Module:No globals

local mt = getmetatable(_G) or {}function mt.__index (t, k)if k ~= 'arg' thenerror('Tried to read nil global ' .. tostring(k), 2)endreturn nilendfunction mt.__newindex(t, k, v)if k ~= 'arg' thenerror('Tried to write global ' .. tostring(k), 2)endrawset(t, k, v)endsetmetatable(_G, mt)