[Python-ideas] Assignments in list/generator expressions

[Nick Coghlan]

On Mon, Apr 11, 2011 at 8:48 AM, Guido van Rossum <guido at python.org> wrote:
> On Sun, Apr 10, 2011 at 12:28 PM, Arnaud Delobelle <arnodel at gmail.com> wrote:
>> OK.  It's clear I don't know enough about the compiling process to be able to understand all the problems.  The f.__name__ issue doesn't seem insurmountable, but I can't see how to get around the locals()["x"] issue in a sane manner (I see what you mean about cursing the locals() function!).  BTW, I think there is a typo in the example above: shouldn't
>>
>>    y = locals("x"), ...
>>
>> be
>>
>>    y = locals()["x"], ...
>
> FWIW, I don't mind if an implementation of this (or anything new,
> really) doesn't work well with locals().

While supporting locals() correctly is a bit of a pain, I find "Does
read access to locals() still work?" to be a useful proxy for "Will
proposing this feature have authors of Python debugging tools massing
outside my front door with pitchforks and torches?" :)

I don't think it's a trade-off that has to be made in the specific
case of PEP 3150 - the copy-in/copy-out idea should be viable and
reasonably intuitive given Python's existing scoping rules.

Cheers,
Nick.

-- 
Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia