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

[Chris Jerdonek]

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".

--Chris