How to write a simple parser?

I neeed to write a simple parser that will interpret simple commands and convert them to HTML. The command tags start and end with square brackets "[]". For example, if someone where to type "[link:www.locatio.com | locatio]" then that would translate into "<a href="www.locatio.com">locatio</a>". It is just a way for users to avoid doing any HTML at all. I tried the regular expression functions but they only return a TRUE/FALSE value. I would like to be able to return the first part of the string, which has the command in it. Thanks in advance. -- ************************************ Ivan R. Quintero E.* (507)228-3477 Aptdo 1263 * (507)228-9105 Balboa, Ancon * Republic of Panama * ************************************