[Tutor] Globals?

[Lloyd Kvam]

It DOES work in current versions of Python, exactly as you coded it.

In older Pythons (e.g. 1.52) you would have had to specifying the
enclosing variables explicitly
	def _(x=x):

A lot of old critiques are still present on the web.  wikipedia has a
terrific article describing Python that is current (at least 2.3.3).

http://en.wikipedia.org/wiki/Python_programming_language



On Sat, 2004-11-13 at 14:07, orbitz wrote:
> In my opinion, this behavior really sucks too. Like when it comes to 
> closures.  As far as I know, Python does not *really* support closures, 
> like you would get with something like lisp. Correct me if I'm wrong.  
> This means code like:
> 
> def fn(x):
>     def _():
>        x += 1
>        return x
>     return _
> 
> Will not work, which can be a pain in the ass.
> 
> 
> Kent Johnson wrote:
> 
> > Liam,
> >
> > When you make any assignment to a variable inside a function, Python 
> > assumes that the variable is local to the function. Then any use of 
> > the variable before it's first assignment is an error.
> >
> > To force a variable in a function to be global, put a 'global' 
> > statement in the function. You need to add
> >   global badConnectCycle
> > to your function getReturns
> >
> > If you don't make any assignment to a variable, then the global 
> > (module) namespace is searched. That is why badUserList works fine - 
> > you never assign it, you just access the list methods.
> >
> > Kent
> >
> > Liam Clarke wrote:
> >
> >> Hi all,
> >> Having trouble with something, it is 3:30am in the morning, so this
> >> may be a dumb problem, if so, I apologise.
> >>
> >> In my prog, there's two variables created right at the get go -
> >>
> >> import imaplib
> >> import email.Parser
> >> import os
> >> import os.path
> >> import datetime
> >> import md5
> >> from pause import *
> >>
> >> badUserList=[]
> >> badConnectCycle=0
> >>
> >> as I want them to be global within this module, so that another module
> >> can pick them out easily.
> >>
> >> Now, I just added badConnectCycle, badUserList has been there awhile,
> >> and it's used in
> >>
> >> the function connectToImap which is called by getReturns which is
> >> called by main(), and my other module can get it no problem, so
> >> badUserList is fine.
> >>
> >> badConnectCycle... is giving me errors -
> >>
> >> badConnectCycle is used in getReturns, as so -
> >> if session == "NoConnect" :             badConnectCycle += 1
> >>             continue
> >>
> >>
> >> function getReturns ends as follows -
> >> if badConnectCycle == len(user) and badConnectCycle > 0: return 
> >> ("NoConnect","")
> >> if badUserList and not sender: return ('NoLogin',"")
> >> if matchindex[0] and not sender: return ('NoNew', '')
> >> if not sender: return ("NoMatch","")
> >> return (sender, msgdata)
> >>
> >> and it's at that line
> >>
> >>  if badConnectCycle == len(user) and badConnectCycle > 0:
> >>
> >> that I get this error:
> >>
> >> UnboundLocalError: local variable 'badConnectCycle' referenced before
> >> assignment.
> >>
> >> Which is confusing me because badUserList is used within a function
> >> called by getReturns, and I've had no problem with it.
> >>
> >> Help anyone? Much appreciated if you can.
> >>
> >> Regards,
> >>
> >> Liam Clarke
> >
> > _______________________________________________
> > Tutor maillist  -  Tutor at python.org
> > http://mail.python.org/mailman/listinfo/tutor
> >
> 
> _______________________________________________
> Tutor maillist  -  Tutor at python.org
> http://mail.python.org/mailman/listinfo/tutor
-- 
Lloyd Kvam
Venix Corp