[Python-ideas] PEP 530: Asynchronous Comprehensions

[Yury Selivanov]

Hi Sven,


On 2016-09-05 4:27 PM, Sven R. Kunze wrote:
> Hi Yury,
>
> just for my understanding:
>
> On 04.09.2016 01:31, Yury Selivanov wrote:
>> We propose to allow the use of ``await`` expressions in both
>> asynchronous and synchronous comprehensions::
>>
>>     result = [await fun() for fun in funcs]
>>     result = {await fun() for fun in funcs}
>>     result = {fun: await fun() for fun in funcs}
>>
>
> This will produce normal lists, sets and dicts, right?

Right.
>
> Whereas the following will produce some sort of async lists, sets, and 
> dicts?
>
>>     result = [await fun() async for fun in funcs]
>>     result = {await fun() async for fun in funcs}
>>     result = {fun: await fun() async for fun in funcs}
>
> If so, how do I read values from an async list/set/dict?

Consider "funcs" to be an asynchronous generator/iterable that produces 
a sequence of awaitables.  The above comprehensions will await on each 
awaitable in funcs, producing regular list, set, and dict.

I doubt that anybody ever would write something like that; this is just 
examples of what the PEP will enable.

There is no concept of asynchronous datastructures in Python.

Thanks,
Yury

>
> Sven
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