beta 2013.01.23 14:04

1 files changed, 98 insertions, 121 deletions

diff --git a/tex/generic/context/luatex/luatex-fonts-merged.lua b/tex/generic/context/luatex/luatex-fonts-merged.lua
index 7b2b0a282..5cb8bcf49 100644
--- a/tex/generic/context/luatex/luatex-fonts-merged.lua
+++ b/tex/generic/context/luatex/luatex-fonts-merged.lua
@@ -1,6 +1,6 @@
 -- merged file : luatex-fonts-merged.lua
 -- parent file : luatex-fonts.lua
--- merge date  : 01/22/13 18:33:20
+-- merge date  : 01/23/13 14:04:19
 
 do -- begin closure to overcome local limits and interference
 
@@ -5793,7 +5793,7 @@ local otf                = fonts.handlers.otf
 
 otf.glists               = { "gsub", "gpos" }
 
-otf.version              = 2.740 -- beware: also sync font-mis.lua
+otf.version              = 2.741 -- beware: also sync font-mis.lua
 otf.cache                = containers.define("fonts", "otf", otf.version, true)
 
 local fontdata           = fonts.hashes.identifiers
@@ -6982,7 +6982,7 @@ actions["reorganize lookups"] = function(data,filename,raw) -- we could check fo
                             for i=1,#current do
                                 current[i] = current_class[current[i]] or { }
                                 if lookups and not lookups[i] then
-                                    lookups[i] = false -- e.g. we can have two lookups and one replacement
+                                    lookups[i] = "" -- (was: false) e.g. we can have two lookups and one replacement
                                 end
                             end
                             rule.current = t_hashed(current,t_h_cache)
@@ -8493,6 +8493,7 @@ if not modules then modules = { } end modules ['node-inj'] = {
 -- that can be of help. Some optimizations can go away when we have faster machines.
 
 local next = next
+local utfchar = utf.char
 
 local trace_injections = false  trackers.register("nodes.injections", function(v) trace_injections = v end)
 
@@ -8626,7 +8627,8 @@ local function trace(head)
             local md = n[a_markdone]
             local cb = n[a_cursbase]
             local cc = n[a_curscurs]
-            report_injections("char U+%05X, font=%s",n.char,n.font)
+            local char = n.char
+            report_injections("char U+%05X, font %s, glyph %s",char,n.font,utfchar(char))
             if kp then
                 local k = kerns[kp]
                 if k[3] then
@@ -9585,8 +9587,7 @@ local onetimemessage     = fonts.loggers.onetimemessage
 
 otf.defaultnodealternate = "none" -- first last
 
--- we share some vars here, after all, we have no nested lookups and
--- less code
+-- we share some vars here, after all, we have no nested lookups and less code
 
 local tfmdata             = false
 local characters          = false
@@ -9814,12 +9815,12 @@ local function toligature(kind,lookupname,start,stop,char,markflag,discfound) --
     return base
 end
 
-function handlers.gsub_single(start,kind,lookupname,replacement)
+function handlers.gsub_single(head,start,kind,lookupname,replacement)
     if trace_singles then
         logprocess("%s: replacing %s by single %s",pref(kind,lookupname),gref(start.char),gref(replacement))
     end
     start.char = replacement
-    return start, true
+    return head, start, true
 end
 
 local function get_alternative_glyph(start,alternatives,value)
@@ -9859,7 +9860,7 @@ local function get_alternative_glyph(start,alternatives,value)
     return choice
 end
 
-local function multiple_glyphs(start,multiple) -- marks ?
+local function multiple_glyphs(head,start,multiple) -- marks ?
     local nofmultiples = #multiple
     if nofmultiples > 0 then
         start.char = multiple[1]
@@ -9877,16 +9878,16 @@ local function multiple_glyphs(start,multiple) -- marks ?
                 start = n
             end
         end
-        return start, true
+        return head, start, true
     else
         if trace_multiples then
             logprocess("no multiple for %s",gref(start.char))
         end
-        return start, false
+        return head, start, false
     end
 end
 
