forked from M-Labs/nac3
partial implementation
parent
e554737b68
commit
291e642699
|
|
@ -1,7 +1,9 @@
|
|||
use ena::unify::{InPlaceUnificationTable, NoError, UnifyKey, UnifyValue};
|
||||
use generational_arena::{Arena, Index};
|
||||
use std::borrow::{BorrowMut, Cow};
|
||||
use std::cell::RefCell;
|
||||
use std::collections::HashMap;
|
||||
use std::collections::BTreeMap;
|
||||
use std::mem::swap;
|
||||
|
||||
// Order:
|
||||
// TVar
|
||||
|
|
@ -24,9 +26,10 @@ impl UnifyValue for TypeIndex {
|
|||
type Error = NoError;
|
||||
fn unify_values(_: &Self, value2: &Self) -> Result<Self, Self::Error> {
|
||||
// WARN: depends on the implementation details of ena.
|
||||
// We do not use this to do unification, instead we perform unification and assign the type
|
||||
// by `union_value(key, new_value)`, which set the value as `unify_values(key.value, new_value)`.
|
||||
// So, we need to return the right one.
|
||||
// We do not use this to do unification, instead we perform unification
|
||||
// and assign the type by `union_value(key, new_value)`, which set the
|
||||
// value as `unify_values(key.value, new_value)`. So, we need to return
|
||||
// the right one.
|
||||
Ok(*value2)
|
||||
}
|
||||
}
|
||||
|
|
@ -40,15 +43,16 @@ impl UnifyKey for Type {
|
|||
Type(u)
|
||||
}
|
||||
fn tag() -> &'static str {
|
||||
"TypeKey"
|
||||
"TypeID"
|
||||
}
|
||||
}
|
||||
|
||||
type VarMapping = HashMap<u32, Type>;
|
||||
type Mapping<K, V = Type> = BTreeMap<K, V>;
|
||||
type VarMap = Mapping<u32>;
|
||||
|
||||
struct Call {
|
||||
posargs: Vec<Type>,
|
||||
kwargs: HashMap<String, Type>,
|
||||
kwargs: BTreeMap<String, Type>,
|
||||
ret: Type,
|
||||
fn_id: usize,
|
||||
}
|
||||
|
|
@ -59,38 +63,44 @@ struct FuncArg {
|
|||
is_optional: bool,
|
||||
}
|
||||
|
||||
// We use a lot of `RefCell`s here as we want to simplify our code.
|
||||
// Pattern:
|
||||
// 1. Take the complex data structure out
|
||||
// 2. Drop the arena (required before unification)
|
||||
// 3. Do unification for each type in the data structure
|
||||
// 4. Put the complex data structure back...
|
||||
enum TypeEnum {
|
||||
TVar {
|
||||
// TODO: upper/lower bound
|
||||
id: u32,
|
||||
},
|
||||
TSeq {
|
||||
index: HashMap<u32, Type>,
|
||||
map: RefCell<VarMap>,
|
||||
},
|
||||
TTuple {
|
||||
index: HashMap<u32, Type>,
|
||||
ty: RefCell<Vec<Type>>,
|
||||
},
|
||||
TList {
|
||||
ty: Type,
|
||||
},
|
||||
TRecord {
|
||||
fields: HashMap<String, Type>,
|
||||
fields: RefCell<Mapping<String>>,
|
||||
},
|
||||
TObj {
|
||||
obj_id: usize,
|
||||
instantiation: VarMapping,
|
||||
fields: RefCell<Mapping<String>>,
|
||||
params: RefCell<VarMap>,
|
||||
},
|
||||
TVirtual {
|
||||
obj_id: usize,
|
||||
instantiation: VarMapping,
|
||||
ty: Type,
|
||||
},
|
||||
TCall {
|
||||
calls: Vec<Call>,
|
||||
calls: RefCell<Vec<Call>>,
|
||||
},
|
||||
TFunc {
|
||||
args: Vec<FuncArg>,
|
||||
args: RefCell<Vec<FuncArg>>,
|
||||
ret: Type,
|
||||
instantiation: VarMapping,
|
||||
params: RefCell<VarMap>,
|
||||
},
|
||||
}
|
||||
|
||||
|
|
@ -115,11 +125,27 @@ impl TypeEnum {
|
|||
let b = other.get_int();
|
||||
(a % b) == 0
|
||||
}
|
||||
|
||||
pub fn get_kind_name(&self) -> &'static str {
|
||||
// this function is for debugging only...
