beta 2010.03.25 23:12

27 files changed, 875 insertions, 266 deletions

diff --git a/tex/context/base/bibl-tra.mkiv b/tex/context/base/bibl-tra.mkiv
index 7ea883e52..7b6fc84cb 100644
--- a/tex/context/base/bibl-tra.mkiv
+++ b/tex/context/base/bibl-tra.mkiv
@@ -306,15 +306,27 @@
 
 \newif\ifbibcitecompress\bibcitecompresstrue
 
-\appendtoks
-  \processaction
-    [\@@pbnumbering]
-    [    \v!yes=>\let\@@pbinumbercommand\firstofoneargument,
-          \v!no=>\let\@@pbinumbercommand\gobbleoneargument,
-       \v!short=>\def\@@pbinumbercommand##1{\bibgetvars\currentpublicationkey},
-         \v!bib=>\def\@@pbinumbercommand##1{\bibgetvarn\currentpublicationkey},
-     \s!unknown=>\let\@@pbinumbercommand\firstofoneargument]%
-\to \everysetuppublications
+% \appendtoks
+%   \processaction
+%     [\@@pbnumbering]
+%     [    \v!yes=>\let\@@pbinumbercommand\firstofoneargument,
+%           \v!no=>\let\@@pbinumbercommand\gobbleoneargument,
+%        \v!short=>\def\@@pbinumbercommand##1{\bibgetvars\currentpublicationkey},
+%          \v!bib=>\def\@@pbinumbercommand##1{\bibgetvarn\currentpublicationkey},
+%      \s!unknown=>\let\@@pbinumbercommand\firstofoneargument]%
+% \to \everysetuppublications
+
+\def\@@pbinumbercommand{\executeifdefined{\??pb:\c!numbercommand:\@@pbnumbering}\firstofoneargument}
+
+\letvalue{\??pb:\c!numbercommand:\v!yes  }\firstofoneargument
+\letvalue{\??pb:\c!numbercommand:\v!no   }\gobbleoneargument
+\setvalue{\??pb:\c!numbercommand:\v!short}#1{\bibgetvars\currentpublicationkey}
+\setvalue{\??pb:\c!numbercommand:\v!bib  }#1{\bibgetvarn\currentpublicationkey}
+
+% to be tested
+%
+% \setvalue{\??pb:\c!numbercommand:\v!short}{\bibgetvars\currentpublicationkey\firstofoneargument}
+% \setvalue{\??pb:\c!numbercommand:\v!bib  }{\bibgetvarn\currentpublicationkey\firstofoneargument}
 
 \appendtoks
   \processaction
diff --git a/tex/context/base/char-def.lua b/tex/context/base/char-def.lua
index f7921f6fc..2ed91eb4b 100644
--- a/tex/context/base/char-def.lua
+++ b/tex/context/base/char-def.lua
@@ -887,7 +887,7 @@ characters.data={
   direction="on",
   linebreak="op",
   mathclass="open",
-  mathname="lbracket",
+  mathname="lbrack",
   mirror=0x005D,
   unicodeslot=0x005B,
  },
@@ -911,7 +911,7 @@ characters.data={
   direction="on",
   linebreak="cl",
   mathclass="close",
-  mathname="rbracket",
+  mathname="rbrack",
   mirror=0x005B,
   unicodeslot=0x005D,
  },
diff --git a/tex/context/base/data-res.lua b/tex/context/base/data-res.lua
index 7299475d3..abee8fc9d 100644
--- a/tex/context/base/data-res.lua
+++ b/tex/context/base/data-res.lua
@@ -1837,7 +1837,7 @@ function resolvers.find_given_files(filename)
     local hashes = instance.hashes
     for k=1,#hashes do
         local hash = hashes[k]
-        local files = instance.files[hash.tag]
+        local files = instance.files[hash.tag] or { }
         local blist = files[bname]
         if not blist then
             local rname = "remap:"..bname
diff --git a/tex/context/base/font-ota.lua b/tex/context/base/font-ota.lua
index e2fa3f290..558e2fc80 100644
--- a/tex/context/base/font-ota.lua
+++ b/tex/context/base/font-ota.lua
@@ -41,6 +41,8 @@ local insert_node_after  = node.insert_after
 local insert_node_before = node.insert_before
 local traverse_node_list = node.traverse
 
+local new_glue_node      = nodes.glue
+
 local fontdata = fonts.ids
 local state    = attributes.private('state')
 
@@ -302,11 +304,12 @@ function fonts.analyzers.methods.arab(head,font,attr) -- maybe make a special ve
     end
     first, last = finish(first,last)
     if removejoiners then
+        -- is never head
         for i=1,#joiners do
-            head = delete_node(head,joiners[i])
+            delete_node(head,joiners[i])
         end
         for i=1,#nonjoiners do
-            head = replace_node(head,nonjoiners[i],nodes.glue(0)) -- or maybe a kern
+            replace_node(head,nonjoiners[i],new_glue_node(0)) -- or maybe a kern
         end
     end
     return head, done
diff --git a/tex/context/base/grph-inc.lua b/tex/context/base/grph-inc.lua
index a91bd1d71..507235545 100644
--- a/tex/context/base/grph-inc.lua
+++ b/tex/context/base/grph-inc.lua
@@ -39,6 +39,7 @@ local format, lower, find, match, gsub, gmatch = string.format, string.lower, st
 local texsprint, texbox = tex.sprint, tex.box
 local contains = table.contains
 local concat = table.concat
+local todimen = string.todimen
 
 local ctxcatcodes = tex.ctxcatcodes
 local variables = interfaces.variables
@@ -47,6 +48,7 @@ local trace_figures    = false  trackers.register("figures.locating",   function
 local trace_bases      = false  trackers.register("figures.bases",      function(v) trace_bases      = v end)
 local trace_programs   = false  trackers.register("figures.programs",   function(v) trace_programs   = v end)
 local trace_conversion = false  trackers.register("figures.conversion", function(v) trace_conversion = v end)
+local trace_inclusion  = false  trackers.register("figures.inclusion",  function(v) trace_inclusion  = v end)
 
 --- some extra img functions ---
 
@@ -794,22 +796,29 @@ end
 
 function figures.checkers.mov(data)
     local dr, du, ds = data.request, data.used, data.status
-    dr.width = (dr.width or figures.defaultwidth):todimen()
-    dr.height = (dr.height or figures.defaultheight):todimen()
-    du.width = dr.width
-    du.height = dr.height
-    du.foundname = du.fullname
-    local code = backends.codeinjections.insertmovie {
-        width      = du.width or dr.width,
-        height     = du.height or dr.height,
-        factor     = number.dimenfactors.bp,
-        ["repeat"] = dr["repeat"],
-        controls   = dr.controls,
-        preview    = dr.preview,
-        label      = dr.label,
-        foundname  = du.foundname,
-    }
-    texsprint(ctxcatcodes,format("\\startfoundexternalfigure{%ssp}{%ssp}%s\\stopfoundexternalfigure",du.width,du.height,code))
+    local width = todimen(dr.width or figures.defaultwidth)
+    local height = todimen(dr.height or figures.defaultheight)
+    local foundname = du.fullname
+    dr.width, dr.height = width, height
+    du.width, du.height, du.foundname = width, height, foundname
+    if trace_inclusion then
+        logs.report("figures","including movie '%s': width %s, height %s",foundname,width,height)
+    end
+    -- we need to push the node.write in between ... we could make a shared helper for this
+    context.startfoundexternalfigure(width .. "sp",height .. "sp")
+    context(function()
+        backends.codeinjections.insertmovie {
+            width      = width,
+            height     = height,
+            factor     = number.dimenfactors.bp,
+            ["repeat"] = dr["repeat"],
+            controls   = dr.controls,
+            preview    = dr.preview,
+            label      = dr.label,
+            foundname  = foundname,
+        }
+    end)
+    context.stopfoundexternalfigure()
     return data
 end
 
diff --git a/tex/context/base/grph-u3d.lua b/tex/context/base/grph-u3d.lua
index 3b1d8365d..f3bf17631 100644
--- a/tex/context/base/grph-u3d.lua
+++ b/tex/context/base/grph-u3d.lua
@@ -8,35 +8,38 @@ if not modules then modules = { } end modules ['grph-u3d'] = {
 
 -- see lpdf-u3d.lua for comment
 
-local format = string.format
+local trace_inclusion = false  trackers.register("figures.inclusion",  function(v) trace_inclusion = v end)
 
