On 7 May 2018 at 12:51, Nick Coghlan <ncogh...@gmail.com> wrote:
> If any other form of comprehension level name binding does eventually get
> accepted, then inline scope declarations could similarly be used to hoist
> values out into the surrounding scope:
>
> rem = None
> while any((nonlocal rem := n % p) for nonlocal p in small_primes):
> # p and rem were declared as nonlocal in the nested scope, so
> our rem and p point to the last bound value
>
Thinking about it a little further, I suspect the parser would reject
"nonlocal name := ..." as creating a parsing ambiguity at statement level
(where it would conflict with the regular nonlocal declaration statement).
The extra keyword in the given clause would avoid that ambiguity problem:
p = rem = None
while any(rem for nonlocal p in small_primes given nonlocal rem = n
% p):
# p and rem were declared as nonlocal in the nested scope, so
our p and rem refer to their last bound values
Such a feature could also be used to make augmented assignments do
something useful at comprehension scope:
input_tally = 0
process_inputs(x for x in input_iter given nonlocal input_tally += x)
Cheers,
Nick.
--
Nick Coghlan | ncogh...@gmail.com | Brisbane, Australia
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