Module:Italic title

This template italicizes page titles. Article titles cannot contain wiki-formatting, such as '', so cannot be italicized in the normal way. Instead, place this template in the article, normally at the very top. It will then have the following effect:

• Titles with no parentheses () are fully italicised:
  • Foo → Foo
  • Talk:Foo → Talk:Foo
• Titles which contain parentheses are italicised before the first opening parenthesis:
  • Foo (bar) → Foo (bar)
  • Talk:Foo (bar) → Talk:Foo (bar)
• Italicization can be forced on parenthesized text with the Template:Para parameter.

This template should only be used in articles that meet the criteria for italic titles given in the Article titles policy.

Usage

Basic usage

{{italic title}}

All parameters

{{italic title|noerror|string=text in title|all=yes}}

Parameters

• 1: if this is set to "noerror", error messages are suppressed. See #Errors for more details.
• all: if this is set to "yes", text in parentheses is italicized.
• string: instead of italicizing the whole title, italicize only some specific text. For example, using Template:Para on the page "List of Ally McBeal episodes" would result in "List of Ally McBeal episodes".

Errors

Sometimes you may see red error messages like this at the top of the page:

This usually means that there is another instance of {{italic title}} on the page, usually added by one of the infoboxes. Certain infoboxes, for example {{infobox album}}, add {{italic title}} by default. Check the template documentation for any infobox used on the page; it may have instructions about how to deal with italic titles. You may be able to adjust the italics from the infobox instead of using {{italic title}} at the top of the article. Or if that doesn't work, you may be able to disable the infobox's italics code altogether.

If you are still having problems, try putting {{italic title}} after the infobox. You can suppress the error message by using the code {{italic title|noerror}}.

Technical details: this template uses the DISPLAYTITLE magic word to italicize the title. Error messages can be produced by any two templates which use this magic word, and are not limited to this template. If you are unsure why you are getting a particular error message, you can ask about it at Wikipedia:Village pump (technical).

Categories

If the Template:Para parameter is used but that string is not found in the title, the page is added to Category:Pages using italic title with no matching string.

---

-- This module implements {{italic title}}.

require('Module:No globals')
local libraryUtil = require('libraryUtil')
local checkType = libraryUtil.checkType
local checkTypeForNamedArg = libraryUtil.checkTypeForNamedArg
local yesno = require('Module:Yesno')

--------------------------------------------------------------------------------
-- ItalicTitle class
--------------------------------------------------------------------------------

local ItalicTitle = {}

do
	----------------------------------------------------------------------------
	-- Class attributes and functions
	-- Things that belong to the class are here. Things that belong to each
	-- object are in the constructor.
	----------------------------------------------------------------------------

	-- Keys of title parts that can be italicized.
	local italicizableKeys = {
		namespace = true,
		title = true,
		dab = true,
	}

	----------------------------------------------------------------------------
	-- ItalicTitle constructor
	-- This contains all the dynamic attributes and methods.
	----------------------------------------------------------------------------

	function ItalicTitle.new()
		local obj = {}

		-- Function for checking self variable in methods.
		local checkSelf = libraryUtil.makeCheckSelfFunction(
			'ItalicTitle',
			'obj',
			obj,
			'ItalicTitle object'
		)

		-- Checks a key is present in a lookup table.
		-- Param: name - the function name.
		-- Param: argId - integer position of the key in the argument list.
		-- Param: key - the key.
		-- Param: lookupTable - the table to look the key up in.
		local function checkKey(name, argId, key, lookupTable)
			if not lookupTable[key] then
				error(string.format(
					"bad argument #%d to '%s' ('%s' is not a valid key)",
					argId,
					name,
					key
				), 3)
			end
		end

		-- Set up object structure.
		local parsed = false
		local categories = {}
		local italicizedKeys = {}
		local italicizedSubstrings = {}

		-- Parses a title object into its namespace text, title, and
		-- disambiguation text.
		-- Param: options - a table of options with the following keys:
		--     title - the title object to parse
		--     ignoreDab - ignore any disambiguation parentheses
		-- Returns the current object.
		function obj:parseTitle(options)
			checkSelf(self, 'parseTitle')
			checkType('parseTitle', 1, options, 'table')
			checkTypeForNamedArg('parseTitle', 'title', options.title, 'table')
			local title = options.title
		
			-- Title and dab text
			local prefix, parentheses
			if not options.ignoreDab then
				prefix, parentheses = mw.ustring.match(
					title.text,
					'^(.+) %(([^%(%)]+)%)$'
				)
			end
			if prefix and parentheses then
				self.title = prefix
				self.dab = parentheses
			else
				self.title = title.text
			end
		
			-- Namespace
			local namespace = mw.site.namespaces[title.namespace].name
			if namespace and #namespace >= 1 then
				self.namespace = namespace
			end

			-- Register the object as having parsed a title.
			parsed = true
		
			return self
		end

		-- Italicizes part of the title.
		-- Param: key - the key of the title part to be italicized. Possible
		-- keys are contained in the italicizableKeys table.
		-- Returns the current object.
		function obj:italicize(key)
			checkSelf(self, 'italicize')
			checkType('italicize', 1, key, 'string')
			checkKey('italicize', 1, key, italicizableKeys)
			italicizedKeys[key] = true
			return self
		end