-function handlers.gsub_alternate(start,kind,lookupname,alternative,sequence)
+function handlers.gsub_alternate(head,start,kind,lookupname,alternative,sequence)
     local value  = featurevalue == true and tfmdata.shared.features[kind] or featurevalue
     local choice = get_alternative_glyph(start,alternative,value)
     if choice then
@@ -9899,17 +9900,17 @@ function handlers.gsub_alternate(start,kind,lookupname,alternative,sequence)
             logwarning("%s: no variant %s for %s",pref(kind,lookupname),tostring(value),gref(start.char))
         end
     end
-    return start, true
+    return head, start, true
 end
 
-function handlers.gsub_multiple(start,kind,lookupname,multiple)
+function handlers.gsub_multiple(head,start,kind,lookupname,multiple)
     if trace_multiples then
         logprocess("%s: replacing %s by multiple %s",pref(kind,lookupname),gref(start.char),gref(multiple))
     end
-    return multiple_glyphs(start,multiple)
+    return multiple_glyphs(head,start,multiple)
 end
 
-function handlers.gsub_ligature(start,kind,lookupname,ligature,sequence)
+function handlers.gsub_ligature(head,start,kind,lookupname,ligature,sequence)
     local s, stop, discfound = start.next, nil, false
     local startchar = start.char
     if marks[startchar] then
@@ -9938,7 +9939,7 @@ function handlers.gsub_ligature(start,kind,lookupname,ligature,sequence)
                 else
                     start = markstoligature(kind,lookupname,start,stop,lig)
                 end
-                return start, true
+                return head, start, true
             else
                 -- ok, goto next lookup
             end
@@ -9982,13 +9983,13 @@ function handlers.gsub_ligature(start,kind,lookupname,ligature,sequence)
                 else
                     start = toligature(kind,lookupname,start,stop,lig,skipmark,discfound)
                 end
-                return start, true
+                return head, start, true
             else
                 -- ok, goto next lookup
             end
         end
     end
-    return start, false
+    return head, start, false
 end
 
 --[[ldx--
@@ -9996,7 +9997,7 @@ end
 we need to explicitly test for basechar, baselig and basemark entries.</p>
 --ldx]]--
 
-function handlers.gpos_mark2base(start,kind,lookupname,markanchors,sequence)
+function handlers.gpos_mark2base(head,start,kind,lookupname,markanchors,sequence)
     local markchar = start.char
     if marks[markchar] then
         local base = start.prev -- [glyph] [start=mark]
@@ -10014,7 +10015,7 @@ function handlers.gpos_mark2base(start,kind,lookupname,markanchors,sequence)
                         if trace_bugs then
                             logwarning("%s: no base for mark %s",pref(kind,lookupname),gref(markchar))
                         end
-                        return start, false
+                        return head, start, false
                     end
                 end
             end
@@ -10035,7 +10036,7 @@ function handlers.gpos_mark2base(start,kind,lookupname,markanchors,sequence)
                                     logprocess("%s, anchor %s, bound %s: anchoring mark %s to basechar %s => (%s,%s)",
                                         pref(kind,lookupname),anchor,bound,gref(markchar),gref(basechar),dx,dy)
                                 end
-                                return start, true
+                                return head, start, true
                             end
                         end
                     end
@@ -10053,10 +10054,10 @@ function handlers.gpos_mark2base(start,kind,lookupname,markanchors,sequence)
     elseif trace_bugs then
         logwarning("%s: mark %s is no mark",pref(kind,lookupname),gref(markchar))
     end
-    return start, false
+    return head, start, false
 end
 
