Module:Documentation

Module documentation

[view] [edit] [history] [purge]

This module displays a blue box containing documentation for templates, Lua modules, or other pages. The {{documentation}} template invokes it.

Normal usage

For most uses, you should use the {{documentation}} template; please see that template's page for its usage instructions and parameters.

Use in other modules

To use this module from another Lua module, first load it with require:

local documentation = require('Module:Documentation').main

Then you can simply call it using a table of arguments.

documentation{content = 'Some documentation', ['link box'] = 'My custom link box'}

Please refer to the template documentation for usage instructions and a list of parameters.

Porting to other wikis

The module has a configuration file at Module:Documentation/config which is intended to allow easy translation and porting to other wikis. Please see the code comments in the config page for instructions. If you have any questions, or you need a feature which is not currently implemented, please leave a message at Template talk:Documentation to get the attention of a developer.

The above documentation is transcluded from Module:Documentation/doc. (edit | history)
Editors can experiment in this module’s sandbox (create | mirror) and testcases (create) pages.
Subpages of this module.

-- This module implements {{documentation}}.

-- Get required modules.
local getArgs = require('Module:Arguments').getArgs
local messageBox = require('Module:Message box')

-- Get the config table.
local cfg = mw.loadData('Module:Documentation/config')
local i18n = mw.loadData('Module:Documentation/i18n')
local p = {}

-- Often-used functions.
local ugsub = mw.ustring.gsub

----------------------------------------------------------------------------
-- Helper functions
--
-- These are defined as local functions, but are made available in the p
-- table for testing purposes.
----------------------------------------------------------------------------

local function message(cfgKey, valArray, expectType)
	--[[
	-- Gets a message from the cfg table and formats it if appropriate.
	-- The function raises an error if the value from the cfg table is not
	-- of the type expectType. The default type for expectType is 'string'.
	-- If the table valArray is present, strings such as $1, $2 etc. in the
	-- message are substituted with values from the table keys [1], [2] etc.
	-- For example, if the message "foo-message" had the value 'Foo $2 bar $1.',
	-- message('foo-message', {'baz', 'qux'}) would return "Foo qux bar baz."
	--]]
	local msg = cfg[cfgKey]
	expectType = expectType or 'string'
	if type(msg) ~= expectType then
		error(require('Module:TNT').format('I18n/Documentation', 'cfg-error-msg-type', cfgKey, expectType, type(msg)), 2)
	end
	if not valArray then
		return msg
	end

	local function getMessageVal(match)
		match = tonumber(match)
		return valArray[match] or error(require('Module:TNT').format('I18n/Documentation', 'cfg-error-msg-empty', '$' .. match, cfgKey), 4)
	end

	local ret = ugsub(msg, '$([1-9][0-9]*)', getMessageVal)
	return ret
end

p.message = message

local function makeWikilink(page, display)
	if display then
		return mw.ustring.format('[[%s|%s]]', page, display)
	else
		return mw.ustring.format('[[%s]]', page)
	end
end

p.makeWikilink = makeWikilink

local function makeCategoryLink(cat, sort)
	local catns = mw.site.namespaces[14].name
	return makeWikilink(catns .. ':' .. cat, sort)
end

p.makeCategoryLink = makeCategoryLink

local function makeUrlLink(url, display)
	return mw.ustring.format('[%s %s]', url, display)
end

p.makeUrlLink = makeUrlLink

local function makeToolbar(...)
	local ret = {}
	local lim = select('#', ...)
	if lim < 1 then
		return nil
	end
	for i = 1, lim do
		ret[#ret + 1] = select(i, ...)
	end
	return '<small style="font-style: normal;">(' .. table.concat(ret, ' &#124; ') .. ')</small>'
end	

p.makeToolbar = makeToolbar

----------------------------------------------------------------------------
-- Argument processing
----------------------------------------------------------------------------

local function makeInvokeFunc(funcName)
	return function (frame)
		local args = getArgs(frame, {
			valueFunc = function (key, value)
				if type(value) == 'string' then
					value = value:match('^%s*(.-)%s*$') -- Remove whitespace.
					if key == 'heading' or value ~= '' then
						return value
					else
						return nil
					end
				else
					return value
				end
			end
		})
		return p[funcName](args)
	end
end

----------------------------------------------------------------------------
-- Load TemplateStyles
----------------------------------------------------------------------------

p.main = function(frame)
	local parent = frame.getParent(frame)
	local output = p._main(parent.args)
	return frame:extensionTag{ name='templatestyles', args = { src= message('templatestyles-scr') } } .. output
end

