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bobbylisp
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Fix block type inferring

tc
azur 2023-04-14 13:16:15 +07:00
parent 50ae682203
commit 9eb4bf27fb
4 changed files with 135 additions and 76 deletions
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23
bin/src/main.rs
View File

@ -5,13 +5,22 @@ use typing::infer::infer_exprs;
fn main() {
let src = "
{
let foo =
let a = true in
let b = false in
a + b;
foo * 2
}
let r = {
let x =
if 0 == 1
then {
let x = true;
if x then 1 else 2
}
else 34 + {
let foo = 30 in
foo + 5
};
let y = { 1 } * 2;
if 1 + 1 == 2
then x
else y
};
".to_string();
let filename = "?".to_string();

29
syntax/src/expr.rs
View File

@ -89,6 +89,15 @@ pub enum Lit<'src> {
#[derive(Clone, Debug)]
pub enum UnaryOp { Neg, Not }
impl Display for UnaryOp {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
match self {
UnaryOp::Neg => write!(f, "-"),
UnaryOp::Not => write!(f, "!"),
}
}
}
#[derive(Clone, Debug)]
pub enum BinaryOp {
Add, Sub, Mul, Div, Rem,
@ -96,6 +105,26 @@ pub enum BinaryOp {
Eq, Ne, Lt, Le, Gt, Ge,
}
impl Display for BinaryOp {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
match self {
BinaryOp::Add => write!(f, "+"),
BinaryOp::Sub => write!(f, "-"),
BinaryOp::Mul => write!(f, "*"),
BinaryOp::Div => write!(f, "/"),
BinaryOp::Rem => write!(f, "%"),
BinaryOp::And => write!(f, "&&"),
BinaryOp::Or => write!(f, "||"),
BinaryOp::Eq => write!(f, "=="),
BinaryOp::Ne => write!(f, "!="),
BinaryOp::Lt => write!(f, "<"),
BinaryOp::Le => write!(f, "<="),
BinaryOp::Gt => write!(f, ">"),
BinaryOp::Ge => write!(f, ">="),
}
}
}
pub type Spanned<T> = (T, Span);
// Clone is needed for type checking since the type checking

