"Sean Givan" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> Hi. I'm new to Python, and downloaded a Windows copy a little while
> ago. I was doing some experiments with nested functions, and ran into
> something strange.
Experiments are good. Strange can be instructive.
...
> I'm thinking this is some bug
Blaming the interpreter is not so good, but amazingly common among
newcomers ;-)
> where the interpreter is getting ahead of itself,
...
> Or am I doing something wrong?
In a sense, you got ahead of yourself. And the issue has nothing to do
with nested scopes per se. When things seem strange, try a simpler
experiment.
>>> x=1
>>> def f():
print x
x = 2
>>> f()
Traceback (most recent call last):
File "<pyshell#5>", line 1, in -toplevel-
f()
File "<pyshell#4>", line 2, in f
print x
UnboundLocalError: local variable 'x' referenced before assignment
The compiler compiles functions in two passes: the first to classify names
as local or global (or nested if relevant, but not really so here), the
second to generate bytecodes which depend on that classification.
Terry Jan Reedy
--
http://mail.python.org/mailman/listinfo/python-list
