Regular Expressions are useful in parsing user input or creating grammars for strings.
Pavils Jurjans bemoaned this fact and created his own RegExp class for Flash 5, which was encapsulated by Joey Lott into a .as file for Actionscript 2. Pavils also created a very handy tester, which together with websina's page, helped me to get started with regular expressions.
The CLIPS programmers have started to use our version of the class, which has been documented with ZenDocs, and includes a trim, rtrim, ltrim and slightly modified replace method. A simple tester .fla is available to interact with the class.
I probably feel as excited learning this new skill as the fellow in this xkcd.com comic.