1 files changed, 1466 insertions, 1466 deletions
diff --git a/tex/context/base/lxml-lpt.lua b/tex/context/base/lxml-lpt.lua
index 51ab321b9..2f57ced5b 100644
--- a/tex/context/base/lxml-lpt.lua
+++ b/tex/context/base/lxml-lpt.lua
@@ -1,1466 +1,1466 @@
-if not modules then modules = { } end modules ['lxml-lpt'] = {
-    version   = 1.001,
-    comment   = "this module is the basis for the lxml-* ones",
-    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
-    copyright = "PRAGMA ADE / ConTeXt Development Team",
-    license   = "see context related readme files"
-}
-
--- e.ni is only valid after a filter run
--- todo: B/C/[get first match]
-
-local concat, remove, insert = table.concat, table.remove, table.insert
-local type, next, tonumber, tostring, setmetatable, load, select = type, next, tonumber, tostring, setmetatable, load, select
-local format, upper, lower, gmatch, gsub, find, rep = string.format, string.upper, string.lower, string.gmatch, string.gsub, string.find, string.rep
-local lpegmatch, lpegpatterns = lpeg.match, lpeg.patterns
-
-local setmetatableindex = table.setmetatableindex
-local formatters = string.formatters -- no need (yet) as paths are cached anyway
-
--- beware, this is not xpath ... e.g. position is different (currently) and
--- we have reverse-sibling as reversed preceding sibling
-
---[[ldx--
-<p>This module can be used stand alone but also inside <l n='mkiv'/> in
-which case it hooks into the tracker code. Therefore we provide a few
-functions that set the tracers. Here we overload a previously defined
-function.</p>
-<p>If I can get in the mood I will make a variant that is XSLT compliant
-but I wonder if it makes sense.</P>
---ldx]]--
-
---[[ldx--
-<p>Expecially the lpath code is experimental, we will support some of xpath, but
-only things that make sense for us; as compensation it is possible to hook in your
-own functions. Apart from preprocessing content for <l n='context'/> we also need
-this module for process management, like handling <l n='ctx'/> and <l n='rlx'/>
-files.</p>
-
-<typing>
-a/b/c /*/c
-a/b/c/first() a/b/c/last() a/b/c/index(n) a/b/c/index(-n)
-a/b/c/text() a/b/c/text(1) a/b/c/text(-1) a/b/c/text(n)
-</typing>
---ldx]]--
-
-local trace_lpath    = false  if trackers then trackers.register("xml.path",    function(v) trace_lpath  = v end) end
-local trace_lparse   = false  if trackers then trackers.register("xml.parse",   function(v) trace_lparse = v end) end
-local trace_lprofile = false  if trackers then trackers.register("xml.profile", function(v) trace_lpath  = v trace_lparse = v trace_lprofile = v end) end
-
-local report_lpath = logs.reporter("xml","lpath")
-
---[[ldx--
-<p>We've now arrived at an interesting part: accessing the tree using a subset
-of <l n='xpath'/> and since we're not compatible we call it <l n='lpath'/>. We
-will explain more about its usage in other documents.</p>
---ldx]]--
-
-local xml = xml
-
-local lpathcalls  = 0  function xml.lpathcalls () return lpathcalls  end
-local lpathcached = 0  function xml.lpathcached() return lpathcached end
-
-xml.functions        = xml.functions or { } -- internal
-local functions      = xml.functions
-
-xml.expressions      = xml.expressions or { } -- in expressions
-local expressions    = xml.expressions
-
-xml.finalizers       = xml.finalizers or { } -- fast do-with ... (with return value other than collection)
-local finalizers     = xml.finalizers
-
-xml.specialhandler   = xml.specialhandler or { }
-local specialhandler = xml.specialhandler
-
-lpegpatterns.xml     = lpegpatterns.xml or { }
-local xmlpatterns    = lpegpatterns.xml
-
-finalizers.xml = finalizers.xml or { }
-finalizers.tex = finalizers.tex or { }
-
-local function fallback (t, name)
-    local fn = finalizers[name]
-    if fn then
-        t[name] = fn
-    else
-        report_lpath("unknown sub finalizer %a",name)
-        fn = function() end
-    end
-    return fn
-end
-
-setmetatableindex(finalizers.xml, fallback)
-setmetatableindex(finalizers.tex, fallback)
-
-xml.defaultprotocol = "xml"
-
--- as xsl does not follow xpath completely here we will also
--- be more liberal especially with regards to the use of | and
--- the rootpath:
---
--- test    : all 'test' under current
--- /test   : 'test' relative to current
--- a|b|c   : set of names
--- (a|b|c) : idem
--- !       : not
---
--- after all, we're not doing transformations but filtering. in
--- addition we provide filter functions (last bit)
---
--- todo: optimizer
---
--- .. : parent
--- *  : all kids
--- /  : anchor here
--- // : /**/
--- ** : all in between
---
--- so far we had (more practical as we don't transform)
---
--- {/test}   : kids 'test' under current node
--- {test}    : any kid with tag 'test'
--- {//test}  : same as above
-
--- evaluator (needs to be redone, for the moment copied)
-
--- todo: apply_axis(list,notable) and collection vs single
-
-local apply_axis = { }
-
-apply_axis['root'] = function(list)
-    local collected = { }
-    for l=1,#list do
-        local ll = list[l]
-        local rt = ll
-        while ll do
-            ll = ll.__p__
-            if ll then
-                rt = ll
-            end
-        end
-        collected[l] = rt
-    end
-    return collected
-end
-
-apply_axis['self'] = function(list)
---~     local collected = { }
---~     for l=1,#list do
---~         collected[l] = list[l]
---~     end
---~     return collected
-    return list
-end
-
-apply_axis['child'] = function(list)
-    local collected, c = { }, 0
-    for l=1,#list do
-        local ll = list[l]
-        local dt = ll.dt
-        if dt then -- weird that this is needed
-            local en = 0
-            for k=1,#dt do
-                local dk = dt[k]
-                if dk.tg then
-                    c = c + 1
-                    collected[c] = dk
-                    dk.ni = k -- refresh
-                    en = en + 1
-                    dk.ei = en
-                end
-            end
-            ll.en = en
-        end
-    end
-    return collected
-end
-
-local function collect(list,collected,c)
-    local dt = list.dt
-    if dt then
-        local en = 0
-        for k=1,#dt do
-            local dk = dt[k]
-            if dk.tg then
-                c = c + 1
-                collected[c] = dk
-                dk.ni = k -- refresh
-                en = en + 1
-                dk.ei = en
-                c = collect(dk,collected,c)
-            end
-        end
-        list.en = en
-    end
-    return c
-end
-
-apply_axis['descendant'] = function(list)
-    local collected, c = { }, 0
-    for l=1,#list do
-        c = collect(list[l],collected,c)
-    end
-    return collected
-end
-
-local function collect(list,collected,c)
-    local dt = list.dt
-    if dt then
-        local en = 0
-        for k=1,#dt do
-            local dk = dt[k]
-            if dk.tg then
-                c = c + 1
-                collected[c] = dk
-                dk.ni = k -- refresh
-                en = en + 1
-                dk.ei = en
-                c = collect(dk,collected,c)
-            end
-        end
-        list.en = en
-    end
-    return c
-end
-apply_axis['descendant-or-self'] = function(list)
-    local collected, c = { }, 0
-    for l=1,#list do
-        local ll = list[l]
-        if ll.special ~= true then -- catch double root
-            c = c + 1
-            collected[c] = ll
-        end
-        c = collect(ll,collected,c)
-    end
-    return collected
-end
-
-apply_axis['ancestor'] = function(list)
-    local collected, c = { }, 0
-    for l=1,#list do
-        local ll = list[l]
-        while ll do
-            ll = ll.__p__
-            if ll then
-                c = c + 1
-                collected[c] = ll
-            end
-        end
-    end
-    return collected
-end
-
-apply_axis['ancestor-or-self'] = function(list)
-    local collected, c = { }, 0
-    for l=1,#list do
-        local ll = list[l]
-        c = c + 1
-        collected[c] = ll
-        while ll do
-            ll = ll.__p__
-            if ll then
-                c = c + 1
-                collected[c] = ll
-            end
-        end
-    end
-    return collected
-end
-
-apply_axis['parent'] = function(list)
-    local collected, c = { }, 0
-    for l=1,#list do
-        local pl = list[l].__p__
-        if pl then
-            c = c + 1
-            collected[c] = pl
-        end
-    end
-    return collected
-end
-
-apply_axis['attribute'] = function(list)
-    return { }
-end
-
-apply_axis['namespace'] = function(list)
-    return { }
-end
-
-apply_axis['following'] = function(list) -- incomplete
---~     local collected, c = { }, 0
---~     for l=1,#list do
---~         local ll = list[l]
---~         local p = ll.__p__
---~         local d = p.dt
---~         for i=ll.ni+1,#d do
---~             local di = d[i]
---~             if type(di) == "table" then
---~                 c = c + 1
---~                 collected[c] = di
---~                 break
---~             end
---~         end
---~     end
---~     return collected
-    return { }
-end
-
-apply_axis['preceding'] = function(list) -- incomplete
---~     local collected, c = { }, 0
---~     for l=1,#list do
---~         local ll = list[l]
---~         local p = ll.__p__
---~         local d = p.dt
---~         for i=ll.ni-1,1,-1 do
---~             local di = d[i]
---~             if type(di) == "table" then
---~                 c = c + 1
---~                 collected[c] = di
---~                 break
---~             end
---~         end
---~     end
---~     return collected
-    return { }
-end
-
-apply_axis['following-sibling'] = function(list)
-    local collected, c = { }, 0
-    for l=1,#list do
-        local ll = list[l]
-        local p = ll.__p__
-        local d = p.dt
-        for i=ll.ni+1,#d do
-            local di = d[i]
-            if type(di) == "table" then
-                c = c + 1
-                collected[c] = di
-            end
-        end
-    end
-    return collected
-end
-
-apply_axis['preceding-sibling'] = function(list)
-    local collected, c = { }, 0
-    for l=1,#list do
-        local ll = list[l]
-        local p = ll.__p__
-        local d = p.dt
-        for i=1,ll.ni-1 do
-            local di = d[i]
-            if type(di) == "table" then
-                c = c + 1
-                collected[c] = di
-            end
-        end
-    end
-    return collected
-end
-
-apply_axis['reverse-sibling'] = function(list) -- reverse preceding
-    local collected, c = { }, 0
-    for l=1,#list do
-        local ll = list[l]
-        local p = ll.__p__
-        local d = p.dt
-        for i=ll.ni-1,1,-1 do
-            local di = d[i]
-            if type(di) == "table" then
-                c = c + 1
-                collected[c] = di
-            end
-        end
-    end
-    return collected
-end
-
-apply_axis['auto-descendant-or-self'] = apply_axis['descendant-or-self']
-apply_axis['auto-descendant']         = apply_axis['descendant']
-apply_axis['auto-child']              = apply_axis['child']
-apply_axis['auto-self']               = apply_axis['self']
-apply_axis['initial-child']           = apply_axis['child']
-
-local function apply_nodes(list,directive,nodes)
-    -- todo: nodes[1] etc ... negated node name in set ... when needed
-    -- ... currently ignored
-    local maxn = #nodes
-    if maxn == 3 then --optimized loop
-        local nns, ntg = nodes[2], nodes[3]
-        if not nns and not ntg then -- wildcard
-            if directive then
-                return list
-            else
-                return { }
-            end
-        else
-            local collected, c, m, p = { }, 0, 0, nil
-            if not nns then -- only check tag
-                for l=1,#list do
-                    local ll = list[l]
-                    local ltg = ll.tg
-                    if ltg then
-                        if directive then
-                            if ntg == ltg then
-                                local llp = ll.__p__ ; if llp ~= p then p, m = llp, 1 else m = m + 1 end
-                                c = c + 1
-                                collected[c], ll.mi = ll, m
-                            end
-                        elseif ntg ~= ltg then
-                            local llp = ll.__p__ ; if llp ~= p then p, m = llp, 1 else m = m + 1 end
-                            c = c + 1
-                            collected[c], ll.mi = ll, m
