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?
~TJ
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