Visual REGEXP , by Laurent Riesterer, is a program that illustrates the mechanics of regular expressions, quickly build efficient regular expressions, etc. Currently at
My raving was deleted, but I reiterate it: never mind similar tools: this app can be improved, but it can't be beaten.
RLH: I use this app all the time. I have tweaked it (wider buttons and a quit button) but other than that I really like it.
aspect: as of 2015-02-26 I have made some tiny tweaks for this so I don't have to be this guy . Eventually it will get into a chiselapp repo. Ping me if you want to hurry that process along.