I recently devoted a little bit of my time to learn Lua's pattern language. It's not an easy endeavour, but it's also not a hard one. Pattern language is similar to .NET regular expressions. Patterns are basically a way to easily substring or substitute your data using a normal string that contains 'character classes', special identifiers or just normal characters. Get in the chat room and discuss. Here's a link to pattern section in the Lua manual..

http://www.lua.org/manual/5.1/manual.html#5.4.1