[Python-Dev] Adding c-api async protocol support

[Stefan Behnel]

Arc Riley schrieb am 25.06.2015 um 04:36:
> A type slot for tp_as_async has already been added (which is good!) but we
> do not currently seem to have protocol functions for awaitable types.
> 
> I would expect to find an Awaitable Protocol listed under Abstract Objects
> Layer, with functions like PyAwait_Check, PyAwaitIter_Check, and
> PyAwaitIter_Next, etc.
> 
> Specifically its currently difficult to test whether an object is awaitable
> or an awaitable iterable, or use said objects from the c-api without
> relying on method testing/calling mechanisms.

FYI, Cython's latest master branch already implements PEP 492 (in Python
2.6+, using slots in Py3.2+). So you can just write "await x" and "async
for ..." and get the expected slot calling code for it, or method calling
fallback code in Python 2.x.

That being said, I guess you're right that CPython would eventually want to
extend the C-API here in order to cover the new protocols also for manually
written C code. I'd wait with that a bit, though, until after Py3.5 is
finally released and the actual needs for C code that want to use the new
features become clearer.

Stefan