Module:Documentation
-- This module implements {{documentation}}.
 
 -- Get required modules.
 local getArgs = require('Module:Arguments').getArgs
 
 -- Get the config table.
 local cfg = mw.loadData('Module:Documentation/config')
 
 local p = {}
 
 -- Often-used functions.
 local ugsub = mw.ustring.gsub
 local format = mw.ustring.format
 
 ----------------------------------------------------------------------------
 -- 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 &quot;foo-message&quot; had the value 'Foo $2 bar $1.',
 	-- message('foo-message', {'baz', 'qux'}) would return &quot;Foo qux bar baz.&quot;
 	--]]
 	local msg = cfg[cfgKey]
 	expectType = expectType or 'string'
 	if type(msg) ~= expectType then
 		error('message: type error in message cfg.' .. cfgKey .. ' (' .. expectType .. ' expected, got ' .. type(msg) .. ')', 2)
 	end
 	if not valArray then
 		return msg
 	end
 
 	local function getMessageVal(match)
 		match = tonumber(match)
 		return valArray[match] or error('message: no value found for key $' .. match .. ' in message cfg.' .. cfgKey, 4)
 	end
 
 	return ugsub(msg, '$([1-9][0-9]*)', getMessageVal)
 end
 
 p.message = message
 
 local function makeWikilink(page, display)
 	if display then
 		return format('[[%s|%s]]', page, display)
 	else
 		return 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 format('[%s %s]', url, display)
 end
 
 p.makeUrlLink = makeUrlLink
 
 local function makeToolbar(...)
 	local ret = {}
 	local lim = select('#', ...)
 	if lim &lt; 1 then
 		return nil
 	end
 	for i = 1, lim do
 		ret[#ret + 1] = select(i, ...)
 	end
 	-- 'documentation-toolbar'
 	return format(
 		'&lt;span class=&quot;%s&quot;&gt;(%s)&lt;/span&gt;',
 		message('toolbar-class'),
 		table.concat(ret, ' &amp;#124; ')
 	)
 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
 
 ----------------------------------------------------------------------------
 -- Entry points
 ----------------------------------------------------------------------------
 
 function p.nonexistent(frame)
 	if mw.title.getCurrentTitle().subpageText == 'testcases' then
 		return frame:expandTemplate{title = 'module test cases notice'}
 	else
 		return p.main(frame)
 	end
 end
 
 p.main = makeInvokeFunc('_main')
 
 function p._main(args)
 	--[[
 	-- This function defines logic flow for the module.
 	-- @args - table of arguments passed by the user
 	--]]
 	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))
 		:tag('div')
 			-- 'documentation-container'
 			:addClass(message('container'))
 			:attr('role', 'complementary')
 			:attr('aria-labelledby', args.heading ~= '' and 'documentation-heading' or nil)
 			:attr('aria-label', args.heading == '' and 'Documentation' or nil)
 			:newline()
 			:tag('div')
 				-- 'documentation'
 				:addClass(message('main-div-classes'))
 				:newline()
 				:wikitext(p._startBox(args, env))
 				:wikitext(p._content(args, env))
 				:tag('div')
 					-- 'documentation-clear'
 					:addClass(message('clear'))
 					:done()
 				:newline()
 				:done()
 			:wikitext(p._endBox(args, env))
 			:done()
 		:wikitext(p.addTrackingCategories(env))
 	-- 'Module:Documentation/styles.css'
 	return mw.getCurrentFrame():extensionTag (
 		'templatestyles', '', {src=cfg['templatestyles']
 	}) .. 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.
 	--
 	-- 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' --&gt; 'sandbox'
 		-- 'testcases-subpage' --&gt; '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' --&gt; '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' --&gt; 'sandbox'
 		--]]
 		return mw.title.new(env.docpageBase .. '/' .. message('sandbox-subpage'))
 	end
 	
