From 817e18d3f6969b1b50b4883ec4d5bb05c985db88 Mon Sep 17 00:00:00 2001
From: Hans Hagen <pragma@wxs.nl>
Date: Fri, 4 Aug 2017 09:53:17 +0200
Subject: 2017-08-04 09:46:00

---
 tex/context/base/mkii/cont-new.mkii                |   2 +-
 tex/context/base/mkii/context.mkii                 |   2 +-
 tex/context/base/mkii/mult-cs.mkii                 |   1 +
 tex/context/base/mkiv/cont-new.mkiv                |   2 +-
 tex/context/base/mkiv/context.mkiv                 |   2 +-
 tex/context/base/mkiv/font-dsp.lua                 |   2 +-
 tex/context/base/mkiv/font-lib.mkvi                |  16 +-
 tex/context/base/mkiv/font-mis.lua                 |   2 +-
 tex/context/base/mkiv/font-nod.lua                 |  38 +++-
 tex/context/base/mkiv/font-osd.lua                 |  74 ++-----
 tex/context/base/mkiv/font-otc.lua                 |  12 +-
 tex/context/base/mkiv/font-otj.lua                 |   3 +
 tex/context/base/mkiv/font-otl.lua                 |   2 +-
 tex/context/base/mkiv/font-ots.lua                 | 208 +++++++++-----------
 tex/context/base/mkiv/font-oup.lua                 |  35 +++-
 tex/context/base/mkiv/font-tra.mkiv                |  84 +++++---
 tex/context/base/mkiv/node-res.lua                 |   3 +-
 tex/context/base/mkiv/status-files.pdf             | Bin 25796 -> 25783 bytes
 tex/context/base/mkiv/status-lua.pdf               | Bin 426318 -> 426325 bytes
 tex/context/interface/mkii/keys-cs.xml             |   1 +
 tex/context/interface/mkiv/i-context.pdf           | Bin 848213 -> 848192 bytes
 tex/context/interface/mkiv/i-readme.pdf            | Bin 60775 -> 60775 bytes
 tex/context/modules/mkiv/s-fnt-20.mkiv             |  16 +-
 tex/generic/context/luatex/luatex-fonts-merged.lua | 216 +++++++++++----------
 24 files changed, 380 insertions(+), 341 deletions(-)

(limited to 'tex')

diff --git a/tex/context/base/mkii/cont-new.mkii b/tex/context/base/mkii/cont-new.mkii
index 422431de5..92f84faee 100644
--- a/tex/context/base/mkii/cont-new.mkii
+++ b/tex/context/base/mkii/cont-new.mkii
@@ -11,7 +11,7 @@
 %C therefore copyrighted by \PRAGMA. See mreadme.pdf for
 %C details.
 
-\newcontextversion{2017.08.03 11:02}
+\newcontextversion{2017.08.04 09:40}
 
 %D This file is loaded at runtime, thereby providing an
 %D excellent place for hacks, patches, extensions and new
diff --git a/tex/context/base/mkii/context.mkii b/tex/context/base/mkii/context.mkii
index d17fff45a..1b97ea1b6 100644
--- a/tex/context/base/mkii/context.mkii
+++ b/tex/context/base/mkii/context.mkii
@@ -20,7 +20,7 @@
 %D your styles an modules.
 
 \edef\contextformat {\jobname}
-\edef\contextversion{2017.08.03 11:02}
+\edef\contextversion{2017.08.04 09:40}
 