----------------------------------------------------------------------------
-- Main function
----------------------------------------------------------------------------

function p._main(args)
	--[[
	-- This function defines logic flow for the module.
	-- @args - table of arguments passed by the user
	-- 
	-- Messages:
	-- 'main-div-id' --> 'template-documentation'
	-- 'main-div-classes' --> 'template-documentation iezoomfix'
	--]]
	local env = p.getEnvironment(args)
	local root = mw.html.create()
	root
		:wikitext(p._getModuleWikitext(args, env))
		:wikitext(p.protectionTemplate(env))
		:wikitext(p.sandboxNotice(args, env))
		 -- This div tag is from {{documentation/start box}}, but moving it here
		 -- so that we don't have to worry about unclosed tags.
		:tag('div')
			:attr('id', message('main-div-id'))
			:addClass(message('main-div-class'))
			:wikitext(p._startBox(args, env))
			:wikitext(p._content(args, env))
			:done()
		:wikitext(p._endBox(args, env))
		:wikitext(p.addTrackingCategories(env))
	return tostring(root)
end

----------------------------------------------------------------------------
-- Environment settings
----------------------------------------------------------------------------

function p.getEnvironment(args)
	--[[
	-- Returns a table with information about the environment, including title objects and other namespace- or
	-- path-related data.
	-- @args - table of arguments passed by the user
	--
	-- Title objects include:
	-- env.title - the page we are making documentation for (usually the current title)
	-- env.templateTitle - the template (or module, file, etc.)
	-- env.docTitle - the /doc subpage.
	-- env.sandboxTitle - the /sandbox subpage.
	-- env.testcasesTitle - the /testcases subpage.
	-- env.printTitle - the print version of the template, located at the /Print subpage.
	--
	-- Data includes:
	-- env.protectionLevels - the protection levels table of the title object.
	-- env.subjectSpace - the number of the title's subject namespace.
	-- env.docSpace - the number of the namespace the title puts its documentation in.
	-- env.docpageBase - the text of the base page of the /doc, /sandbox and /testcases pages, with namespace.
	-- env.compareUrl - URL of the Special:ComparePages page comparing the sandbox with the template.
	-- 
	-- All table lookups are passed through pcall so that errors are caught. If an error occurs, the value
	-- returned will be nil.
	--]]
	
	local env, envFuncs = {}, {}

	-- Set up the metatable. If triggered we call the corresponding function in the envFuncs table. The value
	-- returned by that function is memoized in the env table so that we don't call any of the functions
	-- more than once. (Nils won't be memoized.)
	setmetatable(env, {
		__index = function (t, key)
			local envFunc = envFuncs[key]
			if envFunc then
				local success, val = pcall(envFunc)
				if success then
					env[key] = val -- Memoise the value.
					return val
				end
			end
			return nil
		end
	})	

	function envFuncs.title()
		-- The title object for the current page, or a test page passed with args.page.
		local title
		local titleArg = args.page
		if titleArg then
			title = mw.title.new(titleArg)
		else
			title = mw.title.getCurrentTitle()
		end
		return title
	end

	function envFuncs.templateTitle()
		--[[
		-- The template (or module, etc.) title object.
		-- Messages:
		-- 'sandbox-subpage' --> 'sandbox'
		-- 'testcases-subpage' --> 'testcases'
		--]]
		local subjectSpace = env.subjectSpace
		local title = env.title
		local subpage = title.subpageText
		if subpage == message('sandbox-subpage') or subpage == message('testcases-subpage') then
			return mw.title.makeTitle(subjectSpace, title.baseText)
		else
			return mw.title.makeTitle(subjectSpace, title.text)
		end
	end

	function envFuncs.docTitle()
		--[[
		-- Title object of the /doc subpage.
		-- Messages:
		-- 'doc-subpage' --> 'doc'
		--]]
		local title = env.title
		local docname = args[1] -- User-specified doc page.
		local docpage
		if docname then
			docpage = docname
		else
			docpage = env.docpageBase .. '/' .. message('doc-subpage')
		end
		return mw.title.new(docpage)
	end
	
	function envFuncs.sandboxTitle()
		--[[
		-- Title object for the /sandbox subpage.
		-- Messages:
		-- 'sandbox-subpage' --> 'sandbox'
		--]]
		return mw.title.new(env.docpageBase .. '/' .. message('sandbox-subpage'))
	end
	
	function envFuncs.testcasesTitle()
		--[[
		-- Title object for the /testcases subpage.
		-- Messages:
		-- 'testcases-subpage' --> 'testcases'
		--]]
		return mw.title.new(env.docpageBase .. '/' .. message('testcases-subpage'))
	end
	
	function envFuncs.printTitle()
		--[[
		-- Title object for the /Print subpage.
		-- Messages:
		-- 'print-subpage' --> 'Print'
		--]]
		return env.templateTitle:subPageTitle(message('print-subpage'))
	end

	function envFuncs.protectionLevels()
		-- The protection levels table of the title object.
		return env.title.protectionLevels
	end

	function envFuncs.subjectSpace()
		-- The subject namespace number.
		return mw.site.namespaces[env.title.namespace].subject.id
	end

