Shouldn't typing also have Coroutine? #251

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1. 1st1 commented on Jul 22, 2016

   

   1st1

   on Jul 22, 2016

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   @1st1 do you remember any of this? Do you recall a reason to leave out Coroutine?

   No, I suspect it was left out by mistake.
2. gvanrossum commented on Jul 22, 2016

   

   gvanrossum

   on Jul 22, 2016 via email

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   OK, I'll just add it then.
3. gvanrossum

   modified the milestone: 3.5.3 on Aug 26, 2016
4. thehesiod commented on Oct 24, 2016

   

   thehesiod

   on Oct 24, 2016

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   it would be neat if we could specify the parameters to the coroutine as well...something like:

   async def dummy(dummy_param: int) -> Awaitable[None]:
       return
   
   async needs_typing(co_method: Coroutine[int]):
       await co_method(1)
   
   await needs_typing(dummy)

   I just realized a super neat thing would be also being able to specify the return type of co_method parameter like Callable If it were possible something like:

   async needs_typing(co_method: Coroutine[[int], None]):
       await co_method(1)

   • updated based on new understanding of existing typing.Callable
5. ilevkivskyi commented on Oct 29, 2016

   

   ilevkivskyi

   on Oct 29, 2016

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   @gvanrossum
   I see that you have assigned this issue to yourself, but if you don't mind, I would like to do this (in python/typing and in python/peps). Just a small clarification: should order of type variables be the same as for Generator? So that:

   class Coroutine(Awaitable[ret_type_co], Generic[yield_type_co, send_type_contra, ret_type_co]):
       ...
6. gvanrossum commented on Oct 29, 2016

   

   gvanrossum

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   I'm fine with you doing this, but I had thought that Coroutine would have only one parameter (the return type). I guess this means we'll need to look at some example code to see how it would be used.
7. ilevkivskyi commented on Oct 29, 2016

   

   ilevkivskyi

   on Oct 29, 2016

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   In principle a normal coroutine defined with async def has a trivial .send() method that only accepts None and raises StopIteration. However, one could make a coroutine "manually" by instantiating a non-abstract subclass of collections.abc.Coroutine. Such "manually created" coroutine could have a non-trivial .send() method. But I agree with you that this use case is probably rare. I do not have a preference here. @1st1 what do you think?
8. ilevkivskyi commented on Oct 29, 2016

   

   ilevkivskyi

   on Oct 29, 2016

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   @gvanrossum Yet another option would be to make Coroutie a special form. So that Coroutine[[X, Y], Z] is essentially equivalent to Callable [[X, Y], Awaitable[Z].
9. gvanrossum commented on Oct 29, 2016

   

   gvanrossum

   on Oct 29, 2016

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   Oh, no! I think after all it should indeed mimic Generator.
10. gvanrossum

    closed this as completedin #312on Oct 29, 2016