if not modules then modules = { } end modules ['font-imp-compound'] = {
    version   = 1.001,
    comment   = "companion to font-ini.mkiv",
    author    = "Hans Hagen, PRAGMA ADE",
    copyright = "ConTeXt Development Team",
    license   = "see context related readme files"
}

-- we can also make composed characters this way

local compoundhyphen = fonts.helpers.newprivateslot("compoundhyphen")

local function initialize(tfmdata,key,value)
    if value then
        local characters = tfmdata.characters
        local hyphen     = characters[0x2D]
        if hyphen then
            local width = hyphen.width
            if width then
                characters[compoundhyphen] = {
                    width    = 1.5*width,
                    height   = hyphen.height,
                    depth    = hyphen.depth,
                    unicode  = hyphen.unicode,
                    callback = "compile", -- needs documentation
                    commands = {
                        { "char", 0x2D },
                        { "left", width/2 },
                        { "char", 0x2D }
                    },
                }
            end
        end
    end
end

fonts.handlers.otf.features.register {
    name         = "compoundhyphen",
    description  = "compoundhyphen",
    manipulators = {
        base = initialize,
        node = initialize,
    }
}