156
typing/src/infer.rs
View File

@ -10,11 +10,17 @@ use syntax::{
use super::typed::TExpr;
macro_rules! unbox {
($e:expr) => {
(*$e.0, $e.1)
};
}
#[derive(Clone, Debug)]
struct Infer<'src> {
env: HashMap<&'src str, Type>,
subst: Vec<Type>,
constraints: Vec<(Type, Type)>,
constraints: Vec<(Type, Type, SimpleSpan)>,
}
impl<'src> Infer<'src> {
@ -38,6 +44,11 @@ impl<'src> Infer<'src> {
self.subst.get(i).cloned()
}
/// Add new constraint
fn add_constraint(&mut self, t1: Type, t2: Type, span: SimpleSpan) {
self.constraints.push((t1, t2, span));
}
/// Check if a type variable occurs in a type
fn occurs(&self, i: usize, t: Type) -> bool {
use Type::*;
@ -137,7 +148,7 @@ impl<'src> Infer<'src> {
/// Solve the constraints by unifying them
fn solve(&mut self) -> Result<(), String> {
for (t1, t2) in self.constraints.clone().into_iter() {
for (t1, t2, _span) in self.constraints.clone().into_iter() {
self.unify(t1, t2)?;
}
Ok(())
@ -248,14 +259,15 @@ impl<'src> Infer<'src> {
Block {
exprs: exprst,
void,
ret_ty,
ret_ty: self.substitute(ret_ty),
}
},
}
}
/// Infer the type of an expression
fn infer(&mut self, e: Expr<'src>, expected: Type) -> Result<TExpr<'src>, String> {
fn infer(&mut self, e: (Expr<'src>, SimpleSpan), expected: Type) -> Result<TExpr<'src>, String> {
let (e, span) = e;
match e {
// Literal values
// Push the constraint (expected type to be the literal type) and
@ -267,7 +279,7 @@ impl<'src> Infer<'src> {
Lit::Num(_) => Type::Num,
Lit::Str(_) => Type::Str,
};
self.constraints.push((expected, t));
self.add_constraint(expected, t, span);
Ok(TExpr::Lit(l))
},
@ -276,36 +288,36 @@ impl<'src> Infer<'src> {
Expr::Ident(ref x) => {
let t = self.env.get(x)
.ok_or(format!("Unbound variable: {}", x))?;
self.constraints.push((expected, t.clone()));
self.add_constraint(expected, t.clone(), span);
Ok(TExpr::Ident(x.clone()))
}
// Unary & binary operators
// The type of the left and right hand side are inferred and
// the expected type is determined by the operator
Expr::Unary(op, (expr, espan)) => match op {
Expr::Unary(op, e) => match op {
// Numeric operators (Num -> Num)
UnaryOp::Neg => {
let et = self.infer(*expr, Type::Num)?;
self.constraints.push((expected, Type::Num));
let et = self.infer(unbox!(e), Type::Num)?;
self.add_constraint(expected, Type::Num, span);
Ok(TExpr::Unary {
op,
expr: (Box::new(et), espan),
expr: (Box::new(et), e.1),
ret_ty: Type::Num,
})
},
// Boolean operators (Bool -> Bool)
UnaryOp::Not => {
let et = self.infer(*expr, Type::Bool)?;
self.constraints.push((expected, Type::Bool));
let et = self.infer(unbox!(e), Type::Bool)?;
self.add_constraint(expected, Type::Bool, span);
Ok(TExpr::Unary {
op,
expr: (Box::new(et), espan),
expr: (Box::new(et), e.1),
ret_ty: Type::Bool,
})
},
}
Expr::Binary(op, (lhs, lspan), (rhs, rspan)) => match op {
Expr::Binary(op, lhs, rhs) => match op {
// Numeric operators (Num -> Num -> Num)
BinaryOp::Add
| BinaryOp::Sub
@ -313,13 +325,13 @@ impl<'src> Infer<'src> {
| BinaryOp::Div
| BinaryOp::Rem
=> {
let lt = self.infer(*lhs, Type::Num)?;
let rt = self.infer(*rhs, Type::Num)?;
self.constraints.push((expected, Type::Num));
let lt = self.infer(unbox!(lhs), Type::Num)?;
let rt = self.infer(unbox!(rhs), Type::Num)?;
self.add_constraint(expected, Type::Num, span);
Ok(TExpr::Binary {
op,
lhs: (Box::new(lt), lspan),
rhs: (Box::new(rt), rspan),
lhs: (Box::new(lt), lhs.1),
rhs: (Box::new(rt), rhs.1),
ret_ty: Type::Num,
})
},
@ -327,13 +339,13 @@ impl<'src> Infer<'src> {
BinaryOp::And
| BinaryOp::Or
=> {
let lt = self.infer(*lhs, Type::Bool)?;
let rt = self.infer(*rhs, Type::Bool)?;
self.constraints.push((expected, Type::Bool));
let lt = self.infer(unbox!(lhs), Type::Bool)?;
let rt = self.infer(unbox!(rhs), Type::Bool)?;
self.add_constraint(expected, Type::Bool, span);
Ok(TExpr::Binary {
op,
lhs: (Box::new(lt), lspan),
rhs: (Box::new(rt), rspan),
lhs: (Box::new(lt), lhs.1),
rhs: (Box::new(rt), rhs.1),
ret_ty: Type::Bool,
})
},
@ -349,20 +361,20 @@ impl<'src> Infer<'src> {
// expected type for both the left and right hand side
// so the type on both side have to be the same
let t = self.fresh();
let lt = self.infer(*lhs, t.clone())?;
let rt = self.infer(*rhs, t)?;
self.constraints.push((expected, Type::Bool));
let lt = self.infer(unbox!(lhs), t.clone())?;
let rt = self.infer(unbox!(rhs), t)?;
self.add_constraint(expected, Type::Bool, span);
Ok(TExpr::Binary {
op,
lhs: (Box::new(lt), lspan),
rhs: (Box::new(rt), rspan),
lhs: (Box::new(lt), lhs.1),
rhs: (Box::new(rt), rhs.1),
ret_ty: Type::Bool,
})
},
}
// Lambda
Expr::Lambda(args, ret, (b, bspan)) => {
Expr::Lambda(args, ret, b) => {
// Get the return type or create a fresh type variable
let rt = ret.unwrap_or(self.fresh());
