Документация
local p = {}

p.lower = function(frame)
 local s = mw.text.trim(frame.args[1] or "")
 return mw.ustring.lower(s)
end

p.upper = function(frame)
 local s = mw.text.trim(frame.args[1] or "")
 return mw.ustring.upper(s)
end

return p