 	function envFuncs.testcasesTitle()
 		--[[
 		-- Title object for the /testcases subpage.
 		-- Messages:
 		-- 'testcases-subpage' --&gt; 'testcases'
 		--]]
 		return mw.title.new(env.docpageBase .. '/' .. message('testcases-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.canonicalUrl(
 				'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[&quot;Module:Module wikitext&quot;]
 	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' --&gt; '[[File:Sandbox.svg|50px|alt=|link=]]'
 	-- 'sandbox-notice-blurb' --&gt; 'This is the $1 for $2.'
 	-- 'sandbox-notice-diff-blurb' --&gt; 'This is the $1 for $2 ($3).'
 	-- 'sandbox-notice-pagetype-template' --&gt; '[[Wikipedia:Template test cases|template sandbox]] page'
 	-- 'sandbox-notice-pagetype-module' --&gt; '[[Wikipedia:Template test cases|module sandbox]] page'
 	-- 'sandbox-notice-pagetype-other' --&gt; 'sandbox page'
 	-- 'sandbox-notice-compare-link-display' --&gt; 'diff'
 	-- 'sandbox-notice-testcases-blurb' --&gt; 'See also the companion subpage for $1.'
 	-- 'sandbox-notice-testcases-link-display' --&gt; 'test cases'
 	-- 'sandbox-category' --&gt; 'Template sandboxes'
 	-- 'module-sandbox-category' --&gt; 'Module sandboxes'
 	-- 'other-sandbox-category' --&gt; 'Sandboxes outside of template or module namespace'
 	--]=]
 	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, &quot;image&quot; and &quot;text&quot;.
 	local omargs = {}
 	omargs.image = message('sandbox-notice-image')
 	-- Get the text. We start with the opening blurb, which is something like
 	-- &quot;This is the template sandbox for [[Template:Foo]] (diff).&quot;
 	local text = ''
 	local pagetype, sandboxCat
 	if subjectSpace == 10 then
 		pagetype = message('sandbox-notice-pagetype-template')
 		sandboxCat = message('sandbox-category')
 	elseif subjectSpace == 828 then
 		pagetype = message('sandbox-notice-pagetype-module')
 		sandboxCat = message('module-sandbox-category')
 	else
 		pagetype = message('sandbox-notice-pagetype-other')
 		sandboxCat = message('other-sandbox-category')
 	end
 	local templateLink = makeWikilink(templateTitle.prefixedText)
 	local compareUrl = env.compareUrl
 	if compareUrl then
 		local compareDisplay = message('sandbox-notice-compare-link-display')
 		local compareLink = makeUrlLink(compareUrl, compareDisplay)
 		text = text .. message('sandbox-notice-diff-blurb', {pagetype, templateLink, compareLink})
 	else
 		text = text .. message('sandbox-notice-blurb', {pagetype, templateLink})
 	end
 	-- Get the test cases page blurb if the page exists. This is something like
 	-- &quot;See also the companion subpage for [[Template:Foo/testcases|test cases]].&quot;
 	local testcasesTitle = env.testcasesTitle
 	if testcasesTitle and testcasesTitle.exists then
 		if testcasesTitle.contentModel == &quot;Scribunto&quot; 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 .. '&lt;br /&gt;' .. 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 .. '&lt;br /&gt;' .. message('sandbox-notice-testcases-blurb', {testcasesLink})
 		end
 	end
 	
 	-- Add the sandbox to the sandbox category.
 	omargs.text = text .. makeCategoryLink(sandboxCat)
 
 	-- 'documentation-clear'
 	return '&lt;div class=&quot;' .. message('clear') .. '&quot;&gt;&lt;/div&gt;'
 		.. require('Module:Message box').main('ombox', omargs)
 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' --&gt; 'pp-template'
 	-- 'protection-template-args' --&gt; {docusage = 'yes'}
 	local protectionLevels = env.protectionLevels
 	if not protectionLevels then
 		return nil
 	end
 	local editProt = protectionLevels.edit and protectionLevels.edit[1]
 	local moveProt = protectionLevels.move and protectionLevels.move[1]
 	if editProt then
 		-- The page is edit-protected.
 		return require('Module:Protection banner')._main{
 			message('protection-reason-edit'), small = true
 		}
 	elseif moveProt and moveProt ~= 'autoconfirmed' then
 		-- The page is move-protected but not edit-protected. Exclude move
 		-- protection with the level &quot;autoconfirmed&quot;, as this is equivalent to
 		-- no move protection at all.
 		return require('Module:Protection banner')._main{
 			action = 'move', small = true
 		}
 	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 or args[1] 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' --&gt; 'view'
 	-- 'edit-link-display' --&gt; 'edit'
 	-- 'history-link-display' --&gt; 'history'
 	-- 'purge-link-display' --&gt; 'purge'
 	-- 'module-preload' --&gt; 'Template:Documentation/preload-module-doc'
 	-- 'docpage-preload' --&gt; 'Template:Documentation/preload'
 	-- 'create-link-display' --&gt; '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
 
