Module:Section link

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This module depends on the following other modules:

• Module:Arguments
• Module:No globals
• Module:Yesno

Implements {{Section link}}.

This module was adapted from Module:Section link on Wikipedia.
Adaptation is noted for reference and attribution only. This module may differ from the original in function or in usage. The documentation on Wikipedia may be helpful in understanding this module.

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

-- This module implements {{section link}}.
require('Module:No globals');

local checkType = require('libraryUtil').checkType

local p = {}

local function makeSectionLink(page, section, display)
	display = display or section
	page = page or ''
	-- MediaWiki doesn't allow these in `page`, so only need to do for `section`
	if type(section) == 'string' then
		section = string.gsub(section, "{", "{")
		section = string.gsub(section, "}", "}")
	end
	return string.format('[[%s#%s|%s]]', page, section, display)
end

local function normalizeTitle(title)
	title = mw.ustring.gsub(mw.ustring.gsub(title, "'", ""), '"', '')
	title = mw.ustring.gsub(title, "%b<>", "")
	return mw.title.new(title).prefixedText
end

function p._main(page, sections, options, title)
	-- Validate input.
	checkType('_main', 1, page, 'string', true)
	checkType('_main', 3, options, 'table', true)
	if sections == nil then
		sections = {}
	elseif type(sections) == 'string' then
		sections = {sections}
	elseif type(sections) ~= 'table' then
		error(string.format(
			"type error in argument #2 to '_main' " ..
			"(string, table or nil expected, got %s)",
			type(sections)
		), 2)
	end
	options = options or {}
	title = title or mw.title.getCurrentTitle()

	-- Deal with blank page names elegantly
	if page and not page:find('%S') then
		page = nil
		options.nopage = true
	end

	-- Make the link(s).
	local isShowingPage = not options.nopage
	if #sections <= 1 then
		local linkPage = page or ''
		local section = sections[1] or 'Notes'
		local display = '§&nbsp;' .. section
		if isShowingPage then
			page = page or title.prefixedText
			if options.display and options.display ~= '' then
				if normalizeTitle(options.display) == normalizeTitle(page) then
					display = options.display .. ' ' .. display
				else
					error(string.format(
						'Display title "%s" was ignored since it is ' ..
						"not equivalent to the page's actual title",
						options.display
					), 0)
				end
			else
				display = page .. ' ' .. display
			end
		end
		return makeSectionLink(linkPage, section, display)
	else
		-- Multiple sections. First, make a list of the links to display.
		local ret = {}
		for i, section in ipairs(sections) do
			ret[i] = makeSectionLink(page, section)
		end

		-- Assemble the list of links into a string with mw.text.listToText.
		-- We use the default separator for mw.text.listToText, but a custom
		-- conjunction. There is also a special case conjunction if we only
		-- have two links.
		local conjunction
		if #sections == 2 then
			conjunction = '&#8203; and '
		else
			conjunction = ', and '
		end
		ret = mw.text.listToText(ret, nil, conjunction)

		-- Add the intro text.
		local intro = '§§&nbsp;'
		if isShowingPage then
			intro = (page or title.prefixedText) .. ' ' .. intro
		end
		ret = intro .. ret

		return ret
	end
end

function p.main(frame)
	local yesno = require('Module:Yesno')
	local args = require('Module:Arguments').getArgs(frame, {
		wrappers = 'Template:Section link',
		valueFunc = function (key, value)
			value = value:match('^%s*(.-)%s*$') -- Trim whitespace
			-- Allow blank first parameters, as the wikitext template does this.
			if value ~= '' or key == 1 then
				return value
			end
		end
	})

	for k, v in pairs(args) do													-- replace underscores in the positional parameter values
		if 'number' == type(k) then
			if not yesno (args['keep-underscores']) then						-- unless |keep-underscores=yes
				args[k] = mw.uri.decode (v, 'WIKI');							-- percent-decode; replace underscores with space characters
			else
				args[k] = mw.uri.decode (v, 'PATH');							-- percent-decode; retain underscores
			end
		end
	end

	-- Sort the arguments.
	local page
	local sections, options = {}, {}
	for k, v in pairs(args) do
		if k == 1 then
			-- Doing this in the loop because of a bug in [[Module:Arguments]]
			-- when using pairs with deleted arguments.
			page = mw.text.decode(v, true)
		elseif type(k) == 'number' then
			sections[k] = v
		else
			options[k] = v
		end
	end
	
	options.nopage = yesno (options.nopage);									-- make boolean
	
	-- Extract section from page, if present
	if page then
		local p, s = page:match('^(.-)#(.*)$')
		if p then page, sections[1] = p, s end
	end

	-- Compress the sections array.
	local function compressArray(t)
		local nums, ret = {}, {}
		for num in pairs(t) do
			nums[#nums + 1] = num
		end
		table.sort(nums)
		for i, num in ipairs(nums) do
			ret[i] = t[num]
		end
		return ret
	end
	sections = compressArray(sections)

	return p._main(page, sections, options)
end

return p