[WIP] attr_mode="rw" for writtable attributes

Still does not set the value, just eats it.

Author: alanjds

runtime/descriptor.go

@@ -98,11 +98,13 @@ func propertySet(f *Frame, desc, inst, value *Object) *BaseException {
 
 // makeStructFieldDescriptor creates a descriptor with a getter that returns
 // the field given by fieldName from t's basis structure.
-func makeStructFieldDescriptor(t *Type, fieldName, propertyName string) *Object {
+func makeStructFieldDescriptor(t *Type, fieldName, propertyName string, writtable bool) *Object {
 	field, ok := t.basis.FieldByName(fieldName)
 	if !ok {
 		logFatal(fmt.Sprintf("no such field %q for basis %s", fieldName, nativeTypeName(t.basis)))
 	}
+	nativeFieldType := getNativeType(field.Type)
+
 	getterFunc := func(f *Frame, args Args, _ KWArgs) (*Object, *BaseException) {
 		var ret *Object
 		var raised *BaseException
@@ -117,5 +119,26 @@ func makeStructFieldDescriptor(t *Type, fieldName, propertyName string) *Object
 		}
 		return ret, raised
 	}
+	if writtable {
+		setterFunc := func(f *Frame, args Args, _ KWArgs) (*Object, *BaseException) {
+			var ret *Object
+			var raised *BaseException
+			if raised = checkFunctionArgs(f, fieldName, args, ObjectType, ObjectType); raised == nil {
+				//self := args[0]
+				newvalue := args[1]
+				if !newvalue.isInstance(nativeFieldType) {
+					format := "descriptor '%s' for '%s' objects doesn't apply to '%s' objects"
+					raised = f.RaiseType(TypeErrorType, fmt.Sprintf(format, propertyName, t.Name(), newvalue.typ.Name()))
+				} else {
+					ret, raised = SetNative(f, &field, newvalue)
+				}
+			}
+			return ret, raised
+		}
+		return newProperty(
+			newBuiltinFunction("_get"+fieldName, getterFunc).ToObject(),
+			newBuiltinFunction("_set"+fieldName, setterFunc).ToObject(),
+			None).ToObject()
+	}
 	return newProperty(newBuiltinFunction("_get"+fieldName, getterFunc).ToObject(), None, None).ToObject()
 }

runtime/descriptor_test.go

@@ -90,7 +90,7 @@ func TestMakeStructFieldDescriptor(t *testing.T) {
 			return nil, raised
 		}
 		t := toTypeUnsafe(args[0])
-		desc := makeStructFieldDescriptor(t, toStrUnsafe(args[1]).Value(), toStrUnsafe(args[2]).Value())
+		desc := makeStructFieldDescriptor(t, toStrUnsafe(args[1]).Value(), toStrUnsafe(args[2]).Value(), false)
 		get, raised := GetAttr(f, desc, NewStr("__get__"), nil)
 		if raised != nil {
 			return nil, raised

runtime/native.go

@@ -268,6 +268,14 @@ func initSliceIteratorType(map[string]*Object) {
 	sliceIteratorType.slots.Next = &unaryOpSlot{sliceIteratorNext}
 }
 
+func SetNative(f *Frame, v *reflect.StructField, newvalue *Object) (*Object, *BaseException) {
+	//fmt.Printf("Field: -> %+v <- \n", v)	// DEBUG
+	//fmt.Printf("New Value: -> %+v <- \n", newvalue)	// DEBUG
+	//TODO: DO SET THE VALUE
+	//v.SetInt(WrapNative(f, newvalue))
+	return None, nil
+}
+
 // WrapNative takes a reflect.Value object and converts the underlying Go
 // object to a Python object in the following way:
 //

runtime/type.go

@@ -153,7 +153,11 @@ func prepareBuiltinType(typ *Type, init builtinTypeInit) {
 		for i := 0; i < numFields; i++ {
 			field := basis.Field(i)
 			if attr := field.Tag.Get("attr"); attr != "" {
-				dict[attr] = makeStructFieldDescriptor(typ, field.Name, attr)
+				writtable := false
+				if mode := field.Tag.Get("attr_mode"); mode == "rw" {
+					writtable = true
+				}
+				dict[attr] = makeStructFieldDescriptor(typ, field.Name, attr, writtable)
 			}
 		}
 	}