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

local tostring = tostring

local nuts             = nodes.nuts

local left_box_code    = nodes.listcodes.left
local right_box_code   = nodes.listcodes.right
local hlist_code       = nodes.nodecodes.hlist

local getlist          = nuts.getlist
local getprev          = nuts.getprev
local getnext          = nuts.getnext
local getattribute     = nuts.getattribute
local gettail          = nuts.tail
local getwidth         = nuts.getwidth
local setlist          = nuts.setlist
local setoffsets       = nuts.setoffsets
local flushlist        = nuts.flushlist
local takebox          = nuts.takebox
local setbox           = nuts.setbox
local copynode         = nuts.copynode
local rangedimensions  = nuts.rangedimensions
local traverse_list    = nuts.traversers.list

local expandmacro      = token.expandmacro

local dimension_value  = tokens.values.dimension
local integer_value    = tokens.values.integer

local implement        = interfaces.implement

typesetters            = typesetters or { }
local typesetters      = typesetters

typesetters.localboxes = typesetters.localboxes or { }
local localboxes       = typesetters.localboxes

local a_localboxes     = attributes.private("localboxes")

local starttiming      = statistics.starttiming
local stoptiming       = statistics.stoptiming

do

    local lb_attribute        = 0
    local lb_linenumber       = 0
    local lb_width            = 0
    local lb_offset           = 0
    local lb_leftskip         = 0
    local lb_rightskip        = 0
    local lb_lefthang         = 0
    local lb_righthang        = 0
    local lb_indent           = 0
    local lb_parfillleftskip  = 0
    local lb_parfillrightskip = 0
    local lb_overshoot        = 0

    implement { name = "localboxattribute",        public = true, usage = "value", actions = function() return integer_value,   lb_attribute        end }
    implement { name = "localboxlinenumber",       public = true, usage = "value", actions = function() return integer_value,   lb_linenumber       end }
    implement { name = "localboxwidth",            public = true, usage = "value", actions = function() return dimension_value, lb_width            end }
    implement { name = "localboxoffset",           public = true, usage = "value", actions = function() return dimension_value, lb_offset           end }
    implement { name = "localboxleftskip",         public = true, usage = "value", actions = function() return dimension_value, lb_leftskip         end }
    implement { name = "localboxrightskip",        public = true, usage = "value", actions = function() return dimension_value, lb_rightskip        end }
    implement { name = "localboxlefthang",         public = true, usage = "value", actions = function() return dimension_value, lb_lefthang         end }
    implement { name = "localboxrighthang",        public = true, usage = "value", actions = function() return dimension_value, lb_righthang        end }
    implement { name = "localboxindent",           public = true, usage = "value", actions = function() return dimension_value, lb_indent           end }
    implement { name = "localboxparfillleftskip",  public = true, usage = "value", actions = function() return dimension_value, lb_parfillleftskip  end }
    implement { name = "localboxparfillrightskip", public = true, usage = "value", actions = function() return dimension_value, lb_parfillrightskip end }
    implement { name = "localboxovershoot",        public = true, usage = "value", actions = function() return dimension_value, lb_overshoot        end }

    local function action(current,where)
        -- We can have nested leftboxes!
        local l = getlist(current)
        setlist(current)
        local h = copynode(current)
        setlist(h,l)
        setbox("localboxcontentbox",h)
        expandmacro("localboxcommand") -- no longer pass arguments
        local b = takebox("localboxcontentbox")
        setlist(current,b)
        if where == "left" then
            local w = getwidth(b)
            setoffsets(b,lb_width - lb_offset - w)
        else
            setoffsets(b,lb_offset - lb_width)
        end
    end

    local function processleftbox(box,width)
        local list = getlist(box)
        if not width then
            width = 0
        end
        for current, id, subtype in traverse_list, list do
            if id == hlist_code then
                local a = getattribute(current,a_localboxes)
                if a then
                    lb_attribute = a
                    lb_width     = width + rangedimensions(box,list,getprev(current))
                    action(current,"left")
                end
                if subtype == left_box_code then
                    processleftbox(current,width + rangedimensions(box,list,getprev(current)))
                end
            end
        end
    end

    local function processrightbox(box,width)
        local list = getlist(box)
        local tail = gettail(list)
        if not width then
            width = 0
        end
        for current, id, subtype in traverse_list, list do
            if id == hlist_code then
                local a = getattribute(current,a_localboxes)
                if a then
                    lb_attribute = a
                    lb_width     = width + rangedimensions(box,list,getnext(current),tail)
                    action(current,"right")
                end
                if subtype == right_box_code then
                    processrightbox(current,width + rangedimensions(box,getnext(current),tail))
                end
            end
        end
    end

    local function processlocalboxes(line, leftbox, rightbox, linenumber, leftskip, rightskip, lefthang, righthang, indent, parfillleftskip, parfillrightskip, overshoot)
        --
        lb_attribute        = 0
        lb_linenumber       = linenumber
        lb_width            = 0
     -- lb_offset           = 0
        lb_leftskip         = leftskip
        lb_rightskip        = rightskip
        lb_lefthang         = lefthang
        lb_righthang        = righthang
        lb_indent           = indent
        lb_parfillleftskip  = parfillleftskip
        lb_parfillrightskip = parfillrightskip
        lb_overshoot        = overshoot
        --
        -- for now we always anchor
        --
        if leftbox then
            lb_offset = leftskip + lefthang + indent + parfillleftskip + getwidth(leftbox)
            processleftbox(leftbox)
        end
        if rightbox then
            lb_offset = rightskip + righthang + parfillrightskip + getwidth(rightbox) - overshoot
            processrightbox(rightbox)
        end
    end

    typesetters.localboxes.handler = processlocalboxes

end

local localboxactions = nodes.tasks.actions("localboxes")

function builders.local_box_filter(...)
    starttiming(builders)
    localboxactions(...)
    stoptiming(builders)
end

-- we register the function elsewhere

callbacks.register("local_box_filter", builders.local_box_filter, "process local boxes")