[Laszlo-dev] Undefined pattern in AS3

[André Bargull]

In my recent changeset for RegExp-support in swf8, you'll get an error, 
if you compile the lfc for swf9:

The simple cache class I've added accepts "Objects" as values, so I coded:
> function put (key:String, value:Object) :Object {...}
> function get (key:String) :Object {...}
And in these functions, I've used the "undefined"-pattern described in [1]:
> var old:Object = this.get(key);
> if (*old === void(0)*) {
But this gave me an AS3 compiler-error [2]:
> 1118    Implicit coercion of a value with static type Object to a 
> possibly unrelated type void.

To get around the compiler error, I've just changed the type-declaration 
to "*" (maybe even more reasonable). So far so good, but we've used the 
"void 0"-pattern all along in our code. Therefore do you think it's 
possible to update the compiler to change "void 0" to "undefined" for 
JS2-targets, resp. the other way around, so "undefined" to "void 0" for 
JS1-targets (possibly more straightforward)? Just to ensure the "one 
code, multiple runtimes" idea in OpenLaszlo.

- André


[1] 
http://pt.withy.org/ptalk/archives/2005/06/dont_assume_undefined_is_undefined.html
[2] 
http://livedocs.adobe.com/flash/9.0/ActionScriptLangRefV3/compilerErrors.html