newbie-question: Nested functions and variable scope
Leonardo Boiko
leoboiko at linuxbr.com.br
Wed Sep 4 19:03:35 EDT 2002
Hi, I'm a Python newbie. I'm writing a program that uses expat. Some
code looks like this:
def generate_main(filename="main.xml", (...)):
(...)
outfile = open (filename, "w")
in_reply = 0 # true if we are inside "reply" element
def start_element(name, attrs):
if name == "reply":
in_reply = 1
elif not in_reply:
outfile.write("<" + name.encode(encoding) + ">")
def end_element(name):
if name == "reply":
in_reply = 0
elif not in_reply:
outfile.write("</" + name.encode(encoding) + ">")
(...)
As you may have guessed, this gives me an error:
>>> generate_main()
Traceback (most recent call last):
File "<stdin>", line 1, in ?
File "../xmlgen.py", line 52, in generate_main
parser.ParseFile(file)
File "../xmlgen.py", line 22, in start_element
elif not in_reply:
UnboundLocalError: local variable 'in_reply' referenced before
assignment
If I put "in_reply" outside everything and use "global in_reply"
inside each nested function, it works, but that's evil! What would be
a better way of doing it? Do I need to use a class?
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