M-Labs/nac3
M-Labs/nac3
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added rigid type variable

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This commit is contained in:
pca006132 2021-07-30 11:28:27 +08:00
parent f2c5a9b352
commit 743a9384a3
2 changed files with 51 additions and 9 deletions
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22
nac3core/src/typecheck/typedef/mod.rs
View File

@ -47,6 +47,9 @@ pub enum TypeVarMeta {
#[derive(Clone)]
pub enum TypeEnum {
TRigidVar {
id: u32,
},
TVar {
id: u32,
meta: TypeVarMeta,
@ -74,6 +77,7 @@ pub enum TypeEnum {
impl TypeEnum {
pub fn get_type_name(&self) -> &'static str {
match self {
TypeEnum::TRigidVar { .. } => "TRigidVar",
TypeEnum::TVar { .. } => "TVar",
TypeEnum::TTuple { .. } => "TTuple",
TypeEnum::TList { .. } => "TList",
@ -127,6 +131,12 @@ impl Unifier {
self.unification_table.probe_value(a).clone()
}
pub fn get_fresh_rigid_var(&mut self) -> (Type, u32) {
let id = self.var_id + 1;
self.var_id += 1;
(self.add_ty(TypeEnum::TRigidVar { id }), id)
}
pub fn get_fresh_var(&mut self) -> (Type, u32) {
self.get_fresh_var_with_range(&[])
}
@ -139,9 +149,17 @@ impl Unifier {
(self.add_ty(TypeEnum::TVar { id, range, meta: TypeVarMeta::Generic }), id)
}
/// Unification would not unify rigid variables with other types, but we want to do this for
/// function instantiations, so we make it explicit.
pub fn replace_rigid_var(&mut self, rigid: Type, b: Type) {
assert!(matches!(&*self.get_ty(rigid), TypeEnum::TRigidVar { .. }));
self.set_a_to_b(rigid, b);
}
pub fn is_concrete(&mut self, a: Type, allowed_typevars: &[Type]) -> bool {
use TypeEnum::*;
match &*self.get_ty(a) {
TRigidVar { .. } => true,
TVar { .. } => allowed_typevars.iter().any(|b| self.unification_table.unioned(a, *b)),
TCall { .. } => false,
TList { ty } => self.is_concrete(*ty, allowed_typevars),
@ -435,6 +453,7 @@ impl Unifier {
use TypeVarMeta::*;
let ty = self.unification_table.probe_value(ty).clone();
match ty.as_ref() {
TypeEnum::TRigidVar { id } => var_to_name(*id),
TypeEnum::TVar { id, meta: Generic, .. } => var_to_name(*id),
TypeEnum::TVar { meta: Sequence(map), .. } => {
let fields = map
@ -544,6 +563,7 @@ impl Unifier {
// variables, i.e. things like TRecord, TCall should not occur, and we
// should be safe to not implement the substitution for those variants.
match &*ty {
TypeEnum::TRigidVar { .. } => None,
TypeEnum::TVar { id, meta: Generic, .. } => mapping.get(&id).cloned(),
TypeEnum::TTuple { ty } => {
let mut new_ty = Cow::from(ty);
@ -634,7 +654,7 @@ impl Unifier {
let ty = self.unification_table.probe_value(b).clone();
match ty.as_ref() {
TypeEnum::TVar { meta: Generic, .. } => {}
TypeEnum::TRigidVar { .. } | TypeEnum::TVar { meta: Generic, .. } => {}
TypeEnum::TVar { meta: Sequence(map), .. } => {
for t in map.borrow().values() {
self.occur_check(a, *t)?;

38
nac3core/src/typecheck/typedef/test.rs
View File

@ -419,22 +419,22 @@ fn test_typevar_range() {
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.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.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});
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});
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});
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())
@ -442,12 +442,34 @@ fn test_typevar_range() {
let a = env.unifier.get_fresh_var_with_range(&[int, float]).0;
let b = env.unifier.get_fresh_var().0;
let a_list = env.unifier.add_ty(TypeEnum::TList { ty: a});
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.add_ty(TypeEnum::TList { ty: b });
env.unifier.unify(a_list, b_list).unwrap();
assert_eq!(
env.unifier.unify(b, boolean),
Err("Cannot unify type variable 21 with TObj due to incompatible value range".into())
);
}
#[test]
fn test_rigid_var() {
let mut env = TestEnvironment::new();
let a = env.unifier.get_fresh_rigid_var().0;
let b = env.unifier.get_fresh_rigid_var().0;
let x = env.unifier.get_fresh_var().0;
let list_a = env.unifier.add_ty(TypeEnum::TList { ty: a });
let list_x = env.unifier.add_ty(TypeEnum::TList { ty: x });
let int = env.parse("int", &HashMap::new());
let list_int = env.parse("List[int]", &HashMap::new());
assert_eq!(env.unifier.unify(a, b), Err("Cannot unify TRigidVar with TRigidVar".to_string()));
env.unifier.unify(list_a, list_x).unwrap();
assert_eq!(
env.unifier.unify(list_x, list_int),
Err("Cannot unify TObj with TRigidVar".to_string())
);
env.unifier.replace_rigid_var(a, int);
env.unifier.unify(list_x, list_int).unwrap();
}