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Re: generator/coroutine terminology

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Date Mon, 16 Mar 2015 19:58:22 +1100
Subject Re: generator/coroutine terminology
From Chris Angelico <rosuav@gmail.com>
Cc "python-list@python.org" <python-list@python.org>
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On Mon, Mar 16, 2015 at 7:36 PM, Steven D'Aprano
<steve+comp.lang.python@pearwood.info> wrote:
> I expect that the interpreter can tell the difference between
>
>     yield spam
>
> and
>
>     x = yield spam
>
> and only allow send(), close() and throw() on generators which include the
> second form. If it can't, then that's a limitation, not a feature to be
> emulated.
>

Hmm. That would imply that an expression is different if it's used
somewhere. In Python, there's no difference between these two function
calls:

x = func(1,2,3)
func(1,2,3)

except for the actual name binding. If a yield expression enabled
send() if and only if its return value were used, then it would be
extremely surprising:

def use_and_discard():
    while True:
        _ = (yield 1)

def just_yield():
    while True:
        yield 1

So... I can send into the first but not into the second?

That said, though, it would be quite reasonable for a *linter* to warn
you about sending into a generator that never uses sent values. With a
good type inference system (not sure if MyPy is sufficient here), it
would be possible to distinguish between those two functions and
declare that the first one has the return type "sendable_generator"
and the second one "nonsendable_generator", and give a warning if you
send into the latter. But I don't think that's the language's job.