-local texsprint     = tex.sprint
-local ctxcatcodes   = tex.ctxcatcodes
-local pdfannotation = nodes.pdfannotation
+local pdfannotation   = nodes.pdfannotation
+local todimen         = string.todimen
+
+-- maybe todo: backends.codeinjections.insertu3d
 
 function figures.checkers.u3d(data)
     local dr, du, ds = data.request, data.used, data.status
-    local width = (dr.width or figures.defaultwidth):todimen()
-    local height = (dr.height or figures.defaultheight):todimen()
+    local width = todimen(dr.width or figures.defaultwidth)
+    local height = todimen(dr.height or figures.defaultheight)
     local foundname = du.fullname
     dr.width, dr.height = width, height
     du.width, du.height, du.foundname = width, height, foundname
-    texsprint(ctxcatcodes,format("\\startfoundexternalfigure{%ssp}{%ssp}",width,height))
-    local annot, preview, ref = backends.pdf.helpers.insert3d {
-        foundname = foundname,
-        width     = width,
-        height    = height,
-        factor    = number.dimenfactors.bp,
-        display   = dr.display,
-        controls  = dr.controls,
-        label     = dr.label,
-    }
- -- node.write(pdfannotation(width,-height,0,annot()))
-    texsprint(ctxcatcodes,format("\\pdfannot width %ssp height %ssp {%s}",width,height,annot())) -- brrrr
---~     if ref then -- wrong ! a direct ref should work
---~         texsprint(ctxcatcodes,format("\\smash{\\pdfrefximage%s\\relax}",ref)) -- brrrr
---~     end
-    texsprint(ctxcatcodes,"\\stopfoundexternalfigure")
+    if trace_inclusion then
+        logs.report("figures","including u3d '%s': width %s, height %s",foundname,width,height)
+    end
+    context.startfoundexternalfigure(width .. "sp",height .. "sp")
+    context(function()
+        local annotation, preview, ref = backends.pdf.helpers.insert3d {
+            foundname = foundname,
+            width     = width,
+            height    = height,
+            factor    = number.dimenfactors.bp,
+            display   = dr.display,
+            controls  = dr.controls,
+            label     = dr.label,
+        }
+--~         print(annotation, preview, ref)
+        node.write(pdfannotation(width,height,0,annotation()))
+    end)
+    context.stopfoundexternalfigure()
     return data
 end
 
diff --git a/tex/context/base/l-dimen.lua b/tex/context/base/l-dimen.lua
index a8faa270b..b14a1fa54 100644
--- a/tex/context/base/l-dimen.lua
+++ b/tex/context/base/l-dimen.lua
@@ -128,9 +128,9 @@ capture takes place.</p>
 local amount = (S("+-")^0 * R("09")^0 * P(".")^0 * R("09")^0) + Cc("0")
 local unit   = R("az")^1
 
-local pattern = amount/tonumber * (unit^1/dimenfactors + Cc(1)) -- tonumber is new
+local dimenpair = amount/tonumber * (unit^1/dimenfactors + Cc(1)) -- tonumber is new
 
-lpeg.patterns.dimenpair = pattern
+lpeg.patterns.dimenpair = dimenpair
 
 --[[ldx--
 <p>We use a metatable to intercept errors. When no key is found in
@@ -149,7 +149,7 @@ function string:todimen()
     if type(self) == "number" then
         return self
     else
-        local value, unit = lpegmatch(pattern,self)
+        local value, unit = lpegmatch(dimenpair,self)
         return value/unit
     end
 end
@@ -158,7 +158,7 @@ local amount = S("+-")^0 * R("09")^0 * S(".,")^0 * R("09")^0
 local unit   = P("pt") + P("cm") + P("mm") + P("sp") + P("bp") + P("in")  +
                P("pc") + P("dd") + P("cc") + P("nd") + P("nc")
 
-local pattern = amount * unit
+local validdimen = amount * unit
 
 lpeg.patterns.validdimen = pattern
 
@@ -166,12 +166,12 @@ lpeg.patterns.validdimen = pattern
 <p>This converter accepts calls like:</p>
 
 <typing>
-string.todimen("10"))
-string.todimen(".10"))
-string.todimen("10.0"))
-string.todimen("10.0pt"))
-string.todimen("10pt"))
-string.todimen("10.0pt"))
+string.todimen("10")
+string.todimen(".10")
+string.todimen("10.0")
+string.todimen("10.0pt")
+string.todimen("10pt")
+string.todimen("10.0pt")
 </typing>
 
 <p>And of course the often more efficient:</p>
@@ -371,7 +371,7 @@ function dimen(a)
             if k then
                 a = k
             else
-                local value, unit = lpegmatch(pattern,a)
+                local value, unit = lpegmatch(dimenpair,a)
                 if type(unit) == "function" then
                     k = value/unit()
                 else
@@ -395,7 +395,7 @@ function string:todimen()
     else
         local k = known[self]
         if not k then
-            local value, unit = lpegmatch(pattern,self)
+            local value, unit = lpegmatch(dimenpair,self)
             if value and unit then
                 k = value/unit
             else
diff --git a/tex/context/base/lpdf-ini.lua b/tex/context/base/lpdf-ini.lua
index 3d5a9ba3c..61eceb168 100644
--- a/tex/context/base/lpdf-ini.lua
+++ b/tex/context/base/lpdf-ini.lua
@@ -483,6 +483,10 @@ end
 function lpdf.finalizedocument()
     if not environment.initex then
         run(documentfinalizers,"document")
+        function lpdf.finalizedocument()
+            logs.report("backend","serious error: the document is finalized multiple times")
+            function lpdf.finalizedocument() end
+        end
     end
 end
 
diff --git a/tex/context/base/math-lan.mkiv b/tex/context/base/math-lan.mkiv
index bcf9cdc13..1d3132578 100644
--- a/tex/context/base/math-lan.mkiv
+++ b/tex/context/base/math-lan.mkiv
@@ -61,4 +61,7 @@
 \setupmathlabeltext [\s!pl] [arctg=arc\,tg]
 \setupmathlabeltext [\s!pl] [arcctg=arc\,ctg]
 
+\setupmathlabeltext [\s!nl] [gcd=ggd]
+\setupmathlabeltext [\s!nl] [lcm=kgv]
+
 \protect \endinput
diff --git a/tex/context/base/mult-cld.lua b/tex/context/base/mult-cld.lua
index 372fd858d..1d1542ab7 100644
--- a/tex/context/base/mult-cld.lua
+++ b/tex/context/base/mult-cld.lua
@@ -59,52 +59,53 @@ trackers.register("context.flush",     function(v) if v then context.trace()
 trackers.register("context.intercept", function(v) if v then context.trace(true) end end)
 
 local function writer(k,...)
-    flush(ctxcatcodes,k)
-    local t = { ... }
-    local nt = #t
-    if nt > 0 then
-        for i=1,nt do
-            local ti = t[i]
-            local typ = type(ti)
-            if ti == nil then
-                -- next
-            elseif typ == "function" then
-                flush(ctxcatcodes,"{\\mkivflush{" .. _store_(ti) .. "}}")
-            elseif typ == "string" or typ == "number" then
-                flush(ctxcatcodes,"{",ti,"}")
-            elseif typ == "table" then
-                local c = concat(ti,",")
-                if c ~= "" then
-                    flush(ctxcatcodes,"[",c,"]")
-                else
-                    flush(ctxcatcodes,"[")
-                    local done = false
-                    for k, v in next, ti do
-                        if done then
-                            flush(ctxcatcodes,",",k,'=',v)
-                        else
-                            flush(ctxcatcodes,k,'=',v)
-                            done = true
+    if k then
+        flush(ctxcatcodes,k)
+        local t = { ... }
+        local nt = #t
+        if nt > 0 then
+            for i=1,nt do
+                local ti = t[i]
+                local typ = type(ti)
+                if ti == nil then
+                    -- next
+                elseif typ == "function" then
+                    flush(ctxcatcodes,"{\\mkivflush{" .. _store_(ti) .. "}}")
+                elseif typ == "string" or typ == "number" then
+                    flush(ctxcatcodes,"{",ti,"}")
+                elseif typ == "table" then
+                    local c = concat(ti,",")
+                    if c ~= "" then
+                        flush(ctxcatcodes,"[",c,"]")
+                    else
+                        flush(ctxcatcodes,"[")
+                        local done = false
+                        for k, v in next, ti do
+                            if done then
+                                flush(ctxcatcodes,",",k,'=',v)
+                            else
+                                flush(ctxcatcodes,k,'=',v)
+                                done = true
+                            end
                         end
+                        flush(ctxcatcodes,"]")
                     end
-                    flush(ctxcatcodes,"]")
+            --  elseif typ == "boolean" then
+            --      flush(ctxcatcodes,"\n")
+                elseif ti == true then
+                    flush(ctxcatcodes,"\n")
+                elseif typ == false then
+                --  if force == "direct" then
+                    flush(ctxcatcodes,tostring(ti))
+                --  end
+                else
+                    logs.report("interfaces","error: %s gets a weird argument %s",k,tostring(ti))
                 end
-        --  elseif typ == "boolean" then
-        --      flush(ctxcatcodes,"\n")
-            elseif ti == true then
-                flush(ctxcatcodes,"\n")
-            elseif typ == false then
-            --  if force == "direct" then
-                flush(ctxcatcodes,tostring(ti))
-            --  end
-            else
-                logs.report("interfaces","error: %s gets a weird argument %s",k,tostring(ti))
             end
         end
     end
 end
 