-function handlers.gpos_mark2ligature(start,kind,lookupname,markanchors,sequence)
+function handlers.gpos_mark2ligature(head,start,kind,lookupname,markanchors,sequence)
     -- check chainpos variant
     local markchar = start.char
     if marks[markchar] then
@@ -10075,7 +10076,7 @@ function handlers.gpos_mark2ligature(start,kind,lookupname,markanchors,sequence)
                         if trace_bugs then
                             logwarning("%s: no base for mark %s",pref(kind,lookupname),gref(markchar))
                         end
-                        return start, false
+                        return head, start, false
                     end
                 end
             end
@@ -10098,7 +10099,7 @@ function handlers.gpos_mark2ligature(start,kind,lookupname,markanchors,sequence)
                                             logprocess("%s, anchor %s, index %s, bound %s: anchoring mark %s to baselig %s at index %s => (%s,%s)",
                                                 pref(kind,lookupname),anchor,index,bound,gref(markchar),gref(basechar),index,dx,dy)
                                         end
-                                        return start, true
+                                        return head, start, true
                                     end
                                 end
                             end
@@ -10118,10 +10119,10 @@ function handlers.gpos_mark2ligature(start,kind,lookupname,markanchors,sequence)
     elseif trace_bugs then
         logwarning("%s: mark %s is no mark",pref(kind,lookupname),gref(markchar))
     end
-    return start, false
+    return head, start, false
 end
 
-function handlers.gpos_mark2mark(start,kind,lookupname,markanchors,sequence)
+function handlers.gpos_mark2mark(head,start,kind,lookupname,markanchors,sequence)
     local markchar = start.char
     if marks[markchar] then
         local base = start.prev -- [glyph] [basemark] [start=mark]
@@ -10154,7 +10155,7 @@ function handlers.gpos_mark2mark(start,kind,lookupname,markanchors,sequence)
                                         logprocess("%s, anchor %s, bound %s: anchoring mark %s to basemark %s => (%s,%s)",
                                             pref(kind,lookupname),anchor,bound,gref(markchar),gref(basechar),dx,dy)
                                     end
-                                    return start,true
+                                    return head, start, true
                                 end
                             end
                         end
@@ -10173,10 +10174,10 @@ function handlers.gpos_mark2mark(start,kind,lookupname,markanchors,sequence)
     elseif trace_bugs then
         logwarning("%s: mark %s is no mark",pref(kind,lookupname),gref(markchar))
     end
-    return start,false
+    return head, start, false
 end
 
-function handlers.gpos_cursive(start,kind,lookupname,exitanchors,sequence) -- to be checked
+function handlers.gpos_cursive(head,start,kind,lookupname,exitanchors,sequence) -- to be checked
     local alreadydone = cursonce and start[a_cursbase]
     if not alreadydone then
         local done = false
@@ -10223,30 +10224,30 @@ function handlers.gpos_cursive(start,kind,lookupname,exitanchors,sequence) -- to
                 end
             end
         end
-        return start, done
+        return head, start, done
     else
         if trace_cursive and trace_details then
             logprocess("%s, cursive %s is already done",pref(kind,lookupname),gref(start.char),alreadydone)
         end
-        return start, false
+        return head, start, false
     end
 end
 
-function handlers.gpos_single(start,kind,lookupname,kerns,sequence)
+function handlers.gpos_single(head,start,kind,lookupname,kerns,sequence)
     local startchar = start.char
     local dx, dy, w, h = setpair(start,tfmdata.parameters.factor,rlmode,sequence.flags[4],kerns,characters[startchar])
     if trace_kerns then
         logprocess("%s: shifting single %s by (%s,%s) and correction (%s,%s)",pref(kind,lookupname),gref(startchar),dx,dy,w,h)
     end
-    return start, false
+    return head, start, false
 end
 
-function handlers.gpos_pair(start,kind,lookupname,kerns,sequence)
+function handlers.gpos_pair(head,start,kind,lookupname,kerns,sequence)
     -- todo: kerns in disc nodes: pre, post, replace -> loop over disc too
     -- todo: kerns in components of ligatures
     local snext = start.next
     if not snext then
-        return start, false
+        return head, start, false
     else
         local prev, done = start, false
         local factor = tfmdata.parameters.factor
@@ -10302,7 +10303,7 @@ function handlers.gpos_pair(start,kind,lookupname,kerns,sequence)
                 break
             end
         end
-        return start, done
+        return head, start, done
     end
 end
 
@@ -10335,21 +10336,21 @@ local logwarning = report_chain
 -- We could share functions but that would lead to extra function calls with many
 -- arguments, redundant tests and confusing messages.
 
