implemented inference

rc nightmare...

nac3type/src/inference.rs

@@ -4,7 +4,7 @@ use std::rc::Rc;
 
 fn find_subst(
     ctx: &GlobalContext,
-    assumptions: & HashMap<VariableId, Rc<Type>>,
+    assumptions: &HashMap<VariableId, Rc<Type>>,
     sub: &mut HashMap<VariableId, Rc<Type>>,
     mut a: Rc<Type>,
     mut b: Rc<Type>,
@@ -46,7 +46,7 @@ fn find_subst(
         }
         (TypeVariable(id_a), _) => {
             let v_a = ctx.get_variable(*id_a);
-            if v_a.bound.len() == 1 && &v_a.bound[0] == b.as_ref() {
+            if v_a.bound.len() == 1 && v_a.bound[0].as_ref() == b.as_ref() {
                 Ok(())
             } else {
                 Err("different domain".to_string())
@@ -83,7 +83,7 @@ fn find_subst(
                 parents.extend_from_slice(&c.parents);
             }
             Err("not subtype".to_string())
-        },
+        }
         (ParametricType(id_a, param_a), ParametricType(id_b, param_b)) => {
             if id_a != id_b || param_a.len() != param_b.len() {
                 Err("different parametric types".to_string())
@@ -93,7 +93,7 @@ fn find_subst(
                 }
                 Ok(())
             }
-        },
+        }
         (_, _) => {
             if a == b {
                 Ok(())
@@ -104,4 +104,68 @@ fn find_subst(
     }
 }
 
+pub fn resolve_call(
+    ctx: &GlobalContext,
+    obj: Option<Rc<Type>>,
+    func: &str,
+    args: Rc<Type>,
+    assumptions: &mut HashMap<VariableId, Rc<Type>>,
+) -> Result<Option<Rc<Type>>, String> {
+    let obj = obj.as_ref().map(|v| Rc::new(v.subst(assumptions)));
+    let mut subst = obj
+        .as_ref()
+        .map(|v| v.get_subst(ctx))
+        .unwrap_or(HashMap::new());
 
+    let fun = match &obj {
+        Some(obj) => {
+            let base = match obj.as_ref() {
+                TypeVariable(id) => {
+                    let v = ctx.get_variable(*id);
+                    if v.bound.len() == 0 {
+                        return Err("unbounded type var".to_string());
+                    }
+                    let results: Result<Vec<_>, String> = v
+                        .bound
+                        .iter()
+                        .map(|ins| {
+                            assumptions.insert(*id, ins.clone());
+                            resolve_call(ctx, Some(obj.clone()), func, args.clone(), assumptions)
+                        })
+                        .collect();
+                    let results = results?;
+                    if results.iter().all(|v| v == &results[0]) {
+                        return Ok(results[0].clone());
+                    }
+                    let mut results = results.iter().zip(v.bound.iter()).map(|(r, ins)| {
+                        r.as_ref()
+                            .map(|v| v.inv_subst(&[(ins.clone(), obj.clone().into())]))
+                    });
+                    let first = results.next().unwrap();
+                    if results.all(|v| v == first) {
+                        return Ok(first);
+                    } else {
+                        return Err("divergent type after substitution".to_string());
+                    }
+                },
+                PrimitiveType(id) => &ctx.get_primitive(*id),
+                ClassType(id) | VirtualClassType(id) => &ctx.get_class(*id).base,
+                ParametricType(id, _) => &ctx.get_parametric(*id).base,
+                _ => return Err("not supported".to_string()),
+            };
+            base.methods.get(func)
+        },
+        None => ctx.get_fn(func),
+    }
+    .ok_or("no such function".to_string())?;
+
+    find_subst(ctx, assumptions, &mut subst, args, fun.args.clone())?;
+    let result = fun.result.as_ref().map(|v| v.subst(&subst));
+    Ok(result.map(|result| {
+        if let SelfType = result {
+            obj.unwrap()
+        } else {
+            result.into()
+        }
+    }))
+}

nac3type/src/types.rs

@@ -1,19 +1,19 @@
 use std::collections::HashMap;
 use std::rc::Rc;
 
-#[derive(PartialEq, Eq, Copy, Clone, Hash)]
+#[derive(PartialEq, Eq, Copy, Clone, Hash, Debug)]
 pub struct PrimitiveId(usize);
 
-#[derive(PartialEq, Eq, Copy, Clone, Hash)]
+#[derive(PartialEq, Eq, Copy, Clone, Hash, Debug)]
 pub struct ClassId(usize);
 
-#[derive(PartialEq, Eq, Copy, Clone, Hash)]
+#[derive(PartialEq, Eq, Copy, Clone, Hash, Debug)]
 pub struct ParamId(usize);
 