	function envFuncs.docSpace()
		-- The documentation namespace number. For most namespaces this is the same as the
		-- subject namespace. However, pages in the Article, File, MediaWiki or Category
		-- namespaces must have their /doc, /sandbox and /testcases pages in talk space.
		local subjectSpace = env.subjectSpace
		if subjectSpace == 0 or subjectSpace == 6 or subjectSpace == 8 or subjectSpace == 14 then
			return subjectSpace + 1
		else
			return subjectSpace
		end
	end

	function envFuncs.docpageBase()
		-- The base page of the /doc, /sandbox, and /testcases subpages.
		-- For some namespaces this is the talk page, rather than the template page.
		local templateTitle = env.templateTitle
		local docSpace = env.docSpace
		local docSpaceText = mw.site.namespaces[docSpace].name
		-- Assemble the link. docSpace is never the main namespace, so we can hardcode the colon.
		return docSpaceText .. ':' .. templateTitle.text
	end
	
	function envFuncs.compareUrl()
		-- Diff link between the sandbox and the main template using [[Special:ComparePages]].
		local templateTitle = env.templateTitle
		local sandboxTitle = env.sandboxTitle
		if templateTitle.exists and sandboxTitle.exists then
			local compareUrl = mw.uri.fullUrl(
				'Special:ComparePages',
				{page1 = templateTitle.prefixedText, page2 = sandboxTitle.prefixedText}
			)
			return tostring(compareUrl)
		else
			return nil
		end
	end		

	return env
end	

----------------------------------------------------------------------------
-- Auxiliary templates
----------------------------------------------------------------------------

p.getModuleWikitext = makeInvokeFunc('_getModuleWikitext')

function p._getModuleWikitext(args, env)
	local currentTitle = mw.title.getCurrentTitle()
	if currentTitle.contentModel ~= 'Scribunto' then return end
	pcall(require, currentTitle.prefixedText) -- if it fails, we don't care
	local moduleWikitext =  package.loaded["Module:Module wikitext"]
	if moduleWikitext then
		return moduleWikitext.main()
	end
end

function p.sandboxNotice(args, env)
	--[=[
	-- Generates a sandbox notice for display above sandbox pages.
	-- @args - a table of arguments passed by the user
	-- @env - environment table containing title objects, etc., generated with p.getEnvironment
	-- 
	-- Messages:
	-- 'sandbox-notice-image' --> '[[Image:Sandbox.svg|50px|alt=|link=]]'
	-- 'sandbox-notice-blurb' --> 'This is the $1 for $2.'
	-- 'sandbox-notice-diff-blurb' --> 'This is the $1 for $2 ($3).'
	-- 'sandbox-notice-pagetype-template' --> '[[w:Wikipedia:Template test cases|template sandbox]] page'
	-- 'sandbox-notice-pagetype-module' --> '[[w:Wikipedia:Template test cases|module sandbox]] page'
	-- 'sandbox-notice-pagetype-other' --> 'sandbox page'
	-- 'sandbox-notice-compare-link-display' --> 'diff'
	-- 'sandbox-notice-testcases-blurb' --> 'See also the companion subpage for $1.'
	-- 'sandbox-notice-testcases-link-display' --> 'test cases'
	-- 'sandbox-category' --> 'Template sandboxes'
	--]=]
	local title = env.title
	local sandboxTitle = env.sandboxTitle
	local templateTitle = env.templateTitle
	local subjectSpace = env.subjectSpace
	if not (subjectSpace and title and sandboxTitle and templateTitle and mw.title.equals(title, sandboxTitle)) then
		return nil
	end
	-- Build the table of arguments to pass to {{ombox}}. We need just two fields, "image" and "text".
	local omargs = {}
	omargs.image = message('sandbox-notice-image')
	-- Get the text. We start with the opening blurb, which is something like
	-- "This is the template sandbox for [[Template:Foo]] (diff)."
	local text = ''
	local frame = mw.getCurrentFrame()
	local isPreviewing = frame:preprocess('{{REVISIONID}}') == '' -- True if the page is being previewed.
	local pagetype
	if subjectSpace == 10 then
		pagetype = message('sandbox-notice-pagetype-template')
	elseif subjectSpace == 828 then
		pagetype = message('sandbox-notice-pagetype-module')
	else
		pagetype = message('sandbox-notice-pagetype-other')
	end
	local templateLink = makeWikilink(templateTitle.prefixedText)
	local compareUrl = env.compareUrl
	if isPreviewing or not compareUrl then
		text = text .. message('sandbox-notice-blurb', {pagetype, templateLink})
	else
		local compareDisplay = message('sandbox-notice-compare-link-display')
		local compareLink = makeUrlLink(compareUrl, compareDisplay)
		text = text .. message('sandbox-notice-diff-blurb', {pagetype, templateLink, compareLink})
	end
	-- Get the test cases page blurb if the page exists. This is something like
	-- "See also the companion subpage for [[Template:Foo/testcases|test cases]]."
	local testcasesTitle = env.testcasesTitle
	if testcasesTitle and testcasesTitle.exists then
		if testcasesTitle.contentModel == "Scribunto" then
			local testcasesLinkDisplay = message('sandbox-notice-testcases-link-display')
			local testcasesRunLinkDisplay = message('sandbox-notice-testcases-run-link-display')
			local testcasesLink = makeWikilink(testcasesTitle.prefixedText, testcasesLinkDisplay)
			local testcasesRunLink = makeWikilink(testcasesTitle.talkPageTitle.prefixedText, testcasesRunLinkDisplay)
			text = text .. '<br />' .. message('sandbox-notice-testcases-run-blurb', {testcasesLink, testcasesRunLink})
		else
			local testcasesLinkDisplay = message('sandbox-notice-testcases-link-display')
			local testcasesLink = makeWikilink(testcasesTitle.prefixedText, testcasesLinkDisplay)
			text = text .. '<br />' .. message('sandbox-notice-testcases-blurb', {testcasesLink})
		end
	end
	-- Add the sandbox to the sandbox category.
	text = text .. makeCategoryLink(message('sandbox-category'))
	omargs.text = text
	omargs.class = message('sandbox-class')
	local ret = '<div style="clear: both;"></div>'
	ret = ret .. messageBox.main('ombox', omargs)
	return ret
end

