On Dec 10, 8:13 am, Noah Hoffman <[EMAIL PROTECTED]> wrote:
> I have been trying to write a regular expression that identifies a
> block of text enclosed by (potentially nested) parentheses. I've found
> solutions using other regular expression engines (for example, my text
> editor, BBEdit, which uses the PCRE library), but have not been able
> to replicate it using python's re module.
A pattern that can validly be described as a "regular expression"
cannot count and thus can't match balanced parentheses. Some "RE"
engines provide a method of tagging a sub-pattern so that a match must
include balanced () (or [] or {}); Python's doesn't.
Looks like you need a parser; try pyparsing.
[snip]
> py> rexp = r"""(?P<parens>
> ... \(
> ... (?>
> ... (?> [^()]+ ) |
> ... (?P>parens)
> ... )*
> ... \)
> ... )"""
> py> print re.findall(no_ws(rexp), text)
Ummm ... even if Python's re engine did do what you want, wouldn't you
need flags=re.VERBOSE in there?
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