I've searched these forums and the Sourceforge site, but I can't find the answer to this question. Does ClamWin use PCRE or some other style? I'm having trouble getting regexes to work as I'd expect them.

For example '<zip>' doesn't work to exclude ZIP files but '<zip>' does.

This wouldn't matter if I only wanted to exclude *.ZIPs, but I'm trying to build a more complex expression, which is impossible if the basics don't work as expected.

Sorry don't get it the two syntaxes are identical...
It uses python (or perl) style regex:
https://docs.python.org/lib/re-syntax.html

I don't get it either! Everythime I type out the regex, the BB will not show it. It removes all of the special characters!

try putting it inside [ code ] [ / code ] tags (remove spaces). If that fails email it to me: clamwin at clamwin dot com

The code markers didn't help so I've e-mailed it to you.