Refactor fn arg checking

src/types.h

@@ -62,6 +62,7 @@ typedef struct GroundError {
  */
 typedef struct GroundValue {
     GroundValueType type;
+    struct GroundStruct* customType;
     union {
         int64_t intVal;
         double doubleVal;
@@ -125,6 +126,7 @@ typedef struct GroundProgram {
  */
 typedef struct GroundFunctionArgs {
     GroundValueType type;
+    struct GroundStruct* customType;
     char* name;
 } GroundFunctionArgs;
 
@@ -276,6 +278,11 @@ void freeGroundObject(GroundObject* object);
 // Creates a GroundError.
 GroundError createGroundError(char* what, char* type, GroundInstruction* where, size_t* line);
 
+// Compares types of a value and function args. 
+bool checkFnTypes(GroundValue* left, GroundFunctionArgs* arg);
+
+// Compares types of two values.
+bool checkTypes(GroundValue* left, GroundValue* right);
 
 
 #endif