Hello, this is my first post so bear with me. I made a quick search through the forum and found nothing, so any feedback is appreciated.

Recently I have been studying spam using regular expressions in a mail proxy called SpamPal to cleanly divide each message into folders that best describe their characteristics. I feel I grasp the basics of the language well but I'm still struggling with lookaheads and lookarounds and the like.

I need to match any mutation of a word. but not the actual word itself.
For this case, I'd like an expression that avoids matching 'watch' but matches 'w@tch', 'watches', 'w_a:tch', 'w@+<h35', etc..

One final note - SpamPal's Perl engine does not support backreferencing, so please avoid using it in a solution if possible. Everything else is intact, however.

Thank you in advance.  ~Sean

Check out this link:

http://cs.medicine.ufl.edu/regex/ 

Look on that page for "Create Variant Expression", seems to do a bit of what you want, it all depends on what you want to include in your variants.

BTW, this sort of SPAM filtering is not nearly as effective as a multi-faceted approach by products such as Ironport's hardware SPAM firewall, regexes alone are no match for the creativity of those that send SPAM.

Thanks for the link - it was exactly what I was looking for.

And yes you are right about Ironport's effectiveness - I've read the documentation behind it. I forgot to mention I was only experimenting with regex. Far too much work and estimation involved to be used in the real world.
I'd rather not play with my spam. :)