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

local formatters   = string.formatters
local reporters    = logs.reporters
local xmlserialize = xml.serialize
local xmlcollected = xml.collected
local xmltext      = xml.text
local xmlfirst     = xml.first
local xmlfilter    = xml.filter

-- there is no need for a newhandlers { name = "help", parent = "string" }

local function flagdata(flag)
    local name  = flag.at.name or ""
    local value = flag.at.value or ""
 -- local short = xmlfirst(s,"/short")
 -- local short = xmlserialize(short,xs)
    local short = xmltext(xmlfirst(flag,"/short")) or ""
    return name, value, short
end

local function exampledata(example)
    local command = xmltext(xmlfirst(example,"/command")) or ""
    local comment = xmltext(xmlfirst(example,"/comment")) or ""
    return command, comment
end

local function categorytitle(category)
    return xmltext(xmlfirst(category,"/title")) or ""
end

local exporters = logs.exporters

function exporters.man(specification,...)
    local root = xml.convert(specification.helpinfo or "")
    if not root then
        return
    end
    local xs = xml.gethandlers("string")
    xml.sethandlersfunction(xs,"short",function(e,handler) xmlserialize(e.dt,handler) end)
    xml.sethandlersfunction(xs,"ref",  function(e,handler) handler.handle("--"..e.at.name) end)
    local wantedcategories = select("#",...) == 0 and true or table.tohash { ... }
    local nofcategories = xml.count(root,"/application/flags/category")
    local name    = xmlfilter(root,"/application/metadata/entry[@name='name']/text()")
    local detail  = xmlfilter(root,"/application/metadata/entry[@name='detail']/text()") or name
    local version = xmlfilter(root,"/application/metadata/entry[@name='version']/text()") or "0.00"
    local banner  = specification.banner or detail or name
    --
    local result = { }
    --
    -- .TH "context" "1" "some date" "version" "ConTeXt" -- we use a fake date as I don't want to polute the git repos
    --
    local runner = string.match(name,"^mtx%-(.*)")
    if runner then
        runner = formatters["mtxrun --script %s"](runner)
    else
        runner = name
    end
    --
    result[#result+1] = formatters['.TH "%s" "1" "%s" "version %s" "%s"'](name,os.date("01-01-%Y"),version,detail)
    result[#result+1] = formatters[".SH NAME\n.B %s"](name)
    result[#result+1] = formatters[".SH SYNOPSIS\n.B %s [\n.I OPTIONS ...\n.B ] [\n.I FILENAMES\n.B ]"](runner)
    result[#result+1] = formatters[".SH DESCRIPTION\n.B %s"](detail)
    --
    for category in xmlcollected(root,"/application/flags/category") do
        if nofcategories > 1 then
            result[#result+1] = formatters['.SH OPTIONS: %s'](string.upper(category.at.name or "all"))
        else
            result[#result+1] = ".SH OPTIONS"
        end
        for subcategory in xmlcollected(category,"/subcategory") do
            for flag in xmlcollected(subcategory,"/flag") do
                local name, value, short = flagdata(flag)
                if value == "" then
                    result[#result+1] = formatters[".TP\n.B --%s\n%s"](name,short)
                else
                    result[#result+1] = formatters[".TP\n.B --%s=%s\n%s"](name,value,short)
                end
            end
        end
    end
    local moreinfo = specification.moreinfo
    if moreinfo and moreinfo ~= "" then
        moreinfo = string.gsub(moreinfo,"[\n\r]([%a]+)%s*:%s*",'\n\n.B "%1:"\n')
        result[#result+1] = formatters[".SH AUTHOR\n%s"](moreinfo)
    end
    return table.concat(result,"\n")
end

local craptemplate = [[
<?xml version="1.0"?>
<application>
<metadata>
<entry name="banner">%s</entry>
</metadata>
<verbose>
%s
</verbose>
]]

function exporters.xml(specification,...)
    local helpinfo = specification.helpinfo
    if type(helpinfo) == "string" then
        if string.find(helpinfo,"^<%?xml") then
            return helpinfo
        end
    elseif type(helpinfo) == "table" then
        helpinfo = table.concat(helpinfo,"\n\n")
    else
        helpinfo = "no help"
    end
    return formatters[craptemplate](specification.banner or "?",helpinfo)
end