-function chainprocs.chainsub(start,stop,kind,chainname,currentcontext,lookuphash,lookuplist,chainlookupname)
+function chainprocs.chainsub(head,start,stop,kind,chainname,currentcontext,lookuphash,lookuplist,chainlookupname)
     logwarning("%s: a direct call to chainsub cannot happen",cref(kind,chainname,chainlookupname))
-    return start, false
+    return head, start, false
 end
 
-function chainmores.chainsub(start,stop,kind,chainname,currentcontext,lookuphash,lookuplist,chainlookupname,n)
+function chainmores.chainsub(head,start,stop,kind,chainname,currentcontext,lookuphash,lookuplist,chainlookupname,n)
     logprocess("%s: a direct call to chainsub cannot happen",cref(kind,chainname,chainlookupname))
-    return start, false
+    return head, start, false
 end
 
 -- The reversesub is a special case, which is why we need to store the replacements
 -- in a bit weird way. There is no lookup and the replacement comes from the lookup
 -- itself. It is meant mostly for dealing with Urdu.
 
-function chainprocs.reversesub(start,stop,kind,chainname,currentcontext,lookuphash,replacements)
+function chainprocs.reversesub(head,start,stop,kind,chainname,currentcontext,lookuphash,replacements)
     local char = start.char
     local replacement = replacements[char]
     if replacement then
@@ -10357,9 +10358,9 @@ function chainprocs.reversesub(start,stop,kind,chainname,currentcontext,lookupha
             logprocess("%s: single reverse replacement of %s by %s",cref(kind,chainname),gref(char),gref(replacement))
         end
         start.char = replacement
-        return start, true
+        return head, start, true
     else
-        return start, false
+        return head, start, false
     end
 end
 
@@ -10387,10 +10388,10 @@ local function delete_till_stop(start,stop,ignoremarks) -- keeps start
         repeat -- start x x m x x stop => start m
             local next = start.next
             if not marks[next.char] then
-local components = next.components
-if components then -- probably not needed
-    flush_node_list(components)
-end
+                local components = next.components
+                if components then -- probably not needed
+                    flush_node_list(components)
+                end
                 delete_node(start,next)
             end
             n = n + 1
@@ -10398,10 +10399,10 @@ end
     else -- start x x x stop => start
         repeat
             local next = start.next
-local components = next.components
-if components then -- probably not needed
-    flush_node_list(components)
-end
+            local components = next.components
+            if components then -- probably not needed
+                flush_node_list(components)
+            end
             delete_node(start,next)
             n = n + 1
         until next == stop
@@ -10414,7 +10415,7 @@ end
 match.</p>
 --ldx]]--
 
-function chainprocs.gsub_single(start,stop,kind,chainname,currentcontext,lookuphash,currentlookup,chainlookupname,chainindex)
+function chainprocs.gsub_single(head,start,stop,kind,chainname,currentcontext,lookuphash,currentlookup,chainlookupname,chainindex)
     -- todo: marks ?
     local current = start
     local subtables = currentlookup.subtables
@@ -10432,7 +10433,7 @@ function chainprocs.gsub_single(start,stop,kind,chainname,currentcontext,lookuph
                 end
             else
                 replacement = replacement[currentchar]
-                if not replacement then
+                if not replacement or replacement == "" then
                     if trace_bugs then
                         logwarning("%s: no single for %s",cref(kind,chainname,chainlookupname,lookupname,chainindex),gref(currentchar))
                     end
@@ -10443,14 +10444,14 @@ function chainprocs.gsub_single(start,stop,kind,chainname,currentcontext,lookuph
                     current.char = replacement
                 end
             end
-            return start, true
+            return head, start, true
         elseif current == stop then
             break
         else
             current = current.next
         end
     end
-    return start, false
+    return head, start, false
 end
 
 chainmores.gsub_single = chainprocs.gsub_single
@@ -10460,7 +10461,7 @@ chainmores.gsub_single = chainprocs.gsub_single
 the match.</p>
 --ldx]]--
 
