[Tutor] What exactly does "await" do?

[David]

On Mon, 13 Feb 2023 at 21:41, Alphonsus Okoye <phonokoye at gmail.com> wrote:

> How does the await
> statement suspend the execution of a coroutine and still run the coroutine?
> I know I am missing some fundamentals here. How do I make sense of this?

Let's choose one of the coroutines you posted, as an example to discuss.
This one:

> >    async def say_after(delay, what):
> >        await asyncio.sleep(delay)
> >        print(what)

When execution reaches the 'await' statement in that coroutine,
it suspends the execution of the running coroutine named 'say_after',
and instead runs the coroutine named 'asyncio.sleep'.

That's how 'await' both suspends a coroutine (the one it is in) and runs
a coroutine (a different one that it starts).

When the coroutine named 'asyncio.sleep' returns, the coroutine
named 'say_after' will resume, from the 'print(what)' statement.

A coroutine can be recognised by having 'async def' in its
definition statement, as opposed to just 'def' for the
definition of an ordinary function or method.