 %D For those who want to use this:
 
diff --git a/tex/context/base/mkii/mult-cs.mkii b/tex/context/base/mkii/mult-cs.mkii
index 837a397fb..423d47e26 100644
--- a/tex/context/base/mkii/mult-cs.mkii
+++ b/tex/context/base/mkii/mult-cs.mkii
@@ -687,6 +687,7 @@
 \setinterfaceconstant{bottomoffset}{offsetspodku}
 \setinterfaceconstant{bottomspace}{bottomspace}
 \setinterfaceconstant{bottomstate}{statusspodku}
+\setinterfaceconstant{break}{break}
 \setinterfaceconstant{buffer}{buffer}
 \setinterfaceconstant{cache}{cache}
 \setinterfaceconstant{calculate}{pocitat}
diff --git a/tex/context/base/mkiv/cont-new.mkiv b/tex/context/base/mkiv/cont-new.mkiv
index ea19bb659..9af4f2fd3 100644
--- a/tex/context/base/mkiv/cont-new.mkiv
+++ b/tex/context/base/mkiv/cont-new.mkiv
@@ -11,7 +11,7 @@
 %C therefore copyrighted by \PRAGMA. See mreadme.pdf for
 %C details.
 
-\newcontextversion{2017.08.03 11:02}
+\newcontextversion{2017.08.04 09:40}
 
 %D This file is loaded at runtime, thereby providing an excellent place for
 %D hacks, patches, extensions and new features.
diff --git a/tex/context/base/mkiv/context.mkiv b/tex/context/base/mkiv/context.mkiv
index a1cc5c7b0..0a6301ff1 100644
--- a/tex/context/base/mkiv/context.mkiv
+++ b/tex/context/base/mkiv/context.mkiv
@@ -41,7 +41,7 @@
 %D up and the dependencies are more consistent.
 
 \edef\contextformat {\jobname}
-\edef\contextversion{2017.08.03 11:02}
+\edef\contextversion{2017.08.04 09:40}
 \edef\contextkind   {beta}
 
 %D For those who want to use this:
diff --git a/tex/context/base/mkiv/font-dsp.lua b/tex/context/base/mkiv/font-dsp.lua
index 6741add90..dc1b95e14 100644
--- a/tex/context/base/mkiv/font-dsp.lua
+++ b/tex/context/base/mkiv/font-dsp.lua
@@ -2072,7 +2072,7 @@ do
                 local nofsubtables = #subtables
                 local order        = lookup.order
                 local flags        = lookup.flags
-                -- this is expected in th efont handler (faster checking)
+                -- this is expected in the font handler (faster checking)
                 if flags[1] then flags[1] = "mark" end
                 if flags[2] then flags[2] = "ligature" end
                 if flags[3] then flags[3] = "base" end
diff --git a/tex/context/base/mkiv/font-lib.mkvi b/tex/context/base/mkiv/font-lib.mkvi
index 4dd15812f..0dfdf0842 100644
--- a/tex/context/base/mkiv/font-lib.mkvi
+++ b/tex/context/base/mkiv/font-lib.mkvi
@@ -43,9 +43,21 @@
 \registerctxluafile{font-otl}{1.001}
 \registerctxluafile{font-oto}{1.001}
 \registerctxluafile{font-otj}{1.001}
-\registerctxluafile{font-oup}{1.001}
+
+\doifelsefile{font-oup-new.lua} {
+    \registerctxluafile{font-oup-new}{1.001}
+} {
+    \registerctxluafile{font-oup}{1.001}
+}
+
 \registerctxluafile{font-ota}{1.001}
-\registerctxluafile{font-ots}{1.001}
+
+\doifelsefile{font-ots-new.lua} {
+    \registerctxluafile{font-ots-new}{1.001}
+} {
+    \registerctxluafile{font-ots}{1.001}
+}
+
 \registerctxluafile{font-otd}{1.001}
 \registerctxluafile{font-otc}{1.001}
 \registerctxluafile{font-oth}{1.001}
diff --git a/tex/context/base/mkiv/font-mis.lua b/tex/context/base/mkiv/font-mis.lua
index f0afb35de..1d6ef1f31 100644
--- a/tex/context/base/mkiv/font-mis.lua
+++ b/tex/context/base/mkiv/font-mis.lua
@@ -21,7 +21,7 @@ local readers  = otf.readers
 
