if not modules then modules = { } end modules ['char-con'] = {
    version   = 1.001,
    comment   = "companion to core-con.tex",
    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
    copyright = "PRAGMA ADE / ConTeXt Development Team",
    license   = "see context related readme files"
}

--[[ldx--
<p>This module implements a bunch of conversions. Some are more
efficient than their <l n='tex'/> counterpart, some are even
slower but look nicer this way.</p>

<p>Some code may move to a module in the language namespace.</p>
--ldx]]--

local utf = unicode.utf8

local floor, mod, date, time, concat, format = math.floor, math.mod, os.date, os.time, table.concat, string.format
local texsprint, utfchar = tex.sprint, utf.char

local ctxcatcodes = tex.ctxcatcodes

converters = converters or { }
languages  = languages  or { }

--~     ['arabic-digits'] = {
--~         0x0660, 0x0661, 0x0662, 0x0663, 0x0664,
--~         0x0665, 0x0666, 0x0667, 0x0668, 0x0669
--~     },
--~     ['persian-digits'] = {
--~         0x06F0, 0x06F1, 0x06F2, 0x06F3, 0x06F4,
--~         0x06F5, 0x06F6, 0x06F7, 0x06F8, 0x06F9
--~     },

languages.counters = {
    ['**'] = {
        0x0061, 0x0062, 0x0063, 0x0064, 0x0065,
        0x0066, 0x0067, 0x0068, 0x0069, 0x006A,
        0x006B, 0x006C, 0x006D, 0x006E, 0x006F,
        0x0070, 0x0071, 0x0072, 0x0073, 0x0074,
        0x0075, 0x0076, 0x0077, 0x0078, 0x0079,
        0x007A
    },
    ['slovenian'] = {
        0x0061, 0x0062, 0x0063, 0x010D, 0x0064,
        0x0065, 0x0066, 0x0067, 0x0068, 0x0069,
        0x006A, 0x006B, 0x006C, 0x006D, 0x006E,
        0x006F, 0x0070, 0x0072, 0x0073, 0x0161,
        0x0074, 0x0075, 0x0076, 0x007A, 0x017E
    },
    ['greek'] = { -- this should be the lowercase table
        0x0391, 0x0392, 0x0393, 0x0394, 0x0395,
        0x0396, 0x0397, 0x0398, 0x0399, 0x039A,
        0x039B, 0x039C, 0x039D, 0x039E, 0x039F,
        0x03A0, 0x03A1, 0x03A3, 0x03A4, 0x03A5,
        0x03A6, 0x03A7, 0x03A8, 0x03A9
    },
    ['arabic'] = {
        0x0627, 0x0628, 0x062C, 0x062F, 0x0647,
        0x0648, 0x0632, 0x062D, 0x0637, 0x0649,
        0x0643, 0x0644, 0x0645, 0x0646, 0x0633,
        0x0639, 0x0641, 0x0635, 0x0642, 0x0631,
        0x0634, 0x062A, 0x062B, 0x062E, 0x0630,
        0x0636, 0x0638, 0x063A,
    },
    ['persian'] = {
        0x0627, 0x0628, 0x062C, 0x062F, 0x0647,
        0x0648, 0x0632, 0x062D, 0x0637, 0x0649,
        0x06A9, 0x0644, 0x0645, 0x0646, 0x0633,
        0x0639, 0x0641, 0x0635, 0x0642, 0x0631,
        0x0634, 0x062A, 0x062B, 0x062E, 0x0630,
        0x0636, 0x0638, 0x063A,
    },
    ['thai'] = {
        0xE050, 0xE051, 0xE052, 0xE053, 0xE054,
        0xE055, 0xE056, 0xE057, 0xE058, 0xE059
    },
    ['devangari'] = {
        0x0966, 0x0967, 0x0968, 0x0969, 0x096A,
        0x096B, 0x096C, 0x096D, 0x096E, 0x096F
    },
    ['gurmurkhi'] = {
        0x0A66, 0x0A67, 0x0A68, 0x0A69, 0x0A6A,
        0x0A6B, 0x0A6C, 0x0A6D, 0x0A6E, 0x0A6F
    },
    ['gujarati'] = {
        0x0AE6, 0x0AE7, 0x0AE8, 0x0AE9, 0x0AEA,
        0x0AEB, 0x0AEC, 0x0AED, 0x0AEE, 0x0AEF
    },
    ['tibetan'] = {
        0x0F20, 0x0F21, 0x0F22, 0x0F23, 0x0F24,
        0x0F25, 0x0F26, 0x0F27, 0x0F28, 0x0F29
    },
    ['korean'] = {
        0x3131, 0x3134, 0x3137, 0x3139, 0x3141,
        0x3142, 0x3145, 0x3147, 0x3148, 0x314A,
        0x314B, 0x314C, 0x314D, 0x314E
    },
    ['korean-parent'] = { -- parenthesed
        0x3200, 0x3201, 0x3202, 0x3203, 0x3204,
        0x3205, 0x3206, 0x3207, 0x3208, 0x3209,
        0x320A, 0x320B, 0x320C, 0x320D
    },
    ['korean-circle'] = { -- circled
        0x3260, 0x3261, 0x3262, 0x3263, 0x3264,
        0x3265, 0x3266, 0x3267, 0x3268, 0x3269,
        0x326A, 0x326B, 0x326C, 0x326D
    },
}

