Comments on Jangaroo: Simulating ActionScript in JavaScript: Private Mem...

The follow-up post about untyped private member access is online now!

Bernd, I hope I didn't miss the point of your ...

2011-12-04T23:42:03.073+01:00

Bernd,
I hope I didn't miss the point of your question, but Jangaroo does not try to catch private member access violations at runtime. As said in the blog post, the reason to rename private members is to avoid name clashes, and all renaming is done at compile time.
However, you spotted an issue I skipped in the blog post: What about untyped access to private members? How can the Jangaroo compiler rename access to a private member, if the expression to the left of the dot is untyped?
Since the answer is rather long, I am already working on a follow-up blog post.
The idea you mention to generate different code for debug and release builds is already implemented in Jangaroo. We provide a built-in assert() function that is interpreted by the compiler: If assertions are disabled (using a compiler flag you could set when creating release builds), assert() function calls are completely suppressed in the generated code. So if there were any runtime checks for private member access (which, as said above, is not the case), they could be treated similarily.

This is all very interesting. Thanks for sharing t...

2011-12-04T02:58:40.098+01:00

This is all very interesting. Thanks for sharing those details! The way Jangaroo hides private members is crafty. But I am wondering: Shouldn't most access violations due to accessing private members be caught at compile time? In theory the only reason for checking access violations at runtime is because of untyped code, i.e. assuming that foo() is a private method of Sprite:

var sprite: Sprite = new Sprite();
var spriteObj : Object = sprite;
spriteObj.foo();

I am simply wondering: Shall Jangaroo care about those cases? I think so. But in my opinion Jangaroo should only care about access violations debug builds. In release builds I would not use any code that checks against access violations.
That is what I call the "dart rules". Please see this blog post if you are interested in the details and let me know what you think:
http://blogs.adobe.com/bparadie/2011/11/16/dart-and-types-tennis-without-a-net/