I have created a web page that matches regular expressions against arbitrary input text and displays the results graphically, so you can take some sample text and build regular expressions the easy way, with immediate feedback about what matches and where, where you have errors, and more.
I’ve been working on this for a couple of weeks, a minute here and there as I get time. A few days ago I saw someone created a very nifty similar app over at Rex V. Apparently the pundits are right—never assume you’re the only one with an idea.
I used my work on grouping data visually with row groups and browser variations in
RexExp.exec() to build this tool.