fplua is a project that adds s-expressions to lua. How? String replacement. Yes, it's bad. I know, it's just a proof of concept though. (For now.)
Not all lua syntactical constructs supported yet. For example, if and for are missing, but we'll ignore those for now :P. (Actually, I'll add those next time I work on this.)
The license used (and found in the LICENSE) file is the MIT/X11 license.