Convert type-checking function type

src/schala_lang/mod.rs

@@ -5,7 +5,7 @@ mod parsing;
 mod type_check;
 mod eval;
 
-use self::type_check::{TypeContext, TypeCheckResult};
+use self::type_check::{TypeContext};
 
 pub struct Schala {
   state: eval::ReplState,
@@ -63,9 +63,9 @@ impl ProgrammingLanguageInterface for Schala {
     };
 
     match self.type_context.type_check(&ast) {
-      TypeCheckResult::OK => (),
+      Ok(t) => (),
-      TypeCheckResult::Error(s) => {
+      Err(msg) => {
-        output.add_artifact(TraceArtifact::new("type_check", s));
+        output.add_artifact(TraceArtifact::new("type_check", msg));
         output.add_output(format!("Type error"));
         return output;
       }

src/schala_lang/type_check.rs

@@ -22,16 +22,11 @@ impl TypeContext {
   }
 }
 
-pub enum TypeCheckResult {
+pub struct SchalaType {
-  OK,
-  Error(String)
-}
-impl TypeCheckResult {
-  fn new(msg: &str) -> TypeCheckResult {
-    TypeCheckResult::Error(msg.to_string())
-  }
 }
 
+type TypeCheckResult = Result<SchalaType, String>;
+
 // from Niko's talk
 /* fn type_check(expression, expected_ty) -> Ty {
     let ty = bare_type_check(expression, expected_type);
@@ -53,14 +48,14 @@ impl TypeContext {
     for statement in ast.0.iter() {
       match statement {
         &Statement::Declaration(ref _decl) => {
-          return TypeCheckResult::new("Declarations not supported");
+          return Err(format!("Declarations not supported"));
         },
         &Statement::ExpressionStatement(ref expr) => {
           match (&expr.0, &expr.1) {
             (&IntLiteral(_), &Some(ref t)) => {
               match t {
                 &TypeAnno::Singleton { ref name, ref params } if **name == "Int" && params.len() == 0 => (),
-                t => return TypeCheckResult::new(&format!("Bad type {:?} for int literal", t)),
+                t => return Err(format!("Bad type {:?} for int literal", t)),
               }
             },
             _ => (),
@@ -68,6 +63,6 @@ impl TypeContext {
         }
       }
     }
-    TypeCheckResult::OK
+    Ok(SchalaType { })
   }
 }