[Python-ideas] Unify global and nonlocal

[Amber Yust]

global and nonlocal are different specifically because they do different
things. Yes, there is a reason why nonlocal stops at the first scope up -
because that's what it exists to do.

On Mon Feb 03 2014 at 12:28:42 PM, Manuel Cerón <ceronman at gmail.com> wrote:

> Hello,
>
> The 'global' and 'nonlocal' statements serve very similar purposes.
> They both allow to rebind names in an outer scope. While 'nonlocal'
> allows to rebind a name in the closest outer scope, *except* the
> global module scope, 'global' is used for the later case.
>
> Is there a reason why 'nonlocal' has to stop at the scope immediately
> after the global module scope? If 'nonlocal' could continue until the
> global scope, then it would become (almost) a generalized case of
> 'global'. Having both statements goes against the "There should be one
> - and preferably only one - obvious way to do it" principle.  It's
> also confusing for beginners and people used to a functional style.
>
> I think 'nonlocal' should be changed to support all the enclosing
> scopes, including the global module scope, and the 'global' statement
> should be marked as deprecated.
>
> There is one specific use case that breaks though, which is rebinding
> to global names from a deep function skipping names in the middle, for
> example:
>
> x = 'global'
> def outer1():
>     x = 'outer1'
>     def outer2():
>         global x
>         x = 'outer2' # binds the global module name
>
> But you know "special cases aren't special enough to break the rules".
>
> My apologizes if this topic was already discussed in the past.
>
> Manuel.
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