|
||||
// a proper to_str implementation requires the context
|
||||
match self {
|
||||
TypeEnum::TVar { .. } => "TVar",
|
||||
TypeEnum::TSeq { .. } => "TSeq",
|
||||
TypeEnum::TTuple { .. } => "TTuple",
|
||||
TypeEnum::TList { .. } => "TList",
|
||||
TypeEnum::TRecord { .. } => "TRecord",
|
||||
TypeEnum::TObj { .. } => "TObj",
|
||||
TypeEnum::TVirtual { .. } => "TVirtual",
|
||||
TypeEnum::TCall { .. } => "TCall",
|
||||
TypeEnum::TFunc { .. } => "TFunc",
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
struct ObjDef {
|
||||
name: String,
|
||||
fields: HashMap<String, Type>,
|
||||
fields: Mapping<String>,
|
||||
}
|
||||
|
||||
struct Unifier {
|
||||
|
|
@ -129,14 +155,14 @@ struct Unifier {
|
|||
}
|
||||
|
||||
impl Unifier {
|
||||
fn unify(&self, a: Type, b: Type) {
|
||||
let (i_a, i_b) = {
|
||||
fn unify(&self, a: Type, b: Type) -> Result<(), String> {
|
||||
let (mut i_a, mut i_b) = {
|
||||
let mut table = self.unification_table.borrow_mut();
|
||||
(table.probe_value(a), table.probe_value(b))
|
||||
};
|
||||
|
||||
if i_a == i_b {
|
||||
return;
|
||||
return Ok(());
|
||||
}
|
||||
|
||||
let arena = self.type_arena.borrow();
|
||||
|
|
@ -145,75 +171,348 @@ impl Unifier {
|
|||
|
||||
// simplify our pattern matching...
|
||||
if ty_a.kind_le(ty_b) {
|
||||
std::mem::swap(&mut ty_a, &mut ty_b);
|
||||
swap(&mut i_a, &mut i_b);
|
||||
swap(&mut ty_a, &mut ty_b);
|
||||
}
|
||||
|
||||
// TODO: type variables bound check
|
||||
match (ty_a, ty_b) {
|
||||
(TypeEnum::TVar { .. }, TypeEnum::TVar { .. }) => {
|
||||
self.unification_table.borrow_mut().union(a, b);
|
||||
let old = if self.unification_table.borrow_mut().find(a) == a {
|
||||
i_b
|
||||
} else {
|
||||
i_a
|
||||
}
|
||||
.0;
|
||||
self.type_arena.borrow_mut().remove(old);
|
||||
}
|
||||
(TypeEnum::TVar { .. }, _) => {
|
||||
let mut table = self.unification_table.borrow_mut();
|
||||
table.union(a, b);
|
||||
table.union_value(a, i_b);
|
||||
// TODO: occur check...
|
||||
self.type_arena.borrow_mut().remove(i_a.0);
|
||||
}
|
||||
(TypeEnum::TSeq { .. }, TypeEnum::TSeq { .. }) => {
|
||||
let is_a = {
|
||||
let mut table = self.unification_table.borrow_mut();
|
||||
table.union(a, b);
|
||||
table.find(a) == a
|
||||
};
|
||||
// fighting with the borrow checker...
|
||||
// we have to manually drop this before we call borrow_mut
|
||||
std::mem::drop(arena);
|
||||
let (mut new, old) = {
|
||||
// the mutable arena would be dropped before calling unify later
|
||||
let mut arena = self.type_arena.borrow_mut();
|
||||
let (ty_a, ty_b) = arena.get2_mut(i_a.0, i_b.0);
|
||||
let index1 = if let Some(TypeEnum::TSeq { index }) = ty_a {
|
||||
std::mem::take(index)
|
||||
} else {
|
||||
unreachable!()
|
||||
};
|
||||
let index2 = if let Some(TypeEnum::TSeq { index }) = ty_b {
|
||||
std::mem::take(index)
|
||||
} else {
|
||||
unreachable!()
|
||||
};
|
||||
if is_a {
|
||||
arena.remove(i_b.0);
|
||||
(index1, index2)
|
||||
} else {
|
||||
arena.remove(i_a.0);
|
||||
(index2, index1)
|
||||
match ty_a {
|
||||
TypeEnum::TVar { .. } => {
|
||||
match ty_b {
|
||||
TypeEnum::TVar { .. } => {
|
||||
// TODO: type variables bound check
|
||||
let old = {
|
||||
let mut table = self.unification_table.borrow_mut();
|
||||
table.union(a, b);
|
||||
if table.find(a) == a {
|
||||
i_b
|
||||
} else {
|
||||
i_a
|
||||
}
|
||||
}
|
||||
.0;
|
||||
drop(arena);
|
||||
self.type_arena.borrow_mut().remove(old);
|
||||
}
|
||||
};
|
||||
for (key, value) in old.iter() {
|
||||
if let Some(ty) = new.get(key) {
|
||||
self.unify(*ty, *value);
|
||||
} else {
|
||||
new.insert(*key, *value);
|
||||
_ => {
|
||||
// TODO: type variables bound check and occur check
|
||||
drop(arena);
|
||||
self.set_a_to_b(a, b);
|
||||
}
|
||||
}
|
||||
// put it back
|
||||
let index = if is_a { i_a } else { i_b }.0;
|
||||
if let Some(TypeEnum::TSeq { index }) = self.type_arena.borrow_mut().get_mut(index) {
|
||||
*index = new;
|
||||
}
|
||||
TypeEnum::TSeq { map: map1 } => {
|
||||
match ty_b {
|
||||
TypeEnum::TSeq { map: map2 } => {
|
||||
// we get the tables out first.
