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Thu Nov 23 09:30:54 EST 2017 · https://mail.python.org/pipermail/python-dev/2017-November/150782.html

On 23 November 2017 at 14:24, Ivan Levkivskyi <levkivskyi at gmail.com> wrote:
>> My main concern is that comprehension is not equivalent to a for loop
>> for a specific reason - the scope issue. Has anyone looked back at the
>> original discussions to confirm *why* a function was used?
>>
>> My recollection:
>>
>> >>> i = 1
>> >>> a = [i for i in (1,2,3)]
>> >>> print(i)
>> 1
>>
>> Serihy's approach (and your described expansion) would have print(i)
>> return NameError.
>
>
> Absolutely no, it will still print 1. The internal implementation will use
> unique ids internally (see https://bugs.python.org/issue10544 for details).
>

Ok, cool. My main point still applies though - has anyone confirmed
why a function scope was considered necessary at the time of the
original implementation, but it's apparently not now? I'm pretty sure
it was a deliberate choice, not an accident.

Paul

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[Python-Dev] Tricky way of of creating a generator via a comprehension expression