I'm not sure I understand what parser you mean... Tab completes using the tables and metatables from Lua state, better or worse (usually worse if command is a bit longer or more complex and it's tricky to find right tables since Lua is so flexible)... for example, if you do even in the example from github:
file = io.open("txt", "w")
file.
and then press tab you will (correctly) get a hint line:
read close flush setvbuf write lines seek
If you wrote: 'file.c' and then pressed tab, only 'close' would match, so instead of printed hint, you would get completion and your text would change to 'file.close' automatically.
I have not written a single line of special code to hint for that particular class methods.
Tables and tables that have metatables will work too.
Other types with per type metatable (as string in lua has by default) work too.
As for warnings - yes, I compile with '-Wall -Wno-sign-compare -Wno-switch' so there are errors for missing defaults/switch cases and for signed/unsigned comparison. I'll fix them soon.
Edit: Done, no more warnings under Wall and it didn't make code uglier too much.