On Aug 21, 2008, at 10:50 AM, Lex Spoon wrote:
>>> (function(x, y) {
>>> print(y);
>>> })(2, x)
>>
>> We've been over this. What if you replace print(y) with return y?
>
> Desugaring to closures is highly worthwhile,
Why?
> so it looks worth solving
> these. Defining good variable-definition semantics is hard, as the
> experience with var shows, so it's good to reuse function literals if
> at all possible.
Why do you assume function expressions (not literals in any immutable
sense) have good variable definition semantics for their arguments?
> The problems you describe are actually not hard to fix.
I don't agree, but we'll see how Java closures work out. In the mean
time:
> All that has
> to happen is that return is labeled with the function it applies to.
> If at parse time no label is supplied, then the parser can manufacture
> a label to use.
Propose some unambiguous syntax, since return may have an expression
on its right.
> So, I agree that return, etc.,
arguments.
> need to be fixed up if you desugar to
> closures, but they can indeed be fixed up. Further, you probably want
> non-local return anyway if people are going to use a lot of function
> literals in their code.
This has never in my hearing been requested, and people use lots of
closures in JS. Experience does not back the desire here to invent
something new, or to borrow from languages with different evaluation
models.
TC39 is not going to invent, so the likely outcome in Harmony is
something actually implemented, with user feedback, with small
adjustments also implemented at least in open-source nightly if not
beta-tested fashion.
That's not an invitation to submit patches, btw. I'd rather have some
agreement in the committee before trying more experiments. Mozilla
has done a number over the years. They were worthwhile, but far from
cost-free.
/be
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