 if readers then
 
-    otf.version = otf.version or 3.101
+    otf.version = otf.version or 3.102
     otf.cache   = otf.cache   or containers.define("fonts", "otl", otf.version, true)
 
     function fonts.helpers.getfeatures(name,save)
diff --git a/tex/context/base/mkiv/font-nod.lua b/tex/context/base/mkiv/font-nod.lua
index a4dec4f74..2670a924b 100644
--- a/tex/context/base/mkiv/font-nod.lua
+++ b/tex/context/base/mkiv/font-nod.lua
@@ -18,7 +18,10 @@ local match, rep = string.match, string.rep
 fonts = fonts or { }
 nodes = nodes or { }
 
-local fonts, nodes, node, context = fonts, nodes, node, context
+
+local fonts            = fonts
+local nodes            = nodes
+local context          = context
 
 local tracers          = nodes.tracers or { }
 nodes.tracers          = tracers
@@ -296,24 +299,41 @@ function step_tracers.features()
     local f = collection[1]
     while f do
         if getid(f) == glyph_code then
-            local tfmdata, t = fontidentifiers[getfont(f)], { }
+            local tfmdata  = fontidentifiers[getfont(f)]
+            local features = tfmdata.resources.features
+            local result_1 = { }
+            local result_2 = { }
+            local gpos = features and features.gpos or { }
+            local gsub = features and features.gsub or { }
             for feature, value in table.sortedhash(tfmdata.shared.features) do
                 if feature == "number" or feature == "features" then
-                    -- private
+                    value = false
                 elseif type(value) == "boolean" then
                     if value then
-                        t[#t+1] = formatters["%s=yes"](feature)
+                        value = "yes"
                     else
-                        -- skip
+                        value = false
                     end
                 else
-                    t[#t+1] = formatters["%s=%s"](feature,value)
+                    -- use value
+                end
+                if value then
+                    if gpos[feature] or gsub[feature] or feature == "language" or feature == "script" then
+                        result_1[#result_1+1] = formatters["%s=%s"](feature,value)
+                    else
+                        result_2[#result_2+1] = formatters["%s=%s"](feature,value)
+                    end
                 end
             end
-            if #t > 0 then
-                context(concat(t,", "))
+            if #result_1 > 0 then
+                context("{\\bf[basic:} %, t{\\bf]} ",result_1)
+            else
+                context("{\\bf[}no basic features{\\bf]} ")
+            end
+            if #result_2 > 0 then
+                context("{\\bf[extra:} %, t{\\bf]}",result_2)
             else
-                context("no features")
+                context("{\\bf[}no extra features{\\bf]}")
             end
             return
         end
diff --git a/tex/context/base/mkiv/font-osd.lua b/tex/context/base/mkiv/font-osd.lua
index 9adc8bff2..04fbf88f5 100644
--- a/tex/context/base/mkiv/font-osd.lua
+++ b/tex/context/base/mkiv/font-osd.lua
@@ -461,7 +461,6 @@ local sequence_reorder_matras = {
     nofsteps  = 1,
     steps     = {
         {
-            osdstep  = true,
             coverage = pre_mark,
         }
     }
@@ -476,7 +475,6 @@ local sequence_reorder_reph = {
     nofsteps  = 1,
     steps     = {
         {
-            osdstep  = true,
             coverage = { },
         }
     }
@@ -491,7 +489,6 @@ local sequence_reorder_pre_base_reordering_consonants = {
     nofsteps  = 1,
     steps     = {
         {
-            osdstep  = true,
             coverage = { },
         }
     }
@@ -505,7 +502,7 @@ local sequence_remove_joiners = {
     type      = "devanagari_remove_joiners",
     nofsteps  = 1,
     steps     = {
-        {  osdstep  = true,
+        {
            coverage = both_joiners_true,
         },
     }
@@ -633,35 +630,22 @@ local function initializedevanagi(tfmdata)
                             if coverage then
                                 local reph = false
                                 if kind == "rphf" then
-                                 --
-                                 -- KE: I don't understand the rationale behind osdstep. The original if
-                                 --     statement checked whether coverage is contextual chaining.
-                                 --
-                                 -- HH: The osdstep signals that we deal with our own feature here, not
-                                 --     one in the font itself so it was just a safeguard against us overloading
-                                 --     something driven by the font.
-                                 --
-                                 -- if step.osdstep then -- selective
-                                    if true then -- always
-                                        -- rphf acts on consonant + halant
-                                        for k, v in next, ra do
-                                            local r = coverage[k]
-                                            if r then
-                                                local h = false
-                                                for k, v in next, halant do
-                                                    local h = r[k]
-                                                    if h then
-                                                        reph = h.ligature or false
-                                                        break
-                                                    end
-                                                end
-                                                if reph then
+                                    -- rphf acts on consonant + halant
+                                    for k, v in next, ra do
+                                        local r = coverage[k]
+                                        if r then
+                                            local h = false
+                                            for k, v in next, halant do
+                                                local h = r[k]
+                                                if h then
+                                                    reph = h.ligature or false
                                                     break
                                                 end
                                             end
+                                            if reph then
+                                                break
+                                            end
                                         end
-                                    else
-                                        -- rphf might be result of other handler/chainproc
                                     end
                                 end
                                 seqsubset[#seqsubset+1] = { kind, coverage, reph }
@@ -1289,7 +1273,11 @@ end
 -- 2  Try to find a target position the same way as for pre-base matra. If it is found, reorder pre-base consonant glyph.
 -- 3  If position is not found, reorder immediately before main consonant.
 
