Module:Section link
-- 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 ''
 	return string.format('[[%s#%s|%s]]', page, section, display)
 end
 
 local function normalizeTitle(title)
 	title = mw.ustring.gsub(mw.ustring.gsub(title, &quot;'&quot;, &quot;&quot;), '&quot;', '')
 	title = mw.ustring.gsub(title, &quot;%b&lt;&gt;&quot;, &quot;&quot;)
 	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(
 			&quot;type error in argument #2 to '_main' &quot; ..
 			&quot;(string, table or nil expected, got %s)&quot;,
 			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 &lt;= 1 then
 		local linkPage = page or ''
 		local section = sections[1] or 'Notes'
 		local display = '§&amp;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 &quot;%s&quot; was ignored since it is ' ..
 						&quot;not equivalent to the page's actual title&quot;,
 						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 = '&amp;#8203; and '
 		else
 			conjunction = ', and '
 		end
 		ret = mw.text.listToText(ret, nil, conjunction)
 
 		-- Add the intro text.
 		local intro = '§§&amp;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) and not yesno (args['keep-underscores']) then	-- unless |keep-underscores=yes
 			args[k] = v:gsub ('_', ' ')											-- do the replacement
 		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