I have spent some time about a year ago with the ECMAscript definition. It seemed to address some of these questions but I could not satisfy myself that I really understood. Also it is out of date. Also it seldom said what was impossible which is the essence of security design.

I believe that there is no separation of compile and runtime for ActionScript. How is “this” interpreted? Here is the best description I remember from the ECMA doc:

To evaluate “xxx.ddd(a, b, c)” where xxx is an expression and ddd is an identifier (string):

This is incomplete in several ways: As the body of a function begins that has been invoked by some pattern other than “xxx.ddd(a, b, c)” how is “this” bound? How is the following code executed?
var f = xxx.ddd;
f(a, b, c);
Does the X value get passed along to the body of f?

If you know a document that is clear on these issues and you think it is economical for me to read it, I will be pleased to do so. I have other vague questions as well.