-                        end
-                    end
-                end
-            elseif not ntg then -- only check namespace
-                for l=1,#list do
-                    local ll = list[l]
-                    local lns = ll.rn or ll.ns
-                    if lns then
-                        if directive then
-                            if lns == nns then
-                                local llp = ll.__p__ ; if llp ~= p then p, m = llp, 1 else m = m + 1 end
-                                c = c + 1
-                                collected[c], ll.mi = ll, m
-                            end
-                        elseif lns ~= nns then
-                            local llp = ll.__p__ ; if llp ~= p then p, m = llp, 1 else m = m + 1 end
-                            c = c + 1
-                            collected[c], ll.mi = ll, m
-                        end
-                    end
-                end
-            else -- check both
-                for l=1,#list do
-                    local ll = list[l]
-                    local ltg = ll.tg
-                    if ltg then
-                        local lns = ll.rn or ll.ns
-                        local ok = ltg == ntg and lns == nns
-                        if directive then
-                            if ok then
-                                local llp = ll.__p__ ; if llp ~= p then p, m = llp, 1 else m = m + 1 end
-                                c = c + 1
-                                collected[c], ll.mi = ll, m
-                            end
-                        elseif not ok then
-                            local llp = ll.__p__ ; if llp ~= p then p, m = llp, 1 else m = m + 1 end
-                            c = c + 1
-                            collected[c], ll.mi = ll, m
-                        end
-                    end
-                end
-            end
-            return collected
-        end
-    else
-        local collected, c, m, p = { }, 0, 0, nil
-        for l=1,#list do
-            local ll = list[l]
-            local ltg = ll.tg
-            if ltg then
-                local lns = ll.rn or ll.ns
-                local ok = false
-                for n=1,maxn,3 do
-                    local nns, ntg = nodes[n+1], nodes[n+2]
-                    ok = (not ntg or ltg == ntg) and (not nns or lns == nns)
-                    if ok then
-                        break
-                    end
-                end
-                if directive then
-                    if ok then
-                        local llp = ll.__p__ ; if llp ~= p then p, m = llp, 1 else m = m + 1 end
-                        c = c + 1
-                        collected[c], ll.mi = ll, m
-                    end
-                elseif not ok then
-                    local llp = ll.__p__ ; if llp ~= p then p, m = llp, 1 else m = m + 1 end
-                    c = c + 1
-                    collected[c], ll.mi = ll, m
-                end
-            end
-        end
-        return collected
-    end
-end
-
-local quit_expression = false
-
-local function apply_expression(list,expression,order)
-    local collected, c = { }, 0
-    quit_expression = false
-    for l=1,#list do
-        local ll = list[l]
-        if expression(list,ll,l,order) then -- nasty, order alleen valid als n=1
-            c = c + 1
-            collected[c] = ll
-        end
-        if quit_expression then
-            break
-        end
-    end
-    return collected
-end
-
-local P, V, C, Cs, Cc, Ct, R, S, Cg, Cb = lpeg.P, lpeg.V, lpeg.C, lpeg.Cs, lpeg.Cc, lpeg.Ct, lpeg.R, lpeg.S, lpeg.Cg, lpeg.Cb
-
-local spaces     = S(" \n\r\t\f")^0
-local lp_space   = S(" \n\r\t\f")
-local lp_any     = P(1)
-local lp_noequal = P("!=") / "~=" + P("<=") + P(">=") + P("==")
-local lp_doequal = P("=")  / "=="
-local lp_or      = P("|")  / " or "
-local lp_and     = P("&")  / " and "
-
-local lp_builtin = P (
-        P("text")         / "(ll.dt[1] or '')" + -- fragile
-        P("content")      / "ll.dt" +
-    --  P("name")         / "(ll.ns~='' and ll.ns..':'..ll.tg)" +
-        P("name")         / "((ll.ns~='' and ll.ns..':'..ll.tg) or ll.tg)" +
-        P("tag")          / "ll.tg" +
-        P("position")     / "l" + -- is element in finalizer
-        P("firstindex")   / "1" +
-        P("lastindex")    / "(#ll.__p__.dt or 1)" +
-        P("firstelement") / "1" +
-        P("lastelement")  / "(ll.__p__.en or 1)" +
-        P("first")        / "1" +
-        P("last")         / "#list" +
-        P("rootposition") / "order" +
-        P("order")        / "order" +
-        P("element")      / "(ll.ei or 1)" +
-        P("index")        / "(ll.ni or 1)" +
-        P("match")        / "(ll.mi or 1)" +
-     -- P("namespace")    / "ll.ns" +
-        P("ns")           / "ll.ns"
-    ) * ((spaces * P("(") * spaces * P(")"))/"")
-
--- for the moment we keep namespaces with attributes
-
-local lp_attribute = (P("@") + P("attribute::")) / "" * Cc("(ll.at and ll.at['") * ((R("az","AZ") + S("-_:"))^1) * Cc("'])")
-
--- lp_fastpos_p = (P("+")^0 * R("09")^1 * P(-1)) / function(s) return "l==" .. s end
--- lp_fastpos_n = (P("-")   * R("09")^1 * P(-1)) / function(s) return "(" .. s .. "<0 and (#list+".. s .. "==l))" end
-
-lp_fastpos_p = P("+")^0 * R("09")^1 * P(-1) / "l==%0"
-lp_fastpos_n = P("-")   * R("09")^1 * P(-1) / "(%0<0 and (#list+%0==l))"
-
-local lp_fastpos   = lp_fastpos_n + lp_fastpos_p
-
-local lp_reserved  = C("and") + C("or") + C("not") + C("div") + C("mod") + C("true") + C("false")
-
--- local lp_lua_function = C(R("az","AZ","__")^1 * (P(".") * R("az","AZ","__")^1)^1) * ("(") / function(t) -- todo: better . handling
---     return t .. "("
--- end
-
--- local lp_lua_function = (R("az","AZ","__")^1 * (P(".") * R("az","AZ","__")^1)^1) * ("(") / "%0("
-local lp_lua_function = Cs((R("az","AZ","__")^1 * (P(".") * R("az","AZ","__")^1)^1) * ("(")) / "%0"
-
-local lp_function  = C(R("az","AZ","__")^1) * P("(") / function(t) -- todo: better . handling
-    if expressions[t] then
-        return "expr." .. t .. "("
-    else
-        return "expr.error("
-    end
-end
-
-local lparent  = P("(")
-local rparent  = P(")")
-local noparent = 1 - (lparent+rparent)
-local nested   = P{lparent * (noparent + V(1))^0 * rparent}
-local value    = P(lparent * C((noparent + nested)^0) * rparent) -- P{"("*C(((1-S("()"))+V(1))^0)*")"}
-
-local lp_child   = Cc("expr.child(ll,'") * R("az","AZ","--","__")^1 * Cc("')")
-local lp_number  = S("+-") * R("09")^1
-local lp_string  = Cc("'") * R("az","AZ","--","__")^1 * Cc("'")
-local lp_content = (P("'") * (1-P("'"))^0 * P("'") + P('"') * (1-P('"'))^0 * P('"'))
-
-local cleaner
-
-local lp_special = (C(P("name")+P("text")+P("tag")+P("count")+P("child"))) * value / function(t,s)
-    if expressions[t] then
-        s = s and s ~= "" and lpegmatch(cleaner,s)
-        if s and s ~= "" then
-            return "expr." .. t .. "(ll," .. s ..")"
-        else
-            return "expr." .. t .. "(ll)"
-        end
-    else
-        return "expr.error(" .. t .. ")"
-    end
-end
-
-local content =
-    lp_builtin +
-    lp_attribute +
-    lp_special +
-    lp_noequal + lp_doequal +
-    lp_or + lp_and +
-    lp_reserved +
-    lp_lua_function + lp_function +
-    lp_content + -- too fragile
-    lp_child +
-    lp_any
-
-local converter = Cs (
-    lp_fastpos + (P { lparent * (V(1))^0 * rparent + content } )^0
-)
-
-cleaner = Cs ( (
- -- lp_fastpos +
-    lp_reserved +
-    lp_number +
-    lp_string +
-1 )^1 )
-
-local template_e = [[
-    local expr = xml.expressions
-    return function(list,ll,l,order)
-        return %s
-    end
-]]
-
-local template_f_y = [[
-    local finalizer = xml.finalizers['%s']['%s']
-    return function(collection)
-        return finalizer(collection,%s)
-    end
-]]
-
-local template_f_n = [[
-    return xml.finalizers['%s']['%s']
-]]
-
---
-
-local register_self                    = { kind = "axis", axis = "self"                    } -- , apply = apply_axis["self"]               }
-local register_parent                  = { kind = "axis", axis = "parent"                  } -- , apply = apply_axis["parent"]             }
-local register_descendant              = { kind = "axis", axis = "descendant"              } -- , apply = apply_axis["descendant"]         }
-local register_child                   = { kind = "axis", axis = "child"                   } -- , apply = apply_axis["child"]              }
-local register_descendant_or_self      = { kind = "axis", axis = "descendant-or-self"      } -- , apply = apply_axis["descendant-or-self"] }
-local register_root                    = { kind = "axis", axis = "root"                    } -- , apply = apply_axis["root"]               }
-local register_ancestor                = { kind = "axis", axis = "ancestor"                } -- , apply = apply_axis["ancestor"]           }
-local register_ancestor_or_self        = { kind = "axis", axis = "ancestor-or-self"        } -- , apply = apply_axis["ancestor-or-self"]   }
-local register_attribute               = { kind = "axis", axis = "attribute"               } -- , apply = apply_axis["attribute"]          }
-local register_namespace               = { kind = "axis", axis = "namespace"               } -- , apply = apply_axis["namespace"]          }
-local register_following               = { kind = "axis", axis = "following"               } -- , apply = apply_axis["following"]          }
-local register_following_sibling       = { kind = "axis", axis = "following-sibling"       } -- , apply = apply_axis["following-sibling"]  }
-local register_preceding               = { kind = "axis", axis = "preceding"               } -- , apply = apply_axis["preceding"]          }
-local register_preceding_sibling       = { kind = "axis", axis = "preceding-sibling"       } -- , apply = apply_axis["preceding-sibling"]  }
-local register_reverse_sibling         = { kind = "axis", axis = "reverse-sibling"         } -- , apply = apply_axis["reverse-sibling"]    }
-
-local register_auto_descendant_or_self = { kind = "axis", axis = "auto-descendant-or-self" } -- , apply = apply_axis["auto-descendant-or-self"] }
-local register_auto_descendant         = { kind = "axis", axis = "auto-descendant"         } -- , apply = apply_axis["auto-descendant"] }
-local register_auto_self               = { kind = "axis", axis = "auto-self"               } -- , apply = apply_axis["auto-self"] }
-local register_auto_child              = { kind = "axis", axis = "auto-child"              } -- , apply = apply_axis["auto-child"] }
-
-local register_initial_child           = { kind = "axis", axis = "initial-child"           } -- , apply = apply_axis["initial-child"] }
-
-local register_all_nodes               = { kind = "nodes", nodetest = true, nodes = { true, false, false } }
-
-local skip = { }
-
-local function errorrunner_e(str,cnv)
-    if not skip[str] then
-        report_lpath("error in expression: %s => %s",str,cnv)
-        skip[str] = cnv or str
-    end
-    return false
-end
-
-local function errorrunner_f(str,arg)
-    report_lpath("error in finalizer: %s(%s)",str,arg or "")
-    return false
-end
-
-local function register_nodes(nodetest,nodes)
-    return { kind = "nodes", nodetest = nodetest, nodes = nodes }
-end
-
-local function register_expression(expression)
-    local converted = lpegmatch(converter,expression)
-    local runner = load(format(template_e,converted))
-    runner = (runner and runner()) or function() errorrunner_e(expression,converted) end
-    return { kind = "expression", expression = expression, converted = converted, evaluator = runner }
-end
-
-local function register_finalizer(protocol,name,arguments)
-    local runner
-    if arguments and arguments ~= "" then
-        runner = load(format(template_f_y,protocol or xml.defaultprotocol,name,arguments))
-    else
-        runner = load(format(template_f_n,protocol or xml.defaultprotocol,name))
-    end
-    runner = (runner and runner()) or function() errorrunner_f(name,arguments) end
-    return { kind = "finalizer", name = name, arguments = arguments, finalizer = runner }
-end
-
-local expression = P { "ex",
-    ex = "[" * C((V("sq") + V("dq") + (1 - S("[]")) + V("ex"))^0) * "]",
-    sq = "'" * (1 - S("'"))^0 * "'",
-    dq = '"' * (1 - S('"'))^0 * '"',
-}
-
-local arguments = P { "ar",
-    ar = "(" * Cs((V("sq") + V("dq") + V("nq") + P(1-P(")")))^0) * ")",
-    nq = ((1 - S("),'\""))^1) / function(s) return format("%q",s) end,
