Lua is a lightweight programming language and has good reputation among game engines. In this article, you will learn how to install and use the latest version of Lua (5.2.1) on Mac OS X Mountain Lion, Lion or Snow Leopard.
I personally prefer brew over other package management systems, especially given that it's open source. Rudix is probably just as good, but I can't see other people fixing packages in a github/issue format like i could with brew.
Also check out Luarocks. It has a wide variety of packages, and of people I've spoken to, it's the preferred package manager. It's also available on brew. http://luarocks.org