One of the few things I’ve been missing since moving to OS X fulltime was a decent interactive regex builder app. The one in Eclipse is great, but Eclipse is about as anti-Mac as it gets. Others that I’ve used such as regex buddy and regular expression editor don’t run on the Mac.
Well here’s a widget that does the trick quite well, though interactive highlighting of the target string would be even better.
UPDATE: thanks for mentioning Reggy, this is the one I use regularly now, check it out: