[Python-ideas] Async Lambda syntax

Terry Reedy tjreedy at udel.edu
Fri May 18 17:44:15 EDT 2018

On 5/18/2018 4:53 PM, Noah Simon wrote:
> Hello all,
> I was developing a script using an asyncio-based API, when I came across 
> the need to define an asynchronous lambda.

Not really.

> I found this syntax does not 
> currently exist. Obviously I could have (and did) just write a regular 
> coroutine, but for simple one-line functions and such, I think an 
> asynchronous lambda syntax would be useful. I do not have the experience 
> to write a PEP or implement this, so I was wondering what you all think 
> of the idea.
> What I was thinking:
> foo = async lambda a, b: b + await bar(a

PEP8 intentionally and properly discourages 'name = lambda ...' as 
inferior to 'def name(...'.  For the above,

async def foo(a, b): return b + await bar(a)

> I posted an issue <https://bugs.python.org/issue33447> on the issue 
> tracker suggesting this, and was directed to this mailing list.

Terry Jan Reedy

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