mirror of https://github.com/azur1s/bobbylisp.git
Prepare for proper type inference
parent
4b805823e6
commit
0c79321826
40
src/main.rs
40
src/main.rs
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@ -1,6 +1,6 @@
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use ariadne::{sources, Color, Label, Report, ReportKind};
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use chumsky::{Parser, prelude::Input};
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use self::{parse::parser::{lexer, exprs_parser}, typing::check::check};
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use self::{parse::parser::{lexer, exprs_parser}};
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pub mod parse;
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pub mod typing;
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@ -8,11 +8,10 @@ pub mod typing;
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fn main() {
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let src = "
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{
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let foo : num =
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let a : num = true,
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b : num = 3
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in
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a + b;
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let foo =
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let a = true in
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let b = false in
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a + b;
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foo * 2
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}
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".to_string();
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@ -27,34 +26,7 @@ fn main() {
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.into_output_errors();
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if let Some(ast) = ast.filter(|_| errs.len() + parse_errs.len() == 0) {
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match check(ast.0) {
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Ok(tast) => println!("{:?}", tast),
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Err(ty_err) => {
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let mut r = Report::build(ReportKind::Error, filename.clone(), ty_err.loc.start)
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.with_message(ty_err.msg)
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.with_label(Label::new((filename.clone(), ty_err.loc.into_range()))
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.with_message(match ty_err.note {
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Some(note) => note,
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None => "While type checking this expression".to_string(),
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})
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.with_color(Color::Red)
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);
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if let Some((hint, loc)) = ty_err.hint {
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r = r.with_label(Label::new((filename.clone(), loc.into_range()))
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.with_message(hint)
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.with_color(Color::Yellow),
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);
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}
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r.finish()
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.print(sources([(
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filename.clone(),
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src.clone(),
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)]))
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.unwrap();
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}
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}
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println!("{:?}", ast);
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}
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parse_errs
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@ -178,8 +178,6 @@ pub enum BinaryOp {
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}
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pub type Spanned<T> = (T, Span);
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type Binding<'src> =
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(&'src str, Option<Type>, Spanned<Box<Expr<'src>>>);
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// Clone is needed for type checking since the type checking
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// algorithm is recursive and sometimes consume the AST.
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@ -200,10 +198,16 @@ pub enum Expr<'src> {
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f: Spanned<Box<Self>>,
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},
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Let {
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bindings: Vec<Binding<'src>>,
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name: &'src str,
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ty: Option<Type>,
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value: Spanned<Box<Self>>,
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body: Spanned<Box<Self>>,
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},
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Assign(Vec<Binding<'src>>),
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Define {
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name: &'src str,
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ty: Option<Type>,
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value: Spanned<Box<Self>>,
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},
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Block {
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exprs: Vec<Spanned<Box<Self>>>,
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void: bool, // True if last expression is discarded (ends with semicolon).
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@ -268,8 +272,8 @@ pub fn expr_parser<'tokens, 'src: 'tokens>() -> impl Parser<
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.then(expr.clone())
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.map(|(args, body)| Expr::Lambda(args, boxspan(body)));
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// (ident (: type)?)*
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let binds = symbol
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// ident (: type)?
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let bind = symbol
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.then(
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just(Token::Colon)
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.ignore_then(type_parser())
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@ -277,21 +281,18 @@ pub fn expr_parser<'tokens, 'src: 'tokens>() -> impl Parser<
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)
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.then_ignore(just(Token::Assign))
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.then(expr.clone())
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.map(|((name, ty), expr)| (name, ty, boxspan(expr)))
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.separated_by(just(Token::Comma))
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.allow_trailing()
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.collect::<Vec<_>>();
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.map(|((name, ty), expr)| (name, ty, boxspan(expr)));
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let let_or_assign = just(Token::Let)
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.ignore_then(binds)
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let let_or_define = just(Token::Let)
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.ignore_then(bind)
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.then(
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just(Token::In)
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.ignore_then(expr.clone())
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.or_not()
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)
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.map(|(bindings, body)| match body {
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Some(body) => Expr::Let { bindings, body: boxspan(body) },
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None => Expr::Assign(bindings),
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.map(|((name, ty, expr), body)| match body {
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Some(body) => Expr::Let { name, ty, value: expr, body: boxspan(body) },
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None => Expr::Define { name, ty, value: expr },
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});
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let if_ = just(Token::If)
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@ -333,7 +334,7 @@ pub fn expr_parser<'tokens, 'src: 'tokens>() -> impl Parser<
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.or(ident)
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.or(paren_expr)
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.or(lambda)
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.or(let_or_assign)
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.or(let_or_define)
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.or(if_)
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.or(block)
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.map_with_span(|e, s| (e, s))
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@ -1,425 +0,0 @@
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use crate::parse::parser::{
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Span, Spanned,
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UnaryOp, BinaryOp, Lit, Expr,
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};
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use super::{ty::Type, typed::TExpr};
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#[derive(Clone, Debug)]
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struct TypeContext<'src> {
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bindings: Vec<(&'src str, Type)>,
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funcs: Vec<(&'src str, Vec<Type>, Type)>,
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}
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impl<'src> TypeContext<'src> {
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fn new() -> Self {
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Self {
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bindings: Vec::new(),
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funcs: Vec::new(),
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}
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}
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/// Bind a type to a name.
