Module:Bad title suggestion

local getArgs = require("Module:Arguments").getArgs
local p = {}

function p.main(frame)
	local args = getArgs(frame)
	-- The invalid character, e.g. ">" or "}"
	local chr = args[1]
	-- The escaped bad title, e.g. "Foobar&#62;" or "Foobar&#124;text"
	local title = args[2]
	-- A pipe (|) as the invalid character is a special case; it is not
	-- escaped, so instead the module thinks it got two empty arguments
	-- and the title as the third argument.
	if chr == nil and title == nil then
		chr = "|"
		title = args[3]
	end
	if chr == nil or title == nil then
		return ""
	end
	return p._main(chr, title)
end
function p._main(chr, title)
	local frame = mw.getCurrentFrame()
	-- Determine the suggested title by taking a prefix of the bad title
	-- up to the first invalid character. Only display the suggestion box
	-- if the page exists.
	local index = mw.ustring.find(title, mw.text.nowiki(chr), 1, true)
	local truncate = ""
	if index then
		local page = mw.title.new(mw.ustring.sub(title, 1, index - 1))
		if page and page.exists then
			truncate = '<div class="mw-parser-output">' .. frame:expandTemplate{
				title = "Did you mean box",
				args = { page.fullText }
			} .. '</div>'
		end
	end
	local substitute = ""
	local success, overrides = pcall(function() return mw.loadJsonData("Module:Bad title suggestion/override.json") end)
	local spage
	title = mw.text.decode(title)
	if success and overrides[title] then
		spage = mw.title.new(overrides[title])
	elseif chr == "[" or chr == "]" then
		local replaced = title:gsub("%[","("):gsub("%]",")")
		spage = mw.title.new(replaced)
	end
	if spage and spage.exists then
		substitute = '<div class="mw-parser-output">' .. frame:expandTemplate{
				title = "Did you mean box",
				args = { spage.fullText }
		} .. '</div>'
	end
	return substitute..truncate
end

return p
Module:Bad title suggestion

Usage

Examples
