Module:Documentation

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Template:Distinguish Template:Documentation subpage Template:High-use Template:Shortcut Template:Stack

This is the Template:Tlf template used on almost every template page to contain that template's documented instructions and information.

For detailed instructions on how and when to use this template, see Wikipedia:Template documentation (shortcut: WP:TDOC).

This template displays a green documentation box like you are seeing now and automatically loads the content from a /doc subpage. It can also load the content from other places if instructed to.

This template is intended for documenting templates and other pages that are transcluded onto other pages. It can be used in the template namespace and most other namespaces.

Use of this template allows templates to be protected where necessary, while allowing anyone to edit the documentation and categories.

Usage

Normally this template is used without any parameters, placed at the bottom of the template or page being documented, within a Template:Tag container:

<!--Last line of your template code--><noinclude>
{{Documentation}}
<!-- Add categories to the /doc subpage, interwikis to Wikidata, not here -->
</noinclude>

Then this template automatically loads the content from the /doc subpage of the template it is used on.

This template can also load the content from any other page. Like this:

<!--Last line of your template code--><noinclude>
{{Documentation |Template:Other page/doc}}
</noinclude>

Note that when loading the documentation from a page other than the local /doc page it becomes tricky to handle the categories.

The content can also be fed directly as text. Like this:

<!--Last line of your template code--><noinclude>
{{Documentation
 | content =
(some documentation)
}}</noinclude>

When the Template:Para parameter is used, the doc box normally does not show the [edit] [purge] links in the top right corner. Note that if the /doc page exists, a link to it is still shown in the link box below the doc box.

Parameter Template:Para and the Template:Para parameter can also be combined, like this:

<!--Last line of your template code--><noinclude>
{{Documentation |1=Template:Any page/doc
| content =
{{Template:Any page/doc |parameters}}
}}</noinclude>

Then the pagename fed as parameter 1 is used for the [edit] [purge] links and for the /doc link in the link box below the doc box. But the content parameter is used for the content shown in the doc box. The above code means that the content is transcluded as Template:Tnull. In this example a parameter is also fed to the /doc page being loaded.

Shortcut

To automatically insert the noinclude tags, the template call and the guiding comment, use this substitution code:

{{subst:doc-code}}

Best practice

The code should be added at the bottom of the template code, with no space before Template:Tag (which would cause extra space on pages where the template is used).

Categories that apply to the template itself should be added to the bottom of the /doc subpage, inside Template:Tag tags. Interwiki links that apply to the template should be listed at Wikidata (more at Wikipedia:Wikidata). For more complex cases, see Wikipedia:Template documentation#Categories and interwiki links.

If the documentation page contains Template:Tag or Template:Tag tags as part of the visible documentation text, replace the "<" with "&lt;" or use Template:tag.

Heading

When in the Template namespace, this template shows this heading:

32px Template documentation

In most other namespaces, such as "Wikipedia:", it shows this heading:

Documentation

But when on File (image) pages it shows this heading:

Summary

The heading parameter can be used to set the heading to something else. Like this:

{{Documentation |heading=Infobox documentation}}

If the heading parameter is empty but defined, no heading is shown and no [edit] [purge] links are shown. Like this:

{{Documentation |heading=}}

The heading-style parameter can be fed optional CSS values. Without quotation marks " " but with the ending semicolons ;. For example:

heading-style=font-size:150%;color:red;

Link box

Below the big doc box is a small link box that shows some meta-data about the documentation. The link box shows different things depending on what parameters are fed to this template, and in which namespace it is used. In some cases the link box is not shown at all.

To hide the link box, add the parameter

Template:Para.

You can also insert customised text into the link box, by setting the Template:Para parameter. For example:

  |link box=This documentation is automatically generated by [[Template:Country showdata]]

Automatic functions

If the documentation page does not exist, the [create] link includes a preload page so that clicking it will pre-fill the edit form with the basic documentation page format. Preload text is also used for the /sandbox and /testcases [create] links.

When this template is on a protected template page it now automatically adds pp-template , which shows the grey or red padlock in the top right corner. So no need to manually add Template:Tlf to templates that use Documentation .

When this template is on a /sandbox subpage it automatically adds the Template sandbox notice .

Subject namespaces vs. talk namespaces

Terminology: Subject namespaces are the opposite of talk namespaces. For instance "Template:" is the subject space of "Template talk:".

This template is usually placed in a subject namespace, within Template:Tag tags. But in some cases this template needs to be on the talk page:

  • In the Mediawiki namespace, since Template:Tag often does not work in system messages, and since the Mediawiki namespace needs to be kept clean for performance reasons.

When placed on talk pages, this template usually is placed near the top of the page and without Template:Tag tags.

