On Wed, Apr 22, 2015 at 5:55 PM, Yury Selivanov <yselivanov.ml@gmail.com> wrote:
On 2015-04-22 8:35 PM, Guido van Rossum wrote:
On Wed, Apr 22, 2015 at 5:12 PM, Greg Ewing <greg.ewing@canterbury.ac.nz> wrote:
Guido van Rossum wrote:
On Wed, Apr 22, > OTOH I'm still struggling with what you have to do to
wrap a coroutine in a Task, the way its done in asyncio by the Task() constructor, the loop.create_task() method, and the async() function
That's easy. You can always use costart() to adapt a cofunction for use with something expecting a generator-based coroutine, e.g.
codef my_task_func(arg): ...
my_task = Task(costart(my_task_func, arg))
If you're willing to make changes, Task() et al could be made to recognise cofunctions and apply costart() where needed.
Hm, that feels backwards incompatible (since currently I can write Task(my_task_func(arg)) and also a step backwards in elegance (having to pass the args separately).
OTOH the benefit is that it's much harder to accidentally forget to wait for a coroutine. And maybe the backward compatibility issue is not really a problem because you have to opt in by using codef or async def.
So I'm still torn. :-)
Somebody would need to take a mature asyncio app and see how often this is used (i.e. how many place would require adding costart() as in the above example).
Somewhere in this thread Victor Stinner wrote:
"""A huge part of the asyncio module is based on "yield from fut" where fut is a Future object."""
So how would we do "await fut" if await requires parentheses?
We could make Future a valid co-callable object.
I think that the problem of forgetting 'yield from' is a bit exaggerated. Yes, I myself forgot 'yield from' once or twice. But that's it, it has never happened since.
Maybe, but it *is* a part of everybody's learning curve. -- --Guido van Rossum (python.org/~guido)