I think it work like this
sortChildren( sortOnWidth );
private function sortChildren( compareFunc:Function ) : void
{
var obj1:Object = { name:"obj1" };
var obj2:Object = { name:"obj2" };
compareFunc( obj1, obj2 );
}
private function sortOnWidth( obj1:Object, obj2:Object ) : void
{
trace( obj1.name, obj2.name );
}