--[[     This module is intended for processing of date strings.  Please do not modify this code without applying the changes first at Module:ISOdate/sandbox and testing  at Module:ISOdate/sandbox/testcases and Module talk:ISOdate/sandbox/testcases.  Authors and maintainers:  User:Parent5446 - original version of the function mimicking template:ISOdate  User:Jarekt - original version of the functions mimicking template:Date and template:ISOyear  ]]    local p = {}  -- ======================================= -- === Dependencies ====================== -- ======================================= local D = require('Module:DateI18n') -- the enwp version of c:Module:Date  --[[ ISOyear   This function returns year part of date string.   Usage:    Parameters     1: The date string    Error Handling:    If the string does not look like it contain the year than the function will not return anything.    That is the preferred treatment for the template:Creator which is the main (only?) template calling it. ]] function p.ISOyear( frame ) 	 return p._ISOyear( frame.args[1] ) end  function p._ISOyear( input ) 	if not input then 		return 	end 	input = mw.text.trim( input )      	-- if empty string then return it 	if input == "" then 		return input 	end      	-- if number then return it 	if tonumber( input ) then 		return mw.ustring.format( '%04i', input ) 	end      	-- otherwise use regular expression match 	input = mw.ustring.match( input, '^+?(-?%d%d?%d?%d?)-' ) 	if input and tonumber( input ) then 		return mw.ustring.format( '%04i', input ) 	else 		return  	end end  --[[ ISOdate   This function is the core part of the ISOdate template.    Usage:    Parameters:      1: The date string    lang: The language to display it in   form: Language format (genitive, etc.) for some languages  class: CSS class for the <time> node   Error Handling:    If the string does not look like it contain the proper ISO date than the function will return the original string.        That is the preferred treatment for the template:Information (and similar templates) which calling it. ]] function p.ISOdate(frame) 	local datestr, succeded 	local args = frame.args 	if not (args.lang and mw.language.isSupportedLanguage(args.lang)) then  		args.lang = frame:callParserFunction( "int", "lang" ) -- get user's chosen language  	end 	datestr, succeded = p._ISOdate( 		mw.text.trim(args[1]), 		args.lang,                  -- language 		args.case  or ,           -- allows to specify grammatical case for the month for languages that use them 		args.class or 'dtstart',    -- allows to set the html class of the time node where the date is included.  		args.trim_year or '100-999' -- by default pad one and 2 digit years to be 4 digit long, while keeping 3 digit years as is	 	) 	return datestr end  function p._ISOdate(datestr, lang, case, class, trim_year)  	-- pattern: regexp - regular expresion to test; dlen - number of date elements; tail = which element is a "tail" if any 	-- regexp hints: 	--  1) Strings starting with "^" and ending with "$" indicate whole string match 	--  2) optional tail part copied as-is and following the main parsed part of the date have to be separated from the date by a whitespace, so "(\s.+)?" 	local patterns = { 		-- strings starting with YYYY-MM-DD HH:MM:SS. Year 4 digits (if we know seconds than it was within the last 100 years), the rest 1-2 		-- date and time can be separated by space or "T" and there could be a "Z" on the end indicating "Zulu" time zone 		{dlen=6, tail=7, regexp="^+?(%d%d%d%d)-(%d%d?)-(%d%d?)[ T](%d%d?):(%d%d?):(%d%d?)Z?(%s.*)"},  		{dlen=6, tail=0, regexp="^+?(%d%d%d%d)-(%d%d?)-(%d%d?)[ T](%d%d?):(%d%d?):(%d%d?)Z?$"},  		-- strings starting with YYYY-MM-DD HH:MM. Year 4 digits, the rest 1-2 		-- (if one knows hour and minute than it was probably after a year 1000) 		{dlen=5, tail=6, regexp="^+?(%d%d%d%d)-(%d%d?)-(%d%d?)[ T](%d%d?):(%d%d?)(%s.+)"}, 		{dlen=5, tail=0, regexp="^+?(%d%d%d%d)-(%d%d?)-(%d%d?)[ T](%d%d?):(%d%d?)$"}, 		-- strings starting with YYYY-MM-DD. Year 1-4 digits, the rest 1-2 		{dlen=3, tail=4, regexp="^+?(%d%d?%d?%d?)-(%d%d?)-(%d%d?)(%s.+)"}, 		{dlen=3, tail=0, regexp="^+?(%d%d?%d?%d?)-(%d%d?)-(%d%d?)