On Sat, May 2, 2015 at 1:18 PM, Arnaud Delobelle <arno...@gmail.com> wrote:
> On 1 May 2015 at 20:59, Guido van Rossum <gu...@python.org> wrote: > > On Fri, May 1, 2015 at 12:49 PM, Ron Adam <ron3...@gmail.com> wrote: > >> > >> > >> Another useful async function might be... > >> > >> async def yielding(): > >> pass > >> > >> In a routine is taking very long time, just inserting "await yielding()" > >> in the long calculation would let other awaitables run. > >> > > That's really up to the scheduler, and a function like this should be > > provided by the event loop or scheduler framework you're using. > > Really? I was under the impression that 'await yielding()' as defined > above would actually not suspend the coroutine at all, therefore not > giving any opportunity for the scheduler to resume another coroutine, > and I thought I understood the PEP well enough. Does this mean that > somehow "await x" guarantees that the coroutine will suspend at least > once? > You're correct. That's why I said it should be left up to the framework -- ultimately what you *do* have to put in such a function has to be understood by the framenwork. And that's why in other messages I've used await asyncio.sleep(0) as an example. Look up its definition. > To me the async def above was the equivalent of the following in the > 'yield from' world: > > def yielding(): > return > yield # Just to make it a generator > > Then "yield from yielding()" will not yield at all - which makes its > name rather misleading! > -- --Guido van Rossum (python.org/~guido)
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