Lua Reference/Documentation

Hi all,

is there any reference/documentation regarding writing asterisk dialplan in lua? I found this in mailing list archives but it is quite outdated now.
The reason why I am asking is that I need a way to determine what applications/variables I can use in asterisk related objects. For example ODBC functions can be found in channel object, but except one thread on the internet there is no other reference regarding it. I have tried to display the content of asterisk specific tables, but it always resulted in an empty string, while the original lua builtin tables showed its content correctly.

Thanks for any answer,
Best Regards

PS. Sorry if I messed up the terminology, I am not a programming expert.