proposed PEP: iterator splicing

Georg Brandl g.brandl at gmx.net
Sun Apr 15 19:00:37 CEST 2007


Steven Bethard schrieb:
> Paul Rubin wrote:
>> The boilerplate
>>     
>>     def some_gen():
>>        ...
>>        for x in some_other_gen():
>>            yield x
>>        ...
>> 
>> is so common (including the case where some_other_gen is the same as
>> some_gen, i.e. it's a recursive call) that I find myself wanting
>> a more direct way to express it:
>> 
>>     def some_gen():
>>        ...
>>        yield *some_other_gen()
>> 
>> comes to mind.  Less clutter, and avoids yet another temp variable
>> polluting the namespace.
>> 
>> Thoughts?
> 
> This has been brought up before and there was mixed support:
> 
> http://www.python.org/dev/summary/2006-01-16_2006-01-31/#yielding-from-a-sub-generator
> 
> My guess is that the only way it has any chance is if someone takes the 
> time to implement it and posts a full-fledged PEP to python-dev.

BTW, I've implemented a different feature, namely extended unpacking, such as

a, *b, c = range(10)

where I already had to add the concept of a ``starred'' expression.
If someone wants to do it, we can probably share some code.


Georg


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