--- UNTESTED: NOT CALLED IN EXAMPLE
+-- Here we implement a few handlers:
+--
+--   function(head,start,dataset,sequence,lookupmatch,rlmode,skiphash,step)
+--       return head, start, done
+--   end
 
 function handlers.devanagari_reorder_pre_base_reordering_consonants(head,start)
     local current   = start
@@ -1349,32 +1337,6 @@ function handlers.devanagari_reorder_pre_base_reordering_consonants(head,start)
     return head, start, true
 end
 
--- function handlers.devanagari_remove_joiners(head,start,kind,lookupname,replacement)
---     local stop = getnext(start)
---     local font = getfont(start)
---     while stop do
---         local char = ischar(stop)
---         if char and (char == c_zwnj or char == c_zwj) then
---             stop = getnext(stop)
---         else
---             break
---         end
---     end
---     if stop then
---         setnext(getprev(stop))
---         setprev(stop,getprev(start))
---     end
---     local prev = getprev(start)
---     if prev then
---         setnext(prev,stop)
---     end
---     if head == start then
---     	head = stop
---     end
---     flush_list(start)
---     return head, stop, true
--- end
-
 function handlers.devanagari_remove_joiners(head,start,kind,lookupname,replacement)
     local stop = getnext(start)
     local font = getfont(start)
diff --git a/tex/context/base/mkiv/font-otc.lua b/tex/context/base/mkiv/font-otc.lua
index 0d470c690..7014761f1 100644
--- a/tex/context/base/mkiv/font-otc.lua
+++ b/tex/context/base/mkiv/font-otc.lua
@@ -21,8 +21,9 @@ local otf                 = fonts.handlers.otf
 local registerotffeature  = otf.features.register
 local setmetatableindex   = table.setmetatableindex
 