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fn bind(&mut self, name: &'src str, ty: Type) {
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self.bindings.push((name, ty));
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}
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/// Bind a function (parameters and return type) to a name.
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fn bind_func(&mut self, name: &'src str, args: Vec<Type>, ret_ty: Type) {
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self.funcs.push((name, args, ret_ty));
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}
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fn lookup(&self, name: &str) -> Option<Type> {
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self.bindings.iter()
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.rev()
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.find(|(n, _)| *n == name)
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.map(|(_, t)| t.clone())
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}
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fn lookup_func(&self, name: &str) -> Option<(Vec<Type>, Type)> {
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self.funcs.iter()
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.rev()
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.find(|(n, _, _)| *n == name)
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.map(|(_, args, ret_ty)| (args.clone(), ret_ty.clone()))
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}
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}
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#[derive(Debug)]
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pub struct TypeError {
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pub msg: String,
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pub note: Option<String>,
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pub hint: Option<(String, Span)>,
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pub loc: Span,
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}
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impl TypeError {
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fn new(msg: String, loc: Span) -> Self {
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Self {
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msg,
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note: None,
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hint: None,
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loc,
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}
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}
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fn with_note(mut self, note: String) -> Self {
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self.note = Some(note);
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self
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}
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fn with_hint(mut self, hint: String, loc: Span) -> Self {
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self.hint = Some((hint, loc));
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self
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}
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}
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fn type_expr<'src>(
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env: &mut TypeContext<'src>, expr: Spanned<Expr<'src>>
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) -> Result<Spanned<TExpr<'src>>, TypeError> {
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macro_rules! oks { // Spanned Ok macro.
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($e:expr $(,)?) => {
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Ok(($e, expr.1))
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};
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}
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macro_rules! unbox { // Unbox a Spanned<Box<T>> into a Spanned<T>.
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($e:expr) => {
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(*$e.0, $e.1)
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};
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}
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macro_rules! sbox { // Box the first value of a Spanned<T>.
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($e:expr) => {
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(Box::new($e.0), $e.1)
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};
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}
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match expr.0 {
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Expr::Lit(lit) => match lit {
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Lit::Unit => oks!(TExpr::Lit(Lit::Unit)),
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Lit::Bool(x) => oks!(TExpr::Lit(Lit::Bool(x))),
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Lit::Num(x) => oks!(TExpr::Lit(Lit::Num(x))),
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Lit::Str(x) => oks!(TExpr::Lit(Lit::Str(x))),
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}
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Expr::Ident(name) => {
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let ty = env.lookup(name)
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.ok_or(TypeError::new(format!("Unknown identifier `{}`", name), expr.1))?;
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oks!(TExpr::Ident(name, ty))
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}
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Expr::Unary(op, e) => {
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let te = type_expr(env, unbox!(e))?;
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let ret_ty = match op {
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UnaryOp::Neg => Type::Num,
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UnaryOp::Not => Type::Bool,
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};
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if te.0.ty() != &ret_ty {
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return Err(TypeError::new(format!("Expected `{}` but found `{}`", ret_ty, te.0.ty()), te.1)
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.with_note(format!("This have type `{}`", te.0.ty()))
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.with_hint(format!("This operator requires a `{}`", ret_ty), (te.1.start-1..te.1.start).into()));
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}
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oks!(TExpr::Unary {
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op,
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expr: sbox!(te),
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ret_ty,
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})
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}
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Expr::Binary(op, lhs, rhs) => {
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let tlhs = type_expr(env, unbox!(lhs))?;
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let trhs = type_expr(env, unbox!(rhs))?;
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let op_ty = match op {
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BinaryOp::Add
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| BinaryOp::Sub
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| BinaryOp::Mul
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| BinaryOp::Div
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| BinaryOp::Rem => Some(Type::Num),
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BinaryOp::And
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| BinaryOp::Or => Some(Type::Bool),
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BinaryOp::Eq
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| BinaryOp::Ne
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| BinaryOp::Lt
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| BinaryOp::Le
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| BinaryOp::Gt
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| BinaryOp::Ge => None,
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};
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let ret_ty;
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if let Some(op_ty) = op_ty {
