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[Python-ideas] yield from multiple iterables (was Re: The async API of the future: yield-from)

Christian Tismer tismer at stackless.com
Fri Oct 19 14:55:57 CEST 2012 
Hi Nick,

On 16.10.12 03:49, Nick Coghlan wrote:
> On Tue, Oct 16, 2012 at 10:44 AM, Greg Ewing
> <greg.ewing at canterbury.ac.nz> wrote:
>> My original implementation of yield-from actually *did* avoid
>> this, by keeping a C-level pointer chain of yielding-from frames.
>> But that part was ripped out at the last minute when someone
>> discovered that it had a detrimental effect on tracebacks.
>>
>> There are probably other ways the traceback problem could be
>> fixed, so maybe we will get this optimisation back one day.
> Ah, I thought I remembered something along those lines. IIRC, it was a
> bug report on one of the alphas that prompted us to change it.
>

I was curious and searched quite a lot.
It was v3.3.0a1 from 2012-03-15 as a reaction to #14230 and #14220
from Marc Shannon, patched by Benjamin.

Now I found the original implementation. That looks very much
as I'm thinking it should be.

Quite a dramatic change which works well, but really seems to remove
what I would call "now I can emulate most of Stackless" efficiently.

Maybe I should just try to think it would be implemented as before,
build an abstraction and just use it for now.

I will spend my time at PyCon de for sprinting on "yield from".

cheers - chris

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