This module will transliterate ภาษาอูรดู text. It is also used to transliterate บราฮุอี and ฮินดีเก่า. The module should preferably not be called directly from templates or other modules. To use it from a template, use {{xlit}}. Within a module, use Module:languages#Language:transliterate.

For testcases, see Module:ur-translit/testcases.

tr(text, lang, sc)
Transliterates a given piece of text written in the script specified by the code sc, and language specified by the code lang.
When the transliteration fails, returns nil.

local U = mw.ustring.char
local gsub = mw.ustring.gsub
local export = {}

local fatHataan = U(0x64B)
local zabar = U(0x64E)
local zer = U(0x650)
local pesh = U(0x64F)
local zwnj = U(0x200C) -- Is this even used in Urdu? Why was it included in the previous version?
local highhmz = U(0x654)
local tashdid = U(0x651) -- also called tashdid
local jazm = "ْ"
local he = "ہ"
local ghunna = U(0x658)
local dagger_alif = U(0x670)

local consonants = "ببپتثجچحخدذرزژسشصضطظعغفقکگلࣇمنݨؤہئھٹڈڑ"
local consonantS = "ببپتثجچحخدذرزژسشصضطظعغفقکگلࣇمنݨہھٹڈڑ"
local consonantS2 = "یببپتثجچحخدذرزژسشصضطظعغفقکگلࣇمنݨوؤہھئٹڈڑ" 
local semivowel = "یو"
local vowels = "āایئےۓوؤ"
local indvowels = "آایےوؤ"
local hes = "ہح"
local diacritics = "َُِّْٰ"
local ZZP = "َُِ"
local lrm = U(0x200e) -- left-to-right mark
local rlm = U(0x200f) -- right-to-left mark

local consonants_needing_vowels = "ببپتثجچحخدذرزژسشصضطظعغفقکگلࣇمنںݨہئٹڈڑءﷲ"
-- consonants on the right side; includes alif madda
local rconsonants = consonants_needing_vowels .. "ویآ"
-- consonants on the left side; does not include alif madda
local lconsonants = consonants_needing_vowels
local space_like = "%s'" .. '"'
local space_like_class = "[" .. space_like .. "]"

-- not all letters here are used by urdu
local mapping = {
	["آ"] = 'ā', ["ب"] = 'b', ["پ"] = 'p', ["ت"] = 't', ["ٹ"] = 'ṭ', ["ث"] = 's',
	["ج"] = 'j', ["چ"] = 'c', ["ح"] = 'h', ["خ"] = 'x', 
	["د"] = 'd', ["ڈ"] = 'ḍ', ["ذ"] = 'z', ["ر"] = 'r', ['ڑ'] = "ṛ", ["ز"] = 'z', ["ژ"] = 'ź',
	["س"] = 's', ["ش"] = 'ś', ["ص"] = 's', ["ض"] = 'z', 
	["ط"] = 't', ["ظ"] = 'z', ["غ"] = 'ġ', ["ف"] = 'f', ["ق"] = 'q',
	["ک"] = 'k', ["گ"] = 'g', ["ݨ"] = 'ṇ', ["ࣇ"] = 'ḷ',
	["ل"] = 'l', ["م"] = 'm', ["ن"] = 'n', ["و"] = 'o', ["ہ"] = 'h', ["ی"] = 'e', ["ے"] = 'e', ["۔"] = ".", ["ں"] = '̃',

	["ھ"] = "h",
	

	["ع"] = '\'',
	["ء"] = '\'',
	["أ"] = '',
	
	-- diacritics
	[zabar] = "a",
	[zer] = "i",
	[pesh] = "u",
	[jazm] = "", -- also sukun - no vowel
	[zwnj] = "-", -- ZWNJ (zero-width non-joiner)
	
	-- ligatures
	["ﻻ"] = "lā",
	["ﷲ"] = "allāh",
	
	-- kashida
	["ـ"] = "-", -- kashida, no sound
	
	-- numerals
	["۱"] = "1", ["۲"] = "2", ["۳"] = "3", ["۴"] = "4", ["۵"] = "5",
	["۶"] = "6", ["۷"] = "7", ["۸"] = "8", ["۹"] = "9", ["۰"] = "0",
	
