[DH] >> It's a conflict between python's syntax for regex back references >> and octal number literals. Probably wasn't noticed until way too >> ate, and now it will never change.
[EMAIL PROTECTED] > I suspect it comes from Perl, since Python's regular expression engine tries > pretty hard to be compatible with Perl's, at least for the basics. "No" to all the above <wink>. The limitation to 99 in backreference notation was thoroughly discussed on the Python String-SIG at the time, and it was deliberately not bug-compatible with the Perl of that time. In the Perl of that time (no idea what's true now), e.g., \123 in a regexp was an octal escape if it appeared before or within the 123rd capturing group, but was a backreference to the 123rd capturing group if it appeared after the 123rd capturing group. So, yes, two different instances of "\123" in a single regexp could have different meanings (meaning chr(83) in one place, and a backreference to group 123 in another, and there's no way to tell the difference without counting the number of preceding capturing groups). That's so horridly un-Pythonic that we drew the line there. Nobody had a sane use case for more than 99 backreferences, so "who cares?" won. Note that this isn't a reason for limiting the number of capturing groups. It only accounts for why we didn't care that you couldn't write a _backreference_ to a capturing group higher than number 99 using "\nnn" notation. -- http://mail.python.org/mailman/listinfo/python-list
