A reprieve for ES6 comprehensions

Tab Atkins Jr. jackalmage at gmail.com
Mon Jun 9 10:09:28 PDT 2014

On Sat, Jun 7, 2014 at 3:41 PM, Brendan Eich <brendan at mozilla.org> wrote:
> Tab Atkins Jr. wrote:
>> On Fri, Jun 6, 2014 at 1:57 PM, Andy Wingo<wingo at igalia.com>  wrote:
>>> >  1: Essential differences
>>> >  ==
>>> >
>>> >  Array comprehensions are eager.  Generator comprehensions are lazy.
>>> >  Array comprehensions desugar into a do expression à la ES7.  Generator
>>> >  comprehensions desugar into an IIGFE (immediately-invoked generator
>>> >  function expression) -- sorta, anyway.  (Generator function desugaring
>>> >  is not exact due to arguments/this/etc scoping and properties on the
>>> >  generator function.)
>>> >
>>> >  This is an essential difference in the use of the iterator, and so it
>>> >  makes sense to distinguish these at the source level as well.
>> I'm not sure I understand.  Is this an argument against Python's use
>> of similar syntaxes as well?  That is, do you also disagree with
>> Python's high similarity between array comprehensions and generator
>> comprehensions?
> No, the problem is there's no way to do a generator comprehension in (what
> we saw of) the new syntax.

Ah, getting context from just the slide deck clearly puts me at a
disadvantage.  Am I to understand that the three slides in a row that
have a "for()...for()...if()...{x, y}" syntax are the proposed syntax?


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