-- the following template is optimized a bit for space

-- local bodytemplate = [[
-- <h1>Command line options</h1>
-- <table>
--     <tr>
--         <th style="width: 10em">flag</th>
--         <th style="width: 8em">value</th>
--         <th>description</th>
--     </tr>
--     <?lua
--         for category in xml.collected(variables.root,"/application/flags/category") do
--             if variables.nofcategories > 1 then
--                 ?><tr>
--                     <th colspan="3"><?lua inject(category.at.name) ?></th>
--                 </tr><?lua
--             end
--             for subcategory in xml.collected(category,"/subcategory") do
--                 ?><tr><th/><td/><td/></tr><?lua
--                 for flag in xml.collected(subcategory,"/flag") do
--                     local name, value, short = variables.flagdata(flag)
--                     ?><tr>
--                         <th>--<?lua inject(name) ?></th>
--                         <td><?lua inject(value) ?></td>
--                         <td><?lua inject(short) ?></td>
--                     </tr><?lua
--                 end
--             end
--         end
--     ?>
-- </table>
-- <br/>
-- <?lua
--     for category in xml.collected(variables.root,"/application/examples/category") do
--         local title = variables.categorytitle(category)
--         if title ~= "" then
--             ?><h1><?lua inject(title) ?></h1><?lua
--         end
--         for subcategory in xml.collected(category,"/subcategory") do
--             for example in xml.collected(subcategory,"/example") do
--                 local command, comment = variables.exampledata(example)
--                 ?><tt><?lua inject(command) ?></tt><br/><?lua
--             end
--             ?><br/><?lua
--         end
--     end
--     for comment in xml.collected(root,"/application/comments/comment") do
--         ?><br/><?lua inject(xml.text(comment)) ?><br/><?lua
--     end
-- ?>
-- ]]

local bodytemplate = [[
<h1>Command line options</h1>
<table>
    <tr><th style="width: 10em">flag</th><th style="width: 8em">value</th><th>description</th></tr>
    <?lua for category in xml.collected(variables.root,"/application/flags/category") do if variables.nofcategories > 1 then ?>
    <tr><th colspan="3"><?lua inject(category.at.name) ?></th></tr>
    <?lua end for subcategory in xml.collected(category,"/subcategory") do ?>
    <tr><th/><td/><td/></tr>
    <?lua for flag in xml.collected(subcategory,"/flag") do local name, value, short = variables.flagdata(flag) ?>
    <tr><th>--<?lua inject(name) ?></th><td><?lua inject(value) ?></td><td><?lua inject(short) ?></td></tr>
    <?lua end end end ?>
</table>
<br/>
<?lua for category in xml.collected(variables.root,"/application/examples/category") do local title = variables.categorytitle(category) if title ~= "" then ?>
<h1><?lua inject(title) ?></h1>
<?lua end for subcategory in xml.collected(category,"/subcategory") do for example in xml.collected(subcategory,"/example") do local command, comment = variables.exampledata(example) ?>
<tt><?lua inject(command) ?></tt>
<br/><?lua end ?><br/><?lua end end for comment in xml.collected(root,"/application/comments/comment") do ?>
<br/><?lua inject(xml.text(comment)) ?><br/><?lua end ?>
]]

function exporters.html(specification,...)
    local root = xml.convert(specification.helpinfo or "")
    if not root then
        return
    end
    local xs = xml.gethandlers("string")
    xml.sethandlersfunction(xs,"short",function(e,handler) xmlserialize(e.dt,handler) end)
    xml.sethandlersfunction(xs,"ref",  function(e,handler) handler.handle("--"..e.at.name) end)
    local wantedcategories = select("#",...) == 0 and true or table.tohash { ... }
    local nofcategories = xml.count(root,"/application/flags/category")
    local name    = xmlfilter(root,"/application/metadata/entry[@name='name']/text()")
    local detail  = xmlfilter(root,"/application/metadata/entry[@name='detail']/text()") or name
    local version = xmlfilter(root,"/application/metadata/entry[@name='version']/text()") or "0.00"
    local banner  = specification.banner or detail or name
    --
    dofile(resolvers.findfile("trac-lmx.lua","tex"))
    --
    local htmltemplate = io.loaddata(resolvers.findfile("context-base.lmx","tex")) or "no template"
    --
    local body = lmx.convertstring(bodytemplate, {
        nofcategories    = nofcategories,
        wantedcategories = wantedcategories,
        root             = root,
    --  moreinfo         = specification.moreinfo,
        flagdata         = flagdata,
        exampledata      = exampledata,
        categorytitle    = categorytitle,
    })
    local html = lmx.convertstring(htmltemplate, {
        maintext   = body,
        title      = banner,
        bottomtext = "wiki: http://contextgarden.net | mail: ntg-context@ntg.nl | website: http://www.pragma-ade.nl",
    })
    --
    return html
end