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

local round = math.round

local nuts          = nodes.nuts
local tonut         = nodes.tonut
local tonode        = nodes.tonode
local nodepool      = nuts.pool

local vlist_code    = nodes.nodecodes.vlist

local new_hlist     = nodepool.hlist
local new_vlist     = nodepool.vlist
----- new_glyph     = nodepool.glyph
local new_glyph     = nuts.newmathglyph

local getattrlst    = nuts.getattributelist
local setattrlst    = nuts.setattributelist
local setwhd        = nuts.setwhd
local getwhd        = nuts.getwhd
local getid         = nuts.getid

local chardata      = fonts.hashes.characters
local addcharacters = font.addcharacters

-- not yet ok for compact fonts .. needs checking .. or just make this non-compact only
-- there's also an inaccuracy creeping in: \sqrt{\quad\blackrule[height=25pt,depth=25pt]}

local function register_extensible(font,char,style,box)
    -- We don't share (yet)!
    local bx = tonut(box)
    updaters.apply("tagging.state.disable") -- fast enough
    nodes.handlers.finalizelist(bx)
    updaters.apply("tagging.state.enable")
    local id = getid(bx)
    local al = getattrlst(bx)
    local wd, ht, dp = getwhd(bx)
    local fontdata = chardata[font]
    local oldchar  = fontdata[char]
    local unicode  = oldchar.unicode or char
    -- we cannot have self referencing t3 fonts
    local oldcommands = oldchar.oldcommands
    local newcommands = oldchar.commands
    if oldcommands then
        oldchar.commands = oldcommands
    end
    --
    local private  = fonts.helpers.setboxdirectly(font,unicode,box)
    -- we saved a scaled glyph stream so we now use an unscaled one ...
    local p  = fonts.hashes.parameters[font]
    local g  = new_glyph(font,private,al)
--     if fonts.hashes.properties[font].compactmath then
--         nuts.setscales(g,1000,1000,1000)
--     end
    -- nasty, testcase: bold math sqrt extensible
    local sx = round(1000/p.extendfactor)
    local sy = round(1000/p.squeezefactor)
    nuts.setscales(g,1000,sx,sy)
    -- horrible
if sx ~= 1000 then
    wd = wd * 7200/7227
end
if sy ~= 1000 then
    ht = ht * 7200/7227
    dp = dp * 7200/7227
end
    --
    local n = new_hlist(g)
    --
    if newcommands then
        oldchar.commands = newcommands
    end
    --
 -- local newchar = {
 --     unicode = unicode,
 --     width   = wd,
 --     height  = ht,
 --     depth  =  dp,
 -- }
 -- local p = oldchar.vparts
 -- if p then
 --     local first = fontdata[p[#p].glyph]
 --     local last  = fontdata[p[ 1].glyph]
 --     if first then
 --         newchar.topleft  = first.topleft
 --         newchar.topright = first.topright
 --     end
 --     if last then
 --         newchar.bottomleft  = last.bottomleft
 --         newchar.bottomright = last.bottomright
 --     end
 -- end
 -- addcharacters(font, { [private] = newchar })
    -- so the dimensions of the box don't match the glyph scale!
    setwhd(n,wd,ht,dp)
    setattrlst(n,al)
    if id == vlist_code then
        n = new_vlist(n)
        setwhd(n,wd,ht,dp)
        setattrlst(n,al)
    end
    return tonode(n)
end

directives.register("math.extensibles", function(v)
    callback.register("register_extensible", v and register_extensible or nil)
end)

-- Default per 2022-08-25

callback.register("register_extensible", register_extensible)