local counters = languages.counters

counters['ar']      = counters['arabic']
counters['gr']      = counters['greek']
counters['g']       = counters['greek']
counters['sl']      = counters['slovenian']
counters['kr']      = counters['korean']
counters['kr-p']    = counters['korean-parent']
counters['kr-c']    = counters['korean-circle']

local fallback = utf.byte('0')

function converters.chr(n,m)
    if n > 0 and n < 27 then
        texsprint(utfchar(n+m))
    end
end

function converters.maxchrs(n,m,cmd)
    if n > m then
        converters.maxchrs(floor((n-1)/m),m,cmd)
        n = (n-1)%m + 1
    end
    texsprint(ctxcatcodes, format("%s{%s}",cmd,n))
end
function converters.chrs(n,m)
    if n > 26 then
        converters.chrs(floor((n-1)/26),m)
        n = (n-1)%26 + 1
    end
    texsprint(utfchar(n+m))
end

local function do_alphabetic(n,max,chr)
    if n > max then
        do_alphabetic(floor((n-1)/max),max,chr)
        n = (n-1)%max+1
    end
    characters.flush(chr(n))
end

function converters.alphabetic(n,code)
    local code = counters[code] or counters['**']
    do_alphabetic(n,#code,function(n) return characters.lccode(code[n] or fallback) end) -- lccode catches wrong tables
end

function converters.Alphabetic(n,code)
    local code = counters[code] or counters['**']
    do_alphabetic(n,#code,function(n) return characters.uccode(code[n] or fallback) end)
end

function converters.character(n)  converters.chr (n,96) end
function converters.Character(n)  converters.chr (n,64) end
function converters.characters(n) converters.chrs(n,96) end
function converters.Characters(n) converters.chrs(n,64) end

function converters.weekday(day,month,year)
    texsprint(date("%w",time{year=year,month=month,day=day})+1)
end

function converters.isleapyear(year)
    return (year % 400 == 0) or ((year % 100 ~= 0) and (year % 4 == 0))
end

function converters.leapyear(year)
    if converters.isleapyear(year) then texsprint(1) else texsprint(0) end
end

local days = {
    [false] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
    [true]  = { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
}

function converters.nofdays(year,month)
    texsprint(days[converters.isleapyear(year)][month])
end

function converters.year   () texsprint(date("%Y")) end
function converters.month  () texsprint(date("%m")) end
function converters.hour   () texsprint(date("%H")) end
function converters.minute () texsprint(date("%M")) end
function converters.second () texsprint(date("%S")) end
function converters.textime() texsprint(tonumber(date("%H"))*60+tonumber(date("%M"))) end

local roman = {
    { [0] = '', 'I', 'II', 'III', 'IV', 'V', 'VI', 'VII', 'VIII', 'IX' },
    { [0] = '', 'X', 'XX', 'XXX', 'XL', 'L', 'LX', 'LXX', 'LXXX', 'XC' },
    { [0] = '', 'C', 'CC', 'CCC', 'CD', 'D', 'DC', 'DCC', 'DCCC', 'CM' },
}

function converters.toroman(n)
    if n >= 4000 then
        return converters.toroman(floor(n/1000)) .. " " .. converters.toroman(n%1000)
    else
        return string.rep("M",floor(n/1000)) .. roman[3][floor((n%1000)/100)] ..
            roman[2][floor((n%100)/10)] .. roman[1][floor((n% 10)/1)]
    end
end

function converters.romannumerals(n) return texsprint(string.lower(converters.toroman(n))) end
function converters.Romannumerals(n) return texsprint(             converters.toroman(n) ) end

--~ local small = {
--~     0x0627, 0x066E, 0x062D, 0x062F, 0x0647, 0x0648, 0x0631
--~ }