	-- punctuation (leave on separate lines)
	["؟"] = "?", -- question mark
	["۔"] = ".", -- period
	["،"] = ",", -- comma
	["؛"] = ";", -- semicolon
	["«"] = '“', -- quotation mark
	["»"] = '”', -- quotation mark
	["٪"] = "%", -- percent
	["؉"] = "‰", -- per mille
	["٫"] = ".", -- decimals
	["٬"] = ",", -- thousand
	["ۓ"] = "-ye", 
	[highhmz] = "-yi",
}

local punctuation = ":%(%)%[%]*&٫؛؟،ـ«\".\'!»٪؉۔"
local numbers = "۱۲۳۴۵۶۷۸۹۰"

local ain = 'ع'
local alif = 'ا'
local ye = 'ی'
local ye2 = 'ئ'
local ye3 = "ے"
local vao = "و"
local aspirate = 'ھ'
local highhmz = U(0x654)
local aiu = "āīūآ"
local n_exceptions = "[^" .. aiu .. "]" -- for nasalization exceptions

local before_diacritic_checking_subs = {
	------------ transformations prior to checking for diacritics --------------
	{U(0x06E5), "و"},
	{U(0x06E6), "ی"},
	-- ignore dagger alif placed over regular alif or alif maqṣūra
	{"([" .. alif .. ye .. "])" .. dagger_alif, alif},
	{"([^" .. alif .. ye .. "])" .. fatHataan, alif .. fatHataan},
}

local has_diacritics_subs = {
	-- remove arabic ye (ruins conversions)
	{"لل" ..  he , ""},
	{"لل" .. tashdid ..  he , ""},
	{"لل" .. tashdid .. dagger_alif ..  he , ""},
	{"ۃ" , ""},
	-- aspirated consonants should cound as 1 consonant not two
	{"([" .. consonants .. "][".. ZZP .. diacritics .. "?])" ..  aspirate , "%1"},
	{"([" .. consonants .. "])" ..  aspirate , "%1"},
	{ aspirate , ""},
	-- remove punctuation and tashdid
	{"[" .. punctuation .. tashdid .. highhmz .. zwnj .. numbers .. "]", ""},
	-- noon gunna and silent consonants can be removed
	{ ".. [".. ZZP .. indvowels .. diacritics .. "?] .. ([" .. consonantS2 .. "])" .. "([".. ghunna .. jazm .."])" .. "([" .. consonantS2 .. "])"  , ""},
	{ "([" .. consonants .. "])" .. ghunna , ""},
	{ "([" .. consonantS2 .. "])" .. jazm , ""},
	{ "([" .. consonantS2 .. "])" .. "یٰ" , ""},
	-- must go before removing final consonants
	{"[".. ZZP .. diacritics .. "]" .. alif , alif },
	{fatHataan , "" },
	{ "([" .. consonantS2 .. "])" .. "[" .. ZZP .. diacritics .. indvowels .. "?]" .. "([ںۓۂۂ])", "" },
	{ "([ںۓۂۂ])", "" },
	{ "([" .. ye .. alif .. "])" .. dagger_alif, alif},
	{ dagger_alif .. ye , alif},
	{ alif .. "[".. ZZP .. diacritics .. "]" , ""},
	{ "[".. ZZP .. diacritics .. "]" .. alif , alif},
	{ dagger_alif .. "([" .. ye .. alif .. "])", alif},
	-- Remove consonants at end of word or utterance, so that we're OK with
	-- words lacking iʿrāb (must go before removing other consonants).
	-- If you want to catch places without iʿrāb, comment out the next two lines.
	{"[" .. lconsonants .. "]$", ""},
	-- closed consonants
	{"([" .. consonantS2 .. "])[" .. indvowels .. ZZP .. "]", ""},
	-- remove consonants (or alif) when followed by diacritics
	-- must go after removing tashdid
	-- do not remove the diacritics yet because we need them to handle
	-- long-vowel sequences of diacritic + pseudo-consonant
	{"[" .. lconsonants .. alif .. "]([" .. fatHataan .. zabar .. pesh .. zer .. jazm .. dagger_alif .. "])", "%1"},
	-- the following two must go after removing consonants w/diacritics because
	{"([" .. rconsonants .. "])([".. ZZP .. diacritics .. "?][" .. indvowels .. "?])([" .. consonantS2 .. "])", ""},
	{"[" .. indvowels .. "]([" .. rconsonants .. "])", ""},
	{"[".. ZZP .. diacritics .. "]([" .. lconsonants .. "])", ""},
	{"([" .. consonants .. "])[" .. indvowels .. ZZP .. diacritics .. "]", ""},
	{"([" .. rconsonants .. "])(" .. space_like_class .. ")", ""},
	{"[" .. lconsonants .. "]" .. zabar .. "[".. ye .. ye3 .. vao .. "]", ""},
	-- we only want to treat vocalic wāw/yā' in them (we want to have removed
	-- remove vaw
	{ "[" .. lconsonants .. "]" .. vao, ""},
	{"ؤ" .. pesh , ""},
	{"ؤ", ""},
	-- remove ye
	{ "[" .. lconsonants .. "]" .. ye, ""},
	{ye3, ""},
	{"([" .. consonants .. "][" .. ZZP .. "])" .. he,""},
	-- remove fatḥa/fatḥatan + alif/alif-maqṣūra
	{"[" .. fatHataan .. zabar .. "][" .. alif .. ye .. "]", ""},
	-- remove diacritics and independant vowels
	{"[" .. fatHataan .. zabar .. pesh .. zer .. jazm .. dagger_alif .. "]", ""},
	{ "[" .. indvowels .. "]" , ""},
	{ "[".. semivowel .."]" .. "[" .. indvowels .. "]" , ""},
	-- remove numbers, hamzatu l-waṣl, alif madda
	{"[" .. numbers .. "ٱ" .. "آ" .. "]", ""},
	{"%s", ""},
}