 	-- Create link if /doc doesn't exist.
 	local preload = args.preload
 	if not preload then
 		if subjectSpace == 828 then -- Module namespace
 			preload = message('module-preload')
 		else
 			preload = message('docpage-preload')
 		end
 	end
 	
 	return {
 		title = title,
 		docTitle = docTitle,
 		-- View, display, edit, and purge links if /doc exists.
 		viewLinkDisplay = message('view-link-display'),
 		editLinkDisplay = message('edit-link-display'),
 		historyLinkDisplay = message('history-link-display'),
 		purgeLinkDisplay = message('purge-link-display'),
 		preload = preload,
 		createLinkDisplay = message('create-link-display')
 	}
 end
 
 function p.renderStartBoxLinks(data)
 	--[[
 	-- Generates the [view][edit][history][purge] or [create][purge] links from the data table.
 	-- @data - a table of data generated by p.makeStartBoxLinksData
 	--]]
 	local docTitle = data.docTitle
 	-- yes, we do intend to purge the template page on which the documentation appears
 	local purgeLink = makeWikilink(&quot;Special:Purge/&quot; .. data.title.prefixedText, data.purgeLinkDisplay)
 	
 	if docTitle.exists then
 		local viewLink = makeWikilink(docTitle.prefixedText, data.viewLinkDisplay)
 		local editLink = makeWikilink(&quot;Special:EditPage/&quot; .. docTitle.prefixedText, data.editLinkDisplay)
 		local historyLink = makeWikilink(&quot;Special:PageHistory/&quot; .. docTitle.prefixedText, data.historyLinkDisplay)
 		return &quot;&amp;#91;&quot; .. viewLink .. &quot;&amp;#93; &amp;#91;&quot; .. editLink .. &quot;&amp;#93; &amp;#91;&quot; .. historyLink .. &quot;&amp;#93; &amp;#91;&quot; .. purgeLink .. &quot;&amp;#93;&quot;
 	else
 		local createLink = makeUrlLink(docTitle:canonicalUrl{action = 'edit', preload = data.preload}, data.createLinkDisplay)
 		return  &quot;&amp;#91;&quot; .. createLink .. &quot;&amp;#93; &amp;#91;&quot; .. purgeLink .. &quot;&amp;#93;&quot;
 	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' --&gt; '[[File:Test Template Info-Icon - Version (2).svg|50px|link=|alt=]]'
 	-- 'template-namespace-heading' --&gt; 'Template documentation'
 	-- 'module-namespace-heading' --&gt; 'Module documentation'
 	-- 'file-namespace-heading' --&gt; 'Summary'
 	-- 'other-namespaces-heading' --&gt; 'Documentation'
 	-- 'testcases-create-link-display' --&gt; 'create'
 	--]=]
 	local subjectSpace = env.subjectSpace
 	if not subjectSpace then
 		-- Default to an &quot;other namespaces&quot; 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 = message('documentation-icon-wikitext') .. ' ' .. message('template-namespace-heading')
 	elseif subjectSpace == 828 then -- Module namespace
 		data.heading = message('documentation-icon-wikitext') .. ' ' .. message('module-namespace-heading')
 	elseif subjectSpace == 6 then -- File namespace
 		data.heading = message('file-namespace-heading')
 	else
 		data.heading = message('other-namespaces-heading')
 	end
 	
 	-- Heading CSS
 	local headingStyle = args['heading-style']
 	if headingStyle then
 		data.headingStyleText = headingStyle
 	else
 		-- 'documentation-heading'
 		data.headingClass = message('main-div-heading-class')
 	end
 	
