Even more type work

schala-lang/language/src/typechecking.rs

@@ -24,7 +24,8 @@ impl TypeError {
 enum MonoType {
   Var(Rc<String>),
   Const(TConst),
-  Arrow(Box<MonoType>, Box<MonoType>)
+  Arrow(Box<MonoType>, Box<MonoType>),
+  ExistentialVar(u32)
 }
 
 impl TypeIdentifier {
@@ -87,14 +88,18 @@ impl<'a> TypeContext<'a> {
   fn infer_ast(&mut self, ast: &AST) -> InferResult<MonoType> {
     let mut output = MonoType::Const(TConst::Unit);
     for statement in ast.0.iter() {
-      output = match statement {
-        Statement::ExpressionStatement(ref expr) => self.infer_expr(expr)?,
-        Statement::Declaration(ref decl) => self.infer_decl(decl)?,
-      };
+      output = self.infer_statement(statement)?;
     }
     Ok(output)
   }
 
+  fn infer_statement(&mut self, stmt: &Statement) -> InferResult<MonoType> {
+    match stmt {
+      Statement::ExpressionStatement(ref expr) => self.infer_expr(expr),
+      Statement::Declaration(ref decl) => self.infer_decl(decl),
+    }
+  }
+
   fn infer_expr(&mut self, expr: &Expression) -> InferResult<MonoType> {
     match expr {
       Expression(expr_type, Some(type_anno)) => {
@@ -137,6 +142,14 @@ impl<'a> TypeContext<'a> {
           _ => return TypeError::new("not a function")
         }
       },
+
+      Lambda { params, type_anno, body } => {
+
+        let arg_type = unimplemented!();
+        let result_type = unimplemented!();
+
+        MonoType::Arrow(Box::new(arg_type), Box::new(result_type))
+      }
       _ => MonoType::Const(TConst::user("unimplemented"))
     })
   }
@@ -155,9 +168,21 @@ impl<'a> TypeContext<'a> {
     unimplemented!()
   }
 
+  fn infer_block(&mut self, block: &Block) -> InferResult<MonoType> {
+    let mut output = MonoType::Const(TConst::Unit);
+    for statement in block.iter() {
+      output = self.infer_statement(statement)?;
+    }
+    Ok(output)
+  }
+
   fn unify(&mut self, t1: &MonoType, t2: &MonoType) -> InferResult<MonoType> {
     unimplemented!()
   }
+
+  fn allocate_existential(&mut self) -> MonoType {
+    MonoType::ExistentialVar(0)
+  }
 }
 
 #[cfg(test)]