-- declared as local above
local function has_diacritics(text)
	local count
	text, count = gsub(text, "[" .. lrm .. rlm .. "]", "")
	if count > 0 then
		require("Module:debug").track("ur-translit/lrm or rlm")
	end
	for _, sub in ipairs(has_diacritics_subs) do
		text = gsub(text, unpack(sub))
	end
	return #text == 0
end

function export.tr(text, lang, sc)
	if type(text) == "table" then
		local function f(x) return (x ~= "") and x or nil end
		text, lang, sc, omit_i3raab, force_translit =
			f(text.args[1]), f(text.args[2]), f(text.args[3]), f(text.args[4]), f(text.args[5])
	end
	for _, sub in ipairs(before_diacritic_checking_subs) do
		text = gsub(text, sub[1], sub[2])
	end

	if not force_translit and not has_diacritics(text) then
		require("Module:debug").track("ur-translit/lacking diacritics")
		return nil
	end
	
	--define the "end" of a word
	text = gsub(text, "#", "HASHTAG")
	text = gsub(text, " | ", "# | #")
	text = gsub(text, "\n" , "#".."\n" .. "#")
	text = gsub(text, "(["..punctuation.."])" , "#".."%1" .. "#")
	text = "##" .. gsub(text, " ", "# #") .. "##"
	text = gsub(text, zwnj, "#"..zwnj.."#")
	-- hastags now mark the beginning and end of a word
	
	--exceptions
	text = gsub(text, "#" .. vao .. he .. "#", "#vo#")
	text = gsub(text, "#" .. vao .. pesh .. he .. "#", "#vo#")
	text = gsub(text, "#" .. "پ" .. he .. "#", "#pe#")
	text = gsub(text, "#" .. "پ" .. zer .. he .. "#", "#pe#")
	text = gsub(text, "#" .. ye .. he .. "#", "#ye#")
	text = gsub(text, "#" .. ye .. zer .. he .. "#", "#ye#")
	
	--character reformatting
	--to make an exceptions for a word, put hashtags on both sides
	text = gsub(text, "ۂ", he .. highhmz)
	text = gsub(text, highhmz, "#"..highhmz.."#")
	--text = gsub(text, 'ىٰ', "ā") -- the first letter is U+0649 (Arabic alif maqṣūra), it doesn't belong here
	text = gsub(text, 'یٰ', "ā") -- the first letter is U+06CC
	text = gsub(text, 'ٰ', "ā")
	text = gsub(text, 'ا' .. fatHataan, "an")
	text = gsub(text, 'لا', "ﻻ")
	text = gsub(text, "ة" 	, "ۃ")
	text = gsub(text, "ۃ" .. "([" .. ZZP .. "])", "ت%1")
	text = gsub(text, "ۃ" , he)
	