		-- Un-italicizes part of the title.
		-- Param: key - the key of the title part to be un-italicized. Possible
		-- keys are contained in the italicizableKeys table.
		-- Returns the current object.
		function obj:unitalicize(key)
			checkSelf(self, 'unitalicize')
			checkType('unitalicize', 1, key, 'string')
			checkKey('unitalicize', 1, key, italicizableKeys)
			italicizedKeys[key] = nil
			return self
		end

		-- Italicizes a substring in the title. This only affects the main part
		-- of the title, not the namespace or the disambiguation text.
		-- Param: s - the substring to be italicized.
		-- Returns the current object.
		function obj:italicizeSubstring(s)
			checkSelf(self, 'italicizeSubstring')
			checkType('italicizeSubstring', 1, s, 'string')
			italicizedSubstrings[s] = true
			return self
		end

		-- Un-italicizes a substring in the title. This only affects the main
		-- part of the title, not the namespace or the disambiguation text.
		-- Param: s - the substring to be un-italicized.
		-- Returns the current object.
		function obj:unitalicizeSubstring(s)
			checkSelf(self, 'unitalicizeSubstring')
			checkType('unitalicizeSubstring', 1, s, 'string')
			italicizedSubstrings[s] = nil
			return self
		end

		-- Renders the object into a page name. If no title has yet been parsed,
		-- the current title is used.
		-- Returns string
		function obj:renderTitle()
			checkSelf(self, 'renderTitle')

			-- Italicizes a string
			-- Param: s - the string to italicize
			-- Returns string.
			local function italicize(s)
				assert(type(s) == 'string', 's was not a string')
				assert(s ~= '', 's was the empty string')
				return string.format('<i>%s</i>', s)
			end
		
			-- Escape characters in a string that are magic in Lua patterns.
			-- Param: pattern - the pattern to escape
			-- Returns string.
			local function escapeMagicCharacters(s)
				assert(type(s) == 'string', 's was not a string')
				return s:gsub('%p', '%%%0')
			end

			-- If a title hasn't been parsed yet, parse the current title.
			if not parsed then
				self:parseTitle{title = mw.title.getCurrentTitle()}
			end

			-- Italicize the different parts of the title and store them in a
			-- titleParts table to be joined together later.
			local titleParts = {}

			-- Italicize the italicizable keys.
			for key in pairs(italicizableKeys) do
				if self[key] then
					if italicizedKeys[key] then
						titleParts[key] = italicize(self[key])
					else
						titleParts[key] = self[key]
					end
				end
			end

			-- Italicize substrings. If there are any substrings to be
			-- italicized then start from the raw title, as this overrides any
			-- italicization of the main part of the title.
			if next(italicizedSubstrings) then
				titleParts.title = self.title
				for s in pairs(italicizedSubstrings) do
					local pattern = escapeMagicCharacters(s)
					local italicizedTitle, nReplacements = titleParts.title:gsub(
						pattern,
						italicize
					)
					titleParts.title = italicizedTitle

					-- If we didn't make any replacements then it means that we
					-- have been passed a bad substring or that the page has
					-- been moved to a bad title, so add a tracking category.
					if nReplacements < 1 then
						categories['Pages using italic title with no matching string'] = true
					end
				end
			end

			-- Assemble the title together from the parts.
			local ret = ''
			if titleParts.namespace then
				ret = ret .. titleParts.namespace .. ':'
			end
			ret = ret .. titleParts.title
			if titleParts.dab then
				ret = ret .. ' (' .. titleParts.dab .. ')'
			end

			return ret
		end

		-- Returns an expanded DISPLAYTITLE parser function called with the
		-- result of obj:renderTitle, plus any other optional arguments.
		-- Returns string
		function obj:renderDisplayTitle(...)
			checkSelf(self, 'renderDisplayTitle')
			return mw.getCurrentFrame():callParserFunction(
				'DISPLAYTITLE',
				self:renderTitle(),
				...
			)
		end

		-- Returns an expanded DISPLAYTITLE parser function called with the
		-- result of obj:renderTitle, plus any other optional arguments, plus
		-- any tracking categories.
		-- Returns string
		function obj:render(...)
			checkSelf(self, 'render')
			local ret = self:renderDisplayTitle(...)
			for cat in pairs(categories) do
				ret = ret .. string.format(
					'[[Category:%s]]',
					cat
				)
			end
			return ret
		end

		return obj
	end
end

--------------------------------------------------------------------------------
-- Exports
--------------------------------------------------------------------------------

local p = {}

local function getArgs(frame, wrapper)
	assert(type(wrapper) == 'string', 'wrapper was not a string')
	return require('Module:Arguments').getArgs(frame, {
		wrappers = wrapper
	})
end

-- Main function for {{italic title}}
function p._main(args)
	checkType('_main', 1, args, 'table')
	local italicTitle = ItalicTitle.new()
	italicTitle:parseTitle{
		title = mw.title.getCurrentTitle(),
		ignoreDab = yesno(args.all, false)
	}
	if args.string then
		italicTitle:italicizeSubstring(args.string)
	else
		italicTitle:italicize('title')
	end
	return italicTitle:render(args[1])
end

function p.main(frame)
	return p._main(getArgs(frame, 'Template:Italic title'))
end

function p._dabonly(args)
	return ItalicTitle.new()
		:italicize('dab')
		:render(args[1])
end

function p.dabonly(frame)
	return p._dabonly(getArgs(frame, 'Template:Italic dab'))
end


return p