Why can't I call super method from an in-place event handling function?

Question

I have a overriden function in my class, that adds an event handler like so:

override public function hide():void {
  ...
  tween.addEventListener(TweenEvent.MOTION_FINISH, function(evt:Event):void {
    ...
    super.hide();
  }, false, 0, true);
}

This does not work, Flash tells me: "1006: A super expression can be used only inside class instance methods." (it works if moved to a proper instance method).

So I would like to understand why can't I use call to super.hide(); from my in-place handler function?

I can refer to any instance variables and methods from there without problems, so I thought that that handler had access to proper context. Please help me understand this.

Answer 1

it is, because this in an anonymous function points to [object global] ... have a go, and trace it ...

now an AS3 feature is, that you can access instance members from inside there, but that's a really strange feature ... this.myProp will not work, whereas myProp will ... this is some dark magic, that automatically creates a closure ... for some reason it works with instance members, but not with super ...

IMHO, you should not use anonymous functions anyway, only if it is for prototyping, or as parameters for Array methods as forEach, map, filter and the like ...

Answer 2

I believe you can capture the method in a variable that gets stored in the anonymous method's closure. For instance:

override public function hide():void {
    ...
    var f:Function=super.hide;
    tween.addEventListener(TweenEvent.MOTION_FINISH, function(evt:Event):void {
        ...
        f();
    }, false, 0, true);
}

I can explain further if you are struggling with the concept of closure.