|
||||
// unification requires mutable access to the underlying
|
||||
// structs, so we have to manaully drop the arena first,
|
||||
// do the unification, and then get a mutable reference
|
||||
// and put them back...
|
||||
let mut map1 = map1.take();
|
||||
let map2 = map2.take();
|
||||
drop(arena);
|
||||
self.set_a_to_b(a, b);
|
||||
// unify them to map1
|
||||
for (key, value) in map2.iter() {
|
||||
if let Some(ty) = map1.get(key) {
|
||||
self.unify(*ty, *value)?;
|
||||
} else {
|
||||
map1.insert(*key, *value);
|
||||
}
|
||||
}
|
||||
if let Some(TypeEnum::TSeq { map: mapping }) =
|
||||
self.type_arena.borrow().get(i_b.0)
|
||||
{
|
||||
*mapping.borrow_mut() = map1;
|
||||
} else {
|
||||
unreachable!()
|
||||
}
|
||||
}
|
||||
TypeEnum::TTuple { ty: types } => {
|
||||
let map = map1.take();
|
||||
let types = types.take();
|
||||
drop(arena);
|
||||
self.set_a_to_b(a, b);
|
||||
let len = types.len() as u32;
|
||||
for (k, v) in map.iter() {
|
||||
if *k >= len {
|
||||
return Err(format!(
|
||||
"Tuple index out of range. (Length: {}, Index: {})",
|
||||
types.len(),
|
||||
k
|
||||
));
|
||||
}
|
||||
self.unify(*v, types[*k as usize])?;
|
||||
}
|
||||
|
||||
if let Some(TypeEnum::TTuple { ty }) = self.type_arena.borrow().get(i_b.0) {
|
||||
*ty.borrow_mut() = types;
|
||||
} else {
|
||||
unreachable!()
|
||||
}
|
||||
}
|
||||
TypeEnum::TList { ty } => {
|
||||
let map = map1.take();
|
||||
let ty = *ty;
|
||||
drop(arena);
|
||||
self.set_a_to_b(a, b);
|
||||
for v in map.values() {
|
||||
self.unify(*v, ty)?;
|
||||
}
|
||||
}
|
||||
_ => {
|
||||
return self.report_kind_error(ty_a, ty_b);
|
||||
}
|
||||
}
|
||||
}
|
||||
TypeEnum::TTuple { ty: ty1 } => {
|
||||
if let TypeEnum::TTuple { ty: ty2 } = ty_b {
|
||||
let ty1 = ty1.take();
|
||||
let ty2 = ty2.take();
|
||||
if ty1.len() != ty2.len() {
|
||||
return Err(format!(
|
||||
"Cannot unify tuples with length {} and {}",
|
||||
ty1.len(),
|
||||
ty2.len()
|
||||
));
|
||||
}
|
||||
drop(arena);
|
||||
self.set_a_to_b(a, b);
|
||||
for (a, b) in ty1.iter().zip(ty2.iter()) {
|
||||
self.unify(*a, *b)?;
|
||||
}
|
||||
if let Some(TypeEnum::TTuple { ty }) =
|
||||
self.type_arena.borrow_mut().get_mut(i_b.0)
|
||||
{
|
||||
*ty.borrow_mut().get_mut() = ty1;
|
||||
} else {
|
||||
unreachable!()
|
||||
}
|
||||
} else {
|
||||
unreachable!()
|
||||
return self.report_kind_error(ty_a, ty_b);
|
||||
}
|
||||
}
|
||||
TypeEnum::TList { ty: ty1 } => {
|
||||
if let TypeEnum::TList { ty: ty2 } = ty_b {
|
||||
let ty1 = *ty1;
|
||||
let ty2 = *ty2;
|
||||
drop(arena);
|
||||
self.set_a_to_b(a, b);
|
||||
self.unify(ty1, ty2)?;
|
||||
} else {
|
||||
return self.report_kind_error(ty_a, ty_b);
|
||||
}
|
||||
}
|
||||
TypeEnum::TRecord { fields: fields1 } => {
|
||||
match ty_b {
|
||||
TypeEnum::TRecord { fields: fields2 } => {
|
||||
let mut fields1 = fields1.take();
|
||||
let fields2 = fields2.take();
|
||||
drop(arena);
|
||||
self.set_a_to_b(a, b);
|
||||