	-- Tashdeed
	text = gsub(text, '([' .. consonantS2 .. '])' .. tashdid, "%1%1")
	text = gsub(text, '([' .. consonantS2 .. '])' .. tashdid .. '([' .. ZZP .. '])', "%1%1%2")
	-- For some reason the tashdeed gets pushed after the other diacritics, so this line is necessary for tashdeed to work with other diacritics
	text = gsub(text, '([' .. consonants .. '])' .. '([' .. ZZP .. '])' .. tashdid, "%1%1%2")
	text = gsub(text, '([' .. ZZP .. '])' .. aspirate, aspirate.."%1") 
	text = gsub(text, dagger_alif .. aspirate, aspirate.."%1")
	text = gsub(text, ye .. '([' .. ZZP .. '])' .. tashdid, "yy%1")
	text = gsub(text,  vao .. '([' .. ZZP .. '])' .. tashdid, "vv%1")
	text = gsub(text, ye .. tashdid .. '([' .. ZZP .. '])', "yy%1")
	text = gsub(text, vao .. tashdid .. '([' .. ZZP .. '])', "vv%1")
	

    --initial alif
    text = gsub(text, "(["..consonantS2.."])" .. alif, "%1ā") 
    --alifs paired to a consonant are a vowel
    text = gsub(text, jazm .. alif, "-") -- invisible ZWNJ
    text = gsub(text, jazm .. "آ", "-ā") -- invisible ZWNJ
    text = gsub(text, "(["..consonantS2.."])" .. "آ", "%1'ā") 
    	text = gsub(text, pesh .. vao .. zabar .. alif , "ūā" )
    text = gsub(text, zabar .. alif, "ā")
    text = gsub(text, "(" .. ghunna .. ")" .. alif, "%1ā")
    text = gsub(text, "(["..diacritics.."])" .. alif, "%1")
    text = gsub(text, "(["..ZZP.."])" .. alif, "%1")
    --alifs not paired to a consonant are a glottal stop (not shown currently)
    text = gsub(text, alif.."(["..diacritics.."])".. "(["..consonantS2.."])", "%1%2")
    text = gsub(text, alif..ye.."#", "ī")
    text = gsub(text, alif..ye, "e")
    text = gsub(text, alif..ye3, "e")
    text = gsub(text, alif..zabar..ye3, "ai")
    text = gsub(text, alif..vao, "o")
    text = gsub(text, alif..zer..ye, "ī")
    text = gsub(text, alif..pesh..vao, "ū")
    text = gsub(text, alif.."(["..diacritics.."])", "%1")
    
    
    -- convert semi vowels
    text = gsub(text, vao.. "(["..diacritics..ZZP.."])", "v%1")
    text = gsub(text, ye.. "(["..diacritics..ZZP.."])", "y%1")
    text = gsub(text, ye .. "ā", "yā")
    text = gsub(text, vao.. "ā", "vā")
    text = gsub(text, ye .. "(["..zabar.."]?)" .. ye3, "y%1"..ye3.."")
    text = gsub(text, vao .. "(["..zabar.."]?)" .. ye3, "v%1"..ye3.."")
    text = gsub(text, ye .. "(["..semivowel.."])(["..semivowel.."])", "e%1%2")
    text = gsub(text, vao .. "(["..semivowel.."])(["..semivowel.."])", "o%1%2")
    text = gsub(text, ye .. "(["..semivowel.."])", "y%1")
    text = gsub(text, vao .. "(["..semivowel.."])", "v%1")
    
    -- conversions for vaav/vaw/vao
    text = gsub(text, pesh.. vao, "ū")
    text = gsub(text, zabar .. vao, "au")
    text = gsub(text, vao.. "(["..diacritics..ZZP.."])", "v%1")
    text = gsub(text, "(["..diacritics..ZZP.."])" .. vao, "%1v")
    -- conversions for ye
    text = gsub(text, zer.. ye, "ī")
    text = gsub(text, ye .. "#", "ī#")
    text = gsub(text, zabar.. ye, "ai")
    text = gsub(text, zabar.. ye3, "ai")
    text = gsub(text, ye .. "(["..diacritics..ZZP.."])", "y%1")
    text = gsub(text, "(["..diacritics..ZZP.."])" .. ye , "%1y")
    