-
 -- -- --
 
 --~ local function indexer(t,k)
@@ -131,6 +132,8 @@ end
 local function caller(t,f,a,...)
     if a then
         flush(ctxcatcodes,format(f,a,...))
+    elseif type(f) == "function" then
+        flush(ctxcatcodes,"{\\mkivflush{" .. _store_(f) .. "}}")
     elseif f then
         flush(ctxcatcodes,f)
     else
diff --git a/tex/context/base/node-aux.lua b/tex/context/base/node-aux.lua
index 2dbc974a1..20996a65e 100644
--- a/tex/context/base/node-aux.lua
+++ b/tex/context/base/node-aux.lua
@@ -67,7 +67,7 @@ end
 --         or  id == mark_node
 --         or  id == adjust_node
 --         or  id == penalty_node
---         or (id == glue_node    and a.spec == 0)
+--         or (id == glue_node    and a.spec.writable)
 --         or (id == disc_node    and a.pre == nil and a.post == nil and a.replace == nil)
 --         or (id == math_node    and a.surround == 0)
 --         or (id == kern_node    and (a.kern == 0 or a.subtype == NORMAL))
@@ -112,3 +112,34 @@ end
 --         end
 --     end
 -- end
+--
+-- left-overs
+--
+-- local function round_xn_over_d(x, n, d)
+--     local positive -- was x >= 0
+--     if x >= 0 then
+--         positive = true
+--     else
+--         x = -x
+--         positive = false
+--     end
+--     local t = floor(x % 0x8000) * n              -- 0100000
+--     local f = floor(t / 0x8000)                  -- 0100000
+--     local u = floor(x / 0x8000) * n + f          -- 0100000
+--     local v = floor(u % d) * 0x8000 + f          -- 0100000
+--     if floor(u / d) >= 0x8000 then               -- 0100000
+--         logs.error("parbuilder",'arith_error')
+--     else
+--         u = 0x8000 * floor(u / d) + floor(v / d) -- 0100000
+--     end
+--     v = floor(v % d)
+--     if 2*v >= d then
+--         u = u + 1
+--     end
+--     if positive then
+--         return u
+--     else
+--         return -u
+--     end
+-- end
+
diff --git a/tex/context/base/node-dir.lua b/tex/context/base/node-dir.lua
new file mode 100644
index 000000000..225d2448a
--- /dev/null
+++ b/tex/context/base/node-dir.lua
@@ -0,0 +1,308 @@
+if not modules then modules = { } end modules ['node-mir'] = {
+    version   = 1.001,
+    comment   = "companion to node-ini.mkiv",
+    author    = "Taco Hoekwater and Hans Hagen",
+    copyright = "PRAGMA ADE / ConTeXt Development Team",
+    license   = "see context related readme files"
+}
+
+--[[
+<p>In the process of cleaning up the lua variant of the parbuilder
+we ran into a couple of functions (translated c macros) that were
+somewhat inefficient. More convenient is to use hashes although at
+the c-end still macros are used. In the process directions.h was
+adapted and now has the mappings as comments. This lua file is
+based on that file.
+]]--
+
+
+nodes = nodes or { }
+
+nodes.is_mirrored = {
+ -- TLT = false,
+ -- TRT = false,
+ -- LTL = false,
+ -- RTT = false,
+}
+
+nodes.is_rotated = {
+ -- TLT = false,
+ -- TRT = false,
+ -- LTL = false,
+    RTT = true, ["+RTT"] = true,
+}
+
+nodes.textdir_is_parallel = {
+    TLT = {
+        TLT = true, ["+TLT"] = true,
+        TRT = true, ["+TRT"] = true,
+     -- LTL = false,
+     -- RTT = false,
+    },
+    TRT= {
+        TLT = true, ["+TLT"] = true,
+        TRT = true, ["+TRT"] = true,
+     -- LTL = false,
+     -- RTT = false,
+    },
+    LTL = {
+     -- TLT = false,
+     -- TRT = false,
+        LTL = true, ["+LTL"] = true,
+        RTT = true, ["+RTT"] = true,
+    },
+    RTT = {
+     -- TLT = false,
+     -- TRT = false,
+        LTL = true, ["+LTL"] = true,
+        RTT = true, ["+RTT"] = true,
+    }
+}
+
+nodes.pardir_is_parallel = {
+    TLT = {
+        TLT = true, ["+TLT"] = true,
+        TRT = true, ["+TRT"] = true,
+     -- LTL = false,
+     -- RTT = false,
+    },
+    TRT = {
+        TLT = true, ["+TLT"] = true,
+        TRT = true, ["+TRT"] = true,
+     -- LTL = false,
+     -- RTT = false,
+    },
+    LTL = {
+     -- TLT = false,
+     -- TRT = false,
+        LTL = true, ["+LTL"] = true,
+        RTT = true, ["+RTT"] = true,
+    },
+    RTT = {
+     -- TLT = false,
+     -- TRT = false,
+        LTL = true, ["+LTL"] = true,
+        RTT = true, ["+RTT"] = true,
+    },
+}
+
+nodes.pardir_is_opposite = {
+    TLT = {
+     -- TLT = false,
+     -- TRT = false,
+     -- LTL = false,
+     -- RTT = false,
+    },
+    TRT = {
+     -- TLT = false,
+     -- TRT = false,
+     -- LTL = false,
+     -- RTT = false,
+    },
+    LTL = {
+     -- TLT = false,
+     -- TRT = false,
+     -- LTL = false,
+        RTT = true, ["+RTT"] = true,
+    },
+    RTT = {
+     -- TLT = false,
+     -- TRT = false,
+        LTL = true, ["+LTL"] = true,
+     -- RTT = false,
+    },
+}
+
+nodes.textdir_is_opposite= {
+    TLT = {
+     -- TLT = false,
+        TRT = true, ["+TRT"] = true,
+     -- LTL = false,
+     -- RTT = false,
+    },
+    TRT= {
+        TLT = true, ["+TLT"] = true,
+     -- TRT = false,
+     -- LTL = false,
+     -- RTT = false,
+    },
+    LTL = {
+     -- TLT = false,
+     -- TRT = false,
+     -- LTL = false,
+     -- RTT = false,
+    },
+    RTT = {
+     -- TLT = false,
+     -- TRT = false,
+     -- LTL = false,
+     -- RTT = false,
+    },
+}
+
+nodes.glyphdir_is_opposite = {
+    TLT = {
+     -- TLT = false,
+     -- TRT = false,
+     -- LTL = false,
+     -- RTT = false,
+    },
+    TRT= {
+     -- TLT = false,
+     -- TRT = false,
+     -- LTL = false,
+     -- RTT = false,
+    },
+    LTL = {
+     -- TLT = false,
+     -- TRT = false,
+     -- LTL = false,
+     -- RTT = false,
+    },
+    RTT = {
+     -- TLT = false,
+     -- TRT = false,
+     -- LTL = false,
+     -- RTT = false,
+    },
+}
+
+nodes.pardir_is_eq = {
+    TLT = {
+        TLT = true, ["+TLT"] = true,
+        TRT = true, ["+TRT"] = true,
+     -- LTL = false,
+     -- RTT = false,
+        },
+    TRT= {
+        TLT = true, ["+TLT"] = true,
+        TRT = true, ["+TRT"] = true,
+     -- LTL = false,
+     -- RTT = false,
+    },
+    LTL= {
+     -- TLT = false,
+     -- TRT = false,
+        LTL = true, ["+LTL"] = true,
+     -- RTT = false,
+    },
+    RTT= {
+     -- TLT = false,
+     -- TRT = false,
+     -- LTL = false,
+        RTT = true, ["+RTT"] = true,
+    },
+}
+
+nodes.textdir_is_eq = {
+    TLT = {
+        TLT = true, ["+TLT"] = true,
+     -- TRT = false,
+     -- LTL = false,
+     -- RTT = false,
+    },
+    TRT= {
+     -- TLT = false,
+        TRT = true, ["+TRT"] = true,
+     -- LTL = false,
+     -- RTT = false,
+    },
+    LTL = {
+     -- TLT = false,
+     -- TRT = false,
+        LTL = true, ["+LTL"] = true,
+        RTT = true, ["+RTT"] = true,
+    },
+    RTT = {
+     -- TLT = false,
+     -- TRT = false,
+        LTL = true, ["+LTL"] = true,
+        RTT = true, ["+RTT"] = true,
+    },
+}
+
+nodes.glyphdir_is_eq = {
+    TLT = {
+        TLT = true, ["+TLT"] = true,
+        TRT = true, ["+TRT"] = true,
+     -- LTL = false,
+        RTT = true, ["+RTT"] = true,
+    },
+    TRT= {
+        TLT = true, ["+TLT"] = true,
+        TRT = true, ["+TRT"] = true,
+     -- LTL = false,
+        RTT = true, ["+RTT"] = true,
+    },
+    LTL = {
+     -- TLT = false,
+     -- TRT = false,
+        LTL = true, ["+LTL"] = true,
+     -- RTT = false,
+    },
+    RTT = {
+        TLT = true, ["+TLT"] = true,
+        TRT = true, ["+TRT"] = true,
+     -- LTL = false,
+        RTT = true, ["+RTT"] = true,
+    },
+}
+
+nodes.partextdir_is_eq = {
+    TLT = {
+     -- TLT = false,
+     -- TRT = false,
+        LTL = true, ["+LTL"] = true,
+        RTT = true, ["+RTT"] = true,
+    },
+    TRT= {
+     -- TLT = false,
+     -- TRT = false,
+        LTL = true, ["+LTL"] = true,
+        RTT = true, ["+RTT"] = true,
+    },
+    LTL = {
+        TLT = true, ["+TLT"] = true,
+     -- TRT = false,
+     -- LTL = false,
+     -- RTT = false,
+    },
+    RTT = {
+     -- TLT = false,
+        TRT = true, ["+TRT"] = true,
+     -- LTL = false,
+     -- RTT = false,
+    },
+}
+
+nodes.textdir_is_is = {
+    TLT = true, ["+TLT"] = true,
+ -- TRT = false,
+ -- LTL = false,
+ -- RTT = false,
+}
+
+nodes.glyphdir_is_orthogonal = {
+    TLT = true, ["+TLT"] = true,
+    TRT = true, ["+TRT"] = true,
+    LTL = true, ["+LTL"] = true,
+ -- RTT = false
+}
+
+nodes.dir_is_pop = {
+    ["-TRT"] = true,
+    ["-TLT"] = true,
+    ["-LTL"] = true,
+    ["-RTT"] = true,
+}
+
+nodes.dir_negation = {
+    ["-TRT"] = "+TRT",
+    ["-TLT"] = "+TLT",
+    ["-LTL"] = "+LTL",
+    ["-RTT"] = "+RTT",
+    ["+TRT"] = "-TRT",
+    ["+TLT"] = "-TLT",
+    ["+LTL"] = "-LTL",
+    ["+RTT"] = "-RTT",
+}
diff --git a/tex/context/base/node-ini.lua b/tex/context/base/node-ini.lua
index e21fc70e4..36e240238 100644
--- a/tex/context/base/node-ini.lua
+++ b/tex/context/base/node-ini.lua
@@ -108,10 +108,12 @@ local penalty = node.id('penalty')
 local kern    = node.id('kern')
 local whatsit = node.id('whatsit')
 
-local traverse_id = node.traverse_id
-local traverse    = node.traverse
-local free_node   = node.free
-local remove_node = node.remove
+local traverse_id        = node.traverse_id
+local traverse           = node.traverse
+local free_node          = node.free
+local remove_node        = node.remove
+local insert_node_before = node.insert_before
+local insert_node_after  = node.insert_after
 
 function nodes.remove(head, current, free_too)
    local t = current
@@ -131,8 +133,8 @@ function nodes.delete(head,current)
     return nodes.remove(head,current,true)
 end
 
-nodes.before = node.insert_before
-nodes.after  = node.insert_after
+nodes.before = insert_node_before
+nodes.after  = insert_node_after
 
 -- we need to test this, as it might be fixed now
 
@@ -172,21 +174,31 @@ function nodes.after(h,c,n)
     return n, n
 end
 
-function nodes.replace(head,current,new)
-    if current and next then
-        local p, n = current.prev, current.next
-        new.prev, new.next = p, n
-        if p then
-            p.next = new
-        else
+-- local h, c = nodes.replace(head,current,new)
+-- local c = nodes.replace(false,current,new)
+-- local c = nodes.replace(current,new)
+
+function nodes.replace(head,current,new) -- no head returned if false
+    if not new then
+        head, current, new = false, head, current
+    end
+    local prev, next = current.prev, current.next
+    if next then
+        new.next, next.prev = next, new
+    end
+    if prev then
+        new.prev, prev.next = prev, new
+    end
+    if head then
+        if head == current then
             head = new
         end
-        if n then
-            n.prev = new
-        end
         free_node(current)
+        return head, new
+    else
+        free_node(current)
+        return new
     end
-    return head, current
 end
 
 -- will move
diff --git a/tex/context/base/node-par.lua b/tex/context/base/node-par.lua
index a8ad969fe..8c6ab2c34 100644
--- a/tex/context/base/node-par.lua
+++ b/tex/context/base/node-par.lua
@@ -45,7 +45,13 @@ function parbuilders.constructor(head,followed_by_display)
         if attribute then
             local constructor = names[attribute]
             if constructor then
-                return constructors[constructor](head,followed_by_display)
+                local handler = constructor and constructors[constructor]
+                if handler then
+                    return handler(head,followed_by_display)
+                else
+                    logs.report("parbuilders","handler '%s' is not defined",tostring(constructor))
+                    return true -- let tex break
+                end
             end
         end
         return true -- let tex break
diff --git a/tex/context/base/node-ref.lua b/tex/context/base/node-ref.lua
index 198a810ff..7128b1a6d 100644
--- a/tex/context/base/node-ref.lua
+++ b/tex/context/base/node-ref.lua
@@ -127,10 +127,10 @@ local function inject_list(id,current,reference,make,stack,pardir,txtdir)
                     if prev and prev.id == glue and prev.subtype == 15 then
                         width = dimensions(current,first,prev.prev) -- maybe not current as we already take care of it
                     else
-                        if moveright and first.spec then
+                        if moveright and first.writable then
                             width = width - first.spec.stretch*current.glue_set * current.glue_sign
                         end
-                        if last.spec then
+                        if last.writable then
                             width = width - last.spec.stretch*current.glue_set * current.glue_sign
                         end
                     end
diff --git a/tex/context/base/node-res.lua b/tex/context/base/node-res.lua
index f30f6db1e..2657dfa1e 100644
--- a/tex/context/base/node-res.lua
+++ b/tex/context/base/node-res.lua
@@ -7,7 +7,10 @@ if not modules then modules = { } end modules ['node-res'] = {
 }
 
 local gmatch, format = string.gmatch, string.format
-local copy_node, free_node, free_list, new_node = node.copy, node.free, node.flush_list, node.new
+local copy_node, free_node, free_list, new_node, node_type, node_id = node.copy, node.free, node.flush_list, node.new, node.type, node.id
+local tonumber, round = tonumber, math.round
+
+local glyph_node = node_id("glyph")
 
 --[[ldx--
 <p>The next function is not that much needed but in <l n='context'/> we use
@@ -25,16 +28,21 @@ for k, v in pairs(node.whatsits()) do
     whatsits[k], whatsits[v] = v, k -- two way
 end
 
-function nodes.register(n)
+local function register_node(n)
     reserved[#reserved+1] = n
     return n
 end
 
+nodes.register = register_node
+
 function nodes.cleanup_reserved(nofboxes) -- todo
     nodes.tracers.steppers.reset() -- todo: make a registration subsystem
     local nr, nl = #reserved, 0
     for i=1,nr do
-        free_node(reserved[i])
+        local ri = reserved[i]
+    --  if not (ri.id == glue_spec and not ri.is_writable) then
+            free_node(reserved[i])
+    --  end
     end
     if nofboxes then
         local tb = tex.box
@@ -58,19 +66,37 @@ function nodes.usage()
     return t
 end
 
