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fixed range unification

This commit is contained in:
pca006132 2021-07-26 11:55:37 +08:00
parent 53ebe8d8b2
commit 8618837816
2 changed files with 137 additions and 25 deletions
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116
nac3core/src/typecheck/typedef/mod.rs
View File

@ -204,10 +204,9 @@ impl Unifier {
}
for v1 in old_range2.iter() {
for v2 in range1.iter() {
if !self.shape_match(*v1, *v2) {
continue;
if let Ok(result) = self.shape_match(*v1, *v2){
range2.push(result.unwrap_or(*v2));
}
range2.push(*v2);
}
}
if range2.is_empty() {
@ -648,39 +647,116 @@ impl Unifier {
Ok(())
}
fn shape_match(&mut self, a: Type, b: Type) -> bool {
fn shape_match(&mut self, a: Type, b: Type) -> Result<Option<Type>, ()> {
use TypeEnum::*;
let x = self.get_ty(a);
let y = self.get_ty(b);
match (x.as_ref(), y.as_ref()) {
(TVar { id, range, .. }, _) => self.check_var_compatible(*id, b, &range.borrow()).is_ok(),
(_, TVar { id, range, .. }) => self.check_var_compatible(*id, a, &range.borrow()).is_ok(),
(TTuple { ty: ty1 }, TTuple { ty: ty2 }) => {
ty1.len() == ty2.len()
&& zip(ty1.iter(), ty2.iter()).all(|(a, b)| self.shape_match(*a, *b))
(TVar { range: range1, .. }, TVar { meta, range: range2, .. }) => {
// we should restrict range2
let range1 = range1.borrow();
// new range is the intersection of them
// empty range indicates no constraint
if !range1.is_empty() {
let range2 = range2.borrow();
let mut range = Vec::new();
if range2.is_empty() {
range.extend_from_slice(&range1);
}
for v1 in range2.iter() {
for v2 in range1.iter() {
let result = self.shape_match(*v1, *v2);
if let Ok(result) = result {
range.push(result.unwrap_or(*v2));
}
}
}
if range.is_empty() {
Err(())
} else {
let id = self.var_id + 1;
self.var_id += 1;
let ty = TVar { id, meta: meta.clone(), range: range.into() };
Ok(Some(self.unification_table.new_key(ty.into())))
}
} else {
Ok(Some(b))
}
}
(_, TVar { range, .. }) => {
// range should be restricted to the left hand side
let range = range.borrow();
if range.is_empty() {
Ok(Some(a))
} else {
for v in range.iter() {
let result = self.shape_match(a, *v);
if let Ok(result) = result {
return Ok(result.or(Some(a)));
}
}
Err(())
}
}
(TVar { id, range, .. }, _) => {
self.check_var_compatible(*id, b, &range.borrow()).or(Err(()))
}
(TTuple { ty: ty1 }, TTuple { ty: ty2 }) => {
if ty1.len() != ty2.len() {
return Err(());
}
let mut need_new = false;
let mut ty = ty1.clone();
for (a, b) in zip(ty1.iter(), ty2.iter()) {
let result = self.shape_match(*a, *b)?;
ty.push(result.unwrap_or(*a));
if result.is_some() {
need_new = true;
}
}
if need_new {
Ok(Some(self.add_ty(TTuple { ty })))
} else {
Ok(None)
}
}
(TList { ty: ty1 }, TList { ty: ty2 }) => {
Ok(self.shape_match(*ty1, *ty2)?.map(|ty| self.add_ty(TList { ty })))
}
(TVirtual { ty: ty1 }, TVirtual { ty: ty2 }) => {
Ok(self.shape_match(*ty1, *ty2)?.map(|ty| self.add_ty(TVirtual { ty })))
}
(TObj { obj_id: id1, .. }, TObj { obj_id: id2, .. }) => {
if id1 == id2 {
Ok(None)
} else {
Err(())
}
}
(TList { ty: ty1 }, TList { ty: ty2 })
| (TVirtual { ty: ty1 }, TVirtual { ty: ty2 }) => self.shape_match(*ty1, *ty2),
(TObj { obj_id: id1, .. }, TObj { obj_id: id2, .. }) => id1 == id2,
// don't deal with function shape for now
_ => false,
_ => Err(()),
}
}
fn check_var_compatible(&mut self, id: u32, b: Type, range: &[Type]) -> Result<(), String> {
let mut in_range = range.is_empty();
fn check_var_compatible(
&mut self,
id: u32,
b: Type,
range: &[Type],
) -> Result<Option<Type>, String> {
if range.is_empty() {
return Ok(None);
}
for t in range.iter() {
if self.shape_match(*t, b) {
in_range = true;
let result = self.shape_match(*t, b);
if let Ok(result) = result {
return Ok(result);
}
}
if !in_range {
return Err(format!(
"Cannot unify type variable {} with {} due to incompatible value range",
id,
self.get_ty(b).get_type_name()
));
}
Ok(())
}
}

36
nac3core/src/typecheck/typedef/test.rs
View File

@ -403,4 +403,40 @@ fn test_typevar_range() {
env.unifier.unify(float_list, v),
Err("Cannot unify type variable 8 with TList due to incompatible value range".to_string())
);
let a = env.unifier.get_fresh_var_with_range(&[int, float]).0;
let b = env.unifier.get_fresh_var_with_range(&[boolean, float]).0;
env.unifier.unify(a, b).unwrap();
env.unifier.unify(a, float).unwrap();
let a = env.unifier.get_fresh_var_with_range(&[int, float]).0;
let b = env.unifier.get_fresh_var_with_range(&[boolean, float]).0;
env.unifier.unify(a, b).unwrap();
assert_eq!(
env.unifier.unify(a, int),
Err("Cannot unify type variable 12 with TObj due to incompatible value range".into())
);
let a = env.unifier.get_fresh_var_with_range(&[int, float]).0;
let b = env.unifier.get_fresh_var_with_range(&[boolean, float]).0;
let a_list = env.unifier.add_ty(TypeEnum::TList { ty: a});
let a_list = env.unifier.get_fresh_var_with_range(&[a_list]).0;
let b_list = env.unifier.add_ty(TypeEnum::TList { ty: b});
let b_list = env.unifier.get_fresh_var_with_range(&[b_list]).0;
env.unifier.unify(a_list, b_list).unwrap();
let float_list = env.unifier.add_ty(TypeEnum::TList { ty: float});
env.unifier.unify(a_list, float_list).unwrap();
// previous unifications should not affect a and b
env.unifier.unify(a, int).unwrap();
let a = env.unifier.get_fresh_var_with_range(&[int, float]).0;
let b = env.unifier.get_fresh_var_with_range(&[boolean, float]).0;
let a_list = env.unifier.add_ty(TypeEnum::TList { ty: a});
let b_list = env.unifier.add_ty(TypeEnum::TList { ty: b});
env.unifier.unify(a_list, b_list).unwrap();
let int_list = env.unifier.add_ty(TypeEnum::TList { ty: int});
assert_eq!(
env.unifier.unify(a_list, int_list),
Err("Cannot unify type variable 19 with TObj due to incompatible value range".into())
);
}