function p.protectionTemplate(env)
	-- Generates the padlock icon in the top right.
	-- @env - environment table containing title objects, etc., generated with p.getEnvironment
	-- Messages:
	-- 'protection-template' --> 'pp-template'
	-- 'protection-template-args' --> {docusage = 'yes'}
	local title = env.title
	local protectionLevels
	local protectionTemplate = message('protection-template')
	local namespace = title.namespace
	if not (protectionTemplate and (namespace == 10 or namespace == 828)) then
		-- Don't display the protection template if we are not in the template or module namespaces.
		return nil
	end
	protectionLevels = env.protectionLevels
	if not protectionLevels then
		return nil
	end
	local editLevels = protectionLevels.edit
	local moveLevels = protectionLevels.move
	if moveLevels and moveLevels[1] == 'sysop' or editLevels and editLevels[1] then
		-- The page is full-move protected, or full, template, or semi-protected.
		local frame = mw.getCurrentFrame()
		return frame:expandTemplate{title = protectionTemplate, args = message('protection-template-args', nil, 'table')}
	else
		return nil
	end
end

----------------------------------------------------------------------------
-- Start box
----------------------------------------------------------------------------

p.startBox = makeInvokeFunc('_startBox')

function p._startBox(args, env)
	--[[
	-- This function generates the start box.
	-- @args - a table of arguments passed by the user
	-- @env - environment table containing title objects, etc., generated with p.getEnvironment
	-- 
	-- The actual work is done by p.makeStartBoxLinksData and p.renderStartBoxLinks which make
	-- the [view] [edit] [history] [purge] links, and by p.makeStartBoxData and p.renderStartBox
	-- which generate the box HTML.
	--]]
	env = env or p.getEnvironment(args)
	local links
	local content = args.content
	if not content then
		-- No need to include the links if the documentation is on the template page itself.
		local linksData = p.makeStartBoxLinksData(args, env)
		if linksData then
			links = p.renderStartBoxLinks(linksData)
		end
	end
	-- Generate the start box html.
	local data = p.makeStartBoxData(args, env, links)
	if data then
		return p.renderStartBox(data)
	else
		-- User specified no heading.
		return nil
	end
end

function p.makeStartBoxLinksData(args, env)
	--[[
	-- Does initial processing of data to make the [view] [edit] [history] [purge] links.
	-- @args - a table of arguments passed by the user
	-- @env - environment table containing title objects, etc., generated with p.getEnvironment
	-- 
	-- Messages:
	-- 'view-link-display' --> 'view'
	-- 'edit-link-display' --> 'edit'
	-- 'history-link-display' --> 'history'
	-- 'purge-link-display' --> 'purge'
	-- 'file-docpage-preload' --> 'Template:Documentation/preload-filespace'
	-- 'module-preload' --> 'Template:Documentation/preload-module-doc'
	-- 'docpage-preload' --> 'Template:Documentation/preload'
	-- 'create-link-display' --> 'create'
	--]]
	local subjectSpace = env.subjectSpace
	local title = env.title
	local docTitle = env.docTitle
	if not title or not docTitle then
		return nil
	end
	if docTitle.isRedirect then 
		docTitle = docTitle.redirectTarget
	end

