--[[doc--
Taken from the most recent branch of luaotfload.
--doc]]--
local addotffeature       = fonts.handlers.otf.addfeature
local registerotffeature  = fonts.handlers.otf.features.register

local everywhere = { ["*"] = { ["*"] = true } }

local tlig = {
    {
        type      = "substitution",
        features  = everywhere,
        data      = {
            [0x0022] = 0x201D,                   -- quotedblright
            [0x0027] = 0x2019,                   -- quoteleft
            [0x0060] = 0x2018,                   -- quoteright
        },
        flags     = { },
    },
    {
        type     = "ligature",
        features = everywhere,
        data     = {
            [0x2013] = {0x002D, 0x002D},         -- endash
            [0x2014] = {0x002D, 0x002D, 0x002D}, -- emdash
            [0x201C] = {0x2018, 0x2018},         -- quotedblleft
            [0x201D] = {0x2019, 0x2019},         -- quotedblright
            [0x201E] = {0x002C, 0x002C},         -- quotedblbase
            [0x00A1] = {0x0021, 0x2018},         -- exclamdown
            [0x00BF] = {0x003F, 0x2018},         -- questiondown
        },
        flags    = { },
    },
    {
        type     = "ligature",
        features = everywhere,
        data     = {
            [0x201C] = {0x0060, 0x0060},         -- quotedblleft
            [0x201D] = {0x0027, 0x0027},         -- quotedblright
            [0x00A1] = {0x0021, 0x0060},         -- exclamdown
            [0x00BF] = {0x003F, 0x0060},         -- questiondown
        },
        flags    = { },
    },
}

addotffeature("tlig", tlig)
addotffeature("trep", { }) -- empty, all in tlig now
local anum_arabic = {
    [0x0030] = 0x0660,
    [0x0031] = 0x0661,
    [0x0032] = 0x0662,
    [0x0033] = 0x0663,
    [0x0034] = 0x0664,
    [0x0035] = 0x0665,
    [0x0036] = 0x0666,
    [0x0037] = 0x0667,
    [0x0038] = 0x0668,
    [0x0039] = 0x0669,
}

local anum_persian = {
    [0x0030] = 0x06F0,
    [0x0031] = 0x06F1,
    [0x0032] = 0x06F2,
    [0x0033] = 0x06F3,
    [0x0034] = 0x06F4,
    [0x0035] = 0x06F5,
    [0x0036] = 0x06F6,
    [0x0037] = 0x06F7,
    [0x0038] = 0x06F8,
    [0x0039] = 0x06F9,
}

local function valid(data)
    local features = data.resources.features
    if features then
        for k, v in next, features do
            for k, v in next, v do
                if v.arab then
                    return true
                end
            end
        end
    end
end

local anum_specification = {
    {
        type     = "substitution",
        features = { arab = { far = true, urd = true, snd = true } },
        data     = anum_persian,
        flags    = { },
        valid    = valid,
    },
    {
        type     = "substitution",
features = { arab = { ["*"] = true } },
        data     = anum_arabic,
        flags    = { },
        valid    = valid,
    },
}

addotffeature("anum",anum_specification)

registerotffeature {
    name        = 'anum',
    description = 'arabic digits',
}