Documentation for this module may be created at မော်ဂျူး:Brah-translit/doc

local export = {}
local u = mw.ustring.char

local consonants = {
--consonants
	['𑀓']='k', ['𑀔']='kh', ['𑀕']='g', ['𑀖']='gh', ['𑀗']='ṅ',
	['𑀘']='c', ['𑀙']='ch', ['𑀚']='j', ['𑀛']='jh', ['𑀜']='ñ', 
	['𑀝']='ṭ', ['𑀞']='ṭh', ['𑀟']='ḍ', ['𑀠']='ḍh', ['𑀡']='ṇ', 
	['𑀢']='t', ['𑀣']='th', ['𑀤']='d', ['𑀥']='dh', ['𑀦']='n', 
	['𑀧']='p', ['𑀨']='ph', ['𑀩']='b', ['𑀪']='bh', ['𑀫']='m',
	['𑀬']='y', ['𑀭']='r', ['𑀮']='l', ['𑀯']='v', ['𑀴']='ḷ',
	['𑀰']='ś', ['𑀱']='ṣ', ['𑀲']='s', ['𑀳']='h',
-- Old Tamil
	[u(0x11075)] = 'ḷ',
	['𑀵']='ḻ', ['𑀶']='ṟ', ['𑀷'] ='ṉ',
}

local diacritics = {
--matras
	['𑀸']='ā', ['𑀺']='i', ['𑀻']='ī', ['𑀼']='u', ['𑀽']='ū', ['𑀾']='ṛ', ['𑀿']='ṝ', 
	['𑁀']='l̥', ['𑁁']='l̥̄', ['𑁂']='e', ['𑁃']='ai', ['𑁄']='o', ['𑁅']='au',  ['𑁆']='',

    --bhattiprolu aa
    ['𑀹']='ā',

     --Old Tamil
    ['𑁳']='ĕ', ['𑁴']='ŏ', [u(0x11070)]='',
    
    -- Old Tamil up to and including Unicode 13.0
    ['𑁂𑁆']='ĕ', ['𑁄𑁆']='ŏ', -- Two character vowels!
}

local diatrema = {
	['𑀇']='ï', ['𑀉']='ü',
}

local tt = {

--vowels
	['𑀅']='a', ['𑀆']='ā', ['𑀇']='i', ['𑀈']='ī', ['𑀉']='u', ['𑀊']='ū', ['𑀋']='ṛ', ['𑀌']='ṝ',
	['𑀍']='l̥', ['𑀎']='l̥̄', ['𑀏']='e', ['𑀐']='ai', ['𑀑']='o', ['𑀒']='au', 
    ['𑁱']='ĕ', ['𑁲']='ŏ', --Old Tamil

	-- chandrabindu    
	['𑀀']='m̐', --until a better method is found
	-- anusvara    
	['𑀁']='ṃ', --until a better method is found
	-- visarga    
	['𑀂']='ḥ',
	--numerals
	['𑁦']='0', ['𑁧']='1', ['𑁨']='2', ['𑁩']='3', ['𑁪']='4', ['𑁫']='5', ['𑁬']='6', ['𑁭']='7', ['𑁮']='8', ['𑁯']='9',
	--punctuation        
	['𑁇']='.', --danda
    ['𑁈']='.' --double danda
}

function export.tr(text, lang, sc)
	if sc ~= "Brah" then
		return nil
	end

	if lang == "inc-pra" then -- Route contextually shortened Prakrit vowels through Old Tamil short vowels
		text = mw.ustring.gsub(text, '(𑁂)([𑀅-𑀳]?)(𑁆)([𑀅-𑀳]?)', '𑁳%2%3%4')
		text = mw.ustring.gsub(text, '(𑀏)([𑀅-𑀳]?)(𑁆)([𑀅-𑀳]?)', '𑁱%2%3%4')
		text = mw.ustring.gsub(text, '(𑁄)([𑀅-𑀳]?)(𑁆)([𑀅-𑀳]?)', '𑁴%2%3%4')
		text = mw.ustring.gsub(text, '(𑀑)([𑀅-𑀳]?)(𑁆)([𑀅-𑀳]?)', '𑁲%2%3%4')
	end

	text = mw.ustring.gsub(
		text,
		'([𑀓-𑀷'..u(0x11075)..'])'..
		'([𑀸𑀺𑀺𑀻𑀼𑀽𑀾𑀿𑁀𑁁𑁂𑁃𑁄𑁅𑁆𑀹𑁳𑁴'..u(0x11070)..']?𑁆?)'..
		'([𑀇𑀉]?)',
		function(c, d, e)
			if d == "" and e ~= "" then
				return consonants[c] .. 'a' .. diatrema[e]
			elseif e ~= "" then
				return consonants[c] .. diacritics[d] .. tt[e]
			elseif d == "" then        
				return consonants[c] .. 'a'
			else
				return consonants[c] .. diacritics[d]
			end
		end)

-- Adjacent vowel letters needing dieresis
	text = mw.ustring.gsub(text, '([𑀅])([𑀇𑀉])', function(a, b) return tt[a]..diatrema[b] end)

	text = mw.ustring.gsub(text, '.', tt)
	if (lang == 'sa' or lang == 'pi') and mw.ustring.match(text, 'l̥') then
		text = mw.ustring.gsub(text, 'l̥', 'ḷ')
		text = mw.ustring.toNFC(text)
	end
-- Old Tamil uses macron v. plain for 'e' and 'o'.
	if (lang == 'oty') then
		text = mw.ustring.gsub(text, '.', {e='ē', o='ō', ['ĕ']='e', ['ŏ']='o'})
	end

	return text
end
 
return export