	local data = {}
	data.title = title
	data.docTitle = docTitle
	-- View, display, edit, and purge links if /doc exists.
	data.viewLinkDisplay = i18n['view-link-display']
	data.editLinkDisplay = i18n['edit-link-display']
	data.historyLinkDisplay = i18n['history-link-display']
	data.purgeLinkDisplay = i18n['purge-link-display']
	-- Create link if /doc doesn't exist.
	local preload = args.preload
	if not preload then
		if subjectSpace == 6 then -- File namespace
			preload = message('file-docpage-preload')
		elseif subjectSpace == 828 then -- Module namespace
			preload = message('module-preload')
		else
			preload = message('docpage-preload')
		end
	end
	data.preload = preload
	data.createLinkDisplay = i18n['create-link-display']
	return data
end

function p.renderStartBoxLinks(data)
	--[[
	-- Generates the [view][edit][history][purge] or [create] links from the data table.
	-- @data - a table of data generated by p.makeStartBoxLinksData
	--]]
	
	local function escapeBrackets(s)
		-- Escapes square brackets with HTML entities.
		s = s:gsub('%[', '&#91;') -- Replace square brackets with HTML entities.
		s = s:gsub('%]', '&#93;')
		return s
	end

	local ret
	local docTitle = data.docTitle
	local title = data.title
	if docTitle.exists then
		local viewLink = makeWikilink(docTitle.prefixedText, data.viewLinkDisplay)
		local editLink = makeUrlLink(docTitle:fullUrl{action = 'edit'}, data.editLinkDisplay)
		local historyLink = makeUrlLink(docTitle:fullUrl{action = 'history'}, data.historyLinkDisplay)
		local purgeLink = makeUrlLink(title:fullUrl{action = 'purge'}, data.purgeLinkDisplay)
		ret = '[%s] [%s] [%s] [%s]'
		ret = escapeBrackets(ret)
		ret = mw.ustring.format(ret, viewLink, editLink, historyLink, purgeLink)
	else
		local createLink = makeUrlLink(docTitle:fullUrl{action = 'edit', preload = data.preload}, data.createLinkDisplay)
		ret = '[%s]'
		ret = escapeBrackets(ret)
		ret = mw.ustring.format(ret, createLink)
	end
	return ret
end

function p.makeStartBoxData(args, env, links)
	--[=[
	-- Does initial processing of data to pass to the start-box render function, p.renderStartBox.
	-- @args - a table of arguments passed by the user
	-- @env - environment table containing title objects, etc., generated with p.getEnvironment
	-- @links - a string containing the [view][edit][history][purge] links - could be nil if there's an error.
	--
	-- Messages:
	-- 'documentation-icon-wikitext' --> '[[File:Test Template Info-Icon - Version (2).svg|50px|link=|alt=Documentation icon]]'
	-- 'template-namespace-heading' --> 'Template documentation'
	-- 'module-namespace-heading' --> 'Module documentation'
	-- 'file-namespace-heading' --> 'Summary'
	-- 'other-namespaces-heading' --> 'Documentation'
	-- 'start-box-linkclasses' --> 'mw-editsection-like plainlinks'
	-- 'start-box-link-id' --> 'doc_editlinks'
	-- 'testcases-create-link-display' --> 'create'
	--]=]
	local subjectSpace = env.subjectSpace
	if not subjectSpace then
		-- Default to an "other namespaces" namespace, so that we get at least some output
		-- if an error occurs.
		subjectSpace = 2
	end
	local data = {}
	
	-- Heading
	local heading = args.heading -- Blank values are not removed.
	if heading == '' then
		-- Don't display the start box if the heading arg is defined but blank.
		return nil
	end
	if heading then
		data.heading = heading
	elseif subjectSpace == 10 then -- Template namespace
		data.heading = i18n['template-namespace-heading']
	elseif subjectSpace == 828 then -- Module namespace
		data.heading = i18n['module-namespace-heading']
	elseif subjectSpace == 6 then -- File namespace
		data.heading = i18n['file-namespace-heading']
	else
		data.heading = i18n['other-namespaces-heading']
	end
	
	-- Data for the [view][edit][history][purge] or [create] links.
	if links then
		data.linksClass = message('start-box-linkclasses')
		data.linksId = message('start-box-link-id')
		data.links = links
	end
	
	return data
end

function p.renderStartBox(data)
	-- Renders the start box html.
	-- @data - a table of data generated by p.makeStartBoxData.
	local sbox = mw.html.create('div')
	sbox
		:addClass(message('header-div-class'))
		:tag('div')
			:addClass(message('heading-div-class'))
			:wikitext(data.heading)
	local links = data.links
	if links then
		sbox
			:tag('div')
				:addClass(data.linksClass)
				:attr('id', data.linksId)
				:wikitext(links)
	end
	return tostring(sbox)
end

