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

Andrew Svetlov andrew.svetlov at gmail.com
Sat Dec 22 18:22:55 CET 2012 
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
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