The /doc, /sandbox and /testcases pages should normally be in the subject namespace, except in the namespaces that do not have the MediaWiki subpage feature enabled: Main, File, Mediawiki and Category. (But currently we only show the /sandbox and /testcases links from User, User talk, Template and Template talk namespaces.) There are also a whole bunch of other technical reasons why the /doc page must be stored under the talk page for those (but only those) namespaces.

This template automatically points its [create] links for the /doc, /sandbox and /testcases to the right namespace.

Testing

You can simulate the output for a given page by using the Template:Para parameter. For example, if you use the code Template:Para, the template will behave exactly as if it were on the page Template:Edit protected, including showing the documentation from Template:Edit protected/doc, linking to Template:Edit protected/sandbox, etc. This parameter is useful for testing and is used extensively on the module testcases page.

Technical details

The preload page for the /doc [create] link is Template:Documentation/preload. The preload pages for the /sandbox and /testcases [create] links are Template:Documentation/preload-sandbox and Template:Documentation/preload-testcases. The preload page for the /sandbox [mirror] link is Template:Documentation/mirror.

For more details, see the talk page.

Full syntax

{{Documentation}}

{{Documentation
 | content =
}}

{{Documentation
| [path to documentation page]
| heading-style = 
| heading = 
| link box = 
}}

See also

, a notice placed at the top of a /doc subpage explaining its role and including a link to the page it documents.

, a variant of Documentation

for use with barnstar templates.
presents the color scheme used by Documentation

.

Template:When pagename is


-- 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 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('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

	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

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

p.main = makeInvokeFunc('_main')

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.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-classes'))
			:newline()
			:wikitext(p._startBox(args, env))
			:wikitext(p._content(args, env))
			:tag('div')
				:css('clear', 'both') -- So right or left floating items don't stick out of the doc box.
				:newline()
				:done()
			: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
----------------------------------------------------------------------------

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' --> '[[Wikipedia:Template test cases|template sandbox]] page'
	-- 'sandbox-notice-pagetype-module' --> '[[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 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 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
	-- "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
	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 protectionLevels, mProtectionBanner
	local title = env.title
	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.
		mProtectionBanner = require('Module:Protection banner')
		local reason = message('protection-reason-edit')
		return mProtectionBanner._main{reason, small = true}
	elseif moveProt and moveProt ~= 'autoconfirmed' then
		-- The page is move-protected but not edit-protected. Exclude move
		-- protection with the level "autoconfirmed", as this is equivalent to
		-- no move protection at all.
		mProtectionBanner = require('Module:Protection banner')
		return mProtectionBanner._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' --> '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 = message('view-link-display')
	data.editLinkDisplay = message('edit-link-display')
	data.historyLinkDisplay = message('history-link-display')
	data.purgeLinkDisplay = message('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 = message('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=]]'
	-- '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 = 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
	elseif subjectSpace == 10 then
		-- We are in the template or template talk namespaces.
		data.headingFontWeight = 'bold'
		data.headingFontSize = '125%'
	else
		data.headingFontSize = '150%'
	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
		:css('padding-bottom', '3px')
		:css('border-bottom', '1px solid #aaa')
		:css('margin-bottom', '1ex')
		:newline()
		:tag('span')
			:cssText(data.headingStyleText)
			:css('font-weight', data.headingFontWeight)
			:css('font-size', data.headingFontSize)
			: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 "=== Headings ===" 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
	-- 
	-- Messages:
	-- 'fmbox-id' --> 'documentation-meta-data'
	-- 'fmbox-style' --> 'background-color: #ecfcf4'
	-- 'fmbox-textstyle' --> 'font-style: italic'
	-- 
	-- The HTML is generated by the {{fmbox}} template, courtesy of [[Module:Message box]].
	--]=]
	
	-- 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 arguments for {{fmbox}}.
	local fmargs = {}
	fmargs.id = message('fmbox-id') -- Sets 'documentation-meta-data'
	fmargs.image = 'none'
	fmargs.style = message('fmbox-style') -- Sets 'background-color: #ecfcf4'
	fmargs.textstyle = message('fmbox-textstyle') -- 'font-style: italic;'

	-- Assemble the fmbox 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
	fmargs.text = text

	return messageBox.main('fmbox', fmargs)
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 [[Wikipedia:Template documentation|documentation]] 
	-- is [[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 [[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 editUrl = docTitle:fullUrl{action = 'edit'}
		local editDisplay = message('edit-link-display')
		local editLink = makeUrlLink(editUrl, editDisplay)
		local historyUrl = docTitle:fullUrl{action = 'history'}
		local historyDisplay = message('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 = message('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}
		if subjectSpace == 828 then
			mirrorUrl = sandboxTitle:fullUrl{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:fullUrl{action = 'edit'}
		local testcasesEditDisplay = message('testcases-edit-link-display')
		local testcasesEditLink = makeUrlLink(testcasesEditUrl, testcasesEditDisplay)
		-- for Modules, add testcases run link if exists
		if testcasesTitle.contentModel == "Scribunto"  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: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