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if tlhs.0.ty() != &op_ty {
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return Err(TypeError::new(format!("Expected `{}` but found `{}`", op_ty, tlhs.0.ty()), tlhs.1)
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.with_note(format!("This have type `{}`", tlhs.0.ty()))
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.with_hint(format!("This operator requires a `{}`", op_ty), (tlhs.1.start-1..tlhs.1.start).into()));
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}
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if trhs.0.ty() != &op_ty {
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return Err(TypeError::new(format!("Expected `{}` but found `{}`", op_ty, trhs.0.ty()), trhs.1)
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.with_note(format!("This have type `{}`", trhs.0.ty()))
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.with_hint(format!("This operator requires a `{}`", op_ty), (trhs.1.start-1..trhs.1.start).into()));
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}
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ret_ty = op_ty;
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} else {
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if tlhs.0.ty() != trhs.0.ty() {
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return Err(TypeError::new(format!("Expected `{}` but found `{}`", tlhs.0.ty(), trhs.0.ty()), trhs.1)
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.with_hint(
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format!("Both have to be the same type. Got `{}` and `{}`", tlhs.0.ty(), trhs.0.ty()),
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(tlhs.1.start..trhs.1.end).into(),
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));
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}
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ret_ty = Type::Bool;
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}
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oks!(TExpr::Binary {
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op,
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lhs: sbox!(tlhs),
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rhs: sbox!(trhs),
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ret_ty,
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})
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}
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Expr::Lambda(args, body) => {
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// Create a new type environment.
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let mut new_env = env.clone();
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// Bind the arguments to the new environment.
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let mut arg_tys = Vec::new();
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for (arg, maybe_ty) in args {
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let ty = match maybe_ty {
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Some(ty) => ty,
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None => todo!(), // TODO: infer the type of the argument after type checking the body.
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};
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arg_tys.push((arg, ty.clone()));
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new_env.bind(arg, ty);
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}
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// Type check the body.
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let tbody = type_expr(&mut new_env, unbox!(body))?;
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// Return the typed lambda expression.
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oks!(TExpr::Lambda {
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params: arg_tys,
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body: sbox!(tbody.clone()),
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ret_ty: tbody.0.ty().clone(),
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})
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}
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Expr::Call(func, cargs) => {
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// Get span of the arguments.
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let args_span = cargs.iter()
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.map(|arg| arg.1.into_range())
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.fold(None, |acc: Option<std::ops::Range<usize>>, range| match acc {
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Some(acc) => Some(acc.start..range.end),
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None => Some(range),
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})
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.unwrap_or(func.1.end..func.1.end+2);
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// Type check the arguments.
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let mut targs = Vec::new();
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for arg in cargs {
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let targ = type_expr(env, arg)?;
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targs.push(targ);
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}
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// Type check the function (callee).
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let tfunc = type_expr(env, unbox!(func))?;
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// Get the function type of the callee. (if any).
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if let Some((param_tys, ret_ty)) = tfunc.0.clone().as_fn() {
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// Check if the number of arguments match the number of parameters.
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if param_tys.len() != targs.len() {
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return Err(TypeError::new(
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format!(
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"Expected {} arguments, got {}",
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param_tys.len(),
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targs.len(),
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),
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args_span.into(),
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).with_note(format!(
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"Expected {} arguments",
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param_tys.len(),
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)).with_hint(
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format!(
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"This expect arguments of type `{}`",
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param_tys.iter().map(|ty| ty.to_string()).collect::<Vec<_>>().join(", ")
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),
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func.1,
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));
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}
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// Check if the types of the arguments match the types of the parameters.
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for (arg, param) in targs.iter().zip(param_tys.iter()) {
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if arg.0.ty() != param {
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return Err(TypeError::new(
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format!(
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"Expected argument of type `{}`, got `{}`",
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param,
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arg.0.ty(),
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),
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arg.1,
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).with_note(format!(
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"Expected argument of type `{}`",
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param,
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)));
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}
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}
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// Return the typed call expression.
