Why read-only nested scopes?

[Martin v. Löwis]

Gonçalo Rodrigues <op73418 at mail.telepac.pt> writes:

> >x = 1
> >
> >def foo():
> >  x = 2
> >  def bar():
> >    x = 3
> >    def baz():
> >      global x
> >      x = 4
> >
> >If you invoke baz(), which of the variables is changed? How do you
> >denote that you want to change the others?
> 
> I think that crawling up the scope hierarchy and stopping at the first x
> that one finds (in the above case, the one defined in bar) is a sensible
> solution. 

This solution is not backwards-compatible. global always refers to
globals(), programs may rely on that.

Regards,
Martin