-local disc       = nodes.register(new_node("disc"))
-local kern       = nodes.register(new_node("kern",1))
-local penalty    = nodes.register(new_node("penalty"))
-local glue       = nodes.register(new_node("glue"))
-local glue_spec  = nodes.register(new_node("glue_spec"))
-local glyph      = nodes.register(new_node("glyph",0))
-local textdir    = nodes.register(new_node("whatsit",whatsits.dir)) -- 7 (6 is local par node)
-local rule       = nodes.register(new_node("rule"))
-local latelua    = nodes.register(new_node("whatsit",whatsits.late_lua)) -- 35
-local user_n     = nodes.register(new_node("whatsit",whatsits.user_defined)) user_n.type = 100 -- 44
-local user_l     = nodes.register(new_node("whatsit",whatsits.user_defined)) user_l.type = 110 -- 44
-local user_s     = nodes.register(new_node("whatsit",whatsits.user_defined)) user_s.type = 115 -- 44
-local user_t     = nodes.register(new_node("whatsit",whatsits.user_defined)) user_t.type = 116 -- 44
+local disc              = register_node(new_node("disc"))
+local kern              = register_node(new_node("kern",1))
+local penalty           = register_node(new_node("penalty"))
+local glue              = register_node(new_node("glue")) -- glue.spec = nil
+local glue_spec         = register_node(new_node("glue_spec"))
+local glyph             = register_node(new_node("glyph",0))
+local textdir           = register_node(new_node("whatsit",whatsits.dir)) -- 7 (6 is local par node)
+local rule              = register_node(new_node("rule"))
+local latelua           = register_node(new_node("whatsit",whatsits.late_lua)) -- 35
+local user_n            = register_node(new_node("whatsit",whatsits.user_defined)) user_n.type = 100 -- 44
+local user_l            = register_node(new_node("whatsit",whatsits.user_defined)) user_l.type = 110 -- 44
+local user_s            = register_node(new_node("whatsit",whatsits.user_defined)) user_s.type = 115 -- 44
+local user_t            = register_node(new_node("whatsit",whatsits.user_defined)) user_t.type = 116 -- 44
+local left_margin_kern  = register_node(new_node("margin_kern",0))
+local right_margin_kern = register_node(new_node("margin_kern",1))
+local lineskip          = register_node(new_node("glue",1))
+local baselineskip      = register_node(new_node("glue",2))
+local leftskip          = register_node(new_node("glue",8))
+local rightskip         = register_node(new_node("glue",9))
+local temp              = register_node(new_node("temp",0))
+
+function nodes.zeroglue(n)
+    local s = n.spec
+    return not writable or (
+                     s.width == 0
+         and       s.stretch == 0
+         and        s.shrink == 0
+         and s.stretch_order == 0
+         and  s.shrink_order == 0
+        )
+end
 
 function nodes.glyph(fnt,chr)
     local n = copy_node(glyph)
@@ -78,48 +104,114 @@ function nodes.glyph(fnt,chr)
     if chr then n.char = chr end
     return n
 end
+
 function nodes.penalty(p)
     local n = copy_node(penalty)
     n.penalty = p
     return n
 end
+
 function nodes.kern(k)
     local n = copy_node(kern)
     n.kern = k
     return n
 end
-function nodes.glue(width,stretch,shrink)
-    local n, s = copy_node(glue), copy_node(glue_spec)
-    s.width, s.stretch, s.shrink = width, stretch, shrink
-    n.spec = s
-    return n
-end
+
 function nodes.glue_spec(width,stretch,shrink)
     local s = copy_node(glue_spec)
     s.width, s.stretch, s.shrink = width, stretch, shrink
     return s
 end
+
+local function someskip(skip,width,stretch,shrink)
+    local n = copy_node(skip)
+    if not width then
+        -- no spec
+    elseif tonumber(width) then
+        local s = copy_node(glue_spec)
+        s.width, s.stretch, s.shrink = width, stretch, shrink
+        n.spec = s
+    else
+        -- shared
+        n.spec = copy_node(width)
+    end
+    return n
+end
+
+function nodes.glue(width,stretch,shrink)
+    return someskip(glue,width,stretch,shrink)
+end
+function nodes.leftskip(width,stretch,shrink)
+    return someskip(leftskip,width,stretch,shrink)
+end
+function nodes.rightskip(width,stretch,shrink)
+    return someskip(rightskip,width,stretch,shrink)
+end
+function nodes.lineskip(width,stretch,shrink)
+    return someskip(lineskip,width,stretch,shrink)
+end
+function nodes.baselineskip(width,stretch,shrink)
+    return someskip(baselineskip,width,stretch,shrink)
+end
+
 function nodes.disc()
     return copy_node(disc)
 end
+
 function nodes.textdir(dir)
     local t = copy_node(textdir)
     t.dir = dir
     return t
 end
-function nodes.rule(w,h,d)
+
+function nodes.rule(width,height,depth,dir)
     local n = copy_node(rule)
-    if w then n.width  = w end
-    if h then n.height = h end
-    if d then n.depth  = d end
+    if width  then n.width  = width  end
+    if height then n.height = height end
+    if depth  then n.depth  = depth  end
+    if dir    then n.dir    = dir    end
     return n
 end
+
 function nodes.latelua(code)
     local n = copy_node(latelua)
     n.data = code
     return n
 end
 
+function nodes.leftmarginkern(glyph,width)
+    local n = copy_node(left_margin_kern)
+    if not glyph then
+        logs.fatal("nodes","invalid pointer to left margin glyph node")
+    elseif glyph.id ~= glyph_node then
+        logs.fatal("nodes","invalid node type %s for left margin glyph node",node_type(glyph))
+    else
+        n.glyph = glyph
+    end
+    if width then
+        n.width = width
+    end
+    return n
+end
+
+function nodes.rightmarginkern(glyph,width)
+    local n = copy_node(right_margin_kern)
+    if not glyph then
+        logs.fatal("nodes","invalid pointer to right margin glyph node")
+    elseif glyph.id ~= glyph_node then
+        logs.fatal("nodes","invalid node type %s for right margin glyph node",node_type(p))
+    else
+        n.glyph = glyph
+    end
+    if width then
+        n.width = width
+    end
+    return n
+end
+
+function nodes.temp()
+    return copy_node(temp)
+end
 --[[
 <p>At some point we ran into a problem that the glue specification
 of the zeropoint dimension was overwritten when adapting a glue spec
diff --git a/tex/context/base/node-rul.lua b/tex/context/base/node-rul.lua
index 17b7c7658..0ecb7107c 100644
--- a/tex/context/base/node-rul.lua
+++ b/tex/context/base/node-rul.lua
@@ -7,6 +7,7 @@ if not modules then modules = { } end modules ['node-rul'] = {
 }
 
 -- this will go to an auxiliary module
+-- beware: rules now have a dir field
 
 local glyph = node.id("glyph")
 local disc  = node.id("disc")
@@ -85,7 +86,7 @@ local checkdir = true
 -- we assume {glyphruns} and no funny extra kerning, ok, maybe we need
 -- a dummy character as start and end; anyway we only collect glyphs
 
-local function process_words(attribute,data,flush,head,parent)
+local function process_words(attribute,data,flush,head,parent) -- we have hlistdir and local dir
     local n = head
     if n then
         local f, l, a, d, i, level
@@ -215,7 +216,9 @@ local function flush_ruled(head,f,l,d,level,parent,strip) -- not that fast but a
             insert_after(head,r,k)
         end
         if trace_ruled then
-            logs.report("ruled", "level: %s, width: %s, nodes: %s, text: %s",level,w,n_tostring(f,l),n_tosequence(f,l,true))
+            logs.report("ruled", "level: %s, width: %i, height: %i, depth: %i, nodes: %s, text: %s",
+                level,w,ht,dp,n_tostring(f,l),n_tosequence(f,l,true))
+             -- level,r.width,r.height,r.depth,n_tostring(f,l),n_tosequence(f,l,true))
         end
     end
     return head
diff --git a/tex/context/base/node-shp.lua b/tex/context/base/node-shp.lua
index 1798da771..50b16efa5 100644
--- a/tex/context/base/node-shp.lua
+++ b/tex/context/base/node-shp.lua
@@ -20,7 +20,7 @@ local function cleanup_page(head) -- rough
     local start = head
     while start do
         local id = start.id
-        if id == disc or (id == glue and not start.spec) or (id == kern and start.kern == 0) or id == mark then
+        if id == disc or (id == glue and not start.writable) or (id == kern and start.kern == 0) or id == mark then
             head, start, tmp = remove_node(head,start)
             free_node(tmp)
         elseif id == hlist or id == vlist then
diff --git a/tex/context/base/node-tra.lua b/tex/context/base/node-tra.lua
index 83340331b..d293fdeb1 100644
--- a/tex/context/base/node-tra.lua
+++ b/tex/context/base/node-tra.lua
@@ -31,6 +31,7 @@ local vlist   = node.id('vlist')
 local disc    = node.id('disc')
 local glue    = node.id('glue')
 local kern    = node.id('kern')
+local rule    = node.id('rule')
 local whatsit = node.id('whatsit')
 
 local copy_node_list  = node.copy_list
@@ -347,6 +348,12 @@ function nodes.tosequence(start,stop,compact)
                 end
             elseif id == whatsit and start.subtype == 6 or start.subtype == 7 then
                 t[#t+1] = "[" .. start.dir .. "]"
+            elseif id == rule then
+                if compact then
+                    t[#t+1] = "|"
+                else
+                    t[#t+1] = node_type(id)
+                end
             else
                 if compact then
                     t[#t+1] = "[]"
diff --git a/tex/context/base/node-tst.lua b/tex/context/base/node-tst.lua
index b8154d9d6..d7ea96f26 100644
--- a/tex/context/base/node-tst.lua
+++ b/tex/context/base/node-tst.lua
@@ -17,12 +17,12 @@ local find_node_tail = node.tail or node.slide
 
 local chardata = characters.data
 
-function nodes.leftskip(n)
+function nodes.the_left_margin(n) -- todo: three values
     while n do
         local id = n.id
         if id == glue then
             if n.subtype == 8 then -- 7 in c/web source
-                return (n.spec and n.spec.width) or 0
+                return n.spec.width
             else
                 return 0
             end
@@ -37,14 +37,14 @@ function nodes.leftskip(n)
     return 0
 end
 
