Module:No globals

Lua

CodeDiscussionEditHistoryLinksLink count Subpages:DocumentationTestsResultsSandboxLive code All modules

This page has been nominated for deletion since 15 April 2024. To discuss it, please visit the nomination page. Do not remove this tag until the deletion nomination is closed. Reason for the nomination: see Commons:Deletion requests/Module:No globals

Show further instructions If this template was added because you clicked "Mark for deletion" in the left menu (right when using Vector 2022 skin), please make sure that all necessary pages have been created. If they haven't been created after a few minutes, or if you added this template manually, you should complete these steps: Visit the deletion requests subpage and place the following code: {{subst:delete2|image=Module:No globals|reason=see Commons:Deletion requests/Module:No globals}} ~~~~ Go to the deletion requests log and place the following code at the bottom: {{subst:delete3|pg=Module:No globals}} Notify the item's uploader or the creator of the page by placing the following code on the user's talk page: {{subst:idw|Module:No globals|Module:No globals}} ~~~~ Additionally, you may want to check for Wikimedia projects that use this item and then remove or, if possible, replace with a superior item. For mass deletions: If you want to nominate several related images, please make a mass request by manually adding {{delete|reason=write reason|subpage=write name|year=2024|month=April|day=26}} to each image page and then following the steps hereinbefore. (Help on mass requests.) Note: This template is for requests that may require discussion in order to be deleted. For speedy deletions, you can use {{speedydelete|reason}}. In other languages

 

Module:No globals is deprecated. Please see mw:Extension:Scribunto/Lua reference manual#strict instead. (all invocations)

This module is subject to page protection. It is a highly visible module in use by a very large number of pages, or is substituted very frequently. Because vandalism or mistakes would affect many pages, and even trivial editing might cause substantial load on the servers, it is protected from editing.

This module causes an error if any nil global is read or if any global is written to, with the exception of 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. (See the Scribunto source code here.)

Code

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)