Simplifying amap usage

[florimondmanca]

Reading through the docs it came to my mind that the async with usage of amap doesn’t “look necessary” from a UX perspective.

When using it we always have to do two things:

• Enter a context with async with (looks like an implementation detail)
• Iterate over results with async for

As a user really only care about the second operation.

So what if we moved async with inside the implementation of amap, so that users can just do...

results = [result async for result in amap(process, items)]

[graingert]

you can do this but you'd need to pass the TaskGroup into the amap, and wrap the returned AsyncGenerator with aclosing:

async with anyio.create_task_group() as tg:
    async with aclosing(amap(process, items, tg)) as aiter:
        results = [result async for result in aiter]

[florimondmanca]

@graingert Well indeed, good point. The actual correct comparison would then be this…

(Current situation)

async with aiometer.amap(process, items) as aiter:
    results = [result async for result in aiter]

Compared to this…

(Correct implementation of proposed idea)

async with anyio.create_task_group() as tg:
    async with aclosing(aiometer.amap(process, items, tg)) as aiter:
        results = [result async for result in aiter]

Which instantaneously seems like we don't want amap to change, and the async with (which ensures structured concurrency constraints) + async for is just fine (users would have to add it not to shoot themselves in the foot; and it's likely that an implementation would require the correct implementation anyway, which means there's not even a semi-viable "just async for" alternative).

I think we can close this then?

[graingert]

I think we can aclose this then?