[Python-Dev] Tricky way of of creating a generator via a comprehension expression

[Antoine Pitrou]

On Sat, 25 Nov 2017 03:03:02 +0000
MRAB <python at mrabarnett.plus.com> wrote:

> On 2017-11-25 02:21, Chris Jerdonek wrote:
> > On Fri, Nov 24, 2017 at 5:06 PM, Nathaniel Smith <njs at pobox.com> wrote:  
> >> On Fri, Nov 24, 2017 at 4:22 PM, Guido van Rossum <guido at python.org> wrote:  
> >>> The more I hear about this topic, the more I think that `await`, `yield` and
> >>> `yield from` should all be banned from occurring in all comprehensions and
> >>> generator expressions. That's not much different from disallowing `return`
> >>> or `break`.  
> >>
> >> I would say that banning `yield` and `yield from` is like banning
> >> `return` and `break`, but banning `await` is like banning function
> >> calls.  
> > 
> > I agree. I was going to make the point earlier in the thread that
> > using "await" can mostly just be thought of as a delayed function
> > call, but it didn't seem at risk of getting banned until Guido's
> > comment so I didn't say anything (and there were too many comments
> > anyways).
> > 
> > I think it's in a different category for that reason. It's much easier
> > to reason about than, say, "yield" and "yield from".
> >   
> +1
> 
> Seeing "await" there didn't/doesn't confuse me; seeing "yield" or "yield 
> from" does.

+1 as well.

Regards

Antoine.