feat: implement method referencing and calling methods using boudMethods

Author: aymaneelmaini

src/memory.c

@@ -92,6 +92,11 @@ static void blacken_object(Obj* object)
 #endif  // DEbUG_LOG_GC
     switch (object->type)
     {
+    case OBJ_BOUND_METHOD:
+        ObjBoundMethod* bound = (ObjBoundMethod*)object;
+        mark_value(bound->receiver);
+        mark_object((Obj*)bound->method);
+        break;
     case OBJ_CLASS:
         ObjClass* klass = (ObjClass*)object;
         mark_object((Obj*)klass->name);
@@ -133,6 +138,9 @@ static void free_object(Obj* object)
 
     switch (object->type)
     {
+    case OBJ_BOUND_METHOD:
+        FREE(ObjBoundMethod, object);
+        break;
     case OBJ_CLASS:
         ObjClass* klass = (ObjClass*)object;
         free_table(&klass->methods);

src/object.c

@@ -29,6 +29,14 @@ static Obj* allocate_object(size_t size, ObjType type)
     return object;
 }
 
+ObjBoundMethod* new_bound_method(Value receiver, ObjClosure* method)
+{
+    ObjBoundMethod* bound = ALLOCATE_OBJ(ObjBoundMethod, OBJ_BOUND_METHOD);
+    bound->receiver = receiver;
+    bound->method = method;
+    return bound;
+}
+
 ObjClass* new_class(ObjString* name)
 {
     ObjClass* klass = ALLOCATE_OBJ(ObjClass, OBJ_CLASS);
@@ -157,6 +165,9 @@ void print_object(Value value)
 
     switch (OBJ_TYPE(value))
     {
+    case OBJ_BOUND_METHOD:
+        print_function(AS_BOUND_METHOD(value)->method->function);
+        break;
     case OBJ_CLASS:
         printf("%s", AS_CLASS(value)->name->chars);
         break;

src/object.h

@@ -8,6 +8,9 @@
 
 #define OBJ_TYPE(value) (AS_OBJ(value)->type)
 
+#define IS_BOUND_METHOD(value) is_obj_type(value, OBJ_BOUND_METHOD)
+#define AS_BOUND_METHOD(value) ((ObjBoundMethod*)AS_OBJ(value))
+
 #define IS_CLASS(value) is_obj_type(value, OBJ_CLASS)
 #define AS_CLASS(value) ((ObjClass*)AS_OBJ(value))
 
@@ -29,6 +32,7 @@
 
 typedef enum
 {
+    OBJ_BOUND_METHOD,
     OBJ_CLASS,
     OBJ_CLOSURE,
     OBJ_FUNCTION,
@@ -87,29 +91,37 @@ typedef struct
     int          upvalue_count;
 } ObjClosure;
 
-typedef struct ObjClass
+typedef struct
 {
     Obj        obj;
     ObjString* name;
     Table      methods;
 } ObjClass;
 
-typedef struct ObjInstance
+typedef struct
 {
     Obj       obj;
     ObjClass* klass;
     Table     fields;
 } ObjInstance;
 
-ObjClass*    new_class(ObjString* name);
-ObjClosure*  new_closure(ObjFunction* function);
-ObjFunction* new_function();
-ObjInstance* new_instance(ObjClass* klass);
-ObjNative*   new_native(NativeFn function);
-ObjString*   take_string(char* chars, int length);
-ObjString*   copy_string(const char* chars, int length);
-ObjUpvalue*  new_upvalue(Value* slot);
-void         print_object(Value value);
+typedef struct
+{
+    Obj         obj;
+    Value       receiver;
+    ObjClosure* method;
+} ObjBoundMethod;
+
+ObjBoundMethod* new_bound_method(Value receiver, ObjClosure* method);
+ObjClass*       new_class(ObjString* name);
+ObjClosure*     new_closure(ObjFunction* function);
+ObjFunction*    new_function();
+ObjInstance*    new_instance(ObjClass* klass);
+ObjNative*      new_native(NativeFn function);
+ObjString*      take_string(char* chars, int length);
+ObjString*      copy_string(const char* chars, int length);
+ObjUpvalue*     new_upvalue(Value* slot);
+void            print_object(Value value);
 
 static inline bool is_obj_type(Value value, ObjType type)
 {

src/vm.c

@@ -124,6 +124,9 @@ static bool call_value(Value callee, int arg_count)
     {
         switch (OBJ_TYPE(callee))
         {
+        case OBJ_BOUND_METHOD:
+            ObjBoundMethod* bound = AS_BOUND_METHOD(callee);
+            return call(bound->method, arg_count);
         case OBJ_INSTANCE:
             ObjClass* klass = AS_CLASS(callee);
             vm.stack_top[-arg_count - 1] = OBJ_VAL(new_instance(klass));
@@ -148,6 +151,21 @@ static bool call_value(Value callee, int arg_count)
     return false;
 }
 
+static bool bind_method(ObjClass* klass, ObjString* name)
+{
+    Value method;
+    if (!table_get(&klass->methods, name, &method))
+    {
+        runtime_error("Undefined property %s", name->chars);
+        return false;
+    }
+
+    ObjBoundMethod* bound = new_bound_method(peek(0), AS_CLOSURE(method));
+    pop();
+    push(OBJ_VAL(bound));
+    return true;
+}
+
 static void close_upvalues(Value* last)
 {
     while (vm.open_upvalues != NULL && vm.open_upvalues->location >= last)
@@ -343,8 +361,12 @@ static InterpretResult run()
                 push(value);
                 break;
             }
-            runtime_error("Undefined property %s", name->chars);
-            return INTERPRET_RUNTIME_ERROR;
+
+            if (!bind_method(instance->klass, name))
+            {
+                return INTERPRET_RUNTIME_ERROR;
+            }
+            break;
         }
         case OP_SET_PROPERTY:
         {