Add yield support in async function

[m24h]

Checks

• I agree to follow the MicroPython Code of Conduct to ensure a safe and respectful space for everyone.

• I've searched for existing issues regarding this feature, and didn't find any.

Description

Just in PEP 525, it's really easy to make a async generator instead of coding a new class with aiter and anext .

Just like this:

async def test():
   for i in range(5):
      await something
'     yield i

Code Size

I believe this is an important syntax that makes asynchronous generation as convenient as normal generators.

Implementation

• I intend to implement this feature and would submit a Pull Request if desirable.
• I hope the MicroPython maintainers or community will implement this feature.
• I would like to Sponsor development of this feature.

[dpgeorge]

An initial implementation of PEP 525 is given in #6668.