-function chainprocs.gsub_multiple(start,stop,kind,chainname,currentcontext,lookuphash,currentlookup,chainlookupname)
+function chainprocs.gsub_multiple(head,start,stop,kind,chainname,currentcontext,lookuphash,currentlookup,chainlookupname)
     delete_till_stop(start,stop) -- we could pass ignoremarks as #3 ..
     local startchar = start.char
     local subtables = currentlookup.subtables
@@ -10472,7 +10473,7 @@ function chainprocs.gsub_multiple(start,stop,kind,chainname,currentcontext,looku
         end
     else
         replacements = replacements[startchar]
-        if not replacements then
+        if not replacements or replacement == "" then
             if trace_bugs then
                 logwarning("%s: no multiple for %s",cref(kind,chainname,chainlookupname,lookupname),gref(startchar))
             end
@@ -10480,17 +10481,12 @@ function chainprocs.gsub_multiple(start,stop,kind,chainname,currentcontext,looku
             if trace_multiples then
                 logprocess("%s: replacing %s by multiple characters %s",cref(kind,chainname,chainlookupname,lookupname),gref(startchar),gref(replacements))
             end
-            return multiple_glyphs(start,replacements)
+            return multiple_glyphs(head,start,replacements)
         end
     end
-    return start, false
+    return head, start, false
 end
 
--- function chainmores.gsub_multiple(start,stop,kind,chainname,currentcontext,lookuphash,currentlookup,chainlookupname,n)
---     logprocess("%s: gsub_multiple not yet supported",cref(kind,chainname,chainlookupname))
---     return start, false
--- end
-
 chainmores.gsub_multiple = chainprocs.gsub_multiple
 
 --[[ldx--
@@ -10505,7 +10501,7 @@ chainmores.gsub_multiple = chainprocs.gsub_multiple
 -- marks come last anyway
 -- are there cases where we need to delete the mark
 
-function chainprocs.gsub_alternate(start,stop,kind,chainname,currentcontext,lookuphash,currentlookup,chainlookupname)
+function chainprocs.gsub_alternate(head,start,stop,kind,chainname,currentcontext,lookuphash,currentlookup,chainlookupname)
     local current = start
     local subtables = currentlookup.subtables
     local value  = featurevalue == true and tfmdata.shared.features[kind] or featurevalue
@@ -10536,21 +10532,16 @@ function chainprocs.gsub_alternate(start,stop,kind,chainname,currentcontext,look
                     logwarning("%s: no alternative for %s",cref(kind,chainname,chainlookupname,lookupname),gref(currentchar))
                 end
             end
-            return start, true
+            return head, start, true
         elseif current == stop then
             break
         else
             current = current.next
         end
     end
-    return start, false
+    return head, start, false
 end
 
--- function chainmores.gsub_alternate(start,stop,kind,chainname,currentcontext,lookuphash,currentlookup,chainlookupname,n)
---     logprocess("%s: gsub_alternate not yet supported",cref(kind,chainname,chainlookupname))
---     return start, false
--- end
-
 chainmores.gsub_alternate = chainprocs.gsub_alternate
 
 --[[ldx--
@@ -10559,7 +10550,7 @@ this function (move code inline and handle the marks by a separate function). We
 assume rather stupid ligatures (no complex disc nodes).</p>
 --ldx]]--
 
-function chainprocs.gsub_ligature(start,stop,kind,chainname,currentcontext,lookuphash,currentlookup,chainlookupname,chainindex)
+function chainprocs.gsub_ligature(head,start,stop,kind,chainname,currentcontext,lookuphash,currentlookup,chainlookupname,chainindex)
     local startchar = start.char
     local subtables = currentlookup.subtables
     local lookupname = subtables[1]
@@ -10617,7 +10608,7 @@ function chainprocs.gsub_ligature(start,stop,kind,chainname,currentcontext,looku
                     end
                 end
                 start = toligature(kind,lookupname,start,stop,l2,currentlookup.flags[1],discfound)
-                return start, true, nofreplacements
+                return head, start, true, nofreplacements
             elseif trace_bugs then
                 if start == stop then
                     logwarning("%s: replacing character %s by ligature fails",cref(kind,chainname,chainlookupname,lookupname,chainindex),gref(startchar))
@@ -10627,12 +10618,12 @@ function chainprocs.gsub_ligature(start,stop,kind,chainname,currentcontext,looku
             end
         end
     end
-    return start, false, 0
+    return head, start, false, 0
 end
 
