Global confusion

[William Park]

On Tue, Sep 28, 1999 at 09:25:28PM +0000, Gaetan Corneau wrote:
> Hello,
> 
> I often use scripts like this:
> 
> n = "Hello!"
> 
> def F():
>     print n
> 
> F()
> 
> 
> Today, a friend of mine (a newbie) who is trying to use Python with word,
> wrote the following:
> 
> import win32com.client.dynamic
> 
> Srv = win32com.client.dynamic.Dispatch("word.application")
> 
> Srv.Documents("Document1").Activate # Word must already be running and have
> document1 open
> 
> nbPar = Srv.ActiveDocument.Paragraphs.Count
> Srv.ActiveDocument.Paragraphs(nbPar).Range.InsertParagraphAfter()
> 
> 
> # Function to add a paragraph
> def AddParagraph(style, text):
>     Srv.ActiveDocument.Paragraphs[nbPar].Range.InsertParagraphAfter()
>     Srv.ActiveDocument.Paragraphs[nbPar].Range.Style =
> Srv.ActiveDocument.Styles(style)
>     Srv.ActiveDocument.Paragraphs[nbPar].Range.InsertAfter(text)
>     nbPar = nbPar + 1
> 
> # Create a section
> def AddObjectSection(objName):
>     AddParagraph("Heading 1", objName)
> 
> 
> AddObjectSection("Customer")
> 
> and he got the following:
> 
> Traceback (innermost last):
>   File "D:\harddisk\temp\dantest.py", line 24, in ?
>     AddObjectSection("Customer")
>   File "D:\harddisk\temp\dantest.py", line 21, in AddObjectSection
>     AddParagraph("Heading 1", objName)
>   File "D:\harddisk\temp\dantest.py", line 14, in AddParagraph
>     Srv.ActiveDocument.Paragraphs[nbPar].Range.InsertParagraphAfter()
> NameError: nbPar
> 
> I looked in my "Learning Python" book and told my friend to insert  "global
> nbPar" as the first line of the "AddParagraph" function.
> It works, but I don't understand why he has to do that...
> 
> Anybody who can exlain?

Probably, the line
    nbPar = nbPar + 1
is telling the python interpretor that 'nbPar' is a local variable,
since it is being assigned.  So, when local namespace is searched,
it's not there.

I encountered this kind of problem often, where a variable occurs on
both side of '=' for the first time.

	Yours truly,
	William Park