for (key, value) in fields2.iter() {
|
||||
if let Some(ty) = fields1.get(key) {
|
||||
self.unify(*ty, *value)?;
|
||||
} else {
|
||||
fields1.insert(key.clone(), *value);
|
||||
}
|
||||
}
|
||||
if let Some(TypeEnum::TRecord { fields }) =
|
||||
self.type_arena.borrow().get(i_b.0)
|
||||
{
|
||||
*fields.borrow_mut() = fields1;
|
||||
} else {
|
||||
unreachable!()
|
||||
}
|
||||
}
|
||||
// obj...
|
||||
_ => {
|
||||
return self.report_kind_error(ty_a, ty_b);
|
||||
}
|
||||
}
|
||||
}
|
||||
_ => unimplemented!(),
|
||||
}
|
||||
Ok(())
|
||||
}
|
||||
|
||||
fn set_a_to_b(&self, a: Type, b: Type) {
|
||||
// unify a and b together, and set the value to b's value this would
|
||||
// also deallocate a's previous value in the arena to save space...
|
||||
let mut table = self.unification_table.borrow_mut();
|
||||
let i_a = table.probe_value(a);
|
||||
let i_b = table.probe_value(b);
|
||||
table.union(a, b);
|
||||
table.union_value(a, i_b);
|
||||
self.type_arena.borrow_mut().remove(i_a.0);
|
||||
}
|
||||
|
||||
fn report_kind_error(&self, a: &TypeEnum, b: &TypeEnum) -> Result<(), String> {
|
||||
Err(format!(
|
||||
"Cannot unify {} with {}",
|
||||
a.get_kind_name(),
|
||||
b.get_kind_name()
|
||||
))
|
||||
}
|
||||
|
||||
fn subst(&self, a: Type, mapping: &VarMap) -> Option<Type> {
|
||||
let index = self.unification_table.borrow_mut().probe_value(a);
|
||||
let arena = self.type_arena.borrow();
|
||||
let ty = arena.get(index.0).unwrap();
|
||||
// this function would only be called when we instantiate functions.
|
||||
// function type signature should ONLY contain concrete types and type
|
||||
// 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::TVar { id } => mapping.get(&id).cloned(),
|
||||
TypeEnum::TSeq { map } => {
|
||||
let map = map.take();
|
||||
drop(arena);
|
||||
let new_map = self.subst_map(&map, mapping);
|
||||
if let Some(TypeEnum::TSeq { map: m }) = self.type_arena.borrow().get(index.0) {
|
||||
*m.borrow_mut() = map;
|
||||
} else {
|
||||
unreachable!();
|
||||
};
|
||||
new_map.map(|m| {
|
||||
let index = self
|
||||
.type_arena
|
||||
.borrow_mut()
|
||||
.insert(TypeEnum::TSeq { map: m.into() });
|
||||
self.unification_table
|
||||
.borrow_mut()
|
||||
.new_key(TypeIndex(index))
|
||||
})
|
||||
}
|
||||
TypeEnum::TTuple { ty } => {
|
||||
let ty = ty.take();
|
||||
drop(arena);
|
||||
let mut new_ty = None;
|
||||
for (i, t) in ty.iter().enumerate() {
|
||||
if let Some(t1) = self.subst(*t, mapping) {
|
||||
if new_ty.is_none() {
|
||||
new_ty = Some(ty.clone());
|
||||
}
|
||||
new_ty.as_mut().unwrap()[i] = t1;
|
||||
}
|
||||
}
|
||||
if let Some(TypeEnum::TTuple { ty: t }) = self.type_arena.borrow().get(index.0) {
|
||||
*t.borrow_mut() = ty;
|
||||
} else {
|
||||
unreachable!();
|
||||
};
|
||||
new_ty.map(|t| {
|
||||
let index = self
|
||||
.type_arena
|
||||
.borrow_mut()
|
||||
.insert(TypeEnum::TTuple { ty: t.into() });
|
||||
self.unification_table
|
||||
.borrow_mut()
|
||||