-function nodes.rightskip(n)
+function nodes.the_right_margin(n)
     if n then
         n = find_node_tail(n)
         while n do
             local id = n.id
             if id == glue then
                 if n.subtype == 9 then -- 8 in the c/web source
-                    return (n.spec and n.spec.width) or 0
+                    return n.spec.width
                 else
                     return 0
                 end
diff --git a/tex/context/base/page-lin.lua b/tex/context/base/page-lin.lua
index 444210428..b090dd4a2 100644
--- a/tex/context/base/page-lin.lua
+++ b/tex/context/base/page-lin.lua
@@ -138,7 +138,7 @@ function nodes.lines.boxed.setup(n,configuration)
     return n
 end
 
-local leftskip = nodes.leftskip
+local the_left_margin = nodes.the_left_margin
 
 local function check_number(n,a,skip) -- move inline
     local d = data[a]
@@ -147,7 +147,7 @@ local function check_number(n,a,skip) -- move inline
         current_list[#current_list+1] = { n, s }
         if not skip and s % d.step == 0 then
             local tag = d.tag or ""
-            texsprint(ctxcatcodes, format("\\makenumber{%s}{%s}{%s}{%s}{%s}\\endgraf", tag, s, n.shift, n.width, leftskip(n.list)))
+            texsprint(ctxcatcodes, format("\\makenumber{%s}{%s}{%s}{%s}{%s}\\endgraf", tag, s, n.shift, n.width, the_left_margin(n.list)))
             if trace_numbers then
                 logs.report("numbers","making number %s for setup %s: %s (%s)",#current_list,a,s,d.continue or "no")
             end
diff --git a/tex/context/base/sort-lan.lua b/tex/context/base/sort-lan.lua
index e84c81397..ab04077e8 100644
--- a/tex/context/base/sort-lan.lua
+++ b/tex/context/base/sort-lan.lua
@@ -154,7 +154,7 @@ sorters.mappings['cz'] = {
     ['w']        = 36, -- w
     ['x']        = 37, -- x
     ['y']        = 38, -- y
-    ['z']        = 49, -- z
+    ['z']        = 39, -- z
     [uc(0x017E)] = 40, -- zcaron
 }
 
diff --git a/tex/context/base/spac-ver.lua b/tex/context/base/spac-ver.lua
index 5acfd7dbb..9d4b8ac18 100644
--- a/tex/context/base/spac-ver.lua
+++ b/tex/context/base/spac-ver.lua
@@ -242,14 +242,24 @@ local function snap_hlist(current,method,height,depth) -- method.strut is defaul
     return h, d, ch, cd, (ch+cd)/snaphtdp
 end
 
+--~ local function snap_topskip(current,method)
+--~     local spec = current.spec
+--~     local w = spec.width
+--~     local wd = w
+--~     if spec then
+--~         wd = 0
+--~         spec = writable_spec(current)
+--~         spec.width = wd
+--~     end
+--~     return w, wd
+--~ end
+
 local function snap_topskip(current,method)
     local spec = current.spec
     local w = spec.width
     local wd = w
-    if spec then
-        wd = 0
-        spec = writable_spec(current)
-        spec.width = wd
+    if spec.writable then
+        spec.width, wd = 0, 0
     end
     return w, wd
 end
@@ -397,23 +407,19 @@ local trace_list, tracing_info, before, after = { }, false, "", ""
 
 local function glue_to_string(glue)
     local spec = glue.spec
-    if spec then
-        local t = { }
-        t[#t+1] = aux.strip_zeros(number.topoints(spec.width))
-        if spec.stretch_order and spec.stretch_order ~= 0 then
-            t[#t+1] = format("plus -%sfi%s",spec.stretch/65536,string.rep("l",math.abs(spec.stretch_order)-1))
-        elseif spec.stretch and spec.stretch ~= 0 then
-            t[#t+1] = format("plus %s",aux.strip_zeros(number.topoints(spec.stretch)))
-        end
-        if spec.shrink_order and spec.shrink_order ~= 0 then
-            t[#t+1] = format("minus -%sfi%s",spec.shrink/65536,string.rep("l",math.abs(spec.shrink_order)-1))
-        elseif spec.shrink and spec.shrink ~= 0 then
-            t[#t+1] = format("minus %s",aux.strip_zeros(number.topoints(spec.shrink)))
-        end
-        return concat(t," ")
-    else
-        return "[0pt]"
+    local t = { }
+    t[#t+1] = aux.strip_zeros(number.topoints(spec.width))
+    if spec.stretch_order and spec.stretch_order ~= 0 then
+        t[#t+1] = format("plus -%sfi%s",spec.stretch/65536,string.rep("l",math.abs(spec.stretch_order)-1))
+    elseif spec.stretch and spec.stretch ~= 0 then
+        t[#t+1] = format("plus %s",aux.strip_zeros(number.topoints(spec.stretch)))
+    end
+    if spec.shrink_order and spec.shrink_order ~= 0 then
+        t[#t+1] = format("minus -%sfi%s",spec.shrink/65536,string.rep("l",math.abs(spec.shrink_order)-1))
+    elseif spec.shrink and spec.shrink ~= 0 then
+        t[#t+1] = format("minus %s",aux.strip_zeros(number.topoints(spec.shrink)))
     end
+    return concat(t," ")
 end
 
 local function nodes_to_string(head)
@@ -424,11 +430,7 @@ local function nodes_to_string(head)
         if id == penalty then
             t[#t+1] = format("%s:%s",ty,current.penalty)
         elseif id == glue then
-            if current.spec then
-                t[#t+1] = format("%s:%s",ty,aux.strip_zeros(number.topoints(current.spec.width)))
-            else
-                t[#t+1] = format("%s:[0pt]",ty)
-            end
+            t[#t+1] = format("%s:%s",ty,aux.strip_zeros(number.topoints(current.spec.width)))
         elseif id == kern then
             t[#t+1] = format("%s:%s",ty,aux.strip_zeros(number.topoints(current.kern)))
         else
@@ -537,9 +539,10 @@ local skips = {
 }
 
 local free_glue_node = free_node
-local free_glue_spec = free_node
 local discard, largest, force, penalty, add, disable, nowhite, goback, together = 0, 1, 2, 3, 4, 5, 6, 7, 8
 
