[EMAIL PROTECTED] wrote: > I am not completely knowledgable about the status of lexical scoping in > Python, but it was my understanding that this was added in a long time > ago around python2.1-python2.2 > > I am using python2.4 and the following code throws a "status variable" > not found in the inner-most function, even when I try to "global" it. > > def collect(fields, reducer): > def rule(record): > status = True > def _(x, y): > cstat = reducer(x, y) > if status and not cstat: > status = False > return y > return reduce(_, [record[field] for field in fields]) > return rule > > What gives? > What's happening is that the interpreter, when it compiles the inner function _(), sees an assignment to status and so assumes it is local to the _() function. Consequently, since you reference it inside _() before assignment you get (I presume) an exception reporting an unbound local variable.
The scoping rules do work when you obey them: >>> def f1(a, b): ... s = a+b ... def _(x): ... return s+x ... return _ ... >>> func = f1(12, 13) >>> func(10) 35 >>> Here the nested lexical scopes rule isn't that helpful given the overriding nature of assignment within an inner scope. Using global will simply put the status variable at *module* scope, which also isn't what you want. regards Steve -- Steve Holden +44 150 684 7255 +1 800 494 3119 Holden Web LLC www.holdenweb.com PyCon TX 2006 www.python.org/pycon/ -- http://mail.python.org/mailman/listinfo/python-list