.new_key(TypeIndex(index))
|
||||
})
|
||||
}
|
||||
TypeEnum::TList { ty } => {
|
||||
let ty = *ty;
|
||||
drop(arena);
|
||||
self.subst(ty, mapping).map(|t| {
|
||||
let index = self
|
||||
.type_arena
|
||||
.borrow_mut()
|
||||
.insert(TypeEnum::TList { ty: t });
|
||||
self.unification_table
|
||||
.borrow_mut()
|
||||
.new_key(TypeIndex(index))
|
||||
})
|
||||
}
|
||||
TypeEnum::TVirtual { ty } => {
|
||||
let ty = *ty;
|
||||
drop(arena);
|
||||
self.subst(ty, mapping).map(|t| {
|
||||
let index = self
|
||||
.type_arena
|
||||
.borrow_mut()
|
||||
.insert(TypeEnum::TVirtual { ty: t });
|
||||
self.unification_table
|
||||
.borrow_mut()
|
||||
.new_key(TypeIndex(index))
|
||||
})
|
||||
}
|
||||
TypeEnum::TObj {
|
||||
obj_id,
|
||||
fields,
|
||||
params,
|
||||
} => {
|
||||
let obj_id = *obj_id;
|
||||
let params = params.take();
|
||||
let fields = fields.take();
|
||||
drop(arena);
|
||||
let mut new_params = None;
|
||||
let mut new_fields = None;
|
||||
// Type variables in field types must be present in the type parameter.
|
||||
// If the mapping does not contain any type variables in the
|
||||
// parameter list, we don't need to substitute the fields.
|
||||
// This is also used to prevent infinite substitution...
|
||||
let need_subst = params.values().any(|v| {
|
||||
let index = self.unification_table.borrow_mut().probe_value(*v);
|
||||
let arena = self.type_arena.borrow();
|
||||
let ty = arena.get(index.0).unwrap();
|
||||
if let TypeEnum::TVar { id } = ty {
|
||||
mapping.contains_key(id)
|
||||
} else {
|
||||
false
|
||||
}
|
||||
});
|
||||
if need_subst {
|
||||
new_params = self
|
||||
.subst_map(¶ms, mapping)
|
||||
.or_else(|| Some(params.clone()));
|
||||
new_fields = self
|
||||
.subst_map(&fields, mapping)
|
||||
.or_else(|| Some(fields.clone()));
|
||||
}
|
||||
if let Some(TypeEnum::TObj {
|
||||
params: p,
|
||||
fields: f,
|
||||
..
|
||||
}) = self.type_arena.borrow().get(index.0)
|
||||
{
|
||||
*p.borrow_mut() = params;
|
||||
*f.borrow_mut() = fields;
|
||||
} else {
|
||||
unreachable!();
|
||||
};
|
||||
if need_subst {
|
||||
let index = self.type_arena.borrow_mut().insert(TypeEnum::TObj {
|
||||
obj_id,
|
||||
params: new_params.unwrap().into(),
|
||||
fields: new_fields.unwrap().into(),
|
||||
});
|
||||
Some(
|
||||
self.unification_table
|
||||
.borrow_mut()
|
||||
.new_key(TypeIndex(index)),
|
||||
)
|
||||
} else {
|
||||
None
|
||||
}
|
||||
}
|
||||
_ => unimplemented!(),
|
||||
}
|
||||
}
|
||||
|
||||
fn subst_map<K>(&self, map: &Mapping<K>, mapping: &VarMap) -> Option<Mapping<K>>
|
||||
where
|
||||
K: std::cmp::Ord + std::clone::Clone,
|
||||
{
|
||||
let mut map2 = None;
|
||||
for (k, v) in map.iter() {
|
||||
if let Some(v1) = self.subst(*v, mapping) {
|
||||
if map2.is_none() {
|
||||
map2 = Some(map.clone());
|
||||
}
|
||||
*map2.as_mut().unwrap().get_mut(k).unwrap() = v1;
|
||||
}
|
||||
}
|
||||
map2
|
||||
}
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in New Issue