Can we alias something non existent in the subclass?

[Milena]

I noticed that some subclasses do not have functions that were inherited from the parent class.

Scene_Menu for example, does not have an update, but Scene_MenuBase does. Can I create something like:

var alias_scene_menu_update = Scene_Menu.prototype.update;Scene_Menu.prototype.update = function() { alias_scene_menu_update.call(this);}even if Scene_Menu.prototype.update never existent since its a subclass of Scene_MenuBase?

 

[Hudell]

Instead of aliasing it, you create the method and call the parent:

Scene_Menu.prototype.update = function() {  Scene_MenuBase.prototype.update.call(this);}

 

[Milena]

Thanks! Is this similar to super in RMVXAce?

 

[Hudell]

Not exactly. In JS, we are creating a new method and then calling the old one.

In ruby, the two methods are technically the same.

 

[DarknessFalls]

make sure the parent of the class your sub classing doesn't have said method. because if you do:

parent (has method) -> child (doesn't have method) -> grand child (create method) you are over riding the parent method.

 

[Milena]

Not exactly. In JS, we are creating a new method and then calling the old one.

In ruby, the two methods are technically the same.

I see, I thought it was the same, thanks for the info.

make sure the parent of the class your sub classing doesn't have said method. because if you do:

parent (has method) -> child (doesn't have method) -> grand child (create method) you are over riding the parent method.

Thanks. I think I need to read more of this before continuing what I was coding, its a big help.

 

[Tsukihime]

I noticed that some subclasses do not have functions that were inherited from the parent class.

Scene_Menu for example, does not have an update, but Scene_MenuBase does. Can I create something like:

var alias_scene_menu_update = Scene_Menu.prototype.update;Scene_Menu.prototype.update = function() { alias_scene_menu_update.call(this);}even if Scene_Menu.prototype.update never existent since its a subclass of Scene_MenuBase?

This should work.

Scene_Menu.prototype.update would check its own definitions, and if it can't find it, it'll go up to its parent.

You can verify this in the console:

> Scene_Menu.prototype.updatefunction () { this.updateFade(); this.updateChildren(); AudioManager.checkErrors();}> Scene_MenuBase.prototype.updatefunction () { this.updateFade(); this.updateChildren(); AudioManager.checkErrors();}

make sure the parent of the class your sub classing doesn't have said method. because if you do:

parent (has method) -> child (doesn't have method) -> grand child (create method) you are over riding the parent method.

Wouldn't child also have the method by inheritance?

 

[DarknessFalls]

Wouldn't child also have the method by inheritance?

yes. How ever most people when they alias a method or look for a method on a class, they might not see that "hey this class extends another class." Its rare, but it does happen.