Dynamic regex debugging in a web page: Regex Powertoy
Regex Powertoy is a fun little tool I've put together for playing with regular expressions in a web browser. I just showed it to a small group here at Bar Camp. It requires the latest Java ("5.0"/"1.5") applet support, and as yet has only been tested in Firefox.
immediate highlighting of matches as pattern and input text are editted
drill-down into capturing group details
optional animation of matching progress -- heavy backtracking becomes obvious
"matchmark" bookmarks to prepopulate pattern/input text
Many more bells and whistles are possible. There have been similar tools as downloadable apps before, but nothing quite as interactive inside a web page, as far as I know.
I'm releasing the source code at Sourceforge under the GPL. (It's not pretty code -- quick hacks and whatever experiments survived to do the job.)
Comments, ideas, and contributed features welcome.