Comments on: Super Is (Really) Optional!

By: ThatSnail

ThatSnail — Mon, 19 Dec 2011 21:28:29 +0000

Makes me question the stability of AS3 a little more. Granted, I think it’s bad practice to not inherit the parent’s structure, so I’m not very convinced of the use for this. Still a neat find.

By: jackson

jackson — Wed, 16 Sep 2009 20:42:02 +0000

No problem at all, thank you for the comment. I wrapped your code in the formatting blocks:

…

By: jackson

jackson — Wed, 16 Sep 2009 20:39:58 +0000

Yep, I mentioned this in the last paragraph of the article:

Since constructors are a good place to put initialization code, beware that you’re skipping all of what is assumed to have been necessary to instantiate the class. This may be dangerous, so use it only when you’re really sure that the constructor is not relied on.

It’s definitely a technique for rare circumstances. Actually, I can’t think of much of any reason to ever use it. I really only wrote the article because I accidentally did it while doing some AS3 coding. Your example shows exactly why you want to make sure that your super() call actually gets made. Thanks for the comment!

By: Michael Boucher

Michael Boucher — Wed, 16 Sep 2009 20:39:44 +0000

This is an interesting find though and it appears that functions within Parent still work without the super call.

Nice post and sorry for the ugly code paste above.

By: Michael Boucher

Michael Boucher — Wed, 16 Sep 2009 20:35:35 +0000

Unfortunately there is an added side effect to this. Since super is not called the Parent is not instantiated and thus any inherited properties are not set. Take this for instance.

package
{
    public class Parent
    {
 
        public var message:String = "Super Message";
 
        public function Parent()
        {
            trace("I am the super class");
        }
 
    }
}
 
 
package
{
    public class Child extends Parent
    {
 
        protected var doSuper:Boolean = false;
 
        public function Child()
        {
            if ( this.doSuper )
            {
                super();
            }
 
            trace("I am sub: "+this.message);
        }
 
    }
}

trace:
I am sub: null
From Main: null