--~ local large = {
--~     { 0x0627, 0x0628, 0x062C, 0x062F, 0x0647, 0x0648, 0x0632, 0x062D, 0x0637, },
--~     { 0x064A, 0x0643, 0x0644, 0x0645, 0x0646, 0x0633, 0x0639, 0x0641, 0x0635, },
--~     { 0x0642, 0x0631, 0x0634, 0x062A, 0x062B, 0x062E, 0x0630, 0x0636, 0x0638, },
--~     { 0x063A                                                                  },
--~ }

local small = {
    "ا", "ٮ", "ح", "د", "ه", "و", "ر",
}

local medium = {
     "ا", "ب", "ج", "د", "ه", "و","ز", "ح", "ط" ,
     "ي", "ك", "ل", "م", "ن", "س", "ع", "ف", "ص" ,
     "ق", "ر", "ش", "ت", "ث", "خ", "ذ", "ض", "ظ" ,
     "غ" ,
}

local large = {
    { "ا", "ب", "ج", "د", "ه", "و","ز", "ح", "ط" },
    { "ي", "ك", "ل", "م", "ن", "س", "ع", "ف", "ص" },
    { "ق", "ر", "ش", "ت", "ث", "خ", "ذ", "ض", "ظ" },
    { "غ" },
}

function converters.toabjad(n,what)
    if n <= 0 or n >= 2000 then
        return tostring(n)
    elseif what == 2 and n <= 7 then
        return small[n]
    elseif what == 3 and n <= 28 then
        return medium[n]
    else
        local a, b, c, d
        a, n = floor(n/1000), mod(n,1000)
        b, n = floor(n/ 100), mod(n, 100)
        c, n = floor(n/  10), mod(n,  10)
        d, n = floor(n/   1), mod(n,   1)
        return (large[4][a] or "") .. (large[3][b] or "") .. (large[2][c] or "") .. (large[1][d] or "")
    end
end

function converters.abjadnumerals     (n) return texsprint(converters.toabjad(n,false)) end
function converters.abjadnodotnumerals(n) return texsprint(converters.toabjad(n,true)) end

local vector = {
    normal = {
                [0] = "○",
                [1] = "一",
                [2] = "二",
                [3] = "三",
                [4] = "四",
                [5] = "五",
                [6] = "六",
                [7] = "七",
                [8] = "八",
                [9] = "九",
               [10] = "十",
              [100] = "百",
             [1000] = "千",
            [10000] = "万",
        [100000000] = "亿",
    },
    cap = {
                [0] = "零",
                [1] = "壹",
                [2] = "贰",
                [3] = "叁",
                [4] = "肆",
                [5] = "伍",
                [6] = "陆",
                [7] = "柒",
                [8] = "捌",
                [9] = "玖",
               [10] = "拾",
              [100] = "佰",
             [1000] = "仟",
            [10000] = "萬",
        [100000000] = "亿",
    },
    all = {
                [0] = "○",
                [1] = "一",
                [2] = "二",
                [3] = "三",
                [4] = "四",
                [5] = "五",
                [6] = "六",
                [7] = "七",
                [8] = "八",
                [9] = "九",
               [10] = "十",
               [20] = "廿",
               [30] = "卅",
              [100] = "百",
             [1000] = "千",
            [10000] = "万",
        [100000000] = "亿",
    }
}

function tochinese(n,name) -- normal, caps, all
    local result = { }
    local vector = vector[name] or vector.normal
    while true do
        if n == 0 then
            break
        elseif n >= 100000000 then
            local m = floor(n/100000000)
            if m > 1 then result[#result+1] = tochinese(m) end
            result[#result+1] = vector[100000000]
            n = n % 100000000
        elseif n >= 10000000 then
            result[#result+1] = tochinese(floor(n/10000))
            result[#result+1] = vector[10000]
            n = n % 10000
        elseif n >= 1000000 then
            result[#result+1] = tochinese(floor(n/10000))
            result[#result+1] = vector[10000]
            n = n % 10000
        elseif n >= 100000 then
            result[#result+1] = tochinese(floor(n/10000))
            result[#result+1] = vector[10000]
            n = n % 10000
        elseif n >= 10000 then
            local m = floor(n/10000)
            if m > 1 then result[#result+1] = vector[m] end
            result[#result+1] = vector[10000]
            n = n % 10000
        elseif n >= 1000 then
            local m = floor(n/1000)
            if m > 1 then result[#result+1] = vector[m] end
            result[#result+1] = vector[1000]
            n = n % 1000
        elseif n >= 100 then
            local m = floor(n/100)
            if m > 1 then result[#result+1] = vector[m] end
            result[#result+1] = vector[100]
            n = n % 100
        elseif n >= 10 then
            local m = floor(n/10)
            if vector[m*10] then
                result[#result+1] = vector[m*10]
            else
                result[#result+1] = vector[m]
                result[#result+1] = vector[10]
            end
            n = n % 10
        else
            result[#result+1] = vector[n]
            break
        end
    end
    return concat(result)
end