-local mergesteps          = fonts.helpers.mergesteps
+local checkmerge          = fonts.helpers.checkmerge
 local checkflags          = fonts.helpers.checkflags
+local checksteps          = fonts.helpers.checksteps
 
 local normalized = {
     substitution      = "substitution",
@@ -647,7 +648,8 @@ local function addfeature(data,feature,specifications)
                         end
                     end
                     --
-                    setmetatableindex(steps,mergesteps) -- speedup
+                    checkmerge(specification)
+                    checksteps(specification)
                     --
                     s[i] = {
                         [stepkey] = steps,
@@ -709,8 +711,6 @@ local function addfeature(data,feature,specifications)
                     end
                 end
                 --
-                setmetatableindex(steps,mergesteps) -- speedup
-                --
                 if featureflags[1] then featureflags[1] = "mark" end
                 if featureflags[2] then featureflags[2] = "ligature" end
                 if featureflags[3] then featureflags[3] = "base" end
@@ -725,8 +725,10 @@ local function addfeature(data,feature,specifications)
                     nofsteps  = nofsteps,
                     type      = steptype,
                 }
-                -- new
+                --
                 checkflags(sequence,resources)
+                checkmerge(sequence)
+                checksteps(sequence)
                 -- position | prepend | append
                 local first, last = getrange(sequences,category)
                 inject(specification,sequences,sequence,first,last,category,feature)
diff --git a/tex/context/base/mkiv/font-otj.lua b/tex/context/base/mkiv/font-otj.lua
index 657f1a2a6..580a65dde 100644
--- a/tex/context/base/mkiv/font-otj.lua
+++ b/tex/context/base/mkiv/font-otj.lua
@@ -1042,6 +1042,9 @@ local function inject_everything(head,where)
                 -- kern(w-x) glyph(p) kern(x) mark(n)
                 ox = px - pn.markx - rightkern
              -- report_injections("r2l case 1: %p",ox)
+if not pn.markmark then -- check or not (no longer needed)
+    ox = ox + (pn.leftkern or 0)
+end
             else
                 -- kern(x) glyph(p) kern(w-x) mark(n)
              -- ox = px - getwidth(p) + pn.markx - pp.leftkern
diff --git a/tex/context/base/mkiv/font-otl.lua b/tex/context/base/mkiv/font-otl.lua
index f6d99dbe0..4625c5aaf 100644
--- a/tex/context/base/mkiv/font-otl.lua
+++ b/tex/context/base/mkiv/font-otl.lua
@@ -52,7 +52,7 @@ local report_otf          = logs.reporter("fonts","otf loading")
 local fonts               = fonts
 local otf                 = fonts.handlers.otf
 
-otf.version               = 3.101 -- beware: also sync font-mis.lua and in mtx-fonts
+otf.version               = 3.102 -- beware: also sync font-mis.lua and in mtx-fonts
 otf.cache                 = containers.define("fonts", "otl",  otf.version, true)
 otf.svgcache              = containers.define("fonts", "svg",  otf.version, true)
 otf.sbixcache             = containers.define("fonts", "sbix", otf.version, true)
diff --git a/tex/context/base/mkiv/font-ots.lua b/tex/context/base/mkiv/font-ots.lua
index 6af5aa405..7194109a1 100644
--- a/tex/context/base/mkiv/font-ots.lua
+++ b/tex/context/base/mkiv/font-ots.lua
@@ -693,7 +693,7 @@ function handlers.gsub_single(head,start,dataset,sequence,replacement)
     return head, start, true
 end
 
-function handlers.gsub_alternate(head,start,dataset,sequence,alternative)
+function handlers.gsub_alternate(head,start,dataset,sequence,alternative,rlmode,skiphash)
     local kind  = dataset[4]
     local what  = dataset[1]
     local value = what == true and tfmdata.shared.features[kind] or what
@@ -712,14 +712,17 @@ function handlers.gsub_alternate(head,start,dataset,sequence,alternative)
     return head, start, true
 end
 
-function handlers.gsub_multiple(head,start,dataset,sequence,multiple)
+function handlers.gsub_multiple(head,start,dataset,sequence,multiple,rlmode,skiphash)
     if trace_multiples then
         logprocess("%s: replacing %s by multiple %s",pref(dataset,sequence),gref(getchar(start)),gref(multiple))
     end
     return multiple_glyphs(head,start,multiple,sequence.flags[1],dataset[1])
 end
 
