Module:No globals

This module is currently protected from editing as it is a high-use module. Edits made to it will affect many pages. Please discuss changes on the talk page before implementing them. Test changes in the module's /sandbox or in your sandbox.

Overview

This module causes an error if any nil global is read or if any global is written to, except arg. To use, add require('Module:No globals') to the top of the module using it. The arg variable is excluded because it is necessary for Scribunto's require function to work properly.

Copyright

This page uses content originally from Wikipedia's Module:No globals page; Wikipedia content is licensed under a Creative Commons Attribution-ShareAlike License 4.0. (view page authors).

• Material on this page original to Wikipedia may be used commercially.
• Material on this page original to Fanlore may not be used commercially.

---

local mt = getmetatable(_G) or {}
function mt.__index (t, k)
	if k ~= 'arg' then
		error('Tried to read nil global ' .. tostring(k), 2)
	end
	return nil
end
function mt.__newindex(t, k, v)
	if k ~= 'arg' then
		error('Tried to write global ' .. tostring(k), 2)
	end
	rawset(t, k, v)
end
setmetatable(_G, mt)