add method overloading

Test/JavaSources/TestMethodOverload.java

@@ -0,0 +1,14 @@
+public class TestMethodOverload {
+
+    public void MethodOverload() {
+    }
+
+    public void MethodOverload(int a) {
+    }
+
+    public void test() {
+        int a = 3;
+        MethodOverload(a);
+    }
+    
+}

src/Typecheck.hs

@@ -178,31 +178,35 @@ typeCheckStatementExpression (MethodCall expr methodName args) symtab classes =
     let objExprTyped = typeCheckExpression expr symtab classes
     in case objExprTyped of
         TypedExpression objType _ ->
-            case find (\(Class className _ _) -> className == objType) classes of
-                Just (Class _ methods _) ->
-                    case find (\(MethodDeclaration retType name params _) -> name == methodName) methods of
-                        Just (MethodDeclaration retType _ params _) ->
-                            let args' = zipWith
-                                    (\arg (ParameterDeclaration paramType _) ->
+            case find (\(Class className _ _ _) -> className == objType) classes of
+                Just (Class _ _ methods _) ->
+                    let matchParams (ParameterDeclaration paramType _) arg =
                                         let argTyped = typeCheckExpression arg symtab classes
-                                        in if getTypeFromExpr argTyped == "null" && isObjectType paramType
-                                            then TypedExpression paramType NullLiteral
-                                            else argTyped
-                                    ) args params
-                                expectedTypes = [dataType | ParameterDeclaration dataType _ <- params]
-                                argTypes = map getTypeFromExpr args'
-                                typeMatches = zipWith
-                                    (\expType argType -> (expType == argType || (argType == "null" && isObjectType expType), expType, argType))
-                                    expectedTypes argTypes
-                                mismatches = filter (not . fst3) typeMatches
-                                fst3 (a, _, _) = a
-                            in if null mismatches && length args == length params
-                                then TypedStatementExpression retType (MethodCall objExprTyped methodName args')
-                                else if not (null mismatches)
-                                    then error $ unlines $ ("Argument type mismatches for method '" ++ methodName ++ "':")
-                                        : [ "Expected: " ++ expType ++ ", Found: " ++ argType | (_, expType, argType) <- mismatches ]
-                                    else error $ "Incorrect number of arguments for method '" ++ methodName ++ "'. Expected " ++ show (length expectedTypes) ++ ", found " ++ show (length args) ++ "."
-                        Nothing -> error $ "Method '" ++ methodName ++ "' not found in class '" ++ objType ++ "'."
+                                argType = getTypeFromExpr argTyped
+                            in if argType == "null" && isObjectType paramType
+                               then Just (TypedExpression paramType NullLiteral)
+                               else if argType == paramType
+                               then Just argTyped
+                               else Nothing
+
+                        matchMethod (MethodDeclaration retType name params _) =
+                            let matchedArgs = sequence $ zipWith matchParams params args
+                            in fmap (\checkedArgs -> (MethodDeclaration retType name params (Block []), checkedArgs)) matchedArgs
+
+                        validMethods = filter (\(MethodDeclaration _ name params _, _) -> name == methodName && length params == length args) $ mapMaybe matchMethod methods
+
+                        expectedSignatures = [ map (\(ParameterDeclaration t _) -> t) params | MethodDeclaration _ name params _ <- methods, name == methodName ]
+                        actualSignature = map (\arg -> getTypeFromExpr (typeCheckExpression arg symtab classes)) args
+                        mismatchDetails = "Method not found for class '" ++ objType ++ "' with given arguments.\n" ++
+                                          "Expected signatures for method '" ++ methodName ++ "':\n" ++ unlines (map show expectedSignatures) ++
+                                          "Actual arguments:\n" ++ show actualSignature
+
+                    in case validMethods of
+                        [(MethodDeclaration retType _ params _, checkedArgs)] ->
+                            TypedStatementExpression retType (MethodCall objExprTyped methodName checkedArgs)
+                        [] -> error mismatchDetails
+                        _  -> error $ "Multiple matching methods found for class '" ++ objType ++ "' and method '" ++ methodName ++ "' with given arguments."
+
                 Nothing -> error $ "Class for object type '" ++ objType ++ "' not found."
         _ -> error "Invalid object type for method call. Object must have a class type."