-function handlers.gsub_ligature(head,start,dataset,sequence,ligature)
+-- Don't we deal with disc otherwise now? I need to check if the next one can be
+-- simplified.
+
+function handlers.gsub_ligature(head,start,dataset,sequence,ligature,rlmode,skiphash)
     local current   = getnext(start)
     if not current then
         return head, start, false, nil
@@ -838,7 +841,7 @@ function handlers.gsub_ligature(head,start,dataset,sequence,ligature)
     return head, start, false, discfound
 end
 
-function handlers.gpos_single(head,start,dataset,sequence,kerns,rlmode,step,i,injection)
+function handlers.gpos_single(head,start,dataset,sequence,kerns,rlmode,skiphash,step,injection)
     local startchar = getchar(start)
     local format    = step.format
     if format == "single" or type(kerns) == "table" then -- the table check can go
@@ -855,14 +858,7 @@ function handlers.gpos_single(head,start,dataset,sequence,kerns,rlmode,step,i,in
     return head, start, false
 end
 
--- elseif krn and step.format == "pair"
---     and (not krn[1] or type(krn[1]) == "boolean")
---     and (not krn[2] or type(krn[2]) == "boolean")
---     and marks[nextchar] then	--KE
--- prev = snext	--KE
--- snext = getnext(snext)	--KE
-
-function handlers.gpos_pair(head,start,dataset,sequence,kerns,rlmode,step,i,injection)
+function handlers.gpos_pair(head,start,dataset,sequence,kerns,rlmode,skiphash,step,injection)
     local snext = getnext(start)
     if not snext then
         return head, start, false
@@ -871,17 +867,10 @@ function handlers.gpos_pair(head,start,dataset,sequence,kerns,rlmode,step,i,inje
         while snext do
             local nextchar = ischar(snext,currentfont)
             if nextchar then
-             -- local krn = kerns[nextchar]
-             -- if not krn and marks[nextchar] then
-             --     prev = snext
-             --     snext = getnext(snext)
-             -- elseif not krn then
-             --     break
-             -- else
                 if marks[nextchar] and sequence.flags[1] then
                     prev  = snext
                     snext = getnext(snext)
--- if sequence.skipsome and sequence.skipsome[nextchar] then
+-- if skiphash and skiphash[nextchar] then -- includes marks too when flag
 --     prev  = snext
 --     snext = getnext(snext)
                 else
@@ -938,7 +927,7 @@ end
 we need to explicitly test for basechar, baselig and basemark entries.</p>
 --ldx]]--
 
-function handlers.gpos_mark2base(head,start,dataset,sequence,markanchors,rlmode)
+function handlers.gpos_mark2base(head,start,dataset,sequence,markanchors,rlmode,skiphash)
     local markchar = getchar(start)
     if marks[markchar] then
         local base = getprev(start) -- [glyph] [start=mark]
@@ -993,7 +982,7 @@ function handlers.gpos_mark2base(head,start,dataset,sequence,markanchors,rlmode)
     return head, start, false
 end
 
-function handlers.gpos_mark2ligature(head,start,dataset,sequence,markanchors,rlmode)
+function handlers.gpos_mark2ligature(head,start,dataset,sequence,markanchors,rlmode,skiphash)
     local markchar = getchar(start)
     if marks[markchar] then
         local base = getprev(start) -- [glyph] [optional marks] [start=mark]
@@ -1058,7 +1047,7 @@ function handlers.gpos_mark2ligature(head,start,dataset,sequence,markanchors,rlm
     return head, start, false
 end
 
-function handlers.gpos_mark2mark(head,start,dataset,sequence,markanchors,rlmode)
+function handlers.gpos_mark2mark(head,start,dataset,sequence,markanchors,rlmode,skiphash)
     local markchar = getchar(start)
     if marks[markchar] then
         local base = getprev(start) -- [glyph] [basemark] [start=mark]
@@ -1094,7 +1083,7 @@ function handlers.gpos_mark2mark(head,start,dataset,sequence,markanchors,rlmode)
     return head, start, false
 end
 
-function handlers.gpos_cursive(head,start,dataset,sequence,exitanchors,rlmode,step,i) -- to be checked
+function handlers.gpos_cursive(head,start,dataset,sequence,exitanchors,rlmode,skiphash,step) -- to be checked
     local startchar = getchar(start)
     if marks[startchar] then
         if trace_cursive then
@@ -1162,7 +1151,7 @@ local logwarning = report_chain
 -- 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.
 
