The LUA programming language is a lightweight, reflective, imperative and functional programming language, designed as a scripting language with extensible semantics as a primary goal. As stated by Wikipedia (http://en.wikipedia.org/wiki/Lua_(programming_language)).

The World of Warcraft client uses LUA to design the user interface. This allows third party developers to create unique interface customizations and share them with others, as addons.

I have been playing around with some LUA as it is used in World of Warcraft to change a few things in my client without downloading huge addons that do the same, but offer more features that I don’t want to load. Being that I am trying to be memory efficient and save CPU cycles for the game itself.

  Extra WoW Features (3.1 KiB, 362 Downloads)

This will do the following for you:

Move the casting bar down a little (Change inside .lua file, line 21)
Allow you to talk in your second language with a /lan action (Example: “/lan Hello.” Without quotes, will say hello in Draenei if you are Draenei.)
Open all bags when you talk to a ‘vendor’ and close them all when done.
Move your game-tooltips (not items) to the lower right hand corner of the screen.
Add ‘Targeting: Name Here’ to the game-tooltips.
Auto repair when you visit a merchant that is able to repair your gear.
Add tabs to the profession window that allows access to your professions with only one button.

You can of course edit the .lua file yourself and remove anything you don’t want. This is an addon I use for my purposes. Consider this beta code and may or may not work for you.