[Async-sig] Some thoughts on asynchronous API design in a post-async/await world

[Yury Selivanov]

[..]
> Sorry, this was a bit tongue in cheek.  This was something I said to Guido at the *very* beginning of Tulip development, when asked about mistakes Twisted has made: "don't have a global event loop, you'll never get away from it".
> 
> I still think getting rid of a global loop would always be an improvement, although I suspect it's too late at this point.  `await current_event_loop()` might make more sense in Asyncio as that's not really "global", similar to Curio's trap of the same design; however, I assume that this was an intentional design disagreement for a reason and I don't see that reason as having changed (as Yury indicates).

The latest update of get_event_loop is a step in the right direction. At least now we can document the best practices:

1. Have one “main” coroutine to bootstrap/run your program;

2. Don’t design APIs that accept the loop parameter; instead design coroutine-first APIs and use get_event_loop in your library if you absolutely need the loop.

3. I want to add “asyncio.main(coro)” function, which would create the loop, run the “coro” coroutine, and correctly clean everything up.

What you propose, IIUC is a step further:

* Deprecate get_event_loop();

* Add “current_event_loop()” coroutine.

This will enforce (1) and (2), making asyncio library devs/users to focus more on coroutines and async/await.

Am I understanding this all correctly?

Yury