Learning Lua isn't all that difficult if you have proficiency in other languages. To be honest, however, going this route is somewhat more difficult than simply using XML. It significantly adds to the complexity of your framework, so if you don't really have a genuine need for it and are a relative beginner, you might be better off starting with simple XML/JSON/YAML instead.
I read your article, great job you really know your stuff, ill definitely put learning Lua on my todo list, as i think itll help me later on down the line, as for this project however, i think Lua would probably end up being overkill, thanks for the suggestion though!