-local function reversesub(head,start,stop,dataset,sequence,replacements,rlmode)
+local function reversesub(head,start,stop,dataset,sequence,replacements,rlmode,skiphash)
     local char        = getchar(start)
     local replacement = replacements[char]
     if replacement then
@@ -1216,7 +1205,7 @@ end
 --     logwarning("%s: bad step, no proper return values",cref(dataset,sequence))
 -- end
 
-function chainprocs.gsub_single(head,start,stop,dataset,sequence,currentlookup,chainindex)
+function chainprocs.gsub_single(head,start,stop,dataset,sequence,currentlookup,rlmode,skiphash,chainindex)
     local steps    = currentlookup.steps
     local nofsteps = currentlookup.nofsteps
     if nofsteps > 1 then
@@ -1433,7 +1422,7 @@ function chainprocs.gsub_ligature(head,start,stop,dataset,sequence,currentlookup
     return head, start, false, 0, false
 end
 
-function chainprocs.gpos_single(head,start,stop,dataset,sequence,currentlookup,rlmode,chainindex)
+function chainprocs.gpos_single(head,start,stop,dataset,sequence,currentlookup,rlmode,skiphash,chainindex)
     local steps    = currentlookup.steps
     local nofsteps = currentlookup.nofsteps
     if nofsteps > 1 then
@@ -1465,7 +1454,7 @@ function chainprocs.gpos_single(head,start,stop,dataset,sequence,currentlookup,r
     return head, start, false
 end
 
-function chainprocs.gpos_pair(head,start,stop,dataset,sequence,currentlookup,rlmode,chainindex) -- todo: injections ?
+function chainprocs.gpos_pair(head,start,stop,dataset,sequence,currentlookup,rlmode,skiphash,chainindex) -- todo: injections ?
     local steps    = currentlookup.steps
     local nofsteps = currentlookup.nofsteps
     if nofsteps > 1 then
@@ -1486,17 +1475,10 @@ function chainprocs.gpos_pair(head,start,stop,dataset,sequence,currentlookup,rlm
                     if not nextchar then
                         break
                     end
-                 -- local krn = kerns[nextchar]
-                 -- if not krn and marks[nextchar] then
-                 --     prev = snext
-                 --     snext = getnext(snext)
-                 -- elseif not krn then
-                 --     break
-                 -- else
                     if marks[nextchar] and sequence.flags[1] then
                         prev  = snext
                         snext = getnext(snext)
--- elseif sequence.markclass and sequence.markclass[nextchar] then - skipsome
+-- if skiphash and skiphash[nextchar] then
 --     prev  = snext
 --     snext = getnext(snext)
                     else
@@ -1547,7 +1529,7 @@ function chainprocs.gpos_pair(head,start,stop,dataset,sequence,currentlookup,rlm
     return head, start, false
 end
 
-function chainprocs.gpos_mark2base(head,start,stop,dataset,sequence,currentlookup,rlmode)
+function chainprocs.gpos_mark2base(head,start,stop,dataset,sequence,currentlookup,rlmode,skiphash)
     local steps    = currentlookup.steps
     local nofsteps = currentlookup.nofsteps
     if nofsteps > 1 then
@@ -1615,7 +1597,7 @@ function chainprocs.gpos_mark2base(head,start,stop,dataset,sequence,currentlooku
     return head, start, false
 end
 
