Module:Redirect/sandbox

Main function

The 'main' function of this module accepts the name of a single page. It determines if the page is a redirect; if so it looks up the page, extracts the target, and returns the target name as text. Its usage is {{#invoke:redirect|main|redirect-page-name}}.

The template normally neither takes nor gives square brackets, so to show the result asyty

a link use [[{{#invoke:redirect|main|redirect-page-name}}]].  An error is produced if the redirect does not exist, but for versatility no error is given if the file is not a redirect (returns the original text) or if the file name is blank (returns blank).

However, if the parameter bracket is given a nonblank value, brackets will be passed on if present.

Examples

See Module:Redirect/testcases

produces

WP:AFC

produces

WP:AFD

If the target isnt a redirect:

produces

wikipedia:Articles for deletion

Block function

The 'block' function replaces redirects with the actual names of articles in text entered either directly (using the text= parameter) or by specifying the name of an index page in the first unlabelled parameter. Because checking for redirects is WP:expensive, it only checks a limited number of links, so a feature is given to start only after reaching a link with a particular name. There is also a feature to limit replacements to piped links ([[A|B]] or unpiped links, or to make a piped link when an unpiped link is changed. This allows it to be used to make limited substitutions in articles without disrupting the text.

parameters

1 = provides the name of the page containing the multiple redirects to process. Ignored if text is specified.
text = (or unnamed first parameter) provides a text on which to do substitutions
2 = (or unnamed second parameter) specifies the name of a wikilink (given in its original form, perhaps a redirect) at which to begin substitutions.
pipe =

If omitted, all links are processed: [[A]] -> [[X]], [[A|B]] -> [[X|B]]
If no, unpiped links are processed: [[A]] -> [[X]], [[A|B]] -> [[A|B]]
If yes, piped links are processed: [[A]] -> [[A]], [[A|B]] -> [[X|B]]
If make, all links are processed, pipes are added on rename if absent: [[A]] -> [[A|X]], [[A|B]] -> [[X|B]]. Note that make is the setting most practical for article text to be subsequently screened for duplicate wikilinks.

nowiki = (set to 'no' if some processing of the output is desired; usually you don't want this)

examples

See Module talk:Redirect/sandbox/testcases

-- This module provides functions for getting the target of a redirect page.

local p = {}

-- Gets a mw.title object, using pcall to avoid generating script errors if we
-- are over the expensive function count limit (among other possible causes).
local function getTitle(...)
	local success, titleObj = pcall(mw.title.new, ...)
	if success then
		return titleObj
	else
		return nil
	end
end

-- Gets the name of a page that a redirect leads to, or nil if it isn't a
-- redirect.
function p.getTargetFromText(text)
	local target = string.match(
		text,
		"^%s*#[Rr][Ee][Dd][Ii][Rr][Ee][Cc][Tt]%s*:?%s*%[%[([^%[%]|]-)%]%]"
	) or string.match(
		text,
		"^%s*#[Rr][Ee][Dd][Ii][Rr][Ee][Cc][Tt]%s*:?%s*%[%[([^%[%]|]-)|[^%[%]]-%]%]"
	)
	return target and mw.uri.decode(target, 'PATH')
end

-- Gets the target of a redirect. If the page specified is not a redirect,
-- returns nil.
function p.getTarget(page, fulltext)
	-- Get the title object. Both page names and title objects are allowed
	-- as input.
	local titleObj
	if type(page) == 'string' or type(page) == 'number' then
		titleObj = getTitle(page)
	elseif type(page) == 'table' and type(page.getContent) == 'function' then
		titleObj = page
	else
		error(string.format(
			"bad argument #1 to 'getTarget'"
				.. " (string, number, or title object expected, got %s)",
			type(page)
		), 2)
	end
	if not titleObj then
		return nil
	end
	local targetTitle = titleObj.redirectTarget
	if targetTitle then
		if fulltext then
			return targetTitle.fullText
		else
			return targetTitle.prefixedText
		end
	else
		return nil
	end
end

--[[
-- Given a single page name determines what page it redirects to and returns the
-- target page name, or the passed page name when not a redirect. The passed
-- page name can be given as plain text or as a page link.
--
-- Returns page name as plain text, or when the bracket parameter is given, as a
-- page link. Returns an error message when page does not exist or the redirect
-- target cannot be determined for some reason.
--]]
function p.luaMain(rname, bracket, fulltext)
	if type(rname) ~= "string" or not rname:find("%S") then
		return nil
	end
	bracket = bracket and "[[%s]]" or "%s"
	rname = rname:match("%[%[(.+)%]%]") or rname
	local target = p.getTarget(rname, fulltext)
	local ret = target or rname
	ret = getTitle(ret)
	if ret then
		if fulltext then
			ret = ret.fullText
		else
			ret = ret.prefixedText
		end
		return bracket:format(ret)
	else
		return nil
	end
end

-- Provides access to the luaMain function from wikitext.
function p.main(frame)
	local args = require('Module:Arguments').getArgs(frame, {frameOnly = true})
	return p.luaMain(args[1], args.bracket, args.fulltext) or ''
end

-- Returns true if the specified page is a redirect, and false otherwise.
function p.luaIsRedirect(page)
	local titleObj = getTitle(page)
	if not titleObj then
		return false
	end
	return titleObj.isRedirect
end

-- Provides access to the luaIsRedirect function from wikitext, returning 'yes'
-- if the specified page is a redirect, and the blank string otherwise.
function p.isRedirect(frame)
	local args = require('Module:Arguments').getArgs(frame, {frameOnly = true})
	if p.luaIsRedirect(args[1]) then
		return 'yes'
	else
		return ''
	end
end

return p