-    sq = P("'") * (1 - P("'"))^0 * P("'"),
-    dq = P('"') * (1 - P('"'))^0 * P('"'),
-}
-
--- todo: better arg parser
-
-local function register_error(str)
-    return { kind = "error", error = format("unparsed: %s",str) }
-end
-
--- there is a difference in * and /*/ and so we need to catch a few special cases
-
-local special_1 = P("*")  * Cc(register_auto_descendant) * Cc(register_all_nodes) -- last one not needed
-local special_2 = P("/")  * Cc(register_auto_self)
-local special_3 = P("")   * Cc(register_auto_self)
-
-local no_nextcolon   = P(-1) + #(1-P(":")) -- newer lpeg needs the P(-1)
-local no_nextlparent = P(-1) + #(1-P("(")) -- newer lpeg needs the P(-1)
-
-local pathparser = Ct { "patterns", -- can be made a bit faster by moving some patterns outside
-
-    patterns             = spaces * V("protocol") * spaces * (
-                              ( V("special") * spaces * P(-1)                                                         ) +
-                              ( V("initial") * spaces * V("step") * spaces * (P("/") * spaces * V("step") * spaces)^0 )
-                           ),
-
-    protocol             = Cg(V("letters"),"protocol") * P("://") + Cg(Cc(nil),"protocol"),
-
- -- the / is needed for // as descendant or self is somewhat special
- -- step                 = (V("shortcuts") + V("axis") * spaces * V("nodes")^0 + V("error")) * spaces * V("expressions")^0 * spaces * V("finalizer")^0,
-    step                 = ((V("shortcuts") + P("/") + V("axis")) * spaces * V("nodes")^0 + V("error")) * spaces * V("expressions")^0 * spaces * V("finalizer")^0,
-
-    axis                 = V("descendant") + V("child") + V("parent") + V("self") + V("root") + V("ancestor") +
-                           V("descendant_or_self") + V("following_sibling") + V("following") +
-                           V("reverse_sibling") + V("preceding_sibling") + V("preceding") + V("ancestor_or_self") +
-                           #(1-P(-1)) * Cc(register_auto_child),
-
-    special              = special_1 + special_2 + special_3,
-
-    initial              = (P("/") * spaces * Cc(register_initial_child))^-1,
-
-    error                = (P(1)^1) / register_error,
-
-    shortcuts_a          = V("s_descendant_or_self") + V("s_descendant") + V("s_child") + V("s_parent") + V("s_self") + V("s_root") + V("s_ancestor"),
-
-    shortcuts            = V("shortcuts_a") * (spaces * "/" * spaces * V("shortcuts_a"))^0,
-
-    s_descendant_or_self = (P("***/") + P("/"))  * Cc(register_descendant_or_self), --- *** is a bonus
-    s_descendant         = P("**")               * Cc(register_descendant),
-    s_child              = P("*") * no_nextcolon * Cc(register_child     ),
-    s_parent             = P("..")               * Cc(register_parent    ),
-    s_self               = P("." )               * Cc(register_self      ),
-    s_root               = P("^^")               * Cc(register_root      ),
-    s_ancestor           = P("^")                * Cc(register_ancestor  ),
-
-    descendant           = P("descendant::")         * Cc(register_descendant         ),
-    child                = P("child::")              * Cc(register_child              ),
-    parent               = P("parent::")             * Cc(register_parent             ),
-    self                 = P("self::")               * Cc(register_self               ),
-    root                 = P('root::')               * Cc(register_root               ),
-    ancestor             = P('ancestor::')           * Cc(register_ancestor           ),
-    descendant_or_self   = P('descendant-or-self::') * Cc(register_descendant_or_self ),
-    ancestor_or_self     = P('ancestor-or-self::')   * Cc(register_ancestor_or_self   ),
- -- attribute            = P('attribute::')          * Cc(register_attribute          ),
- -- namespace            = P('namespace::')          * Cc(register_namespace          ),
-    following            = P('following::')          * Cc(register_following          ),
-    following_sibling    = P('following-sibling::')  * Cc(register_following_sibling  ),
-    preceding            = P('preceding::')          * Cc(register_preceding          ),
-    preceding_sibling    = P('preceding-sibling::')  * Cc(register_preceding_sibling  ),
-    reverse_sibling      = P('reverse-sibling::')    * Cc(register_reverse_sibling    ),
-
-    nodes                = (V("nodefunction") * spaces * P("(") * V("nodeset") * P(")") + V("nodetest") * V("nodeset")) / register_nodes,
-
-    expressions          = expression / register_expression,
-
-    letters              = R("az")^1,
-    name                 = (1-S("/[]()|:*!"))^1, -- make inline
-    negate               = P("!") * Cc(false),
-
-    nodefunction         = V("negate") + P("not") * Cc(false) + Cc(true),
-    nodetest             = V("negate") + Cc(true),
-    nodename             = (V("negate") + Cc(true)) * spaces * ((V("wildnodename") * P(":") * V("wildnodename")) + (Cc(false) * V("wildnodename"))),
-    wildnodename         = (C(V("name")) + P("*") * Cc(false)) * no_nextlparent,
-    nodeset              = spaces * Ct(V("nodename") * (spaces * P("|") * spaces * V("nodename"))^0) * spaces,
-
-    finalizer            = (Cb("protocol") * P("/")^-1 * C(V("name")) * arguments * P(-1)) / register_finalizer,
-
-}
-
-xmlpatterns.pathparser = pathparser
-
-local cache = { }
-
-local function nodesettostring(set,nodetest)
-    local t = { }
-    for i=1,#set,3 do
-        local directive, ns, tg = set[i], set[i+1], set[i+2]
-        if not ns or ns == "" then ns = "*" end
-        if not tg or tg == "" then tg = "*" end
-        tg = (tg == "@rt@" and "[root]") or format("%s:%s",ns,tg)
-        t[i] = (directive and tg) or format("not(%s)",tg)
-    end
-    if nodetest == false then
-        return format("not(%s)",concat(t,"|"))
-    else
-        return concat(t,"|")
-    end
-end
-
-local function tagstostring(list)
-    if #list == 0 then
-        return "no elements"
-    else
-        local t = { }
-        for i=1, #list do
-            local li = list[i]
-            local ns, tg = li.ns, li.tg
-            if not ns or ns == "" then ns = "*" end
-            if not tg or tg == "" then tg = "*" end
-            t[i] = (tg == "@rt@" and "[root]") or format("%s:%s",ns,tg)
-        end
-        return concat(t," ")
-    end
-end
-
-xml.nodesettostring = nodesettostring
-
-local lpath -- we have a harmless kind of circular reference
-
-local lshowoptions = { functions = false }
-
-local function lshow(parsed)
-    if type(parsed) == "string" then
-        parsed = lpath(parsed)
-    end
-    report_lpath("%s://%s => %s",parsed.protocol or xml.defaultprotocol,parsed.pattern,
-        table.serialize(parsed,false,lshowoptions))
-end
-
-xml.lshow = lshow
-
-local function add_comment(p,str)
-    local pc = p.comment
-    if not pc then
-        p.comment = { str }
-    else
-        pc[#pc+1] = str
-    end
-end
-
-lpath = function (pattern) -- the gain of caching is rather minimal
-    lpathcalls = lpathcalls + 1
-    if type(pattern) == "table" then
-        return pattern
-    else
-        local parsed = cache[pattern]
-        if parsed then
-            lpathcached = lpathcached + 1
-        else
-            parsed = lpegmatch(pathparser,pattern)
-            if parsed then
-                parsed.pattern = pattern
-                local np = #parsed
-                if np == 0 then
-                    parsed = { pattern = pattern, register_self, state = "parsing error" }
-                    report_lpath("parsing error in pattern: %s",pattern)
-                    lshow(parsed)
-                else
-                    -- we could have done this with a more complex parser but this
-                    -- is cleaner
-                    local pi = parsed[1]
-                    if pi.axis == "auto-child" then
-                        if false then
-                            add_comment(parsed, "auto-child replaced by auto-descendant-or-self")
-                            parsed[1] = register_auto_descendant_or_self
-                        else
-                            add_comment(parsed, "auto-child replaced by auto-descendant")
-                            parsed[1] = register_auto_descendant
-                        end
-                    elseif pi.axis == "initial-child" and np > 1 and parsed[2].axis then
-                        add_comment(parsed, "initial-child removed") -- we could also make it a auto-self
-                        remove(parsed,1)
-                    end
-                    local np = #parsed -- can have changed
-                    if np > 1 then
-                        local pnp = parsed[np]
-                        if pnp.kind == "nodes" and pnp.nodetest == true then
-                            local nodes = pnp.nodes
-                            if nodes[1] == true and nodes[2] == false and nodes[3] == false then
-                                add_comment(parsed, "redundant final wildcard filter removed")
-                                remove(parsed,np)
-                            end
-                        end
-                    end
-                end
-            else
-                parsed = { pattern = pattern }
-            end
-            cache[pattern] = parsed
-            if trace_lparse and not trace_lprofile then
-                lshow(parsed)
-            end
-        end
-        return parsed
-    end
-end
-
-xml.lpath = lpath
-
--- we can move all calls inline and then merge the trace back
--- technically we can combine axis and the next nodes which is
--- what we did before but this a bit cleaner (but slower too)
--- but interesting is that it's not that much faster when we
--- go inline
---
--- beware: we need to return a collection even when we filter
--- else the (simple) cache gets messed up
-
--- caching found lookups saves not that much (max .1 sec on a 8 sec run)
--- and it also messes up finalizers
-
--- watch out: when there is a finalizer, it's always called as there
--- can be cases that a finalizer returns (or does) something in case
--- there is no match; an example of this is count()
-
-local profiled = { }  xml.profiled = profiled
-
-local function profiled_apply(list,parsed,nofparsed,order)
-    local p = profiled[parsed.pattern]
-    if p then
-        p.tested = p.tested + 1
-    else
-        p = { tested = 1, matched = 0, finalized = 0 }
-        profiled[parsed.pattern] = p
-    end
-    local collected = list
-    for i=1,nofparsed do
-        local pi = parsed[i]
-        local kind = pi.kind
-        if kind == "axis" then
-            collected = apply_axis[pi.axis](collected)
-        elseif kind == "nodes" then
-            collected = apply_nodes(collected,pi.nodetest,pi.nodes)
-        elseif kind == "expression" then
-            collected = apply_expression(collected,pi.evaluator,order)
-        elseif kind == "finalizer" then
-            collected = pi.finalizer(collected) -- no check on # here
-            p.matched = p.matched + 1
-            p.finalized = p.finalized + 1
-            return collected
-        end
-        if not collected or #collected == 0 then
-            local pn = i < nofparsed and parsed[nofparsed]
-            if pn and pn.kind == "finalizer" then
-                collected = pn.finalizer(collected)
-                p.finalized = p.finalized + 1
-                return collected
-            end
-            return nil
-        end
-    end
-    if collected then
-        p.matched = p.matched + 1
-    end
-    return collected
-end
-
-local function traced_apply(list,parsed,nofparsed,order)
-    if trace_lparse then
-        lshow(parsed)
-    end
-    report_lpath("collecting: %s",parsed.pattern)
-    report_lpath("root tags : %s",tagstostring(list))
-    report_lpath("order     : %s",order or "unset")
-    local collected = list
-    for i=1,nofparsed do
-        local pi = parsed[i]
-        local kind = pi.kind
-        if kind == "axis" then
-            collected = apply_axis[pi.axis](collected)
-            report_lpath("% 10i : ax : %s",(collected and #collected) or 0,pi.axis)
-        elseif kind == "nodes" then
-            collected = apply_nodes(collected,pi.nodetest,pi.nodes)
-            report_lpath("% 10i : ns : %s",(collected and #collected) or 0,nodesettostring(pi.nodes,pi.nodetest))
-        elseif kind == "expression" then
-            collected = apply_expression(collected,pi.evaluator,order)