----------------------------------------------------------------------------
-- Documentation content
----------------------------------------------------------------------------

p.content = makeInvokeFunc('_content')

function p._content(args, env)
	-- Displays the documentation contents
	-- @args - a table of arguments passed by the user
	-- @env - environment table containing title objects, etc., generated with p.getEnvironment
	env = env or p.getEnvironment(args)
	local docTitle = env.docTitle
	local content = args.content
	if not content and docTitle and docTitle.exists then
		content = args._content or mw.getCurrentFrame():expandTemplate{title = docTitle}
	end
	-- The line breaks below are necessary so that "=== Headings ===" at the start and end
	-- of docs are interpreted correctly.
	local cbox = mw.html.create('div')
	cbox
		:addClass(message('content-div-class'))
		:wikitext('\n' .. (content or '') .. '\n')
	return tostring(cbox)
end

p.contentTitle = makeInvokeFunc('_contentTitle')

function p._contentTitle(args, env)
	env = env or p.getEnvironment(args)
	local docTitle = env.docTitle
	if not args.content and docTitle and docTitle.exists then
		return docTitle.prefixedText
	else
		return ''
	end
end

----------------------------------------------------------------------------
-- End box
----------------------------------------------------------------------------

p.endBox = makeInvokeFunc('_endBox')

function p._endBox(args, env)
	--[=[
	-- This function generates the end box (also known as the link box).
	-- @args - a table of arguments passed by the user
	-- @env - environment table containing title objects, etc., generated with p.getEnvironment
	--]=]
	
	-- Get environment data.
	env = env or p.getEnvironment(args)
	local subjectSpace = env.subjectSpace
	local docTitle = env.docTitle
	if not subjectSpace or not docTitle then
		return nil
	end
		
	-- Check whether we should output the end box at all. Add the end
	-- box by default if the documentation exists or if we are in the
	-- user, module or template namespaces.
	local linkBox = args['link box']
	if linkBox == 'off'
		or not (
			docTitle.exists
			or subjectSpace == 2
			or subjectSpace == 828
			or subjectSpace == 10
		)
	then
		return nil
	end

	-- Assemble the footer text field.
	local text = ''
	if linkBox then
		text = text .. linkBox
	else
		text = text .. (p.makeDocPageBlurb(args, env) or '') -- "This documentation is transcluded from [[Foo]]." 
		if subjectSpace == 2 or subjectSpace == 10 or subjectSpace == 828 then
			-- We are in the user, template or module namespaces.
			-- Add sandbox and testcases links.
			-- "Editors can experiment in this template's sandbox and testcases pages."
			text = text .. (p.makeExperimentBlurb(args, env) or '')
			text = text .. '<br />'
			if not args.content and not args[1] then
				-- "Please add categories to the /doc subpage."
				-- Don't show this message with inline docs or with an explicitly specified doc page,
				-- as then it is unclear where to add the categories.
				text = text .. (p.makeCategoriesBlurb(args, env) or '')
			end
			text = text .. ' ' .. (p.makeSubpagesBlurb(args, env) or '') --"Subpages of this template"
			local printBlurb = p.makePrintBlurb(args, env) -- Two-line blurb about print versions of templates.
			if printBlurb then
				text = text .. '<br />' .. printBlurb
			end
		end
	end

	local ebox = mw.html.create('div')
	ebox
		:addClass(message('footer-div-class'))
		:wikitext(text)
	return tostring(ebox)
end

function p.makeDocPageBlurb(args, env)
	--[=[
	-- Makes the blurb "This documentation is transcluded from [[Template:Foo]] (edit, history)".
	-- @args - a table of arguments passed by the user
	-- @env - environment table containing title objects, etc., generated with p.getEnvironment
	-- 
	-- Messages:
	-- 'edit-link-display' --> 'edit'
	-- 'history-link-display' --> 'history'
	-- 'transcluded-from-blurb' --> 
	-- 'The above [[w:Wikipedia:Template documentation|documentation]] 
	-- is [[w:Wikipedia:Transclusion|transcluded]] from $1.'
	-- 'module-preload' --> 'Template:Documentation/preload-module-doc'
	-- 'create-link-display' --> 'create'
	-- 'create-module-doc-blurb' -->
	-- 'You might want to $1 a documentation page for this [[w:Wikipedia:Lua|Scribunto module]].'
	--]=]
	local docTitle = env.docTitle
	if not docTitle or args.content then
		return nil
	end
	local ret
	if docTitle.exists then
		-- /doc exists; link to it.
		local docLink = makeWikilink(docTitle.prefixedText)
		local editUrl = docTitle:fullUrl{action = 'edit'}
		local editDisplay = i18n['edit-link-display']
		local editLink = makeUrlLink(editUrl, editDisplay)
		local historyUrl = docTitle:fullUrl{action = 'history'}
		local historyDisplay = i18n['history-link-display']
		local historyLink = makeUrlLink(historyUrl, historyDisplay)
		ret = message('transcluded-from-blurb', {docLink})
			.. ' '
			.. makeToolbar(editLink, historyLink)
			.. '<br />'
	elseif env.subjectSpace == 828 then
		-- /doc does not exist; ask to create it.
		local createUrl = docTitle:fullUrl{action = 'edit', preload = message('module-preload')}
		local createDisplay = i18n['create-link-display']
		local createLink = makeUrlLink(createUrl, createDisplay)
		ret = message('create-module-doc-blurb', {createLink})
			.. '<br />'
	end
	return ret
end

