Module:Hatnote list

 --------------------------------------------------------------------------------
 -- Module:Hatnote list --
 -- --
 -- This module produces and formats lists for use in hatnotes. In particular, --
 -- it implements the for-see list, i.e. lists of "For X, see Y" statements, --
 -- as used in {{about}}, {{redirect}}, and their variants. Also introduced --
 -- are andList & orList helpers for formatting lists with those conjunctions. --
 --------------------------------------------------------------------------------

 local mArguments --initialize lazily
 local mFormatLink = require('Module:Format link')
 local mHatnote = require('Module:Hatnote')
 local libraryUtil = require('libraryUtil')
 local checkType = libraryUtil.checkType
 local p = {}

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 -- List stringification helper functions
 --
 -- These functions are used for stringifying lists, usually page lists inside
 -- the "Y" portion of "For X, see Y" for-see items.
 --------------------------------------------------------------------------------

 --default options table used across the list stringification functions
 local stringifyListDefaultOptions = {
	conjunction = "and",
	separator = ",",
	altSeparator = ";",
	space = " ",
	formatted = false
 }

 --Searches display text only
 local function searchDisp(haystack, needle)
	return string.find(
		string.sub(haystack, (string.find(haystack, '|') or 0) + 1), needle
	)
 end

 -- Stringifies a list generically; probably shouldn't be used directly
 local function stringifyList(list, options)
	-- Type-checks, defaults, and a shortcut
	checkType("stringifyList", 1, list, "table")
	if #list == 0 then return nil end
	checkType("stringifyList", 2, options, "table", true)
	options = options or {}
	for k, v in pairs(stringifyListDefaultOptions) do
		if options[k] == nil then options[k] = v end
	end
	local s = options.space
	-- Format the list if requested
	if options.formatted then
		list = mFormatLink.formatPages(
			{categorizeMissing = mHatnote.missingTargetCat}, list
		)
	end
	-- Set the separator; if any item contains it, use the alternate separator
	local separator = options.separator
	for k, v in pairs(list) do
		if searchDisp(v, separator) then
			separator = options.altSeparator
			break
		end
	end
	-- Set the conjunction, apply Oxford comma, and force a comma if #1 has "§"
	local conjunction = s .. options.conjunction .. s
	if #list == 2 and searchDisp(list[1], "§") or #list > 2 then
		conjunction = separator .. conjunction
	end
	-- Return the formatted string
	return mw.text.listToText(list, separator .. s, conjunction)
 end

 --DRY function
 function p.conjList (conj, list, fmt)
	return stringifyList(list, {conjunction = conj, formatted = fmt})
 end

 -- Stringifies lists with "and" or "or"
 function p.andList (...) return p.conjList("and", ...) end
 function p.orList (...) return p.conjList("or", ...) end

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 -- For see
 --
 -- Makes a "For X, see [[Y]]." list from raw parameters. Intended for the
 -- {{about}} and {{redirect}} templates and their variants.
 --------------------------------------------------------------------------------

 --default options table used across the forSee family of functions
 local forSeeDefaultOptions = {
	andKeyword = 'and',
	title = mw.title.getCurrentTitle().text,
	otherText = 'other uses',
	forSeeForm = 'For %s, see %s.',
 }

 --Collapses duplicate punctuation at end of string, ignoring italics and links
 local function punctuationCollapse (text)
 	return text:match("[.?!]('?)%1(%]?)%2%.$") and text:sub(1, -2) or text
 end

 -- Structures arguments into a table for stringification, & options
 function p.forSeeArgsToTable (args, from, options)
	-- Type-checks and defaults
	checkType("forSeeArgsToTable", 1, args, 'table')
	checkType("forSeeArgsToTable", 2, from, 'number', true)
	from = from or 1
	checkType("forSeeArgsToTable", 3, options, 'table', true)
	options = options or {}
	for k, v in pairs(forSeeDefaultOptions) do
		if options[k] == nil then options[k] = v end
	end
	-- maxArg's gotten manually because getArgs() and table.maxn aren't friends
	local maxArg = 0
	for k, v in pairs(args) do
		if type(k) == 'number' and k > maxArg then maxArg = k end
	end
	-- Structure the data out from the parameter list:
	-- * forTable is the wrapper table, with forRow rows
	-- * Rows are tables of a "use" string & a "pages" table of pagename strings
	-- * Blanks are left empty for defaulting elsewhere, but can terminate list
	local forTable = {}
	local i = from
	local terminated = false
	-- If there is extra text, and no arguments are given, give nil value
	-- to not produce default of "For other uses, see foo (disambiguation)"
	if options.extratext and i > maxArg then return nil end
	-- Loop to generate rows
	repeat
		-- New empty row
		local forRow = {}
		-- On blank use, assume list's ended & break at end of this loop
		forRow.use = args[i]
		if not args[i] then terminated = true end
		-- New empty list of pages
		forRow.pages = {}
		-- Insert first pages item if present
		table.insert(forRow.pages, args[i + 1])
		-- If the param after next is "and", do inner loop to collect params
		-- until the "and"'s stop. Blanks are ignored: "1|and||and|3" → {1, 3}
		while args[i + 2] == options.andKeyword do
			if args[i + 3] then
				table.insert(forRow.pages, args[i + 3])
			end
			-- Increment to next "and"
			i = i + 2
		end
		-- Increment to next use
		i = i + 2
		-- Append the row
		table.insert(forTable, forRow)
	until terminated or i > maxArg

	return forTable
 end

 -- Stringifies a table as formatted by forSeeArgsToTable
 function p.forSeeTableToString (forSeeTable, options)
	-- Type-checks and defaults
	checkType("forSeeTableToString", 1, forSeeTable, "table", true)
	checkType("forSeeTableToString", 2, options, "table", true)
	options = options or {}
	for k, v in pairs(forSeeDefaultOptions) do
		if options[k] == nil then options[k] = v end
	end
	-- Stringify each for-see item into a list
	local strList = {}
	if forSeeTable then
		for k, v in pairs(forSeeTable) do
			local useStr = v.use or options.otherText
			local pagesStr =
				p.andList(v.pages, true) or
				mFormatLink._formatLink{
					categorizeMissing = mHatnote.missingTargetCat,
					link = mHatnote.disambiguate(options.title)
				}
			local forSeeStr = string.format(options.forSeeForm, useStr, pagesStr)
			forSeeStr = punctuationCollapse(forSeeStr)
			table.insert(strList, forSeeStr)
		end
	end
	if options.extratext then table.insert(strList, punctuationCollapse(options.extratext..'.')) end
	-- Return the concatenated list
	return table.concat(strList, ' ')
 end

 -- Produces a "For X, see [[Y]]" string from arguments. Expects index gaps
 -- but not blank/whitespace values. Ignores named args and args < "from".
 function p._forSee (args, from, options)
	local forSeeTable = p.forSeeArgsToTable(args, from, options)
	return p.forSeeTableToString(forSeeTable, options)
 end

 -- As _forSee, but uses the frame.
 function p.forSee (frame, from, options)
	mArguments = require('Module:Arguments')
	return p._forSee(mArguments.getArgs(frame), from, options)
 end

 return p