[Python-Dev] assignment expressions: an alternative proposal

[Chris Angelico]

On Wed, Apr 25, 2018 at 2:57 AM, Steven D'Aprano <steve at pearwood.info> wrote:
> On Wed, Apr 25, 2018 at 02:42:08AM +1000, Chris Angelico wrote:
>
>> >     from math import *
>> >     process(arg, (pi = 1), pi+1)  # allowed
>
>
>> 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?).
>
> Of course: local just means the current scope, wherever you happen to
> be. Inside a function, local is the current function scope. Inside a
> class body, local is the class body scope. At the top level of the
> module, local means the module scope (and locals() returns the same dict
> as globals()).
>
> If Yury means for this "cannot mask existing variables" to only operate
> inside functions, that means that you can mask existing variables if you
> use assignment expressions in class bodies or top-level module code.

I don't have a quote for it, but I was under the impression that this
shielding was indeed function-scope-only.

Actually, now that I think about it, I'm not sure whether Yuri's plan
for assignment expressions even included module scope.

ChrisA