 chainmores.gsub_ligature = chainprocs.gsub_ligature
 
-function chainprocs.gpos_mark2base(start,stop,kind,chainname,currentcontext,lookuphash,currentlookup,chainlookupname)
+function chainprocs.gpos_mark2base(head,start,stop,kind,chainname,currentcontext,lookuphash,currentlookup,chainlookupname)
     local markchar = start.char
     if marks[markchar] then
         local subtables = currentlookup.subtables
@@ -10657,7 +10648,7 @@ function chainprocs.gpos_mark2base(start,stop,kind,chainname,currentcontext,look
                             if trace_bugs then
                                 logwarning("%s: no base for mark %s",pref(kind,lookupname),gref(markchar))
                             end
-                            return start, false
+                            return head, start, false
                         end
                     end
                 end
@@ -10675,7 +10666,7 @@ function chainprocs.gpos_mark2base(start,stop,kind,chainname,currentcontext,look
                                         logprocess("%s, anchor %s, bound %s: anchoring mark %s to basechar %s => (%s,%s)",
                                             cref(kind,chainname,chainlookupname,lookupname),anchor,bound,gref(markchar),gref(basechar),dx,dy)
                                     end
-                                    return start, true
+                                    return head, start, true
                                 end
                             end
                         end
@@ -10693,10 +10684,10 @@ function chainprocs.gpos_mark2base(start,stop,kind,chainname,currentcontext,look
     elseif trace_bugs then
         logwarning("%s: mark %s is no mark",cref(kind,chainname,chainlookupname),gref(markchar))
     end
-    return start, false
+    return head, start, false
 end
 
-function chainprocs.gpos_mark2ligature(start,stop,kind,chainname,currentcontext,lookuphash,currentlookup,chainlookupname)
+function chainprocs.gpos_mark2ligature(head,start,stop,kind,chainname,currentcontext,lookuphash,currentlookup,chainlookupname)
     local markchar = start.char
     if marks[markchar] then
         local subtables = currentlookup.subtables
@@ -10721,7 +10712,7 @@ function chainprocs.gpos_mark2ligature(start,stop,kind,chainname,currentcontext,
                             if trace_bugs then
                                 logwarning("%s: no base for mark %s",cref(kind,chainname,chainlookupname,lookupname),markchar)
                             end
-                            return start, false
+                            return head, start, false
                         end
                     end
                 end
@@ -10743,7 +10734,7 @@ function chainprocs.gpos_mark2ligature(start,stop,kind,chainname,currentcontext,
                                             logprocess("%s, anchor %s, bound %s: anchoring mark %s to baselig %s at index %s => (%s,%s)",
                                                 cref(kind,chainname,chainlookupname,lookupname),anchor,a or bound,gref(markchar),gref(basechar),index,dx,dy)
                                         end
-                                        return start, true
+                                        return head, start, true
                                     end
                                 end
                             end
@@ -10762,10 +10753,10 @@ function chainprocs.gpos_mark2ligature(start,stop,kind,chainname,currentcontext,
     elseif trace_bugs then
         logwarning("%s: mark %s is no mark",cref(kind,chainname,chainlookupname),gref(markchar))
     end
-    return start, false
+    return head, start, false
 end
 