-function chainprocs.gpos_mark2ligature(head,start,stop,dataset,sequence,currentlookup,rlmode)
+function chainprocs.gpos_mark2ligature(head,start,stop,dataset,sequence,currentlookup,rlmode,skiphash)
     local steps    = currentlookup.steps
     local nofsteps = currentlookup.nofsteps
     if nofsteps > 1 then
@@ -1687,7 +1669,7 @@ function chainprocs.gpos_mark2ligature(head,start,stop,dataset,sequence,currentl
     return head, start, false
 end
 
-function chainprocs.gpos_mark2mark(head,start,stop,dataset,sequence,currentlookup,rlmode)
+function chainprocs.gpos_mark2mark(head,start,stop,dataset,sequence,currentlookup,rlmode,skiphash)
     local steps    = currentlookup.steps
     local nofsteps = currentlookup.nofsteps
     if nofsteps > 1 then
@@ -1743,7 +1725,7 @@ function chainprocs.gpos_mark2mark(head,start,stop,dataset,sequence,currentlooku
     return head, start, false
 end
 
-function chainprocs.gpos_cursive(head,start,stop,dataset,sequence,currentlookup,rlmode)
+function chainprocs.gpos_cursive(head,start,stop,dataset,sequence,currentlookup,rlmode,skiphash)
     local steps    = currentlookup.steps
     local nofsteps = currentlookup.nofsteps
     if nofsteps > 1 then
@@ -1880,7 +1862,7 @@ end
 
 local noflags = { false, false, false, false }
 
-local function chainrun(head,start,last,dataset,sequence,rlmode,ck,skipsome) -- skipped)
+local function chainrun(head,start,last,dataset,sequence,rlmode,skiphash,ck)
 
     local size         = ck[5] - ck[4] + 1
     local chainlookups = ck[6]
@@ -1904,7 +1886,7 @@ local function chainrun(head,start,last,dataset,sequence,rlmode,ck,skipsome) --
                 local chainproc = chainprocs[chainkind]
                 if chainproc then
                     local ok
-                    head, start, ok = chainproc(head,start,last,dataset,sequence,chainstep,rlmode,1)
+                    head, start, ok = chainproc(head,start,last,dataset,sequence,chainstep,rlmode,skiphash)
                     if ok then
                         done = true
                     end
@@ -1929,19 +1911,15 @@ local function chainrun(head,start,last,dataset,sequence,rlmode,ck,skipsome) --
             -- It's very unlikely that we will have skip classes here but still ... we seldom
             -- enter this branch anyway.
 
-            if skipsome then
-                skipsome = sequence.skipsome
-            end
-
             local i = 1
             local laststart = start
             local nofchainlookups = #chainlookups -- useful?
             while start do
-                if skipsome then -- hm, so we know we skip some
+                if skiphash then -- hm, so we know we skip some
                     while start do
                         local char = ischar(start,currentfont)
                         if char then
-                            if skipsome[char] then
+                            if skiphash and skiphash[char] then
                                 start = getnext(start)
                             else
                                 break
@@ -1959,7 +1937,7 @@ local function chainrun(head,start,last,dataset,sequence,rlmode,ck,skipsome) --
                         local chainproc = chainprocs[chainkind]
                         if chainproc then
                             local ok, n
-                            head, start, ok, n = chainproc(head,start,last,dataset,sequence,chainstep,rlmode,i)
+                            head, start, ok, n = chainproc(head,start,last,dataset,sequence,chainstep,rlmode,skiphash)
                             -- messy since last can be changed !
                             if ok then
                                 done = true
@@ -1992,7 +1970,7 @@ local function chainrun(head,start,last,dataset,sequence,rlmode,ck,skipsome) --
         -- todo: needs checking for holes in the replacements
         local replacements = ck[7]
         if replacements then
-            head, start, done = reversesub(head,start,last,dataset,sequence,replacements,rlmode)
+            head, start, done = reversesub(head,start,last,dataset,sequence,replacements,rