Match::recurse(sub, pat, expr),
(Expr::Const(..), _) => false,
(Expr::Struct(pat), Expr::Struct(expr)) => Match::recurse(sub, pat, expr),
(Expr::Struct(_), _) => false,
(Expr::Make(pat), Expr::Make(expr)) => Match::recurse(sub, pat, expr),
(Expr::Make(..), _) => false,
(Expr::Match(pat), Expr::Match(expr)) => Match::recurse(sub, pat, expr),
(Expr::Match(..), _) => false,
(Expr::Mod(pat), Expr::Mod(expr)) => Match::recurse(sub, pat, expr),
(Expr::Mod(..), _) => false,
(Expr::Fn(pat), Expr::Fn(expr)) => Match::recurse(sub, pat, expr),
@@ -213,10 +185,8 @@ impl<A: Annotation> Match<A> for Expr<A> {
}
Expr::Id(_) | Expr::Lit(_) => {}
Expr::Let(expr) => expr.apply(sub),
Expr::Const(expr) => expr.apply(sub),
Expr::Struct(expr) => expr.apply(sub),
Expr::Make(expr) => expr.apply(sub),
Expr::Match(expr) => expr.apply(sub),
Expr::Mod(expr) => expr.apply(sub),
Expr::Fn(expr) => expr.apply(sub),
Expr::Op(op, exprs) => {
@@ -239,18 +209,6 @@ impl<A: Annotation> Match<A> for MakeArm<A> {
}
}
impl<A: Annotation> Match<A> for MatchArm<A> {
fn recurse(sub: &mut Subst<A>, pat: &Self, expr: &Self) -> bool {
Match::recurse(sub, &pat.0, &expr.0) && Match::recurse(sub, &pat.1, &expr.1)
}
fn apply(&mut self, sub: &Subst<A>) {
let Self(pats, expr) = self;
pats.apply(sub);
expr.apply(sub);
}
}
impl<A: Annotation> Match<A> for Pat {
fn recurse(sub: &mut Subst<A>, pat: &Self, expr: &Self) -> bool {
match (pat, expr) {

158
src/parser.rs
View File

@@ -5,7 +5,7 @@ use crate::{
span::Span,
token::{Lexeme, TKind, Token},
};
use std::{error::Error, fmt::Display, vec};
use std::{error::Error, fmt::Display, iter, vec};
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum ParseError {
@@ -546,8 +546,9 @@ pub enum Ps {
Id, // Identifier
Mid, // MetaIdentifier
Lit, // Literal
Let, // let Pat = Expr
Let, // let Pat = Expr (else Expr)?
Const, // const Pat = Expr
Static, // static Pat = Expr
Typedef, // struct { Pat } | struct ( Pat )
For, // for Pat in Expr Expr else Expr
Fn, // fn ( Pat,* ) Expr
@@ -555,7 +556,6 @@ pub enum Ps {
Lambda, // | Pat,* | Expr
DoubleRef, // && Expr
Make, // Expr{ Expr,* }
Match, // match Expr { MatchArm,* }
Mod, // mod Ty Expr
ImplicitDo, // An implicit semicolon
ExplicitDo, // An explicit leading semicolon
@@ -577,7 +577,7 @@ fn from_prefix(token: &Token) -> PResult<(Ps, Prec)> {
TKind::Public => (Ps::Op(Op::Pub), Prec::Body),
TKind::For => (Ps::For, Prec::Body),
TKind::Fn => (Ps::Fn, Prec::Body),
TKind::Match => (Ps::Match, Prec::Body),
TKind::Match => (Ps::Op(Op::Match), Prec::Body),
TKind::Macro => (Ps::Op(Op::Macro), Prec::Assign),
TKind::Module => (Ps::Mod, Prec::Body),
TKind::Let => (Ps::Let, Prec::Tuple),
@@ -663,17 +663,6 @@ fn from_infix(token: &Token) -> PResult<(Ps, Prec)> {
})
}
impl<'t> Parse<'t> for Const {
type Prec = ();
fn parse(p: &mut Parser<'t>, _level: Self::Prec) -> PResult<Self> {
Ok(Self(
p.consume().parse(PPrec::Tuple)?,
p.expect(TKind::Eq)?.parse(Prec::Tuple.value())?,
))
}
}
impl<'t> Parse<'t> for Typedef {
type Prec = ();
@@ -717,46 +706,36 @@ impl<'t> Parse<'t> for Fn {
}
impl<'t> Parse<'t> for Let {
type Prec = ();
type Prec = LetKind;
fn parse(p: &mut Parser<'t>, _level: Self::Prec) -> PResult<Self> {
let pat = p.consume().parse(PPrec::Tuple)?;
if p.next_if(TKind::Eq).allow_eof()?.is_none_or(|v| v.is_err()) {
return Ok(Self(pat, vec![]));
fn parse(p: &mut Parser<'t>, level: Self::Prec) -> PResult<Self> {
if let LetKind::Match = level {
// |? Pat => Expr
p.next_if(TKind::Bar)?.ok(); // and discard
return Ok(Self(
level,
p.parse(PPrec::Min)?,
vec![p.expect(TKind::FatArrow)?.parse(Prec::Body.next())?],
));
}
// let Pat
let pat = p.consume().parse(PPrec::Tuple)?;
if p.next_if(TKind::Eq).allow_eof()?.is_none_or(|v| v.is_err()) {
return Ok(Self(level, pat, vec![]));
}
// = Expr
let body = p.parse(Prec::Tuple.value())?;
if p.next_if(TKind::Else)
.allow_eof()?
.is_none_or(|v| v.is_err())
{
return Ok(Self(pat, vec![body]));
return Ok(Self(level, pat, vec![body]));
}
Ok(Self(pat, vec![body, p.parse(Prec::Body.next())?]))
}
}
impl<'t> Parse<'t> for Match {
type Prec = ();
fn parse(p: &mut Parser<'t>, _level: Self::Prec) -> PResult<Self> {
Ok(Self(p.consume().parse(Prec::Logical.value())?, {
p.expect(TKind::LCurly)?;
p.list(vec![], Prec::Body.next(), TKind::Comma, TKind::RCurly)?
}))
}
}
impl<'t> Parse<'t> for MatchArm {
type Prec = usize;
fn parse(p: &mut Parser<'t>, level: usize) -> PResult<Self> {
p.next_if(TKind::Bar)?.ok(); // and discard
Ok(MatchArm(
p.parse(PPrec::Min)?,
p.expect(TKind::FatArrow)?.parse(level)?,
))
// else Expr
Ok(Self(level, pat, vec![body, p.parse(Prec::Body.next())?]))
}
}
@@ -809,33 +788,10 @@ fn parse_for<'t>(p: &mut Parser<'t>, _level: ()) -> PResult<Expr> {
},
}
*/
// let mut tmp_p = Parser::new(Lexer::new(
// "match `iter.into_iter() {
// `iterator => loop match `iterator.next() {
// None => break `fail,
// Some(`pat) => `pass,
// },
// }",
// ));
// let mut template: Expr = tmp_p.parse(Prec::MIN)?;
// let mut subst = Subst::<Span> { exp: Default::default(), pat: Default::default() };
// subst.exp.extend([
// ("iterator".into(), Expr::Id("#iter".into())),
// ("iter".into(), iter.0),
// ("fail".into(), fail.0),
// ("pass".into(), pass.0),
// ]);
// subst.pat.extend([
// ("iterator".into(), Pat::Name("#iter".into())),
// ("pat".into(), pat),
// ]);
// template.apply(&subst);
// Ok(template)
Ok(Expr::Match(Box::new(Match(
Ok(Expr::Op(
Op::Match,
vec![
Expr::Op(
Op::Dot,
vec![
@@ -844,41 +800,54 @@ fn parse_for<'t>(p: &mut Parser<'t>, _level: ()) -> PResult<Expr> {
],
)
.anno(cspan),
vec![MatchArm(
Expr::Let(Box::new(Let(
LetKind::Match,
Pat::Name("#iter".into()),
vec![
Expr::Op(
Op::Loop,
vec![
Expr::Match(Box::new(Match(
Expr::Op(
Op::Match,
vec![
Expr::Op(
Op::Dot,
vec![
Expr::Id("#iter".into()).anno(cspan),
Expr::Op(Op::Call, vec![Expr::Id("next".into()).anno(cspan)])
Expr::Op(
Op::Call,
vec![Expr::Id("next".into()).anno(cspan)],
)
.anno(cspan),
],
)
.anno(cspan),
vec![
MatchArm(
Expr::Let(Box::new(Let(
LetKind::Match,
Pat::Name("None".into()),
Expr::Op(Op::Break, vec![fail]).anno(fspan),
),
MatchArm(
vec![Expr::Op(Op::Break, vec![fail]).anno(fspan)],
)))
.anno(fspan),
Expr::Let(Box::new(Let(
LetKind::Match,
Pat::TupStruct(
"Some".into(),
Box::new(Pat::Op(PatOp::Tuple, vec![pat])),
),
pass,
),
],
vec![pass],
)))
.anno(pspan),
],
)
.anno(pspan),
)],
))))
],
)
.anno(pspan),
],
)))
.anno(pspan),
],
))
}
impl<'t> Parse<'t> for Expr {
@@ -907,12 +876,13 @@ impl<'t> Parse<'t> for Expr {
Ps::Id => Expr::Id(p.parse(())?),
Ps::Mid => Expr::MetId(p.consume().next()?.lexeme.to_string()),
Ps::Lit => Expr::Lit(p.parse(())?),
Ps::Let => Expr::Let(p.parse(())?),
Ps::Let => Expr::Let(p.parse(LetKind::Let)?),
Ps::Const => Expr::Let(p.parse(LetKind::Const)?),
Ps::Static => Expr::Let(p.parse(LetKind::Static)?),
Ps::For => parse_for(p, ())?,
Ps::Const => Expr::Const(p.parse(())?),
Ps::Typedef => Expr::Struct(p.parse(())?),
Ps::Match => Expr::Match(p.parse(())?),
Ps::Mod => Expr::Mod(p.parse(())?),
Ps::Op(Op::Match) => parse_match(p)?,
Ps::Op(Op::Meta) => Expr::Op(
Op::Meta,
vec![
@@ -1049,6 +1019,20 @@ fn parse_array<'t>(p: &mut Parser<'t>) -> PResult<Expr> {
})
}
fn parse_match<'t>(p: &mut Parser<'t>) -> PResult<Expr> {
let scrutinee = p.consume().parse(Prec::Logical.value())?;
let arms = p
.expect(TKind::LCurly)?
.list(vec![], LetKind::Match, TKind::Comma, TKind::RCurly)?
.into_iter()
.map(|Anno(arm, span)| Anno(Expr::Let(Box::new(arm)), span));
let expr = Expr::Op(Op::Match, iter::once(scrutinee).chain(arms).collect());
Ok(expr)
}
impl<'t, P: Parse<'t> + Annotation> Parse<'t> for Anno<P> {
type Prec = P::Prec;
fn parse(p: &mut Parser<'t>, level: P::Prec) -> PResult<Self>