Python 3 removes name binding from outer scope

[Chris Angelico]

On Wed, Jul 26, 2017 at 4:36 AM, eryk sun <eryksun at gmail.com> wrote:
> On Tue, Jul 25, 2017 at 8:43 AM, Chris Angelico <rosuav at gmail.com> wrote:
>>
>> I'm not actually sure what happens if you use a global declaration at
>> top level. Is it ignored? Is it an error?
>
> It isn't ignored, but it shouldn't make a difference since normally at
> module level locals and globals are the same. It makes a difference in
> an exec() that uses separate locals and globals dicts. For example:
>
>     >>> exec('print(x)', {'x':'G'}, {'x':'L'})
>     L
>     >>> exec('global x; print(x)', {'x':'G'}, {'x':'L'})
>     G

Thanks. Of course, that doesn't change the fact that it'll look very
odd - but at least it won't cause a problem. Now, if you wanted to
write Py2/Py3 compatibility code inside a function, you'd have issues,
because you can't use nonlocal in Py2... but that's a separate issue.

Hmm. Aside from messing around with exec, is there any way to have a
local and a global with the same name, and use the global? You could
do it with a nonlocal:

x = "G"
def f():
    x = "L"
    def g():
        global x
        print(x)
    g()

but is there any way to engineer this actual situation without exec?

ChrisA