Await/Async, part deux

[ddddxxx]

@QuinceyMorris

AFAIK, the only plausible way of implementing these behaviors is a coroutine, and (no thanks to anything I’ve said or done) that’s what’s actually being proposed, I've been happy to see.

Did you proposing a stackful coroutine? If so async/await keyword is not needed, and:

@John_McCall

If you don't have "colored" async functions, you have to do that for every function that isn't completely trivial. That allocated context then has to be threaded through calls and returns the same way the traditional stack pointer is. Since Swift doesn't already do that for ordinary functions, and we've declared our ABI stable on Apple platforms, this really just isn't an option, even if there were no other downsides.