[Python-Dev] async/await in Python; v2

[MRAB]

On 2015-04-23 18:51, Barry Warsaw wrote:
> On Apr 21, 2015, at 01:26 PM, Yury Selivanov wrote:
>
>>The updated version of the PEP should be available shortly at
>>https://www.python.org/dev/peps/pep-0492 and is also pasted in this email.
>
> There's a lot to like about PEP 492.  I only want to mildly bikeshed a bit on
> the proposed new syntax.
>
> Why "async def" and not "def async"?
>
> My concern is about existing tools that already know that "def" as the first
> non-whitespace on the line starts a function/method definition.  Think of a
> regexp in an IDE that searches backwards from the current line to find the
> function its defined on.  Sure, tools can be updated but it is it *necessary*
> to choose a syntax that breaks tools?
>
>      def async useful():
>
> seems okay to me.
>
> Probably the biggest impact on the PEP would be symmetry with asynchronous
> with and for.  What about:
>
>      with async lock:
>
> and
>
>      for async data in cursor:
>
> That would also preserve at least some behavior of existing tools.
>
> Anyway, since the PEP doesn't explicitly describe this as an alternative, I
> want to bring it up.
>
> (I have mild concerns about __a*__ magic methods, since I think they'll be
> harder to visually separate, but here the PEP does describe the __async_*__
> alternatives.)
>
On the other hand, existing tools might be expecting "def" and "for" to
be followed by a name.