-#[derive(PartialEq, Eq, Copy, Clone, Hash)]
+#[derive(PartialEq, Eq, Copy, Clone, Hash, Debug)]
 pub struct VariableId(usize);
 
-#[derive(PartialEq, Eq, Clone, Hash)]
+#[derive(PartialEq, Eq, Clone, Hash, Debug)]
 pub enum Type {
     BotType,
     SelfType,
@@ -25,8 +25,8 @@ pub enum Type {
 }
 
 pub struct FnDef {
-    pub args: Vec<Type>,
+    pub args: Rc<Type>,
-    pub result: Option<Type>,
+    pub result: Option<Rc<Type>>,
 }
 
 pub struct TypeDef<'a> {
@@ -47,15 +47,22 @@ pub struct ParametricDef<'a> {
 
 pub struct VarDef<'a> {
     pub name: &'a str,
-    pub bound: Vec<Type>,
+    pub bound: Vec<Rc<Type>>,
 }
 
+pub const TUPLE_TYPE: ParamId = ParamId(0);
+pub const LIST_TYPE: ParamId = ParamId(1);
+
+pub const BOOL_TYPE: PrimitiveId = PrimitiveId(0);
+pub const INT32_TYPE: PrimitiveId = PrimitiveId(1);
+
 pub struct GlobalContext<'a> {
     primitive_defs: Vec<TypeDef<'a>>,
     class_defs: Vec<ClassDef<'a>>,
     parametric_defs: Vec<ParametricDef<'a>>,
     var_defs: Vec<VarDef<'a>>,
     sym_table: HashMap<&'a str, Type>,
+    fn_table: HashMap<&'a str, FnDef>,
 }
 
 impl<'a> GlobalContext<'a> {
@@ -69,6 +76,7 @@ impl<'a> GlobalContext<'a> {
             class_defs: Vec::new(),
             parametric_defs: Vec::new(),
             var_defs: Vec::new(),
+            fn_table: HashMap::new(),
             sym_table,
         };
     }
@@ -80,11 +88,12 @@ impl<'a> GlobalContext<'a> {
         );
         self.class_defs.push(def);
     }
+
     pub fn add_parametric(&mut self, def: ParametricDef<'a>) {
         let params = def
             .params
             .iter()
-            .map(|&v| Type::TypeVariable(v).into())
+            .map(|&v| Rc::new(Type::TypeVariable(v)))
             .collect();
         self.sym_table.insert(
             def.base.name,
@@ -105,6 +114,14 @@ impl<'a> GlobalContext<'a> {
         self.var_defs.push(def);
     }
 
+    pub fn add_fn(&'a mut self, name: &'a str, def: FnDef) {
+        self.fn_table.insert(name, def);
+    }
+
+    pub fn get_fn(&self, name: &str) -> Option<&FnDef> {
+        self.fn_table.get(name)
+    }
+
     pub fn get_primitive_mut(&mut self, id: PrimitiveId) -> &mut TypeDef<'a> {
         self.primitive_defs.get_mut(id.0).unwrap()
     }
@@ -144,9 +161,9 @@ impl<'a> GlobalContext<'a> {
 }
 
 impl Type {
-    pub fn subst(&self, map: &HashMap<VariableId, Type>) -> Type {
+    pub fn subst(&self, map: &HashMap<VariableId, Rc<Type>>) -> Type {
         match self {
-            Type::TypeVariable(id) => map.get(id).unwrap_or(self).clone(),
+            Type::TypeVariable(id) => map.get(id).map(|v| v.as_ref()).unwrap_or(self).clone(),
             Type::ParametricType(id, params) => Type::ParametricType(
                 *id,
                 params
@@ -158,9 +175,9 @@ impl Type {
         }
     }
 
-    pub fn inv_subst(&self, map: &Vec<(Type, Type)>) -> Type {
+    pub fn inv_subst(&self, map: &[(Rc<Type>, Rc<Type>)]) -> Rc<Type> {
         for (from, to) in map.iter() {
-            if self == from {
+            if self == from.as_ref() {
                 return to.clone();
             }
         }
@@ -173,16 +190,16 @@ impl Type {
                     .collect(),
             ),
             _ => self.clone(),
-        }
+        }.into()
     }
 
-    pub fn get_subst(&self, ctx: &GlobalContext) -> HashMap<VariableId, Type> {
+    pub fn get_subst(&self, ctx: &GlobalContext) -> HashMap<VariableId, Rc<Type>> {
         match self {
             Type::ParametricType(id, params) => {
                 let vars = &ctx.get_parametric(*id).params;
                 vars.iter()
                     .zip(params)
-                    .map(|(v, p)| (*v, p.as_ref().clone()))
+                    .map(|(v, p)| (*v, p.as_ref().clone().into()))
                     .collect()
             }
             // if this proves to be slow, we can use option type