-function chainprocs.gpos_mark2mark(start,stop,kind,chainname,currentcontext,lookuphash,currentlookup,chainlookupname)
+function chainprocs.gpos_mark2mark(head,start,stop,kind,chainname,currentcontext,lookuphash,currentlookup,chainlookupname)
     local markchar = start.char
     if marks[markchar] then
 --~         local alreadydone = markonce and start[a_markmark]
@@ -10806,7 +10797,7 @@ function chainprocs.gpos_mark2mark(start,stop,kind,chainname,currentcontext,look
                                             logprocess("%s, anchor %s, bound %s: anchoring mark %s to basemark %s => (%s,%s)",
                                                 cref(kind,chainname,chainlookupname,lookupname),anchor,bound,gref(markchar),gref(basechar),dx,dy)
                                         end
-                                        return start, true
+                                        return head, start, true
                                     end
                                 end
                             end
@@ -10827,12 +10818,10 @@ function chainprocs.gpos_mark2mark(start,stop,kind,chainname,currentcontext,look
     elseif trace_bugs then
         logwarning("%s: mark %s is no mark",cref(kind,chainname,chainlookupname),gref(markchar))
     end
-    return start, false
+    return head, start, false
 end
 
--- ! ! ! untested ! ! !
-
-function chainprocs.gpos_cursive(start,stop,kind,chainname,currentcontext,lookuphash,currentlookup,chainlookupname)
+function chainprocs.gpos_cursive(head,start,stop,kind,chainname,currentcontext,lookuphash,currentlookup,chainlookupname)
     local alreadydone = cursonce and start[a_cursbase]
     if not alreadydone then
         local startchar = start.char
@@ -10886,18 +10875,18 @@ function chainprocs.gpos_cursive(start,stop,kind,chainname,currentcontext,lookup
                     end
                 end
             end
-            return start, done
+            return head, start, done
         else
             if trace_cursive and trace_details then
                 logprocess("%s, cursive %s is already done",pref(kind,lookupname),gref(start.char),alreadydone)
             end
-            return start, false
+            return head, start, false
         end
     end
-    return start, false
+    return head, start, false
 end
 
-function chainprocs.gpos_single(start,stop,kind,chainname,currentcontext,lookuphash,currentlookup,chainlookupname,chainindex,sequence)
+function chainprocs.gpos_single(head,start,stop,kind,chainname,currentcontext,lookuphash,currentlookup,chainlookupname,chainindex,sequence)
     -- untested .. needs checking for the new model
     local startchar = start.char
     local subtables = currentlookup.subtables
@@ -10912,12 +10901,12 @@ function chainprocs.gpos_single(start,stop,kind,chainname,currentcontext,lookuph
             end
         end
     end
-    return start, false
+    return head, start, false
 end
 
 -- when machines become faster i will make a shared function
 
-function chainprocs.gpos_pair(start,stop,kind,chainname,currentcontext,lookuphash,currentlookup,chainlookupname,chainindex,sequence)
+function chainprocs.gpos_pair(head,start,stop,kind,chainname,currentcontext,lookuphash,currentlookup,chainlookupname,chainindex,sequence)
 --    logwarning("%s: gpos_pair not yet supported",cref(kind,chainname,chainlookupname))
     local snext = start.next
     if snext then
@@ -10981,11 +10970,11 @@ function chainprocs.gpos_pair(start,stop,kind,chainname,currentcontext,lookuphas
                         break
                     end
                 end
-                return start, done
+                return head, start, done
             end
         end
     end
-    return start, false
+    return head, start, false
 end
 
 -- what pointer to return, spec says stop
@@ -11004,7 +10993,7 @@ local function show_skip(kind,chainname,char,ck,class)
     end
 end
 
