Because the output file will be parsed, of course. For example, I could add structs to Lua and then the input could use structs, and the output would parse it and make it normal Lua.
Imagine vJASS for Lua. Now image that you could simply get the code instead of having to import it. It will take a text file, parse it, and return a new text file. You can also turn on an option to just replace the text in the input file with the output text instead of making a new file. Because Lua is such a widely used language, you can then put this output into any game such as WoW Addons, GMod, etx c.
I will probably make something like that eventually, but I'm mainly doing this for myself and for experience in the language. JAVA parsing is said to be exquisite, and I eventually plan to extend Lua.
Well they gave me a snow blower but it was too wet to do much with with other than compact everything. Oh well, the cop cars can get into there now when they arrest people I guess