-            report_lpath("% 10i : ex : %s -> %s",(collected and #collected) or 0,pi.expression,pi.converted)
-        elseif kind == "finalizer" then
-            collected = pi.finalizer(collected)
-            report_lpath("% 10i : fi : %s : %s(%s)",(type(collected) == "table" and #collected) or 0,parsed.protocol or xml.defaultprotocol,pi.name,pi.arguments or "")
-            return collected
-        end
-        if not collected or #collected == 0 then
-            local pn = i < nofparsed and parsed[nofparsed]
-            if pn and pn.kind == "finalizer" then
-                collected = pn.finalizer(collected)
-                report_lpath("% 10i : fi : %s : %s(%s)",(type(collected) == "table" and #collected) or 0,parsed.protocol or xml.defaultprotocol,pn.name,pn.arguments or "")
-                return collected
-            end
-            return nil
-        end
-    end
-    return collected
-end
-
-local function normal_apply(list,parsed,nofparsed,order)
-    local collected = list
-    for i=1,nofparsed do
-        local pi = parsed[i]
-        local kind = pi.kind
-        if kind == "axis" then
-            local axis = pi.axis
-            if axis ~= "self" then
-                collected = apply_axis[axis](collected)
-            end
-        elseif kind == "nodes" then
-            collected = apply_nodes(collected,pi.nodetest,pi.nodes)
-        elseif kind == "expression" then
-            collected = apply_expression(collected,pi.evaluator,order)
-        elseif kind == "finalizer" then
-            return pi.finalizer(collected)
-        end
-        if not collected or #collected == 0 then
-            local pf = i < nofparsed and parsed[nofparsed].finalizer
-            if pf then
-                return pf(collected) -- can be anything
-            end
-            return nil
-        end
-    end
-    return collected
-end
-
---~ local function applylpath(list,pattern)
---~     -- we avoid an extra call
---~     local parsed = cache[pattern]
---~     if parsed then
---~         lpathcalls = lpathcalls + 1
---~         lpathcached = lpathcached + 1
---~     elseif type(pattern) == "table" then
---~         lpathcalls = lpathcalls + 1
---~         parsed = pattern
---~     else
---~         parsed = lpath(pattern) or pattern
---~     end
---~     if not parsed then
---~         return
---~     end
---~     local nofparsed = #parsed
---~     if nofparsed == 0 then
---~         return -- something is wrong
---~     end
---~     local one = list[1] -- we could have a third argument: isroot and list or list[1] or whatever we like ... todo
---~     if not one then
---~         return -- something is wrong
---~     elseif not trace_lpath then
---~         return normal_apply(list,parsed,nofparsed,one.mi)
---~     elseif trace_lprofile then
---~         return profiled_apply(list,parsed,nofparsed,one.mi)
---~     else
---~         return traced_apply(list,parsed,nofparsed,one.mi)
---~     end
---~ end
-
-local function applylpath(list,pattern)
-    if not list then
-        return
-    end
-    local parsed = cache[pattern]
-    if parsed then
-        lpathcalls = lpathcalls + 1
-        lpathcached = lpathcached + 1
-    elseif type(pattern) == "table" then
-        lpathcalls = lpathcalls + 1
-        parsed = pattern
-    else
-        parsed = lpath(pattern) or pattern
-    end
-    if not parsed then
-        return
-    end
-    local nofparsed = #parsed
-    if nofparsed == 0 then
-        return -- something is wrong
-    end
-    if not trace_lpath then
-        return normal_apply  ({ list },parsed,nofparsed,list.mi)
-    elseif trace_lprofile then
-        return profiled_apply({ list },parsed,nofparsed,list.mi)
-    else
-        return traced_apply  ({ list },parsed,nofparsed,list.mi)
-    end
-end
-
-xml.applylpath = applylpath -- takes a table as first argment, which is what xml.filter will do
-
---[[ldx--
-<p>This is the main filter function. It returns whatever is asked for.</p>
---ldx]]--
-
-function xml.filter(root,pattern) -- no longer funny attribute handling here
-    return applylpath(root,pattern)
-end
-
--- internal (parsed)
-
-expressions.child = function(e,pattern)
-    return applylpath(e,pattern) -- todo: cache
-end
-
-expressions.count = function(e,pattern) -- what if pattern == empty or nil
-    local collected = applylpath(e,pattern) -- todo: cache
-    return pattern and (collected and #collected) or 0
-end
-
--- external
-
--- expressions.oneof = function(s,...)
---     local t = {...}
---     for i=1,#t do
---         if s == t[i] then
---             return true
---         end
---     end
---     return false
--- end
-
-expressions.oneof = function(s,...)
-    for i=1,select("#",...) do
-        if s == select(i,...) then
-            return true
-        end
-    end
-    return false
-end
-
-expressions.error = function(str)
-    xml.errorhandler(format("unknown function in lpath expression: %s",tostring(str or "?")))
-    return false
-end
-
-expressions.undefined = function(s)
-    return s == nil
-end
-
-expressions.quit = function(s)
-    if s or s == nil then
-        quit_expression = true
-    end
-    return true
-end
-
-expressions.print = function(...)
-    print(...)
-    return true
-end
-
-expressions.contains  = find
-expressions.find      = find
-expressions.upper     = upper
-expressions.lower     = lower
-expressions.number    = tonumber
-expressions.boolean   = toboolean
-
-function expressions.contains(str,pattern)
-    local t = type(str)
-    if t == "string" then
-        if find(str,pattern) then
-            return true
-        end
-    elseif t == "table" then
-        for i=1,#str do
-            local d = str[i]
-            if type(d) == "string" and find(d,pattern) then
-                return true
-            end
-        end
-    end
-    return false
-end
-
--- user interface
-
-local function traverse(root,pattern,handle)
- -- report_lpath("use 'xml.selection' instead for pattern: %s",pattern)
-    local collected = applylpath(root,pattern)
-    if collected then
-        for c=1,#collected do
-            local e = collected[c]
-            local r = e.__p__
-            handle(r,r.dt,e.ni)
-        end
-    end
-end
-
-local function selection(root,pattern,handle)
-    local collected = applylpath(root,pattern)
-    if collected then
-        if handle then
-            for c=1,#collected do
-                handle(collected[c])
-            end
-        else
-            return collected
-        end
-    end
-end
-
-xml.traverse      = traverse           -- old method, r, d, k
-xml.selection     = selection          -- new method, simple handle
-
---~ function xml.cachedpatterns()
---~     return cache
---~ end
-
--- generic function finalizer (independant namespace)
-
-local function dofunction(collected,fnc,...)
-    if collected then
-        local f = functions[fnc]
-        if f then
-            for c=1,#collected do
-                f(collected[c],...)
-            end
-        else
-            report_lpath("unknown function %a",fnc)
-        end
-    end
-end
-
-finalizers.xml["function"] = dofunction
-finalizers.tex["function"] = dofunction
-
--- functions
-
-expressions.text = function(e,n)
-    local rdt = e.__p__.dt
-    return rdt and rdt[n] or ""
-end
-
-expressions.name = function(e,n) -- ns + tg
-    local found = false
-    n = tonumber(n) or 0
-    if n == 0 then
-        found = type(e) == "table" and e
-    elseif n < 0 then
-        local d, k = e.__p__.dt, e.ni
-        for i=k-1,1,-1 do
-            local di = d[i]
-            if type(di) == "table" then
-                if n == -1 then
-                    found = di
-                    break
-                else
-                    n = n + 1
-                end
-            end
-        end
-    else
-        local d, k = e.__p__.dt, e.ni
-        for i=k+1,#d,1 do
-            local di = d[i]
-            if type(di) == "table" then
-                if n == 1 then
-                    found = di
-                    break
-                else
-                    n = n - 1
-                end
-            end
-        end
-    end
-    if found then
-        local ns, tg = found.rn or found.ns or "", found.tg
-        if ns ~= "" then
-            return ns .. ":" .. tg
-        else
-            return tg
-        end
-    else
-        return ""
-    end
-end
-
-expressions.tag = function(e,n) -- only tg
-    if not e then
-        return ""
-    else
-        local found = false
-        n = tonumber(n) or 0
-        if n == 0 then
-            found = (type(e) == "table") and e -- seems to fail
-        elseif n < 0 then
-            local d, k = e.__p__.dt, e.ni
-            for i=k-1,1,-1 do
-                local di = d[i]
-                if type(di) == "table" then
-                    if n == -1 then
-                        found = di
-                        break
-                    else
-                        n = n + 1
-                    end
-                end
-            end
-        else
-            local d, k = e.__p__.dt, e.ni
-            for i=k+1,#d,1 do
-                local di = d[i]
-                if type(di) == "table" then
-                    if n == 1 then
-                        found = di
-                        break
-                    else
-                        n = n - 1
-                    end
-                end
-            end
-        end
-        return (found and found.tg) or ""
-    end
-end
-
---[[ldx--
-<p>Often using an iterators looks nicer in the code than passing handler
-functions. The <l n='lua'/> book describes how to use coroutines for that
-purpose (<url href='http://www.lua.org/pil/9.3.html'/>). This permits
-code like:</p>
-
-<typing>
-for r, d, k in xml.elements(xml.load('text.xml'),"title") do
-    print(d[k]) -- old method
-end
-for e in xml.collected(xml.load('text.xml'),"title") do
-    print(e) -- new one
-end
-</typing>
---ldx]]--
-
--- local wrap, yield = coroutine.wrap, coroutine.yield
--- local dummy = function() end
---
--- function xml.elements(root,pattern,reverse) -- r, d, k
---     local collected = applylpath(root,pattern)
---     if collected then
---         if reverse then
---             return wrap(function() for c=#collected,1,-1 do
---                 local e = collected[c] local r = e.__p__ yield(r,r.dt,e.ni)
---             end end)
---         else
---             return wrap(function() for c=1,#collected    do
---                 local e = collected[c] local r = e.__p__ yield(r,r.dt,e.ni)
---             end end)
---         end
---     end
---     return wrap(dummy)
--- end
---
--- function xml.collected(root,pattern,reverse) -- e
---     local collected = applylpath(root,pattern)
---     if collected then
---         if reverse then
---             return wrap(function() for c=#collected,1,-1 do yield(collected[c]) end end)
---         else
---             return wrap(function() for c=1,#collected    do yield(collected[c]) end end)
---         end
---     end
---     return wrap(dummy)
--- end
-
--- faster:
-
-local dummy = function() end
-
-function xml.elements(root,pattern,reverse) -- r, d, k
-    local collected = applylpath(root,pattern)
-    if not collected then
-        return dummy
-    elseif reverse then
-        local c = #collected + 1
-        return function()
-            if c > 1 then
-                c = c - 1
-                local e = collected[c]
-                local r = e.__p__
-                return r, r.dt, e.ni
-            end
-        end
-    else
-        local n, c = #collected, 0
-        return function()
-            if c < n then
-                c = c + 1
-                local e = collected[c]
-                local r = e.__p__
-                return r, r.dt, e.ni
-            end
-        end
-    end
-end
-
-function xml.collected(root,pattern,reverse) -- e
-    local collected = applylpath(root,pattern)
-    if not collected then
-        return dummy
-    elseif reverse then
-        local c = #collected + 1
-        return function()
-            if c > 1 then
-                c = c - 1
-                return collected[c]
-            end
-        end
-    else
-        local n, c = #collected, 0
-        return function()
-            if c < n then
-                c = c + 1
-                return collected[c]
-            end
-        end
-    end
-end
-
--- handy
-
-function xml.inspect(collection,pattern)
-    pattern = pattern or "."