-local function normal_handle_contextchain(start,kind,chainname,contexts,sequence,lookuphash)
+local function normal_handle_contextchain(head,start,kind,chainname,contexts,sequence,lookuphash)
     --  local rule, lookuptype, sequence, f, l, lookups = ck[1], ck[2] ,ck[3], ck[4], ck[5], ck[6]
     local flags        = sequence.flags
     local done         = false
@@ -11230,7 +11219,7 @@ local function normal_handle_contextchain(start,kind,chainname,contexts,sequence
                     if chainlookup then
                         local cp = chainprocs[chainlookup.type]
                         if cp then
-                            start, done = cp(start,last,kind,chainname,ck,lookuphash,chainlookup,chainlookupname,nil,sequence)
+                            head, start, done = cp(head,start,last,kind,chainname,ck,lookuphash,chainlookup,chainlookupname,nil,sequence)
                         else
                             logprocess("%s: %s is not yet supported",cref(kind,chainname,chainlookupname),chainlookup.type)
                         end
@@ -11261,7 +11250,7 @@ local function normal_handle_contextchain(start,kind,chainname,contexts,sequence
                         local cp = chainlookup and chainmores[chainlookup.type]
                         if cp then
                             local ok, n
-                            start, ok, n = cp(start,last,kind,chainname,ck,lookuphash,chainlookup,chainlookupname,i,sequence)
+                            head, start, ok, n = cp(head,start,last,kind,chainname,ck,lookuphash,chainlookup,chainlookupname,i,sequence)
                             -- messy since last can be changed !
                             if ok then
                                 done = true
@@ -11281,7 +11270,7 @@ local function normal_handle_contextchain(start,kind,chainname,contexts,sequence
             else
                 local replacements = ck[7]
                 if replacements then
-                    start, done = chainprocs.reversesub(start,last,kind,chainname,ck,lookuphash,replacements) -- sequence
+                    head, start, done = chainprocs.reversesub(head,start,last,kind,chainname,ck,lookuphash,replacements) -- sequence
                 else
                     done = true -- can be meant to be skipped
                     if trace_contexts then
@@ -11291,7 +11280,7 @@ local function normal_handle_contextchain(start,kind,chainname,contexts,sequence
             end
         end
     end
-    return start, done
+    return head, start, done
 end
 
 -- Because we want to keep this elsewhere (an because speed is less an issue) we
@@ -11304,7 +11293,7 @@ local verbose_handle_contextchain = function(font,...)
 end
 
 otf.chainhandlers = {
-    normal = normal_handle_contextchain,
+    normal  = normal_handle_contextchain,
     verbose = verbose_handle_contextchain,
 }
 
@@ -11511,12 +11500,8 @@ local function featuresprocessor(head,font,attr)
                                         if lookupcache then
                                             local lookupmatch = lookupcache[start.char]
                                             if lookupmatch then
-                                                local headnode = start == head
-                                                start, success = handler(start,dataset[4],lookupname,lookupmatch,sequence,lookuphash,i)
+                                                head, start, success = handler(head,start,dataset[4],lookupname,lookupmatch,sequence,lookuphash,i)
                                                 if success then
-                                                    if headnode then
-                                                        head = start
-                                                    end
                                                     break
                                                 end
                                             end
@@ -11560,14 +11545,10 @@ local function featuresprocessor(head,font,attr)
                                             local lookupmatch = lookupcache[start.char]
                                             if lookupmatch then
                                                 -- sequence kan weg
-                                                local headnode = start == head
                                                 local ok
-                                                start, ok = handler(start,dataset[4],lookupname,lookupmatch,sequence,lookuphash,1)
+                                                head, start, ok = handler(head,start,dataset[4],lookupname,lookupmatch,sequence,lookuphash,1)
                                                 if ok then
                                                     success = true
-                                                    if headnode then
-                                                        head = start
-                                                    end
                                                 end
                                             end
                                             if start then start = start.next end
@@ -11637,14 +11618,10 @@ local function featuresprocessor(head,font,attr)
                                                 local lookupmatch = lookupcache[start.char]
                                                 if lookupmatch then
                                                     -- we could move all code inline but that makes things even more unreadable
-                                                    local headnode = start == head
                                                     local ok
-                                                    start, ok = handler(start,dataset[4],lookupname,lookupmatch,sequence,lookuphash,i)
+                                                    head, start, ok = handler(head,start,dataset[4],lookupname,lookupmatch,sequence,lookuphash,i)
                                                     if ok then
                                                         success = true
-                                                        if headnode then
-                                                            head = start
-                                                        end
                                                         break
                                                     end
                                                 end
@@ -11971,7 +11948,7 @@ registerotffeature {
     }
 }
 
--- this will change but is needed for an experiment:
+-- This can be used for extra handlers, but should be used with care!
 
 otf.handlers = handlers