A tool I find useful enough to warrant purchasing and running in a VM or Wine is RegexBuddy. It is great for debugging / optimizing regexes and supports several different language flavors. Still waiting for Vim and PHP flavors though. :) It allows you to generate code snippits in several languages that use the regex you constructed, and will assist you in performing cross-language translations.

I've written an automated tool to convert Vim-style regexes to Perl-style. This is kind of a dramatic case as the dialect is very different, but it was a fun thing to write.

Is it bi-directional? Is it on the vim.org website somewhere? I find Vim's escape heavy syntax cumbersome and I frequently wish I could write a quick Perl syntax regex and convert it to Vim.

Of course, Vim is one of the few regex engines to support variable width negative look-behinds, so I guess that counts for something. :)

Only Vim -> Perl is fully fleshed out right now. Doing it the other way would be fairly easy though because so much would be reused. Also, with the Vim regexes I had to worry about magicness and so on, the Perl stuff would parse easier.

It's not in Vim.org. I had the code floating around with an MIT license, but it's offline right now. I thought about building a page where you could do the translation (I figured Perl -> Vim is what people would want more) or just use a simple GET request from other code.

Maybe I should do the Perl -> Vim bit and make it available.

Can you make vim use pcre?

From my look in the Vim sources, it would be tons of work to truly make it use pcre internally.

But I think it wouldn't be hard to do a plugin that translates a pcre into a Vim regex, allowing you to search or replace using pcres.

My code though is not integrated with Vim, it takes a free floating regex and converts it. I used it to convert all the regexes in Vim syntax files and build a syntax highlighter. It was a silly project, just for fun.

indeed. grep -P is your friend. (except older grep versions seem to segfault on me constantly with various -P regexes)

sudo aptitude install txt2regex