Scope problem with nested functions.

[AddisonN at iti-ab.com]

Thanks Fredrik, that's fixed it. Apologies for the lazy typing - should
have cut and pasted the whole thing.

-----Original Message-----
From: Fredrik Lundh [mailto:fredrik at pythonware.com] 
Sent: 13 October 2005 08:55
To: python-list at python.org
Subject: Re: Scope problem with nested functions.

<AddisonN at iti-ab.com> wrote

> I'm having trouble resolving a scope problem. I have a module, called 
> from another script, with this structure:

the code you posted gives a syntax error.  if I fix that, and add some
boilerplate to call getCcyMappings from inside the parseFile function, I
get:

Traceback (most recent call last):
  File "script.py", line 19, in ?
    parseFile(0, 0, 0)
  File "script.py", line 17, in parseFile
    getCcyMappings()
  File "script.py", line 8, in getCcyMappings
    ccyMappings['CAN'] = ['CAD'] # for example.
NameError: global name 'ccyMappings' is not defined

which tells you that there is no *global* variable named ccyMappings.

the ccyMappings variable in your example isn't a global variable; it's
local to the parseFile function, and can be accessed from that function
and any inner functions via normal lexical scoping rules (=access, but
not rebind).

however, the global statement tells Python that the given name is a
global variable, and that any attempts to access or rebind that variable
should be done at the global (=module) level.

if you remove the global statement, Python will look for variables using
ordinary lexical scoping, and things will work as expected.

</F> 






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