[Python-Dev] Tricky way of of creating a generator via a comprehension expression (original) (raw)

MRAB python at mrabarnett.plus.com
Fri Nov 24 22:03:02 EST 2017

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.

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