// Fill in the type of the arguments with a fresh type
@ -376,7 +388,7 @@ impl<'src> Infer<'src> {
xs.clone().into_iter().for_each(|(x, t)| { env.insert(x, t); });
let mut inf = self.clone();
inf.env = env;
let bt = inf.infer(*b, rt.clone())?;
let bt = inf.infer(unbox!(b), rt.clone())?;
// Add the substitutions & constraints from the body
// if it doesn't already exist
@ -392,22 +404,22 @@ impl<'src> Infer<'src> {
}
// Push the constraints
self.constraints.push((expected, Type::Func(
self.add_constraint(expected, Type::Func(
xs.clone().into_iter()
.map(|x| x.1)
.collect(),
Box::new(rt.clone()),
)));
), span);
Ok(TExpr::Lambda {
params: xs,
body: (Box::new(bt), bspan),
body: (Box::new(bt), b.1),
ret_ty: rt,
})
},
// Call
Expr::Call((f, fspan), args) => {
Expr::Call(f, args) => {
// Generate fresh types for the arguments
let freshes = args.clone().into_iter()
.map(|_| self.fresh())
@ -418,44 +430,41 @@ impl<'src> Infer<'src> {
Box::new(expected),
);
// Expect the function to have the function type
let ft = self.infer(*f, fsig)?;
let ft = self.infer(unbox!(f), fsig)?;
// Infer the arguments
let xs = args.into_iter()
.zip(freshes.into_iter())
.map(|((x, xspan), t)| {
let xt = self.infer(x, t)?;
Ok((xt, xspan))
})
.map(|(x, t)| Ok((self.infer(x, t)?, span)))
.collect::<Result<Vec<_>, String>>()?;
Ok(TExpr::Call {
func: (Box::new(ft), fspan),
func: (Box::new(ft), f.1),
args: xs,
})
},
// If
Expr::If { cond: (c, cspan), t: (t, tspan), f: (f, fspan) } => {
Expr::If { cond, t, f } => {
// Condition has to be a boolean
let ct = self.infer(*c, Type::Bool)?;
let ct = self.infer(unbox!(cond), Type::Bool)?;
// The type of the if expression is the same as the
// expected type
let tt = self.infer(*t, expected.clone())?;
let et = self.infer(*f, expected.clone())?;
let tt = self.infer(unbox!(t), expected.clone())?;
let et = self.infer(unbox!(f), expected.clone())?;
Ok(TExpr::If {
cond: (Box::new(ct), cspan),
t: (Box::new(tt), tspan),
f: (Box::new(et), fspan),
cond: (Box::new(ct), cond.1),
t: (Box::new(tt), t.1),
f: (Box::new(et), f.1),
br_ty: expected,
})
},
// Let & define
Expr::Let { name, ty, value: (v, vspan), body: (b, bspan) } => {
Expr::Let { name, ty, value, body } => {
// Infer the type of the value
let ty = ty.unwrap_or(self.fresh());
let vt = self.infer(*v, ty.clone())?;
let vt = self.infer(unbox!(value), ty.clone())?;
// Create a new environment and add the binding to it
// and then use the new environment to infer the body
@ -463,47 +472,58 @@ impl<'src> Infer<'src> {
env.insert(name.clone(), ty.clone());
let mut inf = Infer::new();
inf.env = env;
let bt = inf.infer(*b, expected)?;
let bt = inf.infer(unbox!(body), expected.clone())?;
Ok(TExpr::Let {
name, ty,
value: (Box::new(vt), vspan),
body: (Box::new(bt), bspan),
value: (Box::new(vt), value.1),
body: (Box::new(bt), body.1),
})
},
Expr::Define { name, ty, value: (v, vspan) } => {
Expr::Define { name, ty, value } => {
let ty = ty.unwrap_or(self.fresh());
let vt = self.infer(*v, ty.clone())?;
let vt = self.infer(unbox!(value), ty.clone())?;
self.env.insert(name.clone(), ty.clone());
// Define always returns unit
self.constraints.push((expected, Type::Unit));
Ok(TExpr::Define {
name, ty,
value: (Box::new(vt), vspan),
value: (Box::new(vt), value.1),
})
},
// Block
Expr::Block { exprs, void } => {
// Infer the type of each expression
let mut last = None;
let len = exprs.len();
let xs = exprs.into_iter()
.map(|(x, xspan)| {
let xt = self.infer(*x, expected.clone())?;
Ok((xt, xspan))
.enumerate()
.map(|(i, x)| {
let t = self.fresh();
let xt = self.infer(unbox!(x), t.clone())?;
// Save the type of the last expression
if i == len - 1 {
last = Some(t);
}
Ok((xt, x.1))
})
.collect::<Result<Vec<_>, String>>()?;
let ret_ty = if void {
let rt = if void || last.is_none() {
// If the block is void or there is no expression,
// the return type is unit
self.add_constraint(expected, Type::Unit, span);
Type::Unit
} else {
// Otherwise, the return type is the same as the expected type
self.add_constraint(expected.clone(), last.unwrap(), span);
expected
};
Ok(TExpr::Block {
exprs: xs,
void, ret_ty,
void,
ret_ty: rt,
})
},
}
@ -520,11 +540,11 @@ pub fn infer_exprs(es: Vec<(Expr, SimpleSpan)>) -> (Vec<(TExpr, SimpleSpan)>, St
// Errors
let mut errs = vec![];
for e in es {
for (e, s) in es {
let f = inf.fresh();
let t = inf.infer(e.0, f).unwrap();
tes.push(Some((t.clone(), e.1)));
tes_nosub.push((t, e.1));
let t = inf.infer((e, s), f).unwrap();
tes.push(Some((t.clone(), s)));
tes_nosub.push((t, s));
match inf.solve() {
Ok(_) => {

3
typing/src/typed.rs
View File

@ -1,3 +1,4 @@
use chumsky::span::SimpleSpan;
use syntax::{
expr::{
BinaryOp,
@ -57,4 +58,4 @@ pub enum TExpr<'src> {
void: bool,
ret_ty: Type,
},
}
}