[Python-Dev] PEP 492 vs. PEP 3152, new round (original) (raw)

Ethan Furman ethan at stoneleaf.us
Wed Apr 29 17:29:30 CEST 2015

On 04/29, Yury Selivanov wrote:

On 2015-04-29 5:12 AM, Greg Ewing wrote:

Yury Selivanov wrote:

Looking at the grammar -- the only downside of the current approach is that you can't do 'await await fut'. I still think that it reads better with parens. If we put 'await' to 'factor' terminal we would allow

await -fut # await (-fut) Is there really a need to disallow that? It would take a fairly bizarre API to make it meaningful in the first place, but in any case, it's fairly clear what order of operations is intended without the parens. Greg, if grammar can prevent this kind of mistakes - it should. I like my current approach.

That's like saying we should always put parens around the number being raised in

n ** x

because

-2**4 != (-2)**4

Please do not overuse parens. Python is not lisp, and await is not a function, so parens should not be needed in the common case.

-- Ethan

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