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oks!(TExpr::Call {
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func: sbox!(tfunc),
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args: targs,
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ret_ty,
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})
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} else {
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Err(TypeError::new(
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format!("Expected function, got `{}`", tfunc.0.ty()),
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tfunc.1,
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))
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}
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}
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Expr::If { cond, t, f } => {
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let tcond = type_expr(env, unbox!(cond))?;
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let tt = type_expr(env, unbox!(t))?;
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let tf = type_expr(env, unbox!(f))?;
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// Check if the condition is of type `bool`.
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if tcond.0.ty() != &Type::Bool {
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return Err(TypeError::new(
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format!("Expected condition of type `bool`, got `{}`", tcond.0.ty()),
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tcond.1,
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));
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}
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// Check if the true and false branches have the same type.
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if tt.0.ty() != tf.0.ty() {
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return Err(TypeError::new(
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format!(
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"Expected the branches to have the same type, got `{}` and `{}`",
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tt.0.ty(),
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tf.0.ty(),
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),
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tf.1,
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).with_note(format!(
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"Expected this branch to be type of `{}`",
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tt.0.ty(),
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)));
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}
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oks!(TExpr::If {
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cond: sbox!(tcond),
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br_ty: tt.0.ty().clone(),
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t: sbox!(tt),
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f: sbox!(tf),
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})
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}
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Expr::Let { bindings, body } => {
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// Create a new type environment.
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let mut new_env = env.clone();
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// Type check the bindings.
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let mut tbindings = Vec::new();
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for (name, maybe_ty, expr) in bindings {
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let ty = match maybe_ty {
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Some(ty) => ty,
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None => todo!("Type inferrence"), // TODO: infer.
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};
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let texpr = type_expr(&mut new_env, unbox!(expr))?;
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// Check if the type of the binding matches the type of the expression.
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if texpr.0.ty() != &ty {
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return Err(TypeError::new(
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format!(
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"Expected the value to be of type `{}`, got `{}`",
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ty,
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texpr.0.ty(),
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),
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texpr.1,
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).with_note(format!(
|
||||
"Expected this value to be of type `{}`",
|
||||
ty,
|
||||
)));
|
||||
}
|
||||
|
||||
tbindings.push((name, ty.clone(), sbox!(texpr)));
|
||||
new_env.bind(name, ty);
|
||||
}
|
||||
|
||||
// Type check the body.
|
||||
let tbody = type_expr(&mut new_env, unbox!(body))?;
|
||||
|
||||
// Return the typed let expression.
|
||||
oks!(TExpr::Let {
|
||||
bindings: tbindings,
|
||||
body: sbox!(tbody),
|
||||
})
|
||||
}
|
||||
|
||||
Expr::Assign(bindings) => {
|
||||
// Type check the bindings.
|
||||
let mut tbindings = Vec::new();
|
||||
for (name, maybe_ty, expr) in bindings {
|
||||
let ty = match maybe_ty {
|
||||
Some(ty) => ty,
|
||||
None => todo!("Type inferrence"), // TODO: infer.
|
||||
};
|
||||
let texpr = type_expr(env, unbox!(expr))?;
|
||||
|
||||
// Check if the type of the binding matches the type of the expression.
|
||||
if texpr.0.ty() != &ty {
|
||||
return Err(TypeError::new(
|
||||
format!(
|
||||
"Expected the binding to be of type `{}`, got `{}`",
|
||||
ty,
|
||||
texpr.0.ty(),
|
||||
),
|
||||
texpr.1,
|
||||
).with_note(format!(
|
||||
"Expected this binding to be of type `{}`",
|
||||
ty,
|
||||
)));
|
||||
}
|
||||
|
||||
tbindings.push((name, ty.clone(), sbox!(texpr)));
|
||||
env.bind(name, ty);
|
||||
}
|
||||
|
||||
// Return the typed assign expression.
