You don't ever actually change anything in AS2 though; you can't. My example is just showing you are telling the compiler that you are changing it's type; I know full well it's type never changes. You can use Number, int, String, parseInt, and parseFloat; but only 2 of those can be used as datatyping, but no coercion.
----- Original Message ----- From: "Ian Thomas" <[EMAIL PROTECTED]> To: "Flashcoders mailing list" <[email protected]> Sent: Monday, October 31, 2005 10:42 AM Subject: Re: [Flashcoders] Strict Datatyping Question Nope. my_win, the variable, is still declared (to the compiler) as a MovieClip. It only knows about it as type MovieClip. The object it 'points to' happens to be of type MyCustomForm, which is an object that inherits from MovieClip. It does all the things that MovieClip does, just does more stuff too. >From a compiler perspective, you can get away with calling methods of MyCustomForm on your my_win _only because_ MovieClip is a dynamic class, and so the compiler throws away all type-checking for my_win. It does mean that anything you call on my_win will not be properly type checked. If you had used a non-dyamic class in your example, the problem would have become a lot more obvious. For example: class A { public function doSomething() {trace("Do Something");} } class B extends A { public function doSomethingElse() {trace("Do Something Else");} } var my_a:A; my_a=B(createBSomeHow()); // The compiler will choke on this line my_a.doSomething(); // Compiler will be fine with this my_a.doSomethingElse(); // Compiler would choke on this or if it was: var my_a:A; my_a = A(createBSomeHow()); // Perfectly legal 'cos B inherits from A my_a.doSomething(); // No problems my_a.doSomethingElse(); // Compiler chokes, because it only knows that 'a' is an A. So in short - you can do exactly what you wrote down, but: - Only because MovieClip is a dynamic class - You're skipping compiler type-checking because MovieClip is a dynamic class (so any type-signatures of methods of MyCustomForm you call will be unchecked - which might be an issue if you, for example, went back and redefined them later) - You aren't actually changing the type of my_win. It's still a MovieClip, as far as the compiler can see. Cheers, Ian On 10/31/05, JesterXL <[EMAIL PROTECTED]> wrote: > > >>>You can't change the type of a variable during an assignment > > Yes you can. > > var my_win:MovieClip; > > my_win = MyCustomForm(PopUpManager.createPopUp(this, MyCustomForm, > false)); > _______________________________________________ Flashcoders mailing list [email protected] http://chattyfig.figleaf.com/mailman/listinfo/flashcoders _______________________________________________ Flashcoders mailing list [email protected] http://chattyfig.figleaf.com/mailman/listinfo/flashcoders
