Inheritance chain hacking in AS2

applyClassToInstance.as

/**
 * Makes an object inherit from a class.
 * Modifies the inheritance chain and calls the class constructor.
 * Commonly used to make a movie clip such as the root timeline
 * inherit from a custom class, e.g.
 * // on main timeline
 * applyClassToInstance(MyDocumentClass, this);
 * Works for AVM1 only, i.e. AS1 and AS2.
 * @param	theClass
 * @param	theInstance
 * @param	constructorArgs An optional Array of parameters for the class constructor.
 */
function applyClassToInstance(theClass:Function, theInstance:Object, constructorArgs:Array):Void 
{
	theInstance.__proto__ = theClass.prototype;  
	theInstance.__constructor__ = theClass;
	// run the constructor
	theClass.apply(theInstance, constructorArgs);
}