 	-- Data for the [view][edit][history][purge] or [create] links.
 	if links then
 		-- 'mw-editsection-like plainlinks'
 		data.linksClass = message('start-box-link-classes')
 		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
 		-- 'documentation-startbox'
 		:addClass(message('start-box-class'))
 		:newline()
 		:tag('span')
 			:addClass(data.headingClass)
 			:attr('id', 'documentation-heading')
 			:cssText(data.headingStyleText)
 			:wikitext(data.heading)
 	local links = data.links
 	if links then
 		sbox:tag('span')
 			: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.prefixedText}
 	end
 	-- The line breaks below are necessary so that &quot;=== Headings ===&quot; at the start and end
 	-- of docs are interpreted correctly.
 	return '\n' .. (content or '') .. '\n' 
 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 link box.
 	local text = ''
 	if linkBox then
 		text = text .. linkBox
 	else
 		text = text .. (p.makeDocPageBlurb(args, env) or '') -- &quot;This documentation is transcluded from [[Foo]].&quot; 
 		if subjectSpace == 2 or subjectSpace == 10 or subjectSpace == 828 then
 			-- We are in the user, template or module namespaces.
 			-- Add sandbox and testcases links.
 			-- &quot;Editors can experiment in this template's sandbox and testcases pages.&quot;
 			text = text .. (p.makeExperimentBlurb(args, env) or '') .. '&lt;br /&gt;'
 			if not args.content and not args[1] then
 				-- &quot;Please add categories to the /doc subpage.&quot;
 				-- 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 '') --&quot;Subpages of this template&quot;
 		end
 	end
 	
 	local box = mw.html.create('div')
 	-- 'documentation-metadata'
 	box:attr('role', 'note')
 		:addClass(message('end-box-class'))
 		-- 'plainlinks'
 		:addClass(message('end-box-plainlinks'))
 		:wikitext(text)
 		:done()
 
 	return '\n' .. tostring(box)
 end
 
 function p.makeDocPageBlurb(args, env)
 	--[=[
 	-- Makes the blurb &quot;This documentation is transcluded from [[Template:Foo]] (edit, history)&quot;.
 	-- @args - a table of arguments passed by the user
 	-- @env - environment table containing title objects, etc., generated with p.getEnvironment
 	-- 
 	-- Messages:
 	-- 'edit-link-display' --&gt; 'edit'
 	-- 'history-link-display' --&gt; 'history'
 	-- 'transcluded-from-blurb' --&gt; 
 	-- 'The above [[Wikipedia:Template documentation|documentation]] 
 	-- is [[Help:Transclusion|transcluded]] from $1.'
 	-- 'module-preload' --&gt; 'Template:Documentation/preload-module-doc'
 	-- 'create-link-display' --&gt; 'create'
 	-- 'create-module-doc-blurb' --&gt;
 	-- 'You might want to $1 a documentation page for this [[Wikipedia:Lua|Scribunto module]].'
 	--]=]
 	local docTitle = env.docTitle
 	if not docTitle then
 		return nil
 	end
 	local ret
 	if docTitle.exists then
 		-- /doc exists; link to it.
 		local docLink = makeWikilink(docTitle.prefixedText)
 		local editDisplay = message('edit-link-display')
 		local editLink = makeWikilink(&quot;Special:EditPage/&quot; .. docTitle.prefixedText, editDisplay)
 		local historyDisplay = message('history-link-display')
 		local historyLink = makeWikilink(&quot;Special:PageHistory/&quot; .. docTitle.prefixedText, historyDisplay)
 		ret = message('transcluded-from-blurb', {docLink})
 			.. ' '
 			.. makeToolbar(editLink, historyLink)
 			.. '&lt;br /&gt;'
 	elseif env.subjectSpace == 828 then
 		-- /doc does not exist; ask to create it.
 		local createUrl = docTitle:canonicalUrl{action = 'edit', preload = message('module-preload')}
 		local createDisplay = message('create-link-display')
 		local createLink = makeUrlLink(createUrl, createDisplay)
 		ret = message('create-module-doc-blurb', {createLink})
 			.. '&lt;br /&gt;'
 	end
 	return ret
 end
 
