On 23 November 2017 at 01:00, Yury Selivanov <yselivanov...@gmail.com> wrote:
> On Wed, Nov 22, 2017 at 6:46 PM, Ivan Levkivskyi <levkivs...@gmail.com> > wrote: > [..] > > Just found another example of intuitive behaviour: > > > >>>> async def f(): > > ... for i in range(3): > > ... yield i > > ... > >>>> async def g(): > > ... return [(yield i) async for i in f()] > > ... > >>>> g().send(None) > > Traceback (most recent call last): > > File "<stdin>", line 1, in <module> > > File "<stdin>", line 2, in g > > TypeError: object async_generator can't be used in 'await' expression > > > > of course it is obvious for anyone who writes async code, but anyway an > > interesting example. > > I wouldn't say that it's obvious to anyone... > > I think this thread has started to discuss the use of 'yield' > expression in comprehensions, and the outcome of the discussion is > that everyone thinks that we should deprecate that syntax in 3.7, > remove in 3.8. Let's start with that? :) I am not sure everyone agrees with this. My main obstacle is following, consider motivation for the `await` part of PEP 530 which is in my understanding is roughly like this: "People sometimes want to refactor for-loops containing `await` into a comprehension but that doesn't work (particularly because of the hidden function scope) - lets fix this" I don't see how this compare to: "People sometimes want to refactor for-loops containing `yield` into a comprehension but that doesn't work (particularly because of the hidden function scope) - lets make it a SyntaxError" -- Ivan
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