function p.makeExperimentBlurb(args, env)
	--[[
	-- Renders the text "Editors can experiment in this template's sandbox (edit | diff) and testcases (edit) pages."
	-- @args - a table of arguments passed by the user
	-- @env - environment table containing title objects, etc., generated with p.getEnvironment
	-- 
	-- Messages:
	-- 'sandbox-link-display' --> 'sandbox'
	-- 'sandbox-edit-link-display' --> 'edit'
	-- 'compare-link-display' --> 'diff'
	-- 'module-sandbox-preload' --> 'Template:Documentation/preload-module-sandbox'
	-- 'template-sandbox-preload' --> 'Template:Documentation/preload-sandbox'
	-- 'sandbox-create-link-display' --> 'create'
	-- 'mirror-edit-summary' --> 'Create sandbox version of $1'
	-- 'mirror-link-display' --> 'mirror'
	-- 'mirror-link-preload' --> 'Template:Documentation/mirror'
	-- 'sandbox-link-display' --> 'sandbox'
	-- 'testcases-link-display' --> 'testcases'
	-- 'testcases-edit-link-display'--> 'edit'
	-- 'template-sandbox-preload' --> 'Template:Documentation/preload-sandbox'
	-- 'testcases-create-link-display' --> 'create'
	-- 'testcases-link-display' --> 'testcases'
	-- 'testcases-edit-link-display' --> 'edit'
	-- 'module-testcases-preload' --> 'Template:Documentation/preload-module-testcases'
	-- 'template-testcases-preload' --> 'Template:Documentation/preload-testcases'
	-- 'experiment-blurb-module' --> 'Editors can experiment in this module's $1 and $2 pages.'
	-- 'experiment-blurb-template' --> 'Editors can experiment in this template's $1 and $2 pages.'
	--]]
	local subjectSpace = env.subjectSpace
	local templateTitle = env.templateTitle
	local sandboxTitle = env.sandboxTitle
	local testcasesTitle = env.testcasesTitle
	local templatePage = templateTitle.prefixedText
	if not subjectSpace or not templateTitle or not sandboxTitle or not testcasesTitle then
		return nil
	end
	-- Make links.
	local sandboxLinks, testcasesLinks
	if sandboxTitle.exists then
		local sandboxPage = sandboxTitle.prefixedText
		local sandboxDisplay = message('sandbox-link-display')
		local sandboxLink = makeWikilink(sandboxPage, sandboxDisplay)
		local sandboxEditUrl = sandboxTitle:fullUrl{action = 'edit'}
		local sandboxEditDisplay = message('sandbox-edit-link-display')
		local sandboxEditLink = makeUrlLink(sandboxEditUrl, sandboxEditDisplay)
		local compareUrl = env.compareUrl
		local compareLink
		if compareUrl then
			local compareDisplay = message('compare-link-display')
			compareLink = makeUrlLink(compareUrl, compareDisplay)
		end
		sandboxLinks = sandboxLink .. ' ' .. makeToolbar(sandboxEditLink, compareLink)
	else
		local sandboxPreload
		if subjectSpace == 828 then
			sandboxPreload = message('module-sandbox-preload')
		else
			sandboxPreload = message('template-sandbox-preload')
		end
		local sandboxCreateUrl = sandboxTitle:fullUrl{action = 'edit', preload = sandboxPreload}
		local sandboxCreateDisplay = message('sandbox-create-link-display')
		local sandboxCreateLink = makeUrlLink(sandboxCreateUrl, sandboxCreateDisplay)
		local mirrorSummary = message('mirror-edit-summary', {makeWikilink(templatePage)})
		local mirrorPreload = message('mirror-link-preload')
		local mirrorUrl = sandboxTitle:fullUrl{action = 'edit', preload = mirrorPreload, summary = mirrorSummary}
		local mirrorDisplay = message('mirror-link-display')
		local mirrorLink = makeUrlLink(mirrorUrl, mirrorDisplay)
		sandboxLinks = message('sandbox-link-display') .. ' ' .. makeToolbar(sandboxCreateLink, mirrorLink)
	end
	if testcasesTitle.exists then
		local testcasesPage = testcasesTitle.prefixedText
		local testcasesDisplay = message('testcases-link-display')
		local testcasesLink = makeWikilink(testcasesPage, testcasesDisplay)
		local testcasesEditUrl = testcasesTitle:fullUrl{action = 'edit'}
		local testcasesEditDisplay = message('testcases-edit-link-display')
		local testcasesEditLink = makeUrlLink(testcasesEditUrl, testcasesEditDisplay)
		testcasesLinks = testcasesLink .. ' ' .. makeToolbar(testcasesEditLink)
	else
		local testcasesPreload
		if subjectSpace == 828 then
			testcasesPreload = message('module-testcases-preload')
		else
			testcasesPreload = message('template-testcases-preload')
		end
		local testcasesCreateUrl = testcasesTitle:fullUrl{action = 'edit', preload = testcasesPreload}
		local testcasesCreateDisplay = message('testcases-create-link-display')
		local testcasesCreateLink = makeUrlLink(testcasesCreateUrl, testcasesCreateDisplay)
		testcasesLinks = message('testcases-link-display') .. ' ' .. makeToolbar(testcasesCreateLink)
	end
	local messageName
	if subjectSpace == 828 then
		messageName = 'experiment-blurb-module'
	else
		messageName = 'experiment-blurb-template'
	end
	return message(messageName, {sandboxLinks, testcasesLinks})
end