-    for e in xml.collected(collection,pattern or ".") do
-        report_lpath("pattern: %s\n\n%s\n",pattern,xml.tostring(e))
-    end
-end
-
--- texy (see xfdf):
-
-local function split(e)
-    local dt = e.dt
-    if dt then
-        for i=1,#dt do
-            local dti = dt[i]
-            if type(dti) == "string" then
-                dti = gsub(dti,"^[\n\r]*(.-)[\n\r]*","%1")
-                dti = gsub(dti,"[\n\r]+","\n\n")
-                dt[i] = dti
-            else
-                split(dti)
-            end
-        end
-    end
-    return e
-end
-
-function xml.finalizers.paragraphs(c)
-    for i=1,#c do
-        split(c[i])
-    end
-    return c
-end
+if not modules then modules = { } end modules ['lxml-lpt'] = {
+    version   = 1.001,
+    comment   = "this module is the basis for the lxml-* ones",
+    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
+    copyright = "PRAGMA ADE / ConTeXt Development Team",
+    license   = "see context related readme files"
+}
+
+-- e.ni is only valid after a filter run
+-- todo: B/C/[get first match]
+
+local concat, remove, insert = table.concat, table.remove, table.insert
+local type, next, tonumber, tostring, setmetatable, load, select = type, next, tonumber, tostring, setmetatable, load, select
+local format, upper, lower, gmatch, gsub, find, rep = string.format, string.upper, string.lower, string.gmatch, string.gsub, string.find, string.rep
+local lpegmatch, lpegpatterns = lpeg.match, lpeg.patterns
+
+local setmetatableindex = table.setmetatableindex
+local formatters = string.formatters -- no need (yet) as paths are cached anyway
+
+-- beware, this is not xpath ... e.g. position is different (currently) and
+-- we have reverse-sibling as reversed preceding sibling
+
+--[[ldx--
+<p>This module can be used stand alone but also inside <l n='mkiv'/> in
+which case it hooks into the tracker code. Therefore we provide a few
+functions that set the tracers. Here we overload a previously defined
+function.</p>
+<p>If I can get in the mood I will make a variant that is XSLT compliant
+but I wonder if it makes sense.</P>
+--ldx]]--
+
+--[[ldx--
+<p>Expecially the lpath code is experimental, we will support some of xpath, but
+only things that make sense for us; as compensation it is possible to hook in your
+own functions. Apart from preprocessing content for <l n='context'/> we also need
+this module for process management, like handling <l n='ctx'/> and <l n='rlx'/>
+files.</p>
+
+<typing>
+a/b/c /*/c
+a/b/c/first() a/b/c/last() a/b/c/index(n) a/b/c/index(-n)
+a/b/c/text() a/b/c/text(1) a/b/c/text(-1) a/b/c/text(n)
+</typing>
+--ldx]]--
+
+local trace_lpath    = false  if trackers then trackers.register("xml.path",    function(v) trace_lpath  = v end) end
+local trace_lparse   = false  if trackers then trackers.register("xml.parse",   function(v) trace_lparse = v end) end
+local trace_lprofile = false  if trackers then trackers.register("xml.profile", function(v) trace_lpath  = v trace_lparse = v trace_lprofile = v end) end
+
+local report_lpath = logs.reporter("xml","lpath")
+
+--[[ldx--
+<p>We've now arrived at an interesting part: accessing the tree using a subset
+of <l n='xpath'/> and since we're not compatible we call it <l n='lpath'/>. We
+will explain more about its usage in other documents.</p>
+--ldx]]--
+
+local xml = xml
+
+local lpathcalls  = 0  function xml.lpathcalls () return lpathcalls  end
+local lpathcached = 0  function xml.lpathcached() return lpathcached end
+
+xml.functions        = xml.functions or { } -- internal
+local functions      = xml.functions
+
+xml.expressions      = xml.expressions or { } -- in expressions
+local expressions    = xml.expressions
+
+xml.finalizers       = xml.finalizers or { } -- fast do-with ... (with return value other than collection)
+local finalizers     = xml.finalizers
+
+xml.specialhandler   = xml.specialhandler or { }
+local specialhandler = xml.specialhandler
+
+lpegpatterns.xml     = lpegpatterns.xml or { }
+local xmlpatterns    = lpegpatterns.xml
+
+finalizers.xml = finalizers.xml or { }
+finalizers.tex = finalizers.tex or { }
+
+local function fallback (t, name)
+    local fn = finalizers[name]
+    if fn then
+        t[name] = fn
+    else
+        report_lpath("unknown sub finalizer %a",name)
+        fn = function() end
+    end
+    return fn
+end
+
+setmetatableindex(finalizers.xml, fallback)
+setmetatableindex(finalizers.tex, fallback)
+
+xml.defaultprotocol = "xml"
+
+-- as xsl does not follow xpath completely here we will also
+-- be more liberal especially with regards to the use of | and
+-- the rootpath:
+--
+-- test    : all 'test' under current
+-- /test   : 'test' relative to current
+-- a|b|c   : set of names
+-- (a|b|c) : idem
+-- !       : not
+--
+-- after all, we're not doing transformations but filtering. in
+-- addition we provide filter functions (last bit)
+--
+-- todo: optimizer
+--
+-- .. : parent
+-- *  : all kids
+-- /  : anchor here
+-- // : /**/
+-- ** : all in between
+--
+-- so far we had (more practical as we don't transform)
+--
+-- {/test}   : kids 'test' under current node
+-- {test}    : any kid with tag 'test'
+-- {//test}  : same as above
+
+-- evaluator (needs to be redone, for the moment copied)
+
+-- todo: apply_axis(list,notable) and collection vs single
+
+local apply_axis = { }
+
+apply_axis['root'] = function(list)
+    local collected = { }
+    for l=1,#list do
+        local ll = list[l]
+        local rt = ll
+        while ll do
+            ll = ll.__p__
+            if ll then
+                rt = ll
+            end
+        end
+        collected[l] = rt
+    end
+    return collected
+end
+
+apply_axis['self'] = function(list)
+--~     local collected = { }
+--~     for l=1,#list do
+--~         collected[l] = list[l]
+--~     end
+--~     return collected
+    return list
+end
+
+apply_axis['child'] = function(list)
+    local collected, c = { }, 0
+    for l=1,#list do
+        local ll = list[l]
+        local dt = ll.dt
+        if dt then -- weird that this is needed
+            local en = 0
+            for k=1,#dt do
+                local dk = dt[k]
+                if dk.tg then
+                    c = c + 1
+                    collected[c] = dk
+                    dk.ni = k -- refresh
+                    en = en + 1
+                    dk.ei = en
+                end
+            end
+            ll.en = en
+        end
+    end
+    return collected
+end
+
+local function collect(list,collected,c)
+    local dt = list.dt
+    if dt then
+        local en = 0
+        for k=1,#dt do
+            local dk = dt[k]
+            if dk.tg then
+                c = c + 1
+                collected[c] = dk
+                dk.ni = k -- refresh
+                en = en + 1
+                dk.ei = en
+                c = collect(dk,collected,c)
+            end
+        end
+        list.en = en
+    end
+    return c
+end
+
+apply_axis['descendant'] = function(list)
+    local collected, c = { }, 0
+    for l=1,#list do
+        c = collect(list[l],collected,c)
+    end
+    return collected
+end
+
+local function collect(list,collected,c)
+    local dt = list.dt
+    if dt then
+        local en = 0
+        for k=1,#dt do
+            local dk = dt[k]
+            if dk.tg then
+                c = c + 1
+                collected[c] = dk
+                dk.ni = k -- refresh
+                en = en + 1
+                dk.ei = en
+                c = collect(dk,collected,c)
+            end
+        end
+        list.en = en
+    end
+    return c
+end
+apply_axis['descendant-or-self'] = function(list)
+    local collected, c = { }, 0
+    for l=1,#list do
+        local ll = list[l]
+        if ll.special ~= true then -- catch double root
+            c = c + 1
+            collected[c] = ll
+        end
+        c = collect(ll,collected,c)
+    end
+    return collected
+end
+
+apply_axis['ancestor'] = function(list)
+    local collected, c = { }, 0
+    for l=1,#list do
+        local ll = list[l]
+        while ll do
+            ll = ll.__p__
+            if ll then
+                c = c + 1
+                collected[c] = ll
+            end
+        end
+    end
+    return collected
+end
+
+apply_axis['ancestor-or-self'] = function(list)
+    local collected, c = { }, 0
+    for l=1,#list do
+        local ll = list[l]
+        c = c + 1
+        collected[c] = ll
+        while ll do
+            ll = ll.__p__
+            if ll then
+                c = c + 1
+                collected[c] = ll
+            end
+        end
+    end
+    return collected
+end
+
+apply_axis['parent'] = function(list)
+    local collected, c = { }, 0
+    for l=1,#list do
+        local pl = list[l].__p__
+        if pl then
+            c = c + 1
+            collected[c] = pl
+        end
+    end
+    return collected
+end
+
+apply_axis['attribute'] = function(list)
+    return { }
+end
+
+apply_axis['namespace'] = function(list)
+    return { }
+end
+
+apply_axis['following'] = function(list) -- incomplete
+--~     local collected, c = { }, 0
+--~     for l=1,#list do
+--~         local ll = list[l]
+--~         local p = ll.__p__
+--~         local d = p.dt
+--~         for i=ll.ni+1,#d do
+--~             local di = d[i]
+--~             if type(di) == "table" then
+--~                 c = c + 1
+--~                 collected[c] = di
+--~                 break
+--~             end
+--~         end
+--~     end
+--~     return collected
+    return { }
+end
+
+apply_axis['preceding'] = function(list) -- incomplete
+--~     local collected, c = { }, 0
+--~     for l=1,#list do
+--~         local ll = list[l]
+--~         local p = ll.__p__
+--~         local d = p.dt
+--~         for i=ll.ni-1,1,-1 do
+--~             local di = d[i]
+--~             if type(di) == "table" then
+--~                 c = c + 1
+--~                 collected[c] = di
+--~                 break
+--~             end
+--~         end
+--~     end
+--~     return collected
+    return { }
+end
+
+apply_axis['following-sibling'] = function(list)
+    local collected, c = { }, 0
+    for l=1,#list do
+        local ll = list[l]
+        local p = ll.__p__
+        local d = p.dt
+        for i=ll.ni+1,#d do
+            local di = d[i]
+            if type(di) == "table" then
+                c = c + 1
+                collected[c] = di
+            end
+        end
+    end
+    return collected
+end
+
+apply_axis['preceding-sibling'] = function(list)
+    local collected, c = { }, 0
+    for l=1,#list do
+        local ll = list[l]
+        local p = ll.__p__
+        local d = p.dt
+        for i=1,ll.ni-1 do
+            local di = d[i]
+            if type(di) == "table" then
+                c = c + 1
+                collected[c] = di
+            end
+        end
+    end
+    return collected
+end
+
+apply_axis['reverse-sibling'] = function(list) -- reverse preceding
+    local collected, c = { }, 0
+    for l=1,#list do
+        local ll = list[l]
+        local p = ll.__p__
+        local d = p.dt
+        for i=ll.ni-1,1,-1 do
+            local di = d[i]
+            if type(di) == "table" then
+                c = c + 1
+                collected[c] = di
+            end
+        end
+    end
+    return collected
+end
+
+apply_axis['auto-descendant-or-self'] = apply_axis['descendant-or-self']
+apply_axis['auto-descendant']         = apply_axis['descendant']
+apply_axis['auto-child']              = apply_axis['child']
+apply_axis['auto-self']               = apply_axis['self']
+apply_axis['initial-child']           = apply_axis['child']
+
+local function apply_nodes(list,directive,nodes)
+    -- todo: nodes[1] etc ... negated node name in set ... when needed
+    -- ... currently ignored
+    local maxn = #nodes
+    if maxn == 3 then --optimized loop
+        local nns, ntg = nodes[2], nodes[3]
+        if not nns and not ntg then -- wildcard
+            if directive then
+                return list
+            else
+                return { }
+            end
+        else
+            local collected, c, m, p = { }, 0, 0, nil
+            if not nns then -- only check tag
+                for l=1,#list do
+                    local ll = list[l]
+                    local ltg = ll.tg
+                    if ltg then
+                        if directive then
+                            if ntg == ltg then
+                                local llp = ll.__p__ ; if llp ~= p then p, m = llp, 1 else m = m + 1 end
+                                c = c + 1
+                                collected[c], ll.mi = ll, m
+                            end
+                        elseif ntg ~= ltg then
+                            local llp = ll.__p__ ; if llp ~= p then p, m = llp, 1 else m = m + 1 end
