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

-- A historic intermediate version can be found in the mkiv variant. The code
-- can probably be improved but performance etc is not really an issue here.

local insert, remove = table.insert, table.remove

local context           = context
local ctx_doifelse      = commands.doifelse

local nodecodes         = nodes.nodecodes
local boundarycodes     = nodes.boundarycodes
local subtypes          = nodes.subtypes

local glyph_code        = nodecodes.glyph
local par_code          = nodecodes.par
local boundary_code     = nodecodes.boundary

local wordboundary_code = boundarycodes.word

local texgetnest        = tex.getnest -- to be used
local texsetcount       = tex.setcount

local flushnode         = nodes.flushnode
local flushlist         = nodes.flushlist

local settexattribute   = tex.setattribute
local ispunctuation     = characters.is_punctuation

local variables         = interfaces.variables
local v_all             = variables.all
local v_reset           = variables.reset

local stack             = { }

local a_marked          = attributes.numbers['marked']
local lastmarked        = 0
local marked            = {
    [v_all]   = 1,
    [""]      = 1,
    [v_reset] = attributes.unsetvalue,
}

local function pickup()
    local list = texgetnest()
    if list then
        local tail = list.tail
        if tail and tail.id == glyph_code and ispunctuation[tail.char] then
            local prev = tail.prev
            list.tail = prev
            if prev then
                prev.next = nil
            end
            list.tail = prev
            tail.prev = nil
            return tail
        end
    end
end

local actions = {
    remove = function(specification)
        local n = pickup()
        if n then
            flushnode(n)
        end
    end,
    push = function(specification)
        local n = pickup()
        if n then
            insert(stack,n or false)
        end
    end,
    pop = function(specification)
        local n = remove(stack)
        if n then
            context(n)
        end
    end,
}

local function pickuppunctuation(specification)
    local action = actions[specification.action or "remove"]
    if action then
        action(specification)
    end
end

-- I played with nested marked content but it makes no sense and gives
-- complex code. Also, it's never needed so why bother.

local function pickup(head,tail,str)
    local attr = marked[str]
    local last = tail
    if last[a_marked] == attr then
        local first = last
        while true do
            local prev = first.prev
            if prev and prev[a_marked] == attr then
                if prev.id == par_code then -- and startofpar(prev)
                    break
                else
                    first = prev
                end
            else
                break
            end
        end
        return first, last
    end
end

local function found(str)
    local list = texgetnest()
    if list then
        local tail = list.tail
        return tail and tail[a_marked] == marked[str]
    end
end

local actions = {
    remove = function(specification)
        local list = texgetnest()
        if list then
            local head = list.head
            local tail = list.tail
            local first, last = pickup(head,tail,specification.mark)
            if first then
                if first == head then
                    list.head = nil
                    list.tail = nil
                else
                    local prev = first.prev
                    list.tail  = prev
                    prev.next  = nil
                end
                flushlist(first)
            end
        end
    end,
}

local function pickupmarkedcontent(specification)
    local action = actions[specification.action or "remove"]
    if action then
        action(specification)
    end
end

local function markcontent(str)
    local currentmarked = marked[str or v_all]
    if not currentmarked then
        lastmarked    = lastmarked + 1
        currentmarked = lastmarked
        marked[str]   = currentmarked
    end
    settexattribute(a_marked,currentmarked)
end

interfaces.implement {
    name      = "pickuppunctuation",
    actions   = pickuppunctuation,
    arguments = {
        {
            { "action" }
        }
    }
}

interfaces.implement {
    name      = "pickupmarkedcontent",
    actions   = pickupmarkedcontent,
    arguments = {
        {
            { "action" },
            { "mark" }
        }
    }
}

interfaces.implement {
    name      = "markcontent",
    actions   = markcontent,
    arguments = "string",
}

interfaces.implement {
    name      = "doifelsemarkedcontent",
    actions   = function(str) ctx_doifelse(found(str)) end,
    arguments = "string",
}

-- We just put these here.

interfaces.implement {
    name    = "lastnodeidstring",
    public  = true,
    actions = function()
        local list = texgetnest() -- "top"
        local okay = false
        if list then
            local tail = list.tail
            if tail then
                okay = nodecodes[tail.id]
            end
        end
        context(okay or "")
    end,
}

-- local t_lastnodeid = token.create("c_syst_last_node_id")
--
-- interfaces.implement {
--     name    = "lastnodeid",
--     public  = true,
--     actions = function()
--         ...
--         tex.setcount("c_syst_last_node_id",okay)
--         context.sprint(t_lastnodeid)
--     end,
-- }

-- not needed in lmtx ...

local c_syst_last_node_id = tex.iscount("c_syst_last_node_id")

interfaces.implement {
    name    = "lastnodeid",
    actions = function()
        local list = texgetnest() -- "top"
        local okay = -1
        if list then
            local tail = list.tail
            if tail then
                okay = tail.id
            end
        end
        texsetcount(c_syst_last_node_id,okay)
    end,
}

interfaces.implement {
    name    = "lastnodesubtypestring",
    public  = true,
    actions = function()
        local list = texgetnest() -- "top"
        local okay = false
        if list then
            local tail = list.tail
            if head then
                okay = subtypes[tail.id][tail.subtype]
            end
        end
        context(okay or "")
    end,
}

local function lastnodeequals(id,subtype)
    local list = texgetnest() -- "top"
    local okay = false
    if list then
        local tail = list.tail
        if tail then
            local i = tail.id
            okay = i == id or i == nodecodes[id]
            if subtype then
                local s = tail.subtype
                okay = s == subtype or s == subtypes[i][subtype]
            end
        end
    end
    ctx_doifelse(okay)
end

interfaces.implement {
    name      = "lastnodeequals",
    arguments = "2 strings",
    actions   = lastnodeequals,
}

interfaces.implement {
    name    = "atwordboundary",
    actions = function()
        lastnodeequals(boundary_code,wordboundary_code)
    end,
}