function p.makeCategoriesBlurb(args, env)
	--[[
	-- Generates the text "Please add categories to the /doc subpage."
	-- @args - a table of arguments passed by the user
	-- @env - environment table containing title objects, etc., generated with p.getEnvironment
	-- Messages:
	-- 'doc-link-display' --> '/doc'
	-- 'add-categories-blurb' --> 'Please add categories to the $1 subpage.'
	--]]
	local docTitle = env.docTitle
	if not docTitle then
		return nil
	end
	local docPathLink = makeWikilink(docTitle.prefixedText, message('doc-link-display'))
	return message('add-categories-blurb', {docPathLink})
end

function p.makeSubpagesBlurb(args, env)
	--[[
	-- Generates the "Subpages of this template" link.
	-- @args - a table of arguments passed by the user
	-- @env - environment table containing title objects, etc., generated with p.getEnvironment
	
	-- Messages:
	-- 'template-pagetype' --> 'template'
	-- 'module-pagetype' --> 'module'
	-- 'default-pagetype' --> 'page'
	-- 'subpages-link-display' --> 'Subpages of this $1'
	--]]
	local subjectSpace = env.subjectSpace
	local templateTitle = env.templateTitle
	if not subjectSpace or not templateTitle then
		return nil
	end
	local pagetype
	if subjectSpace == 10 then
		pagetype = message('template-pagetype')
	elseif subjectSpace == 828 then
		pagetype = message('module-pagetype')
	else
		pagetype = message('default-pagetype')
	end
	local subpagesLink = makeWikilink(
		'Special:PrefixIndex/' .. templateTitle.prefixedText .. '/',
		message('subpages-link-display', {pagetype})
	)
	return message('subpages-blurb', {subpagesLink})
end

function p.makePrintBlurb(args, env)
	--[=[
	-- Generates the blurb displayed when there is a print version of the template available.
	-- @args - a table of arguments passed by the user
	-- @env - environment table containing title objects, etc., generated with p.getEnvironment
	--
	-- Messages:
	-- 'print-link-display' --> '/Print'
	-- 'print-blurb' --> 'A [[Help:Books/for experts#Improving the book layout|print version]]'
	--		.. ' of this template exists at $1.'
	--		.. ' If you make a change to this template, please update the print version as well.'
	-- 'display-print-category' --> true
	-- 'print-category' --> 'Templates with print versions'
	--]=]
	local printTitle = env.printTitle
	if not printTitle then
		return nil
	end
	local ret
	if printTitle.exists then
		local printLink = makeWikilink(printTitle.prefixedText, message('print-link-display'))
		ret = message('print-blurb', {printLink})
		local displayPrintCategory = message('display-print-category', nil, 'boolean')
		if displayPrintCategory then
			ret = ret .. makeCategoryLink(message('print-category'))
		end
	end
	return ret
end

----------------------------------------------------------------------------
-- Tracking categories
----------------------------------------------------------------------------

function p.addTrackingCategories(env)
	--[[
	-- Check if {{documentation}} is transcluded on a /doc or /testcases page.
	-- @env - environment table containing title objects, etc., generated with p.getEnvironment
	
	-- Messages:
	-- 'display-strange-usage-category' --> true
	-- 'doc-subpage' --> 'doc'
	-- 'testcases-subpage' --> 'testcases'
	-- 'strange-usage-category' --> 'Wikipedia pages with strange ((documentation)) usage'
	-- 
	-- /testcases pages in the module namespace are not categorised, as they may have
	-- {{documentation}} transcluded automatically.
	--]]
	local title = env.title
	local subjectSpace = env.subjectSpace
	if not title or not subjectSpace then
		return nil
	end
	local subpage = title.subpageText
	local ret = ''
	if message('display-strange-usage-category', nil, 'boolean')
		and (
			subpage == message('doc-subpage')
			or subjectSpace ~= 828 and subpage == message('testcases-subpage')
		)
	then
		ret = ret .. makeCategoryLink(message('strange-usage-category'))
	end
	return ret
end

return p