$"}, 		-- strings starting with YYYY-MM. Year 3-4 digits, month 2 digits 		-- (want to avoit converting to dates strings like 10-5 = 5 		{dlen=2, tail=3, regexp="^+?(%d%d%d%d?)-(%d%d)(%s.+)"},  		-- if whole string is in YYYY-MM form: If Year 1-4 digits, month 1-2 digits 		{dlen=2, tail=0, regexp="^+?(%d%d?%d?%d?)-(%d%d?)$"},  		-- string starts with a number -> it has to be 3 or 4 digit long to be a year 		{dlen=1, tail=2, regexp="^+?(%d%d%d%d?)(%s.+)"},	 		 -- if whole string is a number (1-4 digit long) than it will be interpreted as a year 		{dlen=1, tail=0, regexp="^+?(%d%d?%d?%d?)$"}, 	} 	 	-- create datevec based on which variables are provided 	local datevec, tail, formatNum 	datevec, tail, formatNum = p.test_date_formats(datestr or , patterns) 	if datevec[1]== or datevec[1]==nil then 		-- quickly return if datestr does not look like date (it could be a template) 		return datestr, false 	end  	-- call p._Date function to format date string 	local succeded, datestr2 	succeded, datestr2 = pcall( D._Date, datevec, lang, case, class, trim_year) 	if succeded and datestr2~= then 		return mw.text.trim( datestr2 .. tail), true 	else -- in case of errors return the original string 		return datestr, false 	end	 end  function p.ISOdate_extended(frame) 	-- pattern: regexp - regular expresion to test; dlen - number of date elements; tail = which element is a "tail" if any 	-- regexp hints: 	--  1) Strings starting with "^" and ending with "$" indicate whole string match 	--  2) optional tail part copied as-is and following the main parsed part of the date have to be separated from the date by a whitespace, so "(\s.+)?"  	local datestr, succeded 	local args = frame.args 	if not (args.lang and mw.language.isSupportedLanguage(args.lang)) then  		args.lang = frame:callParserFunction( "int", "lang" ) -- get user's chosen language  	end 	datestr, succeded = p._ISOdate( 		mw.text.trim(args[1]), 		args.lang,                  -- language 		args.case  or ,           -- allows to specify grammatical case for the month for languages that use them 		args.class or 'dtstart',    -- allows to set the html class of the time node where the date is included.  		args.trim_year or '100-999' -- by default pad one and 2 digit years to be 4 digit long, while keeping 3 digit years as is	 	) 	if succeded then 		return datestr 	end  	local patterns = { 		-- Exended set of recognized formats: like MM/DD/YYYY 		{dlen=3, tail=4, regexp="^(%d%d?)[-./](%d%d?)[-./](%d%d%d%d)(%s.+)"}, 		{dlen=3, tail=0, regexp="^(%d%d?)[-./](%d%d?)[-./](%d%d%d%d)$"}, 		{dlen=3, tail=0, regexp="^(%d%d?)%s(%w+)%s(%d%d%d%d)$"}, 		{dlen=3, tail=0, regexp="^(%w+)%s(%d%d?),%s(%d%d%d%d)$"}, 	} 	 	local datevec, tail, formatNum, category =  	datevec, tail, formatNum = p.test_date_formats(frame.args[1], patterns) 	if formatNum==1 or formatNum==2 then 		vec = datevec; 		if tonumber(datevec[1])>12 then 			frame.args[1] = string.format('%04i-%02i-%02i', datevec[3], datevec[2], datevec[1] ) 			category = 'Category:Date in DD/MM/YYYY format' 			return mw.text.trim( p.ISOdate(frame) .. tail); 		elseif tonumber(datevec[2])>12 then 			frame.args[1] = string.format('%04i-%02i-%02i', datevec[3], datevec[1], datevec[2] ) 			category = 'Category:Date in MM/DD/YYYY format' 			return mw.text.trim( p.ISOdate(frame) .. tail); 		end 	elseif (formatNum==3 or formatNum==4) and (datevec[3]== or datevec[3]~=nil) then 		local str = mw.getCurrentFrame():callParserFunction( "#time", { 'Y-m-d', datestr} ) 		local vec = {str:match( "^(%d%d?%d?%d?)-(%d%d?)-(%d%d?)$" )} 		if vec and vec[1]~=nil then 			frame.args[1] = string.format('%04i-%02i-%02i', vec[1], vec[2], vec[3] ) 			category = 'Category:Date in word format' 			return p.ISOdate(frame); 		end 	end	 	return datestr end  function p.test_date_formats(datestr, patterns) 	-- pattern: regexp - regular expresion to test; dlen - number of date elements; tail = which element is a "tail" if any  	local datevec = {,,,,,} 	local tail =  	local vec, pat 	local formatNum = 0 	for i, pat in ipairs( patterns ) do 		vec = {datestr:match( pat.regexp )} 		if vec and vec[1]~=nil then 			for j=1,pat.dlen do 				datevec[j] = vec[j] 			end 			if pat.tail>0 and vec[pat.tail]~=nil then 				tail = mw.ustring.gsub(' ' .. vec[pat.tail], ' +', ' ') 			end 			formatNum = i 			break 		end 	end 	return datevec, tail, formatNum end  return p