ChrisA

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Thread

generator/coroutine terminology Rustom Mody <rustompmody@gmail.com> - 2015-03-12 06:35 -0700
  Re: generator/coroutine terminology Chris Angelico <rosuav@gmail.com> - 2015-03-13 00:55 +1100
  Re: generator/coroutine terminology breamoreboy@gmail.com - 2015-03-12 06:57 -0700
  Re: generator/coroutine terminology Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-03-13 03:27 +1100
    Re: generator/coroutine terminology Rustom Mody <rustompmody@gmail.com> - 2015-03-12 09:52 -0700
      Re: generator/coroutine terminology Marko Rauhamaa <marko@pacujo.net> - 2015-03-12 19:55 +0200
        Re: generator/coroutine terminology Rustom Mody <rustompmody@gmail.com> - 2015-03-12 19:23 -0700
          Re: generator/coroutine terminology Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-03-13 14:30 +1100
            Re: generator/coroutine terminology Rustom Mody <rustompmody@gmail.com> - 2015-03-12 22:28 -0700
              Re: generator/coroutine terminology Chris Angelico <rosuav@gmail.com> - 2015-03-13 19:23 +1100
                Re: generator/coroutine terminology Rustom Mody <rustompmody@gmail.com> - 2015-03-13 02:12 -0700
                Re: generator/coroutine terminology Marko Rauhamaa <marko@pacujo.net> - 2015-03-13 11:36 +0200
                Re: generator/coroutine terminology Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-03-14 17:04 +1100
                Re: generator/coroutine terminology Marko Rauhamaa <marko@pacujo.net> - 2015-03-14 09:54 +0200
                Re: generator/coroutine terminology Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-03-14 08:04 +0000
                Re: generator/coroutine terminology Marko Rauhamaa <marko@pacujo.net> - 2015-03-14 10:30 +0200
                Re: generator/coroutine terminology Ian Kelly <ian.g.kelly@gmail.com> - 2015-03-14 14:14 -0600
                Re: generator/coroutine terminology Rustom Mody <rustompmody@gmail.com> - 2015-03-14 21:15 -0700
                Re: generator/coroutine terminology Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-03-14 20:31 +0000
                Re: generator/coroutine terminology Rustom Mody <rustompmody@gmail.com> - 2015-03-14 08:29 -0700
                Re: generator/coroutine terminology Chris Angelico <rosuav@gmail.com> - 2015-03-15 02:56 +1100
                Re: generator/coroutine terminology Rustom Mody <rustompmody@gmail.com> - 2015-03-14 08:59 -0700
                Re: generator/coroutine terminology Chris Angelico <rosuav@gmail.com> - 2015-03-15 03:14 +1100
                Re: generator/coroutine terminology Rustom Mody <rustompmody@gmail.com> - 2015-03-14 09:33 -0700
                Re: generator/coroutine terminology Chris Angelico <rosuav@gmail.com> - 2015-03-15 03:51 +1100
                Re: generator/coroutine terminology Rustom Mody <rustompmody@gmail.com> - 2015-03-14 10:17 -0700
                Re: generator/coroutine terminology Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-03-14 16:56 +0000
                Re: generator/coroutine terminology Dave Angel <davea@davea.name> - 2015-03-14 13:07 -0400
                Re: generator/coroutine terminology albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-03-31 12:57 +0000
                Re: generator/coroutine terminology Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-03-15 19:37 +1100
                Re: generator/coroutine terminology CHIN Dihedral <dihedral88888@gmail.com> - 2015-04-18 11:07 -0700
                Re: generator/coroutine terminology Chris Angelico <rosuav@gmail.com> - 2015-03-13 22:32 +1100
      Re: generator/coroutine terminology Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2015-03-14 22:02 +0000
        Re: generator/coroutine terminology Marko Rauhamaa <marko@pacujo.net> - 2015-03-15 00:15 +0200
          Re: generator/coroutine terminology Chris Angelico <rosuav@gmail.com> - 2015-03-15 09:24 +1100
            Re: generator/coroutine terminology Marko Rauhamaa <marko@pacujo.net> - 2015-03-15 02:15 +0200
              Re: generator/coroutine terminology Chris Angelico <rosuav@gmail.com> - 2015-03-15 11:22 +1100
                Re: generator/coroutine terminology Marko Rauhamaa <marko@pacujo.net> - 2015-03-15 02:48 +0200
                Re: generator/coroutine terminology Chris Angelico <rosuav@gmail.com> - 2015-03-15 13:02 +1100
              Re: generator/coroutine terminology Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-03-16 12:03 +1100
                Re: generator/coroutine terminology Marko Rauhamaa <marko@pacujo.net> - 2015-03-16 09:12 +0200
                Re: generator/coroutine terminology Chris Angelico <rosuav@gmail.com> - 2015-03-16 18:21 +1100
                Re: generator/coroutine terminology Marko Rauhamaa <marko@pacujo.net> - 2015-03-16 09:40 +0200
                Re: generator/coroutine terminology Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-03-16 22:59 +1100
                Re: generator/coroutine terminology Ian Kelly <ian.g.kelly@gmail.com> - 2015-03-16 01:37 -0600
                Re: generator/coroutine terminology Marko Rauhamaa <marko@pacujo.net> - 2015-03-16 09:52 +0200
                Re: generator/coroutine terminology Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-03-16 23:02 +1100
                Re: generator/coroutine terminology Marko Rauhamaa <marko@pacujo.net> - 2015-03-16 14:42 +0200
                Re: generator/coroutine terminology Jonas Wielicki <jonas@wielicki.name> - 2015-03-16 13:39 +0100
                Re: generator/coroutine terminology Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-03-16 19:36 +1100
                Re: generator/coroutine terminology Chris Angelico <rosuav@gmail.com> - 2015-03-16 19:58 +1100
                Re: generator/coroutine terminology Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-03-16 22:51 +1100
                Re: generator/coroutine terminology Chris Angelico <rosuav@gmail.com> - 2015-03-17 00:16 +1100
                Re: generator/coroutine terminology Marko Rauhamaa <marko@pacujo.net> - 2015-03-16 14:32 +0200
                Re: generator/coroutine terminology Rustom Mody <rustompmody@gmail.com> - 2015-03-16 05:51 -0700
                Re: generator/coroutine terminology Marko Rauhamaa <marko@pacujo.net> - 2015-03-16 15:13 +0200
                Re: generator/coroutine terminology Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-03-17 01:32 +1100
                Re: generator/coroutine terminology Ian Kelly <ian.g.kelly@gmail.com> - 2015-03-16 08:45 -0600
                Re: generator/coroutine terminology Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-03-17 00:39 +1100
                Re: generator/coroutine terminology Rustom Mody <rustompmody@gmail.com> - 2015-03-16 07:19 -0700
                Re: generator/coroutine terminology Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-03-16 14:26 +0000
                Re: generator/coroutine terminology Rustom Mody <rustompmody@gmail.com> - 2015-03-16 07:37 -0700
                Re: generator/coroutine terminology Rustom Mody <rustompmody@gmail.com> - 2015-03-16 07:55 -0700
                Re: generator/coroutine terminology Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-03-16 18:19 +0000
                Re: generator/coroutine terminology Rustom Mody <rustompmody@gmail.com> - 2015-03-16 19:52 -0700
                Re: generator/coroutine terminology Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-03-17 03:07 +0000
                Re: generator/coroutine terminology Rustom Mody <rustompmody@gmail.com> - 2015-03-16 20:18 -0700
                Re: generator/coroutine terminology Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-03-17 03:25 +0000
                Re: generator/coroutine terminology Rustom Mody <rustompmody@gmail.com> - 2015-03-16 20:33 -0700
                Re: generator/coroutine terminology Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-03-17 03:55 +0000
                Re: generator/coroutine terminology Mario Figueiredo <marfig@gmail.com> - 2015-03-17 04:22 +0100
                Re: generator/coroutine terminology Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-03-17 01:35 +1100
                Re: generator/coroutine terminology Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-03-17 01:36 +1100
                Re: generator/coroutine terminology Ian Kelly <ian.g.kelly@gmail.com> - 2015-03-16 08:52 -0600
                Re: generator/coroutine terminology Marko Rauhamaa <marko@pacujo.net> - 2015-03-16 17:09 +0200
                Re: generator/coroutine terminology Ian Kelly <ian.g.kelly@gmail.com> - 2015-03-16 09:26 -0600
                Re: generator/coroutine terminology Marko Rauhamaa <marko@pacujo.net> - 2015-03-16 18:05 +0200
                Re: generator/coroutine terminology albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-03-31 13:18 +0000
                Re: generator/coroutine terminology Dave Angel <davea@davea.name> - 2015-03-31 09:38 -0400
                Re: generator/coroutine terminology albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-03-31 15:03 +0000
                Re: generator/coroutine terminology Chris Angelico <rosuav@gmail.com> - 2015-04-01 02:36 +1100
                Re: generator/coroutine terminology Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-04-03 17:02 +1100
                Re: generator/coroutine terminology albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-04-18 17:52 +0000
                Re: generator/coroutine terminology Paul Rubin <no.email@nospam.invalid> - 2015-04-02 23:46 -0700
  Re: generator/coroutine terminology Terry Reedy <tjreedy@udel.edu> - 2015-03-12 16:11 -0400
    Re: generator/coroutine terminology Marko Rauhamaa <marko@pacujo.net> - 2015-03-12 22:22 +0200

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