[Python-Dev] PEP 492: async/await in Python; v3

[Yury Selivanov]

Hi Walter,

On 2015-04-28 10:23 AM, Walter Dörwald wrote:
>> Key properties of coroutines:
>>
>> * ``async def`` functions are always coroutines, even if they do not
>> contain ``await`` expressions.
>>
>> * It is a ``SyntaxError`` to have ``yield`` or ``yield from``
>> expressions in an ``async`` function.
>
> Does this mean it's not possible to implement an async version of 
> os.walk() if we had an async version of os.listdir()?
>
> I.e. for async code we're back to implementing iterators "by hand" 
> instead of using generators for it. 


For now yes.  Unfortunately, we don't have time to implement 
coroutine-generators properly in 3.5.

Thanks,
Yury