    -- final he and izafa/ezafe
    text = gsub(text, "e" .. zer .. "#", "e-yi#")
    text = gsub(text, "ī" .. zer .. "#", "ī-yi#")
    text = gsub(text, "y" .. zer .. "#", "-yi#")
    text = gsub(text, zer .. "#", "-i#")
    text = gsub(text, "(["..ZZP.."])" .. he .. "#" .. zwnj, "%1-")
    text = gsub(text, "(["..ZZP.."])" .. he .. "#", "%1#")
    text = gsub(text, zabar .. he .. "#", "a#")
    
    -- noon ghunna assimilation/nasalization
    --remove impossible nasal vowels
    text = mw.ustring.gsub(text, "ن" .. ghunna .. "([ب])", "m%1") -- nasal vowels are impossible before b
    text = mw.ustring.gsub(text, "ن" .. ghunna .. "ت" .. aspirate, "nth") 
    text = mw.ustring.gsub(text, "ن" .. ghunna .. "([قگ])",	"ṅ%1") -- impossible before q and g
    text = mw.ustring.gsub(text, "(" .. n_exceptions .. ")" .. "ن" .. ghunna .. "ٹ"	.. aspirate	, "%1ṇṭh")
    text = mw.ustring.gsub(text, "(" .. n_exceptions .. ")" .. "ن" .. ghunna .. "پ" .. aspirate, "%1mph")
    text = mw.ustring.gsub(text, "(" .. n_exceptions .. ")" .. "ن" .. ghunna .. "ک" .. aspirate, "%1ṅkh")
    text = mw.ustring.gsub(text, "ن" .. ghunna .. "([ج])", "ñ%1") -- impossible before j
    text = mw.ustring.gsub(text, "ن".. ghunna .. "ڈ" .. aspirate, "ṇḍh") -- aspirated d/D cant be nasalized
    text = mw.ustring.gsub(text, "ن".. ghunna .. "د" .. aspirate, "ndh") -- aspirated d/D cant be nasalized
    --other nasals
    text = mw.ustring.gsub(text, "ن" .. jazm .. "([کگق])" .. "#",	"ṅ%1#")
	text = mw.ustring.gsub(text, "ن" .. jazm .. "([دتر])", "n%1") -- dental
	text = mw.ustring.gsub(text, "ن" .. jazm .. "([چج])", "ñ%1") -- postalveolar
	-- if noon ghunna cannot assimilate, it becomes a nasal vowel.
	text = mw.ustring.gsub(text, "ن" .. ghunna, "ں")
    
    -- get rid of hashtags (not needed)
    text = gsub(text, "#", "")
    text = gsub(text, "HASHTAG", "#")
    text = string.gsub(text, lrm, "")
	text = string.gsub(text, rlm, "")
    -- convert all characters
    text = mw.ustring.gsub(text, '.', mapping)
    
    -- vowel fixes
    -- nasalized dipthongs
    text = gsub(text, 'a([iu])̃', 'a͠%1')
	
	-- alif
	-- Final corrections
	text = mw.ustring.gsub(text, "lll", "ll")
	text = mw.ustring.gsub(text, "āa", "ā")
	text = mw.ustring.gsub(text, "aaa", "ā")
	text = mw.ustring.gsub(text, "āā", "ā")
	text = mw.ustring.gsub(text, "aa", "ā")
	
	--now get rid of the zero consonants
	text = mw.ustring.gsub(text, "ئ", "")
	text = mw.ustring.gsub(text, "u" .. "ؤ" , "u")
	text = mw.ustring.gsub(text, "ؤ" .. "u" .. "$", "ū")  -- ؤُ is rendered 'ū' word-finally, short 'u' otherwise
	text = mw.ustring.gsub(text, "ؤ" .. "u" .. "([ ,.;?!-])", "ū%1")
	text = mw.ustring.gsub(text, "ؤ" .. "u" , "u")
	text = mw.ustring.gsub(text, "ؤ", "o")
	
	text = mw.ustring.toNFC(text)
	
	return text
end

return export