+                            c = c + 1
+                            collected[c], ll.mi = ll, m
+                        end
+                    end
+                end
+            elseif not ntg then -- only check namespace
+                for l=1,#list do
+                    local ll = list[l]
+                    local lns = ll.rn or ll.ns
+                    if lns then
+                        if directive then
+                            if lns == nns then
+                                local llp = ll.__p__ ; if llp ~= p then p, m = llp, 1 else m = m + 1 end
+                                c = c + 1
+                                collected[c], ll.mi = ll, m
+                            end
+                        elseif lns ~= nns then
+                            local llp = ll.__p__ ; if llp ~= p then p, m = llp, 1 else m = m + 1 end
+                            c = c + 1
+                            collected[c], ll.mi = ll, m
+                        end
+                    end
+                end
+            else -- check both
+                for l=1,#list do
+                    local ll = list[l]
+                    local ltg = ll.tg
+                    if ltg then
+                        local lns = ll.rn or ll.ns
+                        local ok = ltg == ntg and lns == nns
+                        if directive then
+                            if ok then
+                                local llp = ll.__p__ ; if llp ~= p then p, m = llp, 1 else m = m + 1 end
+                                c = c + 1
+                                collected[c], ll.mi = ll, m
+                            end
+                        elseif not ok then
+                            local llp = ll.__p__ ; if llp ~= p then p, m = llp, 1 else m = m + 1 end
+                            c = c + 1
+                            collected[c], ll.mi = ll, m
+                        end
+                    end
+                end
+            end
+            return collected
+        end
+    else
+        local collected, c, m, p = { }, 0, 0, nil
+        for l=1,#list do
+            local ll = list[l]
+            local ltg = ll.tg
+            if ltg then
+                local lns = ll.rn or ll.ns
+                local ok = false
+                for n=1,maxn,3 do
+                    local nns, ntg = nodes[n+1], nodes[n+2]
+                    ok = (not ntg or ltg == ntg) and (not nns or lns == nns)
+                    if ok then
+                        break
+                    end
+                end
+                if directive then
+                    if ok then
+                        local llp = ll.__p__ ; if llp ~= p then p, m = llp, 1 else m = m + 1 end
+                        c = c + 1
+                        collected[c], ll.mi = ll, m
+                    end
+                elseif not ok then
+                    local llp = ll.__p__ ; if llp ~= p then p, m = llp, 1 else m = m + 1 end
+                    c = c + 1
+                    collected[c], ll.mi = ll, m
+                end
+            end
+        end
+        return collected
+    end
+end
+
+local quit_expression = false
+
+local function apply_expression(list,expression,order)
+    local collected, c = { }, 0
+    quit_expression = false
+    for l=1,#list do
+        local ll = list[l]
+        if expression(list,ll,l,order) then -- nasty, order alleen valid als n=1
+            c = c + 1
+            collected[c] = ll
+        end
+        if quit_expression then
+            break
+        end
+    end
+    return collected
+end
+
+local P, V, C, Cs, Cc, Ct, R, S, Cg, Cb = lpeg.P, lpeg.V, lpeg.C, lpeg.Cs, lpeg.Cc, lpeg.Ct, lpeg.R, lpeg.S, lpeg.Cg, lpeg.Cb
+
+local spaces     = S(" \n\r\t\f")^0
+local lp_space   = S(" \n\r\t\f")
+local lp_any     = P(1)
+local lp_noequal = P("!=") / "~=" + P("<=") + P(">=") + P("==")
+local lp_doequal = P("=")  / "=="
+local lp_or      = P("|")  / " or "
+local lp_and     = P("&")  / " and "
+
+local lp_builtin = P (
+        P("text")         / "(ll.dt[1] or '')" + -- fragile
+        P("content")      / "ll.dt" +
+    --  P("name")         / "(ll.ns~='' and ll.ns..':'..ll.tg)" +
+        P("name")         / "((ll.ns~='' and ll.ns..':'..ll.tg) or ll.tg)" +
+        P("tag")          / "ll.tg" +
+        P("position")     / "l" + -- is element in finalizer
+        P("firstindex")   / "1" +
+        P("lastindex")    / "(#ll.__p__.dt or 1)" +
+        P("firstelement") / "1" +
+        P("lastelement")  / "(ll.__p__.en or 1)" +
+        P("first")        / "1" +
+        P("last")         / "#list" +
+        P("rootposition") / "order" +
+        P("order")        / "order" +
+        P("element")      / "(ll.ei or 1)" +
+        P("index")        / "(ll.ni or 1)" +
+        P("match")        / "(ll.mi or 1)" +
+     -- P("namespace")    / "ll.ns" +
+        P("ns")           / "ll.ns"
+    ) * ((spaces * P("(") * spaces * P(")"))/"")
+
+-- for the moment we keep namespaces with attributes
+
+local lp_attribute = (P("@") + P("attribute::")) / "" * Cc("(ll.at and ll.at['") * ((R("az","AZ") + S("-_:"))^1) * Cc("'])")
+
+-- lp_fastpos_p = (P("+")^0 * R("09")^1 * P(-1)) / function(s) return "l==" .. s end
+-- lp_fastpos_n = (P("-")   * R("09")^1 * P(-1)) / function(s) return "(" .. s .. "<0 and (#list+".. s .. "==l))" end
+
+lp_fastpos_p = P("+")^0 * R("09")^1 * P(-1) / "l==%0"
+lp_fastpos_n = P("-")   * R("09")^1 * P(-1) / "(%0<0 and (#list+%0==l))"
+
+local lp_fastpos   = lp_fastpos_n + lp_fastpos_p
+
+local lp_reserved  = C("and") + C("or") + C("not") + C("div") + C("mod") + C("true") + C("false")
+
+-- local lp_lua_function = C(R("az","AZ","__")^1 * (P(".") * R("az","AZ","__")^1)^1) * ("(") / function(t) -- todo: better . handling
+--     return t .. "("
+-- end
+
+-- local lp_lua_function = (R("az","AZ","__")^1 * (P(".") * R("az","AZ","__")^1)^1) * ("(") / "%0("
+local lp_lua_function = Cs((R("az","AZ","__")^1 * (P(".") * R("az","AZ","__")^1)^1) * ("(")) / "%0"
+
+local lp_function  = C(R("az","AZ","__")^1) * P("(") / function(t) -- todo: better . handling
+    if expressions[t] then
+        return "expr." .. t .. "("
+    else
+        return "expr.error("
+    end
+end
+
+local lparent  = P("(")
+local rparent  = P(")")
+local noparent = 1 - (lparent+rparent)
+local nested   = P{lparent * (noparent + V(1))^0 * rparent}
+local value    = P(lparent * C((noparent + nested)^0) * rparent) -- P{"("*C(((1-S("()"))+V(1))^0)*")"}
+
+local lp_child   = Cc("expr.child(ll,'") * R("az","AZ","--","__")^1 * Cc("')")
+local lp_number  = S("+-") * R("09")^1
+local lp_string  = Cc("'") * R("az","AZ","--","__")^1 * Cc("'")
+local lp_content = (P("'") * (1-P("'"))^0 * P("'") + P('"') * (1-P('"'))^0 * P('"'))
+
+local cleaner
+
+local lp_special = (C(P("name")+P("text")+P("tag")+P("count")+P("child"))) * value / function(t,s)
+    if expressions[t] then
+        s = s and s ~= "" and lpegmatch(cleaner,s)
+        if s and s ~= "" then
+            return "expr." .. t .. "(ll," .. s ..")"
+        else
+            return "expr." .. t .. "(ll)"
+        end
+    else
+        return "expr.error(" .. t .. ")"
+    end
+end
+
+local content =
+    lp_builtin +
+    lp_attribute +
+    lp_special +
+    lp_noequal + lp_doequal +
+    lp_or + lp_and +
+    lp_reserved +
+    lp_lua_function + lp_function +
+    lp_content + -- too fragile
+    lp_child +
+    lp_any
+
+local converter = Cs (
+    lp_fastpos + (P { lparent * (V(1))^0 * rparent + content } )^0
+)
+
+cleaner = Cs ( (
+ -- lp_fastpos +
+    lp_reserved +
+    lp_number +
+    lp_string +
+1 )^1 )
+
+local template_e = [[
+    local expr = xml.expressions
+    return function(list,ll,l,order)
+        return %s
+    end
+]]
+
+local template_f_y = [[
+    local finalizer = xml.finalizers['%s']['%s']
+    return function(collection)
+        return finalizer(collection,%s)
+    end
+]]
+
+local template_f_n = [[
+    return xml.finalizers['%s']['%s']
+]]
+
+--
+
+local register_self                    = { kind = "axis", axis = "self"                    } -- , apply = apply_axis["self"]               }
+local register_parent                  = { kind = "axis", axis = "parent"                  } -- , apply = apply_axis["parent"]             }
+local register_descendant              = { kind = "axis", axis = "descendant"              } -- , apply = apply_axis["descendant"]         }
+local register_child                   = { kind = "axis", axis = "child"                   } -- , apply = apply_axis["child"]              }
+local register_descendant_or_self      = { kind = "axis", axis = "descendant-or-self"      } -- , apply = apply_axis["descendant-or-self"] }
+local register_root                    = { kind = "axis", axis = "root"                    } -- , apply = apply_axis["root"]               }
+local register_ancestor                = { kind = "axis", axis = "ancestor"                } -- , apply = apply_axis["ancestor"]           }
+local register_ancestor_or_self        = { kind = "axis", axis = "ancestor-or-self"        } -- , apply = apply_axis["ancestor-or-self"]   }
+local register_attribute               = { kind = "axis", axis = "attribute"               } -- , apply = apply_axis["attribute"]          }
+local register_namespace               = { kind = "axis", axis = "namespace"               } -- , apply = apply_axis["namespace"]          }
+local register_following               = { kind = "axis", axis = "following"               } -- , apply = apply_axis["following"]          }
+local register_following_sibling       = { kind = "axis", axis = "following-sibling"       } -- , apply = apply_axis["following-sibling"]  }
+local register_preceding               = { kind = "axis", axis = "preceding"               } -- , apply = apply_axis["preceding"]          }
+local register_preceding_sibling       = { kind = "axis", axis = "preceding-sibling"       } -- , apply = apply_axis["preceding-sibling"]  }
+local register_reverse_sibling         = { kind = "axis", axis = "reverse-sibling"         } -- , apply = apply_axis["reverse-sibling"]    }
+
+local register_auto_descendant_or_self = { kind = "axis", axis = "auto-descendant-or-self" } -- , apply = apply_axis["auto-descendant-or-self"] }
+local register_auto_descendant         = { kind = "axis", axis = "auto-descendant"         } -- , apply = apply_axis["auto-descendant"] }
+local register_auto_self               = { kind = "axis", axis = "auto-self"               } -- , apply = apply_axis["auto-self"] }
+local register_auto_child              = { kind = "axis", axis = "auto-child"              } -- , apply = apply_axis["auto-child"] }
+
+local register_initial_child           = { kind = "axis", axis = "initial-child"           } -- , apply = apply_axis["initial-child"] }
+
+local register_all_nodes               = { kind = "nodes", nodetest = true, nodes = { true, false, false } }
+
+local skip = { }
+
+local function errorrunner_e(str,cnv)
+    if not skip[str] then
+        report_lpath("error in expression: %s => %s",str,cnv)
+        skip[str] = cnv or str
+    end
+    return false
+end
+
+local function errorrunner_f(str,arg)
+    report_lpath("error in finalizer: %s(%s)",str,arg or "")
+    return false
+end
+
+local function register_nodes(nodetest,nodes)
+    return { kind = "nodes", nodetest = nodetest, nodes = nodes }
+end
+
+local function register_expression(expression)
+    local converted = lpegmatch(converter,expression)
+    local runner = load(format(template_e,converted))
+    runner = (runner and runner()) or function() errorrunner_e(expression,converted) end
+    return { kind = "expression", expression = expression, converted = converted, evaluator = runner }
+end
+
+local function register_finalizer(protocol,name,arguments)
+    local runner
+    if arguments and arguments ~= "" then
+        runner = load(format(template_f_y,protocol or xml.defaultprotocol,name,arguments))
+    else
+        runner = load(format(template_f_n,protocol or xml.defaultprotocol,name))
+    end
+    runner = (runner and runner()) or function() errorrunner_f(name,arguments) end
+    return { kind = "finalizer", name = name, arguments = arguments, finalizer = runner }
+end
+
+local expression = P { "ex",
+    ex = "[" * C((V("sq") + V("dq") + (1 - S("[]")) + V("ex"))^0) * "]",
+    sq = "'" * (1 - S("'"))^0 * "'",
+    dq = '"' * (1 - S('"'))^0 * '"',
+}
+
+local arguments = P { "ar",
+    ar = "(" * Cs((V("sq") + V("dq") + V("nq") + P(1-P(")")))^0) * ")",
+    nq = ((1 - S("),'\""))^1) / function(s) return format("%q",s) end,
+    sq = P("'") * (1 - P("'"))^0 * P("'"),
+    dq = P('"') * (1 - P('"'))^0 * P('"'),
+}
+
+-- todo: better arg parser
+
