There is an ongoing discussion in the NetBSD community about the "right" language for data representation. The idea is to replace an older system called "proplib". The discussion rotaes a bit around JSON and Lua as possible candidates, with probably a majority leaning towards JSON because it is smaller (some say a factor of ~16 compared to Lua).
One statement by a colleague is: "Now for the data transfer representation, as in D.'s proposal, JSON is an option, but LUA is not, simply because we have no (and there can not be any) small C binding to it."
I'd like to do a quick poll to see whether Lua is used as a language for data representation. If you know of such uses, please mail me some details.
Of course general comments on the subject matter are welcome as well.