 function p.makeExperimentBlurb(args, env)
 	--[[
 	-- Renders the text &quot;Editors can experiment in this template's sandbox (edit | diff) and testcases (edit) pages.&quot;
 	-- @args - a table of arguments passed by the user
 	-- @env - environment table containing title objects, etc., generated with p.getEnvironment
 	-- 
 	-- Messages:
 	-- 'sandbox-link-display' --&gt; 'sandbox'
 	-- 'sandbox-edit-link-display' --&gt; 'edit'
 	-- 'compare-link-display' --&gt; 'diff'
 	-- 'module-sandbox-preload' --&gt; 'Template:Documentation/preload-module-sandbox'
 	-- 'template-sandbox-preload' --&gt; 'Template:Documentation/preload-sandbox'
 	-- 'sandbox-create-link-display' --&gt; 'create'
 	-- 'mirror-edit-summary' --&gt; 'Create sandbox version of $1'
 	-- 'mirror-link-display' --&gt; 'mirror'
 	-- 'mirror-link-preload' --&gt; 'Template:Documentation/mirror'
 	-- 'sandbox-link-display' --&gt; 'sandbox'
 	-- 'testcases-link-display' --&gt; 'testcases'
 	-- 'testcases-edit-link-display'--&gt; 'edit'
 	-- 'template-sandbox-preload' --&gt; 'Template:Documentation/preload-sandbox'
 	-- 'testcases-create-link-display' --&gt; 'create'
 	-- 'testcases-link-display' --&gt; 'testcases'
 	-- 'testcases-edit-link-display' --&gt; 'edit'
 	-- 'module-testcases-preload' --&gt; 'Template:Documentation/preload-module-testcases'
 	-- 'template-testcases-preload' --&gt; 'Template:Documentation/preload-testcases'
 	-- 'experiment-blurb-module' --&gt; 'Editors can experiment in this module's $1 and $2 pages.'
 	-- 'experiment-blurb-template' --&gt; '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 sandboxEditDisplay = message('sandbox-edit-link-display')
 		local sandboxEditLink = makeWikilink(&quot;Special:EditPage/&quot; .. sandboxPage, 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:canonicalUrl{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:canonicalUrl{action = 'edit', preload = mirrorPreload, summary = mirrorSummary}
 		if subjectSpace == 828 then
 			mirrorUrl = sandboxTitle:canonicalUrl{action = 'edit', preload = templateTitle.prefixedText, summary = mirrorSummary}
 		end
 		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:canonicalUrl{action = 'edit'}
 		local testcasesEditDisplay = message('testcases-edit-link-display')
 		local testcasesEditLink = makeWikilink(&quot;Special:EditPage/&quot; .. testcasesPage, testcasesEditDisplay)
 		-- for Modules, add testcases run link if exists
 		if testcasesTitle.contentModel == &quot;Scribunto&quot;  and testcasesTitle.talkPageTitle and testcasesTitle.talkPageTitle.exists then
 			local testcasesRunLinkDisplay = message('testcases-run-link-display')
 			local testcasesRunLink = makeWikilink(testcasesTitle.talkPageTitle.prefixedText, testcasesRunLinkDisplay)
 			testcasesLinks = testcasesLink .. ' ' .. makeToolbar(testcasesEditLink, testcasesRunLink)
 		else
 			testcasesLinks = testcasesLink .. ' ' .. makeToolbar(testcasesEditLink)
 		end
 	else
 		local testcasesPreload
 		if subjectSpace == 828 then
 			testcasesPreload = message('module-testcases-preload')
 		else
 			testcasesPreload = message('template-testcases-preload')
 		end
 		local testcasesCreateUrl = testcasesTitle:canonicalUrl{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 &quot;Please add categories to the /doc subpage.&quot;
 	-- @args - a table of arguments passed by the user
 	-- @env - environment table containing title objects, etc., generated with p.getEnvironment
 	-- Messages:
 	-- 'doc-link-display' --&gt; '/doc'
 	-- 'add-categories-blurb' --&gt; '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 &quot;Subpages of this template&quot; link.
 	-- @args - a table of arguments passed by the user
 	-- @env - environment table containing title objects, etc., generated with p.getEnvironment
 	
 	-- Messages:
 	-- 'template-pagetype' --&gt; 'template'
 	-- 'module-pagetype' --&gt; 'module'
 	-- 'default-pagetype' --&gt; 'page'
 	-- 'subpages-link-display' --&gt; '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
 
 ----------------------------------------------------------------------------
 -- 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' --&gt; true
 	-- 'doc-subpage' --&gt; 'doc'
 	-- 'testcases-subpage' --&gt; 'testcases'
 	-- 'strange-usage-category' --&gt; '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