+local function register_error(str)
+    return { kind = "error", error = format("unparsed: %s",str) }
+end
+
+-- there is a difference in * and /*/ and so we need to catch a few special cases
+
+local special_1 = P("*")  * Cc(register_auto_descendant) * Cc(register_all_nodes) -- last one not needed
+local special_2 = P("/")  * Cc(register_auto_self)
+local special_3 = P("")   * Cc(register_auto_self)
+
+local no_nextcolon   = P(-1) + #(1-P(":")) -- newer lpeg needs the P(-1)
+local no_nextlparent = P(-1) + #(1-P("(")) -- newer lpeg needs the P(-1)
+
+local pathparser = Ct { "patterns", -- can be made a bit faster by moving some patterns outside
+
+    patterns             = spaces * V("protocol") * spaces * (
+                              ( V("special") * spaces * P(-1)                                                         ) +
+                              ( V("initial") * spaces * V("step") * spaces * (P("/") * spaces * V("step") * spaces)^0 )
+                           ),
+
+    protocol             = Cg(V("letters"),"protocol") * P("://") + Cg(Cc(nil),"protocol"),
+
+ -- the / is needed for // as descendant or self is somewhat special
+ -- step                 = (V("shortcuts") + V("axis") * spaces * V("nodes")^0 + V("error")) * spaces * V("expressions")^0 * spaces * V("finalizer")^0,
+    step                 = ((V("shortcuts") + P("/") + V("axis")) * spaces * V("nodes")^0 + V("error")) * spaces * V("expressions")^0 * spaces * V("finalizer")^0,
+
+    axis                 = V("descendant") + V("child") + V("parent") + V("self") + V("root") + V("ancestor") +
+                           V("descendant_or_self") + V("following_sibling") + V("following") +
+                           V("reverse_sibling") + V("preceding_sibling") + V("preceding") + V("ancestor_or_self") +
+                           #(1-P(-1)) * Cc(register_auto_child),
+
+    special              = special_1 + special_2 + special_3,
+
+    initial              = (P("/") * spaces * Cc(register_initial_child))^-1,
+
+    error                = (P(1)^1) / register_error,
+
+    shortcuts_a          = V("s_descendant_or_self") + V("s_descendant") + V("s_child") + V("s_parent") + V("s_self") + V("s_root") + V("s_ancestor"),
+
+    shortcuts            = V("shortcuts_a") * (spaces * "/" * spaces * V("shortcuts_a"))^0,
+
+    s_descendant_or_self = (P("***/") + P("/"))  * Cc(register_descendant_or_self), --- *** is a bonus
+    s_descendant         = P("**")               * Cc(register_descendant),
+    s_child              = P("*") * no_nextcolon * Cc(register_child     ),
+    s_parent             = P("..")               * Cc(register_parent    ),
+    s_self               = P("." )               * Cc(register_self      ),
+    s_root               = P("^^")               * Cc(register_root      ),
+    s_ancestor           = P("^")                * Cc(register_ancestor  ),
+
+    descendant           = P("descendant::")         * Cc(register_descendant         ),
+    child                = P("child::")              * Cc(register_child              ),
+    parent               = P("parent::")             * Cc(register_parent             ),
+    self                 = P("self::")               * Cc(register_self               ),
+    root                 = P('root::')               * Cc(register_root               ),
+    ancestor             = P('ancestor::')           * Cc(register_ancestor           ),
+    descendant_or_self   = P('descendant-or-self::') * Cc(register_descendant_or_self ),
+    ancestor_or_self     = P('ancestor-or-self::')   * Cc(register_ancestor_or_self   ),
+ -- attribute            = P('attribute::')          * Cc(register_attribute          ),
+ -- namespace            = P('namespace::')          * Cc(register_namespace          ),
+    following            = P('following::')          * Cc(register_following          ),
+    following_sibling    = P('following-sibling::')  * Cc(register_following_sibling  ),
+    preceding            = P('preceding::')          * Cc(register_preceding          ),
+    preceding_sibling    = P('preceding-sibling::')  * Cc(register_preceding_sibling  ),
+    reverse_sibling      = P('reverse-sibling::')    * Cc(register_reverse_sibling    ),
+
+    nodes                = (V("nodefunction") * spaces * P("(") * V("nodeset") * P(")") + V("nodetest") * V("nodeset")) / register_nodes,
+
+    expressions          = expression / register_expression,
+
+    letters              = R("az")^1,
+    name                 = (1-S("/[]()|:*!"))^1, -- make inline
+    negate               = P("!") * Cc(false),
+
+    nodefunction         = V("negate") + P("not") * Cc(false) + Cc(true),
+    nodetest             = V("negate") + Cc(true),
+    nodename             = (V("negate") + Cc(true)) * spaces * ((V("wildnodename") * P(":") * V("wildnodename")) + (Cc(false) * V("wildnodename"))),
+    wildnodename         = (C(V("name")) + P("*") * Cc(false)) * no_nextlparent,
+    nodeset              = spaces * Ct(V("nodename") * (spaces * P("|") * spaces * V("nodename"))^0) * spaces,
+
+    finalizer            = (Cb("protocol") * P("/")^-1 * C(V("name")) * arguments * P(-1)) / register_finalizer,
+
+}
+
+xmlpatterns.pathparser = pathparser
+
+local cache = { }
+
+local function nodesettostring(set,nodetest)
+    local t = { }
+    for i=1,#set,3 do
+        local directive, ns, tg = set[i], set[i+1], set[i+2]
+        if not ns or ns == "" then ns = "*" end
+        if not tg or tg == "" then tg = "*" end
+        tg = (tg == "@rt@" and "[root]") or format("%s:%s",ns,tg)
+        t[i] = (directive and tg) or format("not(%s)",tg)
+    end
+    if nodetest == false then
+        return format("not(%s)",concat(t,"|"))
+    else
+        return concat(t,"|")
+    end
+end
+
+local function tagstostring(list)
+    if #list == 0 then
+        return "no elements"
+    else
+        local t = { }
+        for i=1, #list do
+            local li = list[i]
+            local ns, tg = li.ns, li.tg
+            if not ns or ns == "" then ns = "*" end
+            if not tg or tg == "" then tg = "*" end
+            t[i] = (tg == "@rt@" and "[root]") or format("%s:%s",ns,tg)
+        end
+        return concat(t," ")
+    end
+end
+
+xml.nodesettostring = nodesettostring
+
+local lpath -- we have a harmless kind of circular reference
+
+local lshowoptions = { functions = false }
+
+local function lshow(parsed)
+    if type(parsed) == "string" then
+        parsed = lpath(parsed)
+    end
+    report_lpath("%s://%s => %s",parsed.protocol or xml.defaultprotocol,parsed.pattern,
+        table.serialize(parsed,false,lshowoptions))
+end
+
+xml.lshow = lshow
+
+local function add_comment(p,str)
+    local pc = p.comment
+    if not pc then
+        p.comment = { str }
+    else
+        pc[#pc+1] = str
+    end
+end
+
+lpath = function (pattern) -- the gain of caching is rather minimal
+    lpathcalls = lpathcalls + 1
+    if type(pattern) == "table" then
+        return pattern
+    else
+        local parsed = cache[pattern]
+        if parsed then
+            lpathcached = lpathcached + 1
+        else
+            parsed = lpegmatch(pathparser,pattern)
+            if parsed then
+                parsed.pattern = pattern
+                local np = #parsed
+                if np == 0 then
+                    parsed = { pattern = pattern, register_self, state = "parsing error" }
+                    report_lpath("parsing error in pattern: %s",pattern)
+                    lshow(parsed)
+                else
+                    -- we could have done this with a more complex parser but this
+                    -- is cleaner
+                    local pi = parsed[1]
+                    if pi.axis == "auto-child" then
+                        if false then
+                            add_comment(parsed, "auto-child replaced by auto-descendant-or-self")
+                            parsed[1] = register_auto_descendant_or_self
+                        else
+                            add_comment(parsed, "auto-child replaced by auto-descendant")
+                            parsed[1] = register_auto_descendant
+                        end
+                    elseif pi.axis == "initial-child" and np > 1 and parsed[2].axis then
+                        add_comment(parsed, "initial-child removed") -- we could also make it a auto-self
+                        remove(parsed,1)
+                    end
+                    local np = #parsed -- can have changed
+                    if np > 1 then
+                        local pnp = parsed[np]
+                        if pnp.kind == "nodes" and pnp.nodetest == true then
+                            local nodes = pnp.nodes
+                            if nodes[1] == true and nodes[2] == false and nodes[3] == false then
+                                add_comment(parsed, "redundant final wildcard filter removed")
+                                remove(parsed,np)
+                            end
+                        end
+                    end
+                end
+            else
+                parsed = { pattern = pattern }
+            end
+            cache[pattern] = parsed
+            if trace_lparse and not trace_lprofile then
+                lshow(parsed)
+            end
+        end
+        return parsed
+    end
+end
+
+xml.lpath = lpath
+
+-- we can move all calls inline and then merge the trace back
+-- technically we can combine axis and the next nodes which is
+-- what we did before but this a bit cleaner (but slower too)
+-- but interesting is that it's not that much faster when we
+-- go inline
+--
+-- beware: we need to return a collection even when we filter
+-- else the (simple) cache gets messed up
+
+-- caching found lookups saves not that much (max .1 sec on a 8 sec run)
+-- and it also messes up finalizers
+
+-- watch out: when there is a finalizer, it's always called as there
+-- can be cases that a finalizer returns (or does) something in case
+-- there is no match; an example of this is count()
+
+local profiled = { }  xml.profiled = profiled
+
+local function profiled_apply(list,parsed,nofparsed,order)
+    local p = profiled[parsed.pattern]
+    if p then
+        p.tested = p.tested + 1
+    else
+        p = { tested = 1, matched = 0, finalized = 0 }
+        profiled[parsed.pattern] = p
+    end
+    local collected = list
+    for i=1,nofparsed do
+        local pi = parsed[i]
+        local kind = pi.kind
+        if kind == "axis" then
+            collected = apply_axis[pi.axis](collected)
+        elseif kind == "nodes" then
+            collected = apply_nodes(collected,pi.nodetest,pi.nodes)
+        elseif kind == "expression" then
+            collected = apply_expression(collected,pi.evaluator,order)
+        elseif kind == "finalizer" then
+            collected = pi.finalizer(collected) -- no check on # here
+            p.matched = p.matched + 1
+            p.finalized = p.finalized + 1
+            return collected
+        end
+        if not collected or #collected == 0 then
+            local pn = i < nofparsed and parsed[nofparsed]
+            if pn and pn.kind == "finalizer" then
+                collected = pn.finalizer(collected)
+                p.finalized = p.finalized + 1
+                return collected
+            end
+            return nil
+        end
+    end
+    if collected then
+        p.matched = p.matched + 1
+    end
+    return collected
+end
+
+local function traced_apply(list,parsed,nofparsed,order)
+    if trace_lparse then
+        lshow(parsed)
+    end
+    report_lpath("collecting: %s",parsed.pattern)
+    report_lpath("root tags : %s",tagstostring(list))
+    report_lpath("order     : %s",order or "unset")
+    local collected = list
+    for i=1,nofparsed do
+        local pi = parsed[i]
+        local kind = pi.kind
+        if kind == "axis" then
+            collected = apply_axis[pi.axis](collected)
+            report_lpath("% 10i : ax : %s",(collected and #collected) or 0,pi.axis)
+        elseif kind == "nodes" then
+            collected = apply_nodes(collected,pi.nodetest,pi.nodes)
+            report_lpath("% 10i : ns : %s",(collected and #collected) or 0,nodesettostring(pi.nodes,pi.nodetest))
+        elseif kind == "expression" then
+            collected = apply_expression(collected,pi.evaluator,order)
+            report_lpath("% 10i : ex : %s -> %s",(collected and #collected) or 0,pi.expression,pi.converted)
+        elseif kind == "finalizer" then
+            collected = pi.finalizer(collected)
+            report_lpath("% 10i : fi : %s : %s(%s)",(type(collected) == "table" and #collected) or 0,parsed.protocol or xml.defaultprotocol,pi.name,pi.arguments or "")
+            return collected
+        end
