global, was Re: None assigment

[Jeremy Hylton]

In article <9613mn$9v$1 at news.mathworks.com>,
  Joshua Marshall <jmarshal at mathworks.com> wrote:
> Michael Hudson <mwh21 at cam.ac.uk> wrote:
> > Michael Hudson <mwh21 at cam.ac.uk> writes:
>
> >> Which version are you using?  They all print 4 for me, and all but
> >> foo() do modify the value of `b'.  foo() doesn't because what
follows
> >> an
>
> > OTOH, that was a version that had the PEP 227 code checked into it.
> > With an older version, I see what you see.  Wierd.
>
> Sounds like a bug fix.
>

As Tim will explain in a post that hasn't made it to DejaNews yet,
earlier versions of Python did not define the behavior of assignment
before a global statement.

The recent round of compiler changes uses separate passes to determine a
name's scope and to generate code for loads and stores.  As a result,
the global statement affects all assignments.

It's unclear what we should happen in this case.  It could be an error,
since it's dodgy and the behavior will change with 2.1.

--
-- Jeremy Hylton, <http://www.python.org/~jeremy/>


Sent via Deja.com
http://www.deja.com/