[Python-Dev] PEP 3156 - Asynchronous IO Support Rebooted

[Guido van Rossum]

On Tue, Jan 8, 2013 at 9:26 PM, Yuriy Taraday <yorik.sar at gmail.com> wrote:
>
>
>
> On Wed, Jan 9, 2013 at 9:14 AM, Guido van Rossum <guido at python.org> wrote:
>>
>> On Tue, Jan 8, 2013 at 9:02 PM, Yuriy Taraday <yorik.sar at gmail.com> wrote:
>> > Should transports be bound to event loop on creation? I wonder, what
>> > would
>> > happen if someone changes current event loop between these calls.
>>
>> Yes, this is what the transport implementation does.
>
>
> But in theory every sock_ call is independent and returns Future bound to
> current event loop.

It is bound to the event loop whose sock_<call>() method you called.

> So if one change event loop with active transport, nothing bad should
> happen. Or I'm missing something.

Changing event loops in the middle of event processing is not a common
(or even useful) pattern. You start the event loop and then leave it
alone.

>> > I understand why it should be a method, but still if it's a getter, it
>> > should have either get_ or is_ prefix.
>>
>> Why? That's not a universal coding standard. The names seem clear enough
>> to me.
>
>
> When I see (in autocompletion, for example) or remember name like "running",
> it triggers thought that it's a field. When I remember smth like is_running,
> it definitely associates with method.

That must pretty specific to your personal experience.

>> > Are there any way to change this with 'Final' PEP?
>>
>> No, the concurrent.futures package has been released (I forget if it
>> was Python 3.2 or 3.3) and we're bound to backwards compatibility.
>> Also I really don't think it's a big deal at all.
>
>
> Yes, not a big deal.
>>
>>
>> >> > 5. I think, protocol and transport methods' names are not easy or
>> >> > understanding enough:
>> >> > - write_eof() does not write anything but closes smth, should be
>> >> > close_writing or smth alike;
>> >> > - the same way eof_received() should become smth like receive_closed;
>> >>
>> >> I am indeed struggling a bit with these names, but "writing an EOF" is
>> >> actually how I think of this (maybe I am dating myself to the time of
>> >> mag tapes though :-).
>> >>
>> > I never saw a computer working with a tape, but it's clear to me what
>> > does
>> > they do.
>> > I've just imagined the amount of words I'll have to say to students
>> > about
>> > EOFs instead of simple "it closes our end of one half of a socket".
>>
>> But which half? A socket is two independent streams, one in each
>> direction. Twisted uses half_close() for this concept but unless you
>> already know what this is for you are left wondering which half. Which
>> is why I like using 'write' in the name.
>
>
> Yes, 'write' part is good, I should mention it. I meant to say that I won't
> need to explain that there were days when we had to handle a special marker
> at the end of file.

But even today you have to mark the end somehow, to distinguish it
from "not done yet, more could be coming". The equivalent is typing ^D
into a UNIX terminal (or ^Z on Windows).

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