[Python-ideas] Async API: some code to review

Guido van Rossum guido at python.org
Mon Oct 29 19:10:42 CET 2012

On Mon, Oct 29, 2012 at 11:02 AM, Andrew Svetlov
<andrew.svetlov at gmail.com> wrote:
> Pollster has to support any object as file descriptor.
> The use case is ZeroMQ sockets: they are implemented at user level and
> socket is just some opaque structure wrapped by Python object.
> ZeroMQ has own poll function to process zmq sockets as well as regular
> sockets/pipes/files.

Good call! This seem to be an excellent use case to validate the
pollster design. Are you saying that the approach I used for
SslTransport doesn't work here? (I can believe it, I've never looked
at 0MQ, but I can't tell from your message.) The insistence on
isinstance(fd, int) is mostly there so that I don't accidentally
register a socket object *and* its file descriptor at the same time --
but there are other ways to ensure that. I've added a TODO item for

> I would to see add_{reader,writer} and call_{soon,later} accepting
> **kwargs as well as *args. At least to respect functions with
> keyword-only arguments.

Hmm... I intentionally ruled those out because I wanted to leave the
door open for keyword args that modify the registration function
(add_reader etc.); it is awkward to require conventions like "your
function cannot have a keyword arg named X because we use that for our
own API" and it is even more awkward to have to retrofit new values of
X into that rule. Maybe we can come up with a simple wrapper.

> +1 for explicit passing loop instance and clearing role of DelayedCall.

Will do. (I think you meant clarifying?)

> Decorating coroutines with setting some flag looks good to me, but I
> expect some problems with setting extra attribute to objects like
> staticmethod/classmethod.


--Guido van Rossum (python.org/~guido)

More information about the Python-ideas mailing list