Hi Nathaniel,
BTW, I'm going to reply to you in the other thread about
context-local objects soon. I have some thoughts on the
topic.
On 2015-04-29 3:14 PM, Nathaniel Smith wrote:
On Apr 29, 2015 11:49 AM, "Yury Selivanov" <yselivanov...@gmail.com> wrote:
Hi Ethan,
On 2015-04-29 2:32 PM, Ethan Furman wrote:
On 04/29, Yury Selivanov wrote:
On 2015-04-29 1:25 PM, Ethan Furman wrote:
cannot also just work and be the same as the parenthesized
version.
Because it does not make any sense.
I obviously don't understand your position that "it does not make
any sense" -- perhaps you could explain a bit?
What I see is a suspension point that is waiting for the results of
coro(), which will be negated (and returned/assigned/whatever).
What part of that doesn't make sense?
Because you want operators to be resolved in the
order you see them, generally.
You want '(await -fut)' to:
1. Suspend on fut;
2. Get the result;
3. Negate it.
This is a non-obvious thing. I would myself interpret it
as:
1. Get fut.__neg__();
2. await on it.
So I want to make this syntactically incorrect:
As a bystander, I don't really care either way about whether await -fut is
syntactically valid (since like you say it's semantically nonsense
regardless and no one will ever write it). But I would rather like to
actually know what the syntax actually is, not just have a list of examples
(which kinda gives me perl flashbacks). Is there any simple way to state
what the rules for parsing await are? Or do I just have to read the parser
code if I want to know that?
There is a summary of grammar changes in the PEP:
https://www.python.org/dev/peps/pep-0492/#grammar-updates
You can also see the actual grammar file from the reference
implementation:
https://github.com/1st1/cpython/blob/await/Grammar/Grammar
Thanks,
Yury
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