+--~ local function free_glue_node(n) free_node(n.spec) free_node(n) end
+
 function vspacing.snap_box(n,how)
     local sv = snapmethods[how]
     if sv then
@@ -602,10 +605,9 @@ local function collapser(head,where,what,trace,snap) -- maybe also pass tail
         if glue_data then
             if force_glue then
                 if trace then trace_done("flushed due to " .. why,glue_data) end
-                local spec = glue_data.spec
-                head, _ = forced_skip(head,current,(spec and spec.width) or 0,"before",trace)
+                head, _ = forced_skip(head,current,glue_data.spec.width,"before",trace)
                 free_glue_node(glue_data)
-            elseif glue_data.spec then
+            elseif glue_data.spec.writable then
                 if trace then trace_done("flushed due to " .. why,glue_data) end
                 head, _ = insert_node_before(head,current,glue_data)
             else
@@ -693,12 +695,12 @@ local function collapser(head,where,what,trace,snap) -- maybe also pass tail
                     local previous = current.prev
                     if previous and previous.id == glue and previous.subtype == 0 then
                         local ps = previous.spec
-                        if ps then
+                        if ps.writable then
                             local cs = current.spec
-                            if cs and ps.stretch_order == 0 and ps.shrink_order == 0 and cs.stretch_order == 0 and cs.shrink_order == 0 then
+                            if cs.writable and ps.stretch_order == 0 and ps.shrink_order == 0 and cs.stretch_order == 0 and cs.shrink_order == 0 then
                                 local pw, pp, pm = ps.width, ps.stretch, ps.shrink
                                 local cw, cp, cm = cs.width, cs.stretch, cs.shrink
-                                ps = writable_spec(previous)
+                                ps = writable_spec(previous) -- no writable needed here
                                 ps.width, ps.stretch, ps.shrink = pw + cw, pp + cp, pm + cm
                                 if trace then trace_natural("removed",current) end
                                 head, current = remove_node(head, current, true)
@@ -749,8 +751,7 @@ local function collapser(head,where,what,trace,snap) -- maybe also pass tail
                 -- is now exclusive, maybe support goback as combi, else why a set
                 if sc == largest then
                     local cs, gs = current.spec, glue_data.spec
-                    local cw = (cs and cs.width) or 0
-                    local gw = (gs and gs.width) or 0
+                    local cw, gw = cs.width, gs.width
                     if cw > gw then
                         if trace then trace_skip('largest',sc,so,sp,current) end
                         free_glue_node(glue_data) -- also free spec
@@ -800,9 +801,8 @@ local function collapser(head,where,what,trace,snap) -- maybe also pass tail
                 local s = has_attribute(current,snap_method)
                 if s and s ~= 0 then
                     set_attribute(current,snap_method,0)
-                    local spec = current.spec
-                    if spec then
-                        spec = writable_spec(current)
+                    if current.spec.writable then
+                        local spec = writable_spec(current)
                         spec.width = 0
                         if trace_vsnapping then
                             logs.report("snapper", "lineskip set to zero")
@@ -822,8 +822,8 @@ local function collapser(head,where,what,trace,snap) -- maybe also pass tail
                 local s = has_attribute(current,snap_method)
                 if s and s ~= 0 then
                     set_attribute(current,snap_method,0)
-                    local spec = current.spec
-                    if spec then
+                    if current.spec.writable then
+                        local spec = writable_spec(current)
                         spec.width = 0
                         if trace_vsnapping then
                             logs.report("snapper", "baselineskip set to zero")
@@ -845,7 +845,7 @@ local function collapser(head,where,what,trace,snap) -- maybe also pass tail
                 head, current = remove_node(head, current, true)
             elseif glue_data then
                 local ps, gs = current.spec, glue_data.spec
-                if ps and gs and ps.width > gs.width then
+                if ps.writable and gs.writable and ps.width > gs.width then
                     glue_data.spec = copy_node(ps)
                     if trace then trace_natural("taking parskip",current) end
                 else
@@ -900,7 +900,7 @@ local function collapser(head,where,what,trace,snap) -- maybe also pass tail
             current = current.next
             --
         else -- other glue
-            if snap and trace_vsnapping and current.spec and current.spec.width ~= 0 then
+            if snap and trace_vsnapping and current.spec.writable and current.spec.width ~= 0 then
                 logs.report("snapper", "%s of %s (kept)",skips[subtype],current.spec.width)
             --~ current.spec.width = 0
             end
diff --git a/tex/context/base/tabl-ntb.mkii b/tex/context/base/tabl-ntb.mkii
index 1f9a9d574..0bfcc20c6 100644
--- a/tex/context/base/tabl-ntb.mkii
+++ b/tex/context/base/tabl-ntb.mkii
@@ -1213,6 +1213,7 @@
        \fi
         \advance\xxrowTBL\plusone}%
      % distribute overshoot equally
+\ifdim\dimen2>\zeropoint % see natural-003
      \ifdim\dimen4<\dimen0
        \advance\dimen0 -\dimen4
        \divide\dimen0 \!!countb
@@ -1231,6 +1232,7 @@
      \else\ifdim\dimen4>\dimen0
        \settblhei\xrowTBL{\the\dimen2}%
      \fi\fi
+\fi
    \fi}
 
 \def\checktblheightsone
diff --git a/tex/context/base/tabl-ntb.mkiv b/tex/context/base/tabl-ntb.mkiv
index 796c09546..b2ac83aa5 100644
--- a/tex/context/base/tabl-ntb.mkiv
+++ b/tex/context/base/tabl-ntb.mkiv
@@ -1237,26 +1237,28 @@
        \fi
         \advance\xxrowTBL\plusone}%
      % distribute overshoot equally
-     \ifdim\dimen4<\dimen0
-       \advance\dimen0 -\dimen4
-       \divide\dimen0 \!!countb
-       \xxrowTBL\xrowTBL
-       \settblhei\xrowTBL{\the\dimen2}%
-       \dorecurse\!!countb
-         {\dorecurse\maximumcol
-            {\ifnum\recurselevel=\xcolTBL\else
-               \scratchdimen\dimexpr\gettblht\xxrowTBL\recurselevel+\dimen0\relax
-               \settblht\xxrowTBL\recurselevel{\the\scratchdimen}%
-               \ifdim\gettblhei\xxrowTBL<\scratchdimen
-                 \settblhei\xxrowTBL{\the\scratchdimen}%
-               \fi
-             \fi}%
-          \advance\xxrowTBL\plusone}%
-     \else\ifdim\dimen4>\dimen0
-        \iftightTBLrowspan
-          \settblhei\xrowTBL{\the\dimen2}%
-        \fi
-     \fi\fi
+     \ifdim\dimen2>\zeropoint % new: test on natural-003
+       \ifdim\dimen4<\dimen0
+         \advance\dimen0 -\dimen4
+         \divide\dimen0 \!!countb
+         \xxrowTBL\xrowTBL
+         \settblhei\xrowTBL{\the\dimen2}%
+         \dorecurse\!!countb
+           {\dorecurse\maximumcol
+              {\ifnum\recurselevel=\xcolTBL\else
+                 \scratchdimen\dimexpr\gettblht\xxrowTBL\recurselevel+\dimen0\relax
+                 \settblht\xxrowTBL\recurselevel{\the\scratchdimen}%
+                 \ifdim\gettblhei\xxrowTBL<\scratchdimen
+                   \settblhei\xxrowTBL{\the\scratchdimen}%
+                 \fi
+               \fi}%
+            \advance\xxrowTBL\plusone}%
+       \else\ifdim\dimen4>\dimen0
+         \iftightTBLrowspan
+           \settblhei\xrowTBL{\the\dimen2}%
+         \fi
+       \fi\fi
+     \fi
    \fi}
 
 \def\checktblheightsone
diff --git a/tex/context/base/typo-krn.lua b/tex/context/base/typo-krn.lua
index 3de601911..6fe345953 100644
--- a/tex/context/base/typo-krn.lua
+++ b/tex/context/base/typo-krn.lua
@@ -6,6 +6,8 @@ if not modules then modules = { } end modules ['typo-krn'] = {
     license   = "see context related readme files"
 }
 
+-- todo: insertbefore etc
+
 local utf = unicode.utf8
 
 local next, type = next, type
diff --git a/tex/generic/context/luatex-fonts-merged.lua b/tex/generic/context/luatex-fonts-merged.lua
index 514a4e077..aac55170c 100644
--- a/tex/generic/context/luatex-fonts-merged.lua
+++ b/tex/generic/context/luatex-fonts-merged.lua
@@ -1,6 +1,6 @@
 -- merged file : luatex-fonts-merged.lua
 -- parent file : luatex-fonts.lua
--- merge date  : 03/20/10 22:59:11
+-- merge date  : 03/25/10 23:12:19
 
 do -- begin closure to overcome local limits and interference
 
@@ -2237,10 +2237,12 @@ local penalty = node.id('penalty')
 local kern    = node.id('kern')
 local whatsit = node.id('whatsit')
 
-local traverse_id = node.traverse_id
-local traverse    = node.traverse
-local free_node   = node.free
-local remove_node = node.remove
+local traverse_id        = node.traverse_id
+local traverse           = node.traverse
+local free_node          = node.free
+local remove_node        = node.remove
+local insert_node_before = node.insert_before
+local insert_node_after  = node.insert_after
 
 function nodes.remove(head, current, free_too)
    local t = current
@@ -2260,8 +2262,8 @@ function nodes.delete(head,current)
     return nodes.remove(head,current,true)
 end
 
-nodes.before = node.insert_before
-nodes.after  = node.insert_after
+nodes.before = insert_node_before
+nodes.after  = insert_node_after
 
 -- we need to test this, as it might be fixed now
 
@@ -2301,21 +2303,31 @@ function nodes.after(h,c,n)
     return n, n
 end
 
-function nodes.replace(head,current,new)
-    if current and next then
-        local p, n = current.prev, current.next
-        new.prev, new.next = p, n
-        if p then
-            p.next = new
-        else
+-- local h, c = nodes.replace(head,current,new)
+-- local c = nodes.replace(false,current,new)
+-- local c = nodes.replace(current,new)
+
+function nodes.replace(head,current,new) -- no head returned if false
+    if not new then
+        head, current, new = false, head, current
+    end
+    local prev, next = current.prev, current.next
+    if next then
+        new.next, next.prev = next, new
+    end
+    if prev then
+        new.prev, prev.next = prev, new
+    end
+    if head then
+        if head == current then
             head = new
         end
-        if n then
-            n.prev = new
-        end
         free_node(current)
+        return head, new
+    else
+        free_node(current)
+        return new
     end
-    return head, current
 end
 
