[Python-Dev] PEP 492 vs. PEP 3152, new round

[Greg Ewing]

Guido van Rossum wrote:
> Sorry, when I wrote "future" (lower-case 'f') I really meant what Yury 
> calls *awaitable*. That's either a coroutine or something with an 
> __await__ emthod.

But how is an awaitable supposed to raise StopIteration
if it's implemented by a generator or async def[*] function?
Those things use StopIteration to wrap return values.

I like the idea of allowing StopIteration to be raised
in an async def function and wrapping it somehow. I'd
add that it could also be unwrapped automatically when
it emerges from 'await', so that code manually invoking
__anext__ can catch StopIteration as usual.

I don't think this could conflict with any existing
uses of StopIteration, since raising it inside generators
is currently forbidden.

[*] I'm still struggling with what to call those things.
Calling them just "coroutines" seems far too ambiguous.
(There should be a Zen item something along the lines
of "If you can't think of a concise and unambiguous name
for it, it's probably a bad idea".)

-- 
Greg