On Mon, Feb 16, 2015 at 8:30 PM, Guido van Rossum <guido@python.org> wrote:
This is brought up from time to time. I believe it is based on a misunderstanding of coroutines.
Thanks, Guido, if you could elaborate that would be great. Meanwhile I'll try to guess what you may be referring to, please correct me if I am wrong: the misunderstanding has to do with the fact that between the priming next() and the first send(), the client code should be doing something interesting. If that is not the case, then the client code and the coroutine are not cooperating fully. Is that it? Best, Luciano
On Mon, Feb 16, 2015 at 4:53 AM, Luciano Ramalho <luciano@ramalho.org> wrote:
Coroutines are useless until primed by a next(my_coro) call. There are decorators to solve this by returning a primed coroutine. Such decorators add another problem: now the user may be unsure whether a specific coroutine from a third-party API should be primed or not prior to use.
How about having a built-in function named send() with the signature send(coroutine, value) that does the right thing: sends a value to the coroutine, priming it if necessary. So instead of writing this:
next(my_coro) my_coro.send(a_value)
You could always write this:
send(my_coro, a_value)
At a high level, the behavior of send() would be like this:
def send(coroutine, value): if inspect.getgeneratorstate() == 'GEN_CREATED': next(coroutine) coroutine.send(value)
Consider the above pseudo-code. Proper handling of other generator states should be added.
This would make coroutines easier to use, and would make their basic usage more consistent with the usage of plain generators using a function syntax -- eg. next(my_gen) -- instead of method call syntax.
What do you think? If this has been discussed before, please send me a link (I searched but came up empty).
Best,
Luciano
-- Luciano Ramalho Twitter: @ramalhoorg
Professor em: http://python.pro.br Twitter: @pythonprobr _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
-- --Guido van Rossum (python.org/~guido)
-- Luciano Ramalho Twitter: @ramalhoorg Professor em: http://python.pro.br Twitter: @pythonprobr