 -- will move
@@ -2373,7 +2385,10 @@ if not modules then modules = { } end modules ['node-res'] = {
 }
 
 local gmatch, format = string.gmatch, string.format
-local copy_node, free_node, free_list, new_node = node.copy, node.free, node.flush_list, node.new
+local copy_node, free_node, free_list, new_node, node_type, node_id = node.copy, node.free, node.flush_list, node.new, node.type, node.id
+local tonumber, round = tonumber, math.round
+
+local glyph_node = node_id("glyph")
 
 --[[ldx--
 <p>The next function is not that much needed but in <l n='context'/> we use
@@ -2391,16 +2406,21 @@ for k, v in pairs(node.whatsits()) do
     whatsits[k], whatsits[v] = v, k -- two way
 end
 
-function nodes.register(n)
+local function register_node(n)
     reserved[#reserved+1] = n
     return n
 end
 
+nodes.register = register_node
+
 function nodes.cleanup_reserved(nofboxes) -- todo
     nodes.tracers.steppers.reset() -- todo: make a registration subsystem
     local nr, nl = #reserved, 0
     for i=1,nr do
-        free_node(reserved[i])
+        local ri = reserved[i]
+    --  if not (ri.id == glue_spec and not ri.is_writable) then
+            free_node(reserved[i])
+    --  end
     end
     if nofboxes then
         local tb = tex.box
@@ -2424,19 +2444,37 @@ function nodes.usage()
     return t
 end
 
-local disc       = nodes.register(new_node("disc"))
-local kern       = nodes.register(new_node("kern",1))
-local penalty    = nodes.register(new_node("penalty"))
-local glue       = nodes.register(new_node("glue"))
-local glue_spec  = nodes.register(new_node("glue_spec"))
-local glyph      = nodes.register(new_node("glyph",0))
-local textdir    = nodes.register(new_node("whatsit",whatsits.dir)) -- 7 (6 is local par node)
-local rule       = nodes.register(new_node("rule"))
-local latelua    = nodes.register(new_node("whatsit",whatsits.late_lua)) -- 35
-local user_n     = nodes.register(new_node("whatsit",whatsits.user_defined)) user_n.type = 100 -- 44
-local user_l     = nodes.register(new_node("whatsit",whatsits.user_defined)) user_l.type = 110 -- 44
-local user_s     = nodes.register(new_node("whatsit",whatsits.user_defined)) user_s.type = 115 -- 44
-local user_t     = nodes.register(new_node("whatsit",whatsits.user_defined)) user_t.type = 116 -- 44
+local disc              = register_node(new_node("disc"))
+local kern              = register_node(new_node("kern",1))
+local penalty           = register_node(new_node("penalty"))
+local glue              = register_node(new_node("glue")) -- glue.spec = nil
+local glue_spec         = register_node(new_node("glue_spec"))
+local glyph             = register_node(new_node("glyph",0))
+local textdir           = register_node(new_node("whatsit",whatsits.dir)) -- 7 (6 is local par node)
+local rule              = register_node(new_node("rule"))
+local latelua           = register_node(new_node("whatsit",whatsits.late_lua)) -- 35
+local user_n            = register_node(new_node("whatsit",whatsits.user_defined)) user_n.type = 100 -- 44
+local user_l            = register_node(new_node("whatsit",whatsits.user_defined)) user_l.type = 110 -- 44
+local user_s            = register_node(new_node("whatsit",whatsits.user_defined)) user_s.type = 115 -- 44
+local user_t            = register_node(new_node("whatsit",whatsits.user_defined)) user_t.type = 116 -- 44
+local left_margin_kern  = register_node(new_node("margin_kern",0))
+local right_margin_kern = register_node(new_node("margin_kern",1))
+local lineskip          = register_node(new_node("glue",1))
+local baselineskip      = register_node(new_node("glue",2))
+local leftskip          = register_node(new_node("glue",8))
+local rightskip         = register_node(new_node("glue",9))
+local temp              = register_node(new_node("temp",0))
+
+function nodes.zeroglue(n)
+    local s = n.spec
+    return not writable or (
+                     s.width == 0
+         and       s.stretch == 0
+         and        s.shrink == 0
+         and s.stretch_order == 0
+         and  s.shrink_order == 0
+        )
+end
 
 function nodes.glyph(fnt,chr)
     local n = copy_node(glyph)
@@ -2444,48 +2482,114 @@ function nodes.glyph(fnt,chr)
     if chr then n.char = chr end
     return n
 end
+
 function nodes.penalty(p)
     local n = copy_node(penalty)
     n.penalty = p
     return n
 end
+
 function nodes.kern(k)
     local n = copy_node(kern)
     n.kern = k
     return n
 end
-function nodes.glue(width,stretch,shrink)
-    local n, s = copy_node(glue), copy_node(glue_spec)
-    s.width, s.stretch, s.shrink = width, stretch, shrink
-    n.spec = s
-    return n
-end
+
 function nodes.glue_spec(width,stretch,shrink)
     local s = copy_node(glue_spec)
     s.width, s.stretch, s.shrink = width, stretch, shrink
     return s
 end
+
+local function someskip(skip,width,stretch,shrink)
+    local n = copy_node(skip)
+    if not width then
+        -- no spec
+    elseif tonumber(width) then
+        local s = copy_node(glue_spec)
+        s.width, s.stretch, s.shrink = width, stretch, shrink
+        n.spec = s
+    else
+        -- shared
+        n.spec = copy_node(width)
+    end
+    return n
+end
+
+function nodes.glue(width,stretch,shrink)
+    return someskip(glue,width,stretch,shrink)
+end
+function nodes.leftskip(width,stretch,shrink)
+    return someskip(leftskip,width,stretch,shrink)
+end
+function nodes.rightskip(width,stretch,shrink)
+    return someskip(rightskip,width,stretch,shrink)
+end
+function nodes.lineskip(width,stretch,shrink)
+    return someskip(lineskip,width,stretch,shrink)
+end
+function nodes.baselineskip(width,stretch,shrink)
+    return someskip(baselineskip,width,stretch,shrink)
+end
+
 function nodes.disc()
     return copy_node(disc)
 end
+
 function nodes.textdir(dir)
     local t = copy_node(textdir)
     t.dir = dir
     return t
 end
-function nodes.rule(w,h,d)
+
+function nodes.rule(width,height,depth,dir)
     local n = copy_node(rule)
-    if w then n.width  = w end
-    if h then n.height = h end
-    if d then n.depth  = d end
+    if width  then n.width  = width  end
+    if height then n.height = height end
+    if depth  then n.depth  = depth  end
+    if dir    then n.dir    = dir    end
     return n
 end
+
 function nodes.latelua(code)
     local n = copy_node(latelua)
     n.data = code
     return n
 end
 
+function nodes.leftmarginkern(glyph,width)
+    local n = copy_node(left_margin_kern)
+    if not glyph then
+        logs.fatal("nodes","invalid pointer to left margin glyph node")
+    elseif glyph.id ~= glyph_node then
+        logs.fatal("nodes","invalid node type %s for left margin glyph node",node_type(glyph))
+    else
+        n.glyph = glyph
+    end
+    if width then
+        n.width = width
+    end
+    return n
+end
+
+function nodes.rightmarginkern(glyph,width)
+    local n = copy_node(right_margin_kern)
+    if not glyph then
+        logs.fatal("nodes","invalid pointer to right margin glyph node")
+    elseif glyph.id ~= glyph_node then
+        logs.fatal("nodes","invalid node type %s for right margin glyph node",node_type(p))
+    else
+        n.glyph = glyph
+    end
+    if width then
+        n.width = width
+    end
+    return n
+end
+
+function nodes.temp()
+    return copy_node(temp)
+end
 --[[
 <p>At some point we ran into a problem that the glue specification
 of the zeropoint dimension was overwritten when adapting a glue spec
@@ -10501,6 +10605,8 @@ local insert_node_after  = node.insert_after
 local insert_node_before = node.insert_before
 local traverse_node_list = node.traverse
 
+local new_glue_node      = nodes.glue
+
 local fontdata = fonts.ids
 local state    = attributes.private('state')
 
@@ -10762,11 +10868,12 @@ function fonts.analyzers.methods.arab(head,font,attr) -- maybe make a special ve
     end
     first, last = finish(first,last)
     if removejoiners then
+        -- is never head
         for i=1,#joiners do
-            head = delete_node(head,joiners[i])
+            delete_node(head,joiners[i])
         end
         for i=1,#nonjoiners do
-            head = replace_node(head,nonjoiners[i],nodes.glue(0)) -- or maybe a kern
+            replace_node(head,nonjoiners[i],new_glue_node(0)) -- or maybe a kern
         end
     end
     return head, done