LDoc is 
Lua documentation generator intended to be compatible with 
LuaDoc and thus follows the pattern set by the various Doc tools:
--- Summary ends with a period.
-- Some description, can be over several lines.
-- @param p1 first parameter
-- @param p2 second parameter
-- @return a string value
-- @see second_fun
function mod1.first_fun(p1,p2)
end
Tags such as see and usage are supported, and generally the names of functions and modules can be inferred from the code.
LDoc is designed to give better diagnostics: if a @see reference cannot be found, then the line number of the reference is given. LDoc knows about modules which do not use module(). This is important since this function has become deprecated in Lua 5.2. And you can avoid having to embed HTML in commments by using Markdown.
LDoc will also work with Lua C extension code, and provides some convenient shortcuts.