|
||||
oks!(TExpr::Assign(tbindings))
|
||||
}
|
||||
|
||||
Expr::Block { exprs, void } => {
|
||||
let texprs = exprs
|
||||
.into_iter()
|
||||
.map(|e| type_expr(env, unbox!(e)))
|
||||
.collect::<Result<Vec<_>, _>>()?;
|
||||
|
||||
let ret_ty = if void {
|
||||
Type::Unit
|
||||
} else if let Some(texpr) = texprs.last() {
|
||||
texpr.0.ty().clone()
|
||||
} else {
|
||||
Type::Unit
|
||||
};
|
||||
|
||||
oks!(TExpr::Block {
|
||||
exprs: texprs,
|
||||
void,
|
||||
ret_ty,
|
||||
})
|
||||
}
|
||||
|
||||
#[allow(unreachable_patterns)]
|
||||
_ => todo!(),
|
||||
}
|
||||
}
|
||||
|
||||
pub fn check(es: Vec<Spanned<Expr<'_>>>) -> Result<Vec<Spanned<TExpr<'_>>>, TypeError> {
|
||||
let mut env = TypeContext::new();
|
||||
let mut tes = Vec::new();
|
||||
for e in es {
|
||||
let te = type_expr(&mut env, e)?;
|
||||
tes.push(te);
|
||||
}
|
||||
Ok(tes)
|
||||
}
|
||||
|
|
@ -1,3 +1,2 @@
|
|||
pub mod ty;
|
||||
pub mod check;
|
||||
pub mod typed;
|
||||
|
|
@ -6,14 +6,11 @@ use crate::parse::parser::{
|
|||
Spanned,
|
||||
};
|
||||
|
||||
type TypedBinding<'src> =
|
||||
(&'src str, Type, Spanned<Box<TExpr<'src>>>);
|
||||
|
||||
// Typed version of the expression.
|
||||
#[derive(Clone, Debug)]
|
||||
pub enum TExpr<'src> {
|
||||
Lit(Lit<'src>),
|
||||
Ident(&'src str, Type),
|
||||
Ident(&'src str),
|
||||
|
||||
Unary {
|
||||
op: UnaryOp,
|
||||
|
|
@ -35,7 +32,6 @@ pub enum TExpr<'src> {
|
|||
Call {
|
||||
func: Spanned<Box<Self>>,
|
||||
args: Vec<Spanned<Self>>,
|
||||
ret_ty: Type,
|
||||
},
|
||||
If {
|
||||
cond: Spanned<Box<Self>>,
|
||||
|
|
@ -44,52 +40,19 @@ pub enum TExpr<'src> {
|
|||
br_ty: Type,
|
||||
},
|
||||
Let {
|
||||
bindings: Vec<TypedBinding<'src>>,
|
||||
name: &'src str,
|
||||
ty: Type,
|
||||
value: Spanned<Box<Self>>,
|
||||
body: Spanned<Box<Self>>,
|
||||
},
|
||||
Assign(Vec<TypedBinding<'src>>),
|
||||
Define {
|
||||
name: &'src str,
|
||||
ty: Type,
|
||||
value: Spanned<Box<Self>>,
|
||||
},
|
||||
Block {
|
||||
exprs: Vec<Spanned<Self>>,
|
||||
void: bool,
|
||||
ret_ty: Type,
|
||||
},
|
||||
}
|
||||
|
||||
impl<'src> TExpr<'src> {
|
||||
pub fn ty(&self) -> &Type {
|
||||
match self {
|
||||
TExpr::Lit(lit) => match lit {
|
||||
Lit::Unit => &Type::Unit,
|
||||
Lit::Bool(_) => &Type::Bool,
|
||||
Lit::Num(_) => &Type::Num,
|
||||
Lit::Str(_) => &Type::Str,
|
||||
},
|
||||
TExpr::Ident(_, ty) => ty,
|
||||
TExpr::Unary { ret_ty, .. } => ret_ty,
|
||||
TExpr::Binary { ret_ty, .. } => ret_ty,
|
||||
TExpr::Lambda { ret_ty, .. } => ret_ty,
|
||||
TExpr::Call { ret_ty, .. } => ret_ty,
|
||||
TExpr::If { br_ty, .. } => br_ty,
|
||||
// Get the type from the body.
|
||||
TExpr::Let { body, .. } => body.0.ty(),
|
||||
// Assignment is always unit.
|
||||
TExpr::Assign { .. } => &Type::Unit,
|
||||
// Get the type from the last expression in the block
|
||||
// if the expression is not ended with a semicolon.
|
||||
TExpr::Block { ret_ty, .. } => ret_ty,
|
||||
}
|
||||
}
|
||||
|
||||
pub fn as_fn(self) -> Option<(Vec<Type>, Type)> {
|
||||
match self {
|
||||
TExpr::Ident(_, Type::Func(params, ret_ty)) => Some((params, *ret_ty)),
|
||||
TExpr::Lambda { params, ret_ty, .. } => {
|
||||
let p = params.into_iter()
|
||||
.map(|(_, ty)| ty)
|
||||
.collect();
|
||||
Some((p, ret_ty))
|
||||
}
|
||||
_ => None,
|
||||
}
|
||||
}
|
||||
}
|
||||
Loading…
Reference in New Issue