--~ for k, v in ipairs { 1,10,15,25,35,45,11,100,111,1111,10000,11111,100000,111111,1111111,11111111,111111111,100000000,1111111111,11111111111,111111111111,1111111111111 } do
--~     print(v,tochinese(v),tochinese(v,"all"),tochinese(v,"cap"))
--~ end

function converters.chinesenumerals   (n) return texsprint(tochinese(n,"normal")) end
function converters.chinesecapnumerals(n) return texsprint(tochinese(n,"cap"   )) end
function converters.chineseallnumerals(n) return texsprint(tochinese(n,"all"   )) end

--~ Well, since the one asking for this didn't test it the following code is not
--~ enabled.
--~
--~ -- This Lua version is based on a Javascript by Behdad Esfahbod which in turn
--~ -- is based on GPL'd code by Roozbeh Pournader of the The FarsiWeb Project
--~ -- Group: http://www.farsiweb.info/jalali/jalali.js.
--~ --
--~ -- We start tables at one, I kept it zero based in order to stay close to
--~ -- the original.
--~ --
--~ -- Conversion by Hans Hagen
--~
--~ local g_days_in_month = { [0]=31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
--~ local j_days_in_month = { [0]=31, 31, 31, 31, 31, 31, 30, 30, 30, 30, 30, 29 }
--~
--~ local function div(a,b)
--~   return math.floor(a/b)
--~ end
--~
--~ local function remainder(a,b)
--~   return a - div(a,b)*b
--~ end
--~
--~ function gregorian_to_jalali(gy,gm,gd)
--~     local jy, jm, jd, g_day_no, j_day_no, j_np, i
--~     gy, gm, gd = gy - 1600, gm - 1, gd - 1
--~     g_day_no = 365*gy + div((gy+3),4) - div((gy+99),100) + div((gy+399),400)
--~     i = 0
--~     while i < gm do
--~         g_day_no = g_day_no + g_days_in_month[i]
--~         i = i + 1
--~     end
--~     if (gm>1 and ((gy%4==0 and gy%100~=0) or (gy%400==0))) then
--~         g_day_no = g_day_no + 1
--~     end
--~     g_day_no = g_day_no + gd
--~     j_day_no = g_day_no - 79
--~     j_np = div(j_day_no,12053)
--~     j_day_no = remainder(j_day_no,12053)
--~     jy = 979 + 33*j_np + 4*div(j_day_no,1461)
--~     j_day_no = remainder(j_day_no,1461)
--~     if j_day_no >= 366 then
--~         jy = jy + div((j_day_no-1),365)
--~         j_day_no = remainder((j_day_no-1),365)
--~     end
--~     i = 0
--~     while i < 11 and j_day_no >= j_days_in_month[i] do
--~         j_day_no = j_day_no - j_days_in_month[i]
--~         i = i + 1
--~     end
--~     jm = i + 1
--~     jd = j_day_no + 1
--~     return jy, jm, jd
--~ end
--~
--~ function jalali_to_gregorian(jy,jm,jd)
--~     local gy, gm, gd, g_day_no, j_day_no, leap, i
--~     jy, jm, jd = jy - 979, jm - 1, jd - 1
--~     j_day_no = 365*jy + div(jy,33)*8 + div((remainder(jy,33)+3),4)
--~     i = 0
--~     while i < jm do
--~         j_day_no = j_day_no + j_days_in_month[i]
--~         i = i + 1
--~     end
--~     j_day_no = j_day_no + jd
--~     g_day_no = j_day_no + 79
--~     gy = 1600 + 400*div(g_day_no,146097)
--~     g_day_no = remainder (g_day_no, 146097)
--~     leap = 1
--~     if g_day_no >= 36525 then
--~         g_day_no = g_day_no - 1
--~         gy = gy + 100*div(g_day_no,36524)
--~         g_day_no = remainder (g_day_no, 36524)
--~         if g_day_no >= 365 then
--~             g_day_no = g_day_no + 1
--~         else
--~             leap = 0
--~         end
--~     end
--~     gy = gy  + 4*div(g_day_no,1461)
--~     g_day_no = remainder (g_day_no, 1461)
--~     if g_day_no >= 366 then
--~         leap = 0
--~         g_day_no = g_day_no - 1
--~         gy = gy + div(g_day_no, 365)
--~         g_day_no = remainder(g_day_no, 365)
--~     end
--~     i = 0
--~     while g_day_no >= g_days_in_month[i] + ((i == 1 and leap) or 0) do
--~         g_day_no = g_day_no - g_days_in_month[i] + ((i == 1 and leap) or 0)
--~         i = i + 1
--~     end
--~     gm = i + 1
--~     gd = g_day_no + 1
--~     return gy, gm, gd
--~ end
--~
--~ print(gregorian_to_jalali(2009,02,24))
--~ print(jalali_to_gregorian(1387,12,06))
