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

local hlist_code   <const> = nodes.nodecodes.hlist
local penalty_code <const> = nodes.nodecodes.penalty

local nuts         = nodes.nuts
local getprev      = nuts.getprev
local getid        = nuts.getid
----- getattr      = nuts.getattribute
local getdepth     = nuts.getdepth
local newglue      = nuts.pool.glue
local insertafter  = nuts.insertafter

local texgetdimen  = tex.getdimen

----- a_adjuster   = attributes.system("adjuster")

local function correct_depth(head,tail)
    local prev = getprev(tail)
    if getid(prev) == penalty_code then -- linebreakpenalty
        prev = getprev(prev)
    end
    if getid(prev) == hlist_code then -- line
        local delta = getdepth(tail) - getdepth(prev)
        if delta > 0 then
            head = insertafter(head,prev,newglue(delta))
        end
        tex.prevdepth = getdepth(tail)
    end
    return head
end

local function block_baselineskip(head,tail)
 -- tex.prevdepth = -1000 * 65536 -- ignoredepth
    tex.prevdepth = texgetdimen("ignoredepthcriterion") -- todo: c_...
    return head
end

local preactions = {
    [1] = correct_depth,
    [2] = block_baselineskip,
}

local postactions = {
    [1] = correct_depth,
    [2] = block_baselineskip,
}

-- function nodes.handlers.adjusters(head,where,tail)
--     if where == "preadjust" then
--         local a = getattr(tail,a_adjuster)
--         if a then
--             a = preactions[a]
--             if a then
--                 head = a(head,tail)
--             end
--         end
--     elseif where == "postadjust" then
--         local a = getattr(tail,a_adjuster)
--         if a then
--             a = postactions[a]
--             if a then
--                 head = a(head,tail)
--             end
--         end
--     else
--         -- can't happen
--     end
--     return head
-- end

function nodes.handlers.adjusters(head,where,tail,index)
    if where == "preadjust" then
        local a = preactions[index]
        if a then
            head = a(head,tail)
        end
    else -- if where == "postadjust" then
        local a = postactions[index]
        if a then
            head = a(head,tail)
        end
    end
    return head
end