+        if not collected or #collected == 0 then
+            local pn = i < nofparsed and parsed[nofparsed]
+            if pn and pn.kind == "finalizer" then
+                collected = pn.finalizer(collected)
+                report_lpath("% 10i : fi : %s : %s(%s)",(type(collected) == "table" and #collected) or 0,parsed.protocol or xml.defaultprotocol,pn.name,pn.arguments or "")
+                return collected
+            end
+            return nil
+        end
+    end
+    return collected
+end
+
+local function normal_apply(list,parsed,nofparsed,order)
+    local collected = list
+    for i=1,nofparsed do
+        local pi = parsed[i]
+        local kind = pi.kind
+        if kind == "axis" then
+            local axis = pi.axis
+            if axis ~= "self" then
+                collected = apply_axis[axis](collected)
+            end
+        elseif kind == "nodes" then
+            collected = apply_nodes(collected,pi.nodetest,pi.nodes)
+        elseif kind == "expression" then
+            collected = apply_expression(collected,pi.evaluator,order)
+        elseif kind == "finalizer" then
+            return pi.finalizer(collected)
+        end
+        if not collected or #collected == 0 then
+            local pf = i < nofparsed and parsed[nofparsed].finalizer
+            if pf then
+                return pf(collected) -- can be anything
+            end
+            return nil
+        end
+    end
+    return collected
+end
+
+--~ local function applylpath(list,pattern)
+--~     -- we avoid an extra call
+--~     local parsed = cache[pattern]
+--~     if parsed then
+--~         lpathcalls = lpathcalls + 1
+--~         lpathcached = lpathcached + 1
+--~     elseif type(pattern) == "table" then
+--~         lpathcalls = lpathcalls + 1
+--~         parsed = pattern
+--~     else
+--~         parsed = lpath(pattern) or pattern
+--~     end
+--~     if not parsed then
+--~         return
+--~     end
+--~     local nofparsed = #parsed
+--~     if nofparsed == 0 then
+--~         return -- something is wrong
+--~     end
+--~     local one = list[1] -- we could have a third argument: isroot and list or list[1] or whatever we like ... todo
+--~     if not one then
+--~         return -- something is wrong
+--~     elseif not trace_lpath then
+--~         return normal_apply(list,parsed,nofparsed,one.mi)
+--~     elseif trace_lprofile then
+--~         return profiled_apply(list,parsed,nofparsed,one.mi)
+--~     else
+--~         return traced_apply(list,parsed,nofparsed,one.mi)
+--~     end
+--~ end
+
+local function applylpath(list,pattern)
+    if not list then
+        return
+    end
+    local parsed = cache[pattern]
+    if parsed then
+        lpathcalls = lpathcalls + 1
+        lpathcached = lpathcached + 1
+    elseif type(pattern) == "table" then
+        lpathcalls = lpathcalls + 1
+        parsed = pattern
+    else
+        parsed = lpath(pattern) or pattern
+    end
+    if not parsed then
+        return
+    end
+    local nofparsed = #parsed
+    if nofparsed == 0 then
+        return -- something is wrong
+    end
+    if not trace_lpath then
+        return normal_apply  ({ list },parsed,nofparsed,list.mi)
+    elseif trace_lprofile then
+        return profiled_apply({ list },parsed,nofparsed,list.mi)
+    else
+        return traced_apply  ({ list },parsed,nofparsed,list.mi)
+    end
+end
+
+xml.applylpath = applylpath -- takes a table as first argment, which is what xml.filter will do
+
+--[[ldx--
+<p>This is the main filter function. It returns whatever is asked for.</p>
+--ldx]]--
+
+function xml.filter(root,pattern) -- no longer funny attribute handling here
+    return applylpath(root,pattern)
+end
+
+-- internal (parsed)
+
+expressions.child = function(e,pattern)
+    return applylpath(e,pattern) -- todo: cache
+end
+
+expressions.count = function(e,pattern) -- what if pattern == empty or nil
+    local collected = applylpath(e,pattern) -- todo: cache
+    return pattern and (collected and #collected) or 0
+end
+
+-- external
+
+-- expressions.oneof = function(s,...)
+--     local t = {...}
+--     for i=1,#t do
+--         if s == t[i] then
+--             return true
+--         end
+--     end
+--     return false
+-- end
+
+expressions.oneof = function(s,...)
+    for i=1,select("#",...) do
+        if s == select(i,...) then
+            return true
+        end
+    end
+    return false
+end
+
+expressions.error = function(str)
+    xml.errorhandler(format("unknown function in lpath expression: %s",tostring(str or "?")))
+    return false
+end
+
+expressions.undefined = function(s)
+    return s == nil
+end
+
+expressions.quit = function(s)
+    if s or s == nil then
+        quit_expression = true
+    end
+    return true
+end
+
+expressions.print = function(...)
+    print(...)
+    return true
+end
+
+expressions.contains  = find
+expressions.find      = find
+expressions.upper     = upper
+expressions.lower     = lower
+expressions.number    = tonumber
+expressions.boolean   = toboolean
+
+function expressions.contains(str,pattern)
+    local t = type(str)
+    if t == "string" then
+        if find(str,pattern) then
+            return true
+        end
+    elseif t == "table" then
+        for i=1,#str do
+            local d = str[i]
+            if type(d) == "string" and find(d,pattern) then
+                return true
+            end
+        end
+    end
+    return false
+end
+
+-- user interface
+
+local function traverse(root,pattern,handle)
+ -- report_lpath("use 'xml.selection' instead for pattern: %s",pattern)
+    local collected = applylpath(root,pattern)
+    if collected then
+        for c=1,#collected do
+            local e = collected[c]
+            local r = e.__p__
+            handle(r,r.dt,e.ni)
+        end
+    end
+end
+
+local function selection(root,pattern,handle)
+    local collected = applylpath(root,pattern)
+    if collected then
+        if handle then
+            for c=1,#collected do
+                handle(collected[c])
+            end
+        else
+            return collected
+        end
+    end
+end
+
+xml.traverse      = traverse           -- old method, r, d, k
+xml.selection     = selection          -- new method, simple handle
+
+--~ function xml.cachedpatterns()
+--~     return cache
+--~ end
+
+-- generic function finalizer (independant namespace)
+
+local function dofunction(collected,fnc,...)
+    if collected then
+        local f = functions[fnc]
+        if f then
+            for c=1,#collected do
+                f(collected[c],...)
+            end
+        else
+            report_lpath("unknown function %a",fnc)
+        end
+    end
+end
+
+finalizers.xml["function"] = dofunction
+finalizers.tex["function"] = dofunction
+
+-- functions
+
+expressions.text = function(e,n)
+    local rdt = e.__p__.dt
+    return rdt and rdt[n] or ""
+end
+
+expressions.name = function(e,n) -- ns + tg
+    local found = false
+    n = tonumber(n) or 0
+    if n == 0 then
+        found = type(e) == "table" and e
+    elseif n < 0 then
+        local d, k = e.__p__.dt, e.ni
+        for i=k-1,1,-1 do
+            local di = d[i]
+            if type(di) == "table" then
+                if n == -1 then
+                    found = di
+                    break
+                else
+                    n = n + 1
+                end
+            end
+        end
+    else
+        local d, k = e.__p__.dt, e.ni
+        for i=k+1,#d,1 do
+            local di = d[i]
+            if type(di) == "table" then
+                if n == 1 then
+                    found = di
+                    break
+                else
+                    n = n - 1
+                end
+            end
+        end
+    end
+    if found then
+        local ns, tg = found.rn or found.ns or "", found.tg
+        if ns ~= "" then
+            return ns .. ":" .. tg
+        else
+            return tg
+        end
+    else
+        return ""
+    end
+end
+
+expressions.tag = function(e,n) -- only tg
+    if not e then
+        return ""
+    else
+        local found = false
+        n = tonumber(n) or 0
+        if n == 0 then
+            found = (type(e) == "table") and e -- seems to fail
+        elseif n < 0 then
+            local d, k = e.__p__.dt, e.ni
+            for i=k-1,1,-1 do
+                local di = d[i]
+                if type(di) == "table" then
+                    if n == -1 then
+                        found = di
+                        break
+                    else
+                        n = n + 1
+                    end
+                end
+            end
+        else
+            local d, k = e.__p__.dt, e.ni
+            for i=k+1,#d,1 do
+                local di = d[i]
+                if type(di) == "table" then
+                    if n == 1 then
+                        found = di
+                        break
+                    else
+                        n = n - 1
+                    end
+                end
+            end
+        end
+        return (found and found.tg) or ""
+    end
+end
+
+--[[ldx--
+<p>Often using an iterators looks nicer in the code than passing handler
+functions. The <l n='lua'/> book describes how to use coroutines for that
+purpose (<url href='http://www.lua.org/pil/9.3.html'/>). This permits
+code like:</p>
+
+<typing>
+for r, d, k in xml.elements(xml.load('text.xml'),"title") do
+    print(d[k]) -- old method
+end
+for e in xml.collected(xml.load('text.xml'),"title") do
+    print(e) -- new one
+end
+</typing>
+--ldx]]--
+
+-- local wrap, yield = coroutine.wrap, coroutine.yield
+-- local dummy = function() end
+--
+-- function xml.elements(root,pattern,reverse) -- r, d, k
+--     local collected = applylpath(root,pattern)
+--     if collected then
+--         if reverse then
+--             return wrap(function() for c=#collected,1,-1 do
+--                 local e = collected[c] local r = e.__p__ yield(r,r.dt,e.ni)
+--             end end)
+--         else
+--             return wrap(function() for c=1,#collected    do
+--                 local e = collected[c] local r = e.__p__ yield(r,r.dt,e.ni)
+--             end end)
+--         end
+--     end
+--     return wrap(dummy)
+-- end
+--
+-- function xml.collected(root,pattern,reverse) -- e
+--     local collected = applylpath(root,pattern)
+--     if collected then
+--         if reverse then
+--             return wrap(function() for c=#collected,1,-1 do yield(collected[c]) end end)
+--         else
+--             return wrap(function() for c=1,#collected    do yield(collected[c]) end end)
+--         end
+--     end
+--     return wrap(dummy)
+-- end
+
+-- faster:
+
+local dummy = function() end
+
+function xml.elements(root,pattern,reverse) -- r, d, k
+    local collected = applylpath(root,pattern)
+    if not collected then
+        return dummy
+    elseif reverse then
+        local c = #collected + 1
+        return function()
+            if c > 1 then
+                c = c - 1
+                local e = collected[c]
+                local r = e.__p__
+                return r, r.dt, e.ni
+            end
+        end
+    else
+        local n, c = #collected, 0
+        return function()
+            if c < n then
+                c = c + 1
+                local e = collected[c]
+                local r = e.__p__
+                return r, r.dt, e.ni
+            end
+        end
+    end
+end
+
+function xml.collected(root,pattern,reverse) -- e
+    local collected = applylpath(root,pattern)
+    if not collected then
+        return dummy
+    elseif reverse then
+        local c = #collected + 1
+        return function()
+            if c > 1 then
+                c = c - 1
+                return collected[c]
+            end
+        end
+    else
+        local n, c = #collected, 0
+        return function()
+            if c < n then
+                c = c + 1
+                return collected[c]
+            end
+        end
+    end
+end
+
+-- handy
+
+function xml.inspect(collection,pattern)
+    pattern = pattern or "."
+    for e in xml.collected(collection,pattern or ".") do
+        report_lpath("pattern: %s\n\n%s\n",pattern,xml.tostring(e))
+    end
+end
+
+-- texy (see xfdf):
+
+local function split(e)
+    local dt = e.dt
+    if dt then
+        for i=1,#dt do
+            local dti = dt[i]
+            if type(dti) == "string" then
+                dti = gsub(dti,"^[\n\r]*(.-)[\n\r]*","%1")
+                dti = gsub(dti,"[\n\r]+","\n\n")
+                dt[i] = dti
+            else
+                split(dti)
+            end
+        end
+    end
+    return e
+end
+
+function xml.finalizers.paragraphs(c)
+    for i=1,#c do
+        split(c[i])
+    end
+    return c
+end