I need to run code in a class declaration before its instanciation. This would be especially useful to automatically register classes in a factory. See:

// Main.as
public class Main extends Sprite 
{
    public function Main() : void
    {
        var o : Object = Factory.make(42);
    }
}

// Factory.as
public class Factory
{
    private static var _factory : Array = new Array();

    public static function registerClass(id : uint, c : Class) : void
    {
        _factory[id] = function () : Object { return new c(); };   
    }

    public static function make(id : uint) : Object
    {
        return _factory[id]();
    }
}

// Foo.as
public class Foo
{
    // Run this code before instanciating Foo!
    Factory.registerClass(42, Foo);
}

AFAIK, the JIT machine for the ActionScript language won't let me do that since no reference to Foo is made in the Main method. The Foo class being generated, I can't (and don't want to) register the classes in Main: I'd like to register all the exported classes in a specific package (or library). Ideally, this would be done through package introspection, which doesn't exist in ActionScript 3.

Do you know any fix (or other solution) to my design issue?