So in the child swf’s document class

class childSWF extends MovieClip {

public var parentInstance:*;
// other variables…

}

In the main (parent class), when you load the child, after you trigger your ‘complete’ handler, you can then set the instance of the child.

Parent Class, after loading child…

this.loadedSwf.parentInstance = this;

You have now passed an instance of the parent class to the child .swf, including its document class. This means your methods in the child can now access properties and methods of the main swf. This is because the ‘parentInstance’ variable in the child .swf’s document class was untyped and can be set to any type of object, and the compiler won’t complain.

Untyped variables are cool.