On 03/03/2011 04:41 PM, Allen Wirfs-Brock wrote:
I think your real question reduces to this:
//none strict mode code
globalObj= function() {return this}();
print(otherGlobal.eval("this") === globalObj) //??
The two different calls and the "indirect" name in your example may make the
question seen like it is about something else (direct/indirect eval).
Not quite so. For the example I gave, yes -- but you could see the
direct/indirect distinction by putting the code I provided inside a function
(and a little more gussying to demonstrate behavior better):
var global = this;
function f()
{
var indirect = otherGlobal.eval;
eval = indirect;
print(eval("this") === this);
print(eval("this) === global);
print(eval("this") === otherGlobal);
print(indirect("this") === this);
print(indirect("this") === global);
print(indirect("this") === otherGlobal);
}
new f();
IE9/Opera prints false/false/true and false/false/true. Chrome/Safari throws
EvalError every time. Firefox prints true/false/false and false/false/true if
otherGlobal is same-origin, false/false/true and false/false/true if
otherGlobal is different-origin-but-same-document.domain.
A more generally, do built-in functions capture their global environment at
the time of their creation or do they they operate in the dynamic context of an
ambient global environment. I hope it is the former.
An example of the more general question would be:
print((Object.getPrototypeOf(new otherGlobal.Array(0)) === Array.prototype)
I believe the second example prints false for all browser implementations.
This is an orthogonal issue, I believe, but I might as well respond since it's
being discussed. There's a Firefox 4 bug that makes this not the case, ran out
of time to fix it for release. It'll be fixed in 5.0, and I could imagine I
might get a fix for it in a 4.0 point release, although with a fast release
cycle that may not be necessary. If I recall correctly Nitro may be buggy this
same way as well. I think Chrome/IE9/Opera did not demonstrate the bug in my
testing. But in any case, printing false there is in my opinion the correct
behavior.
Jeff
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