On Wed, 9 Jan 2008 13:47:30 -0500 (EST) "Steven W. Orr" <[EMAIL PROTECTED]>
wrote:
> So sorry because I know I'm doing something wrong.
>
> 574 > cat c2.py
> #! /usr/local/bin/python2.4
>
> def inc(jj):
> def dummy():
> jj = jj + 1
> return jj
> return dummy
>
> h = inc(33)
> print 'h() = ', h()
> 575 > c2.py
> h() =
> Traceback (most recent call last):
> File "./c2.py", line 10, in ?
> print 'h() = ', h()
> File "./c2.py", line 5, in dummy
> jj = jj + 1
> UnboundLocalError: local variable 'jj' referenced before assignment
>
> I could have sworn I was allowed to do this. How do I fix it?
Nope. This is one of the things that makes lisper's complain that
Python doesn't have "real closures": you can't rebind names outside
your own scope (except via global, which won't work here).
Using a class is the canonical way to hold state. However, any of the
standard hacks for working around binding issues work. For instance:
>>> def inc(jj):
... def dummy():
... box[0] = box[0] + 1
... return box[0]
... box = [jj]
... return dummy
...
>>> h = inc(33)
>>> h()
34
<mike
--
Mike Meyer <[EMAIL PROTECTED]> http://www.mired.org/consulting.html
Independent Network/Unix/Perforce consultant, email for more information.
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