[Python-Dev] assignment expressions: an alternative proposal (original) (raw)

Chris Angelico rosuav at gmail.com
Tue Apr 24 12:42:08 EDT 2018

On Wed, Apr 25, 2018 at 2:23 AM, Steven D'Aprano <steve at pearwood.info> wrote:

On Tue, Apr 24, 2018 at 11:25:58AM -0400, Yury Selivanov wrote:

No, it doesn't. The check is performed during compile phase, and Python does not unroll loops. Anyways, read below. What does unrolling loops have to do with anything? And besides, loop unrolling is an implementation detail -- maybe Python will unroll loops, maybe it won't. If you insist that the check is only done at compile time, then your description is wrong and your rule that "it is not allowed to mask names in the current local scope" is false. It is allowed to shadow names in the local scope, but only names that cannot be determined at compile-time. from math import * process(arg, (pi = 1), pi+1) # allowed That's more and worse complexity.

That's not allowed at local scope (at least, it's not allowed at function scope - is there any other "local scope" at which it is allowed?). Not sure if you can craft equivalent shenanigans with 'exec'.

ChrisA

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