[Python-Dev] PEP 492 vs. PEP 3152, new round

[Nathaniel Smith]

On Wed, Apr 29, 2015 at 5:05 PM, Yury Selivanov <yselivanov.ml at gmail.com> wrote:
> Nathaniel,
>
> On 2015-04-29 7:58 PM, Nathaniel Smith wrote:
>>
>> On Wed, Apr 29, 2015 at 4:48 PM, Yury Selivanov <yselivanov.ml at gmail.com>
>> wrote:
>>>
>>> Nathaniel,
>>>
>>> On 2015-04-29 7:35 PM, Nathaniel Smith wrote:
>>>>
>>>> What I do feel strongly about
>>>> is that whatever syntax we end up with, there should be*some*
>>>> accurate human-readable description of*what it is*. AFAICT the PEP
>>>> currently doesn't have that.
>>>
>>> How to define human-readable description of how unary
>>> minus operator works?
>>
>> Hah, good question :-). Of course we all learned how to parse
>> arithmetic in school, so perhaps it's a bit cheating to refer to that
>> knowledge. Except of course basically all our users *do* have that
>> knowledge (or else are forced to figure it out anyway). So I would be
>> happy with a description of "await" that just says "it's like unary
>> minus but higher precedence".
>>
>> Even if we put aside our trained intuitions about arithmetic, I think
>> it's correct to say that the way unary minus is parsed is: everything
>> to the right of it that has a tighter precedence gets collected up and
>> parsed as an expression, and then it takes that expression as its
>> argument. Still pretty simple.
>
>
> Well, await is defined exactly like that ;)

So you're saying that "await -fut" and "await await fut" are actually
legal syntax after all, contra what the PEP says? Because "- -fut" is
totally legal syntax, so if await and unary minus work the same...
(Again I don't care about those examples in their own right, I just
find it frustrating that I can't answer these questions without asking
you each time.)

-n

-- 
Nathaniel J. Smith -- http://vorpus.org