Renamed all the type-related types

src/schala_lang/type_check.rs

@@ -20,32 +20,37 @@ use schala_lang::parsing::{AST, Statement, Declaration, Signature, Expression, E
 // typeInfer :: Expr a -> Matching (Type a)
 // unify :: Type a -> Type b -> Matching (Type c)
 
+#[derive(Debug, PartialEq, Clone)]
+pub enum Type {
+  TVar(TypeVar),
+  TConst(TypeConst),
+}
 
 #[derive(Debug, PartialEq, Clone)]
-pub enum TypeVariable {
-  Univ(UVar),
+pub enum TypeVar {
+  Univ(String),
   Exist(u64),
 }
 
 #[derive(Debug, PartialEq, Clone)]
-pub enum UVar {
+pub enum TypeConst {
   Integer,
   Float,
-  String,
+  StringT,
   Boolean,
   Unit,
-  Function(Box<TypeVariable>, Box<TypeVariable>),
+  FunctionT(Box<Type>, Box<Type>),
   Bottom,
 }
 
-type TypeCheckResult = Result<TypeVariable, String>;
+type TypeCheckResult = Result<Type, String>;
 
 #[derive(Debug, PartialEq, Eq, Hash)]
 struct PathSpecifier(Rc<String>);
 
 #[derive(Debug, PartialEq, Clone)]
 struct TypeContextEntry {
-  type_var: TypeVariable,
+  type_var: Type,
   constant: bool
 }
 
@@ -99,46 +104,51 @@ impl TypeContext {
   pub fn debug_symbol_table(&self) -> String  {
     format!("Symbol table:\n {:?}", self.symbol_table)
   }
-  fn get_existential_type(&mut self) -> TypeVariable {
-    let ret = TypeVariable::Exist(self.existential_type_label_count);
+  fn get_existential_type(&mut self) -> Type {
+    let ret = Type::TVar(TypeVar::Exist(self.existential_type_label_count));
     self.existential_type_label_count += 1;
     ret
   }
 
-  fn from_anno(&mut self, anno: &TypeName) -> TypeVariable {
-    use self::TypeVariable::*;
-    use self::UVar::*;
+  fn from_anno(&mut self, anno: &TypeName) -> Type {
+    use self::Type::*;
+    use self::TypeConst::*;
 
     match anno {
       &TypeName::Singleton { ref name, .. } => {
         match name.as_ref().as_ref() {
-          "Int" => Univ(Integer),
-          "Bool" => Univ(Boolean),
+          "Int" => TConst(Integer),
+          "Bool" => TConst(Boolean),
           _ => self.get_existential_type()
         }
       },
-      _ => Univ(Bottom),
+      _ => TConst(Bottom)
     }
   }
 
-  fn from_signature(&mut self, sig: &Signature) -> TypeVariable {
-    use self::TypeVariable::Univ;
-    use self::UVar::{Unit, Function};
+  fn from_signature(&mut self, sig: &Signature) -> Type {
+    use self::Type::*;
+    use self::TypeConst::*;
+
     let return_type = sig.type_anno.as_ref().map(|anno| self.from_anno(&anno)).unwrap_or_else(|| { self.get_existential_type() });
     if sig.params.len() == 0 {
-      Univ(Function(Box::new(Univ(Unit)), Box::new(return_type)))
+      TConst(FunctionT(Box::new(TConst(Unit)), Box::new(return_type)))
     } else {
       let mut output_type = return_type;
       for p in sig.params.iter() {
         let p_type = p.1.as_ref().map(|anno| self.from_anno(anno)).unwrap_or_else(|| { self.get_existential_type() });
-        output_type = Univ(Function(Box::new(p_type), Box::new(output_type)));
+        output_type = TConst(FunctionT(Box::new(p_type), Box::new(output_type)));
       }
       output_type
     }
   }
 
   pub fn type_check(&mut self, ast: &AST) -> TypeCheckResult {
-    let mut last = TypeVariable::Univ(UVar::Unit);
+    use self::Type::*;
+    use self::TypeConst::*;
+
+    let mut last = TConst(Unit);
+
     for statement in ast.0.iter() {
       match statement {
         &Statement::Declaration(ref _decl) => {
@@ -154,17 +164,18 @@ impl TypeContext {
 
   fn infer(&mut self, expr: &Expression) -> TypeCheckResult {
     use self::ExpressionType::*;
-    use self::TypeVariable::*;
+    use self::Type::*;
+    use self::TypeConst::*;
 
     Ok(match (&expr.0, &expr.1) {
       (ref _t, &Some(ref anno)) => {
         //TODO make this better,
         self.from_anno(anno)
       },
-      (&IntLiteral(_), _) => Univ(UVar::Integer),
-      (&FloatLiteral(_), _) => Univ(UVar::Float),
-      (&StringLiteral(_), _) => Univ(UVar::String),
-      (&BoolLiteral(_), _) => Univ(UVar::Boolean),
+      (&IntLiteral(_), _) => TConst(Integer),
+      (&FloatLiteral(_), _) => TConst(Float),
+      (&StringLiteral(_), _) => TConst(StringT),
+      (&BoolLiteral(_), _) => TConst(Boolean),
       (&Variable(ref name), _) => self.lookup(name).map(|entry| entry.type_var)
         .ok_or(format!("Couldn't find {}", name))?,
       (&BinExp(ref op, box ref lhs, box ref rhs), _) => {
@@ -177,31 +188,33 @@ impl TypeContext {
         let f_type = self.infer(&*f)?;
         let arg_type = self.infer(arguments.get(0).unwrap())?; // TODO fix later
         match f_type {
-          Univ(UVar::Function(box t1, box ret_type)) => {
+          TConst(FunctionT(box t1, box ret_type)) => {
             let _ = self.unify(&t1, &arg_type)?;
             ret_type
           },
           _ => return Err(format!("Type error"))
         }
       },
-      _ => Univ(UVar::Unit),
+      _ => TConst(Unit)
     })
   }
 
   fn infer_op(&mut self, _op: &Operation) -> TypeCheckResult {
-    use self::TypeVariable::*;
+    use self::Type::*;
+    use self::TypeConst::*;
+
     Ok(
-      Univ(UVar::Function(
-        Box::new(Univ(UVar::Integer)),
-        Box::new(Univ(UVar::Function(
-          Box::new(Univ(UVar::Integer)),
-          Box::new(Univ(UVar::Integer))
+      TConst(FunctionT(
+        Box::new(TConst(Integer)),
+        Box::new(TConst(FunctionT(
+          Box::new(TConst(Integer)),
+          Box::new(TConst(Integer))
           )))
         ))
       )
   }
 
-  fn unify(&mut self, t1: &TypeVariable, t2: &TypeVariable) -> TypeCheckResult {
+  fn unify(&mut self, t1: &Type, t2: &Type) -> TypeCheckResult {
     if t1 == t2 {
       Ok(t1.clone())
     } else {
@@ -212,8 +225,9 @@ impl TypeContext {
 
 #[cfg(test)]
 mod tests {
-  use super::{TypeContext, TypeVariable, UVar};
-  use super::TypeVariable::*;
+  use super::{Type, TypeVar, TypeConst, TypeContext};
+  use super::Type::*;
+  use super::TypeConst::*;
   use schala_lang::parsing::{parse, tokenize};
 
   macro_rules! type_test {
@@ -228,7 +242,7 @@ mod tests {
 
   #[test]
   fn basic_inference() {
-    type_test!("30", Univ(UVar::Integer))
+    type_test!("30", TConst(Integer));
   }
 }