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

Andrew Svetlov andrew.svetlov at gmail.com
Tue Apr 28 14:22:56 CEST 2015

I prefer option #3.

On Mon, Apr 27, 2015 at 4:44 PM, Yury Selivanov <yselivanov.ml at gmail.com> wrote:

Hi Greg,

I don't want this: "await a() * b()" to be parsed, it's not meaningful. Likely you'll see "await await a()" only once in your life, so I'm fine to use parens for it (moreover, I think it reads better with parens) Yury

On 2015-04-27 8:52 AM, Greg Ewing wrote:

Yury Selivanov wrote:

I've done some experiments with grammar, and it looks like we indeed can parse await quite differently from yield. Three different options: You don't seem to have tried what I suggested, which is to make 'await' a unary operator with the same precedence as '-', i.e. replace factor: ('+'|'-'|'~') factor | power with factor: ('+'|'-'|'~'|'await') factor | power That would allow await a() res = await a() + await b() res = await await a() if await a(): pass return await a() print(await a()) func(arg=await a()) await a() * b()

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-- Thanks, Andrew Svetlov

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