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[Python-ideas] ``with from`` statement

Andrew Svetlov andrew.svetlov at gmail.com
Sat Dec 22 18:25:32 CET 2012 
Python syntax looks like use of time machine day by day. I like it!

On Sat, Dec 22, 2012 at 7:22 PM, Andrew Svetlov
<andrew.svetlov at gmail.com> wrote:
> Yes, Nick's proposal is just awesome.
>
> I cannot figure out is __exit__ can be generator which use ``yield
> from`` also inside?
>
> On Sat, Dec 22, 2012 at 7:15 PM, Guido van Rossum <guido at python.org> wrote:
>> Nick already proposed "with (yield from ...): ..."
>>
>> Maybe in 3.4 we can tweak the syntax so the paresns are not needed.
>>
>> I am quite glad that we had the foresight (when we designed 'with') to make
>> this possible.
>>
>>
>> On Saturday, December 22, 2012, Andrew Svetlov wrote:
>>>
>>> Crazy idea.
>>> Guido van Rossum mentioned after working on PEP 3156 that context
>>> managers cannot use
>>> yield from statement inside __enter__ and __exit__ magic methods.
>>> Explicit call for entering and leaving context (for locking for
>>> example) is not convenient.
>>>
>>> What do you think about
>>>
>>> with from f():
>>>    do_our_work()
>>>
>>>
>>> ``with from ...` construction calls __enter_from__ generator  and
>>> iterates via ``yield from`` for that.
>>> Returned value is our context manager.
>>>
>>> The same for __exit_from__ — do``yield from`` for that and stop on
>>> StopIteration or exception.
>>>
>>> --
>>> Thanks,
>>> Andrew Svetlov
>>> _______________________________________________
>>> Python-ideas mailing list
>>> Python-ideas at python.org
>>> http://mail.python.org/mailman/listinfo/python-ideas
>>
>>
>>
>> --
>> --Guido van Rossum (python.org/~guido)
>
>
>
> --
> Thanks,
> Andrew Svetlov



-- 
Thanks,
Andrew Svetlov
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