[haXe] casting attached MovieClips

[Nicolas Cannasse]

> I know the previous example doesn't compile (the attachMovie() call is
> ok, but the cast fails), but is there any better way of doing this
> rather than casting everything manually (without sacrifing type
> safety)? I guess I'm looking for a mechanism similar to C++ function
> templates, where one could write (hypothetically)
> 
> public static void doAttach<T>(mc:MovieClip):T {
>   return cast(mc.attachMovie(T + "", "foo", mc.getNextHighestDepth(), null), T);
> }
> 
> public static main() {
>   var clip:MyClip = doAttach<MyClip>(mc);
> }

That's not so easy. In particular, the type T can't be used as an
expression in method body right now. However, the following should work:

public static function doAttach<T>(mc:MovieClip,cl : Dynamic) : T {
    var depth = mc.getNextHighestDepth();
    var sub = mc.attachMovie(cl.__name__.join("."),"foo"+depth,depth);
    if( !Std.is(sub,cl) )
        throw "doAttach failed";
    return untyped sub;
}

Then :

doAttach<MyClip>(root,MyClip)

Nicolas