A reprieve for ES6 comprehensions

Brendan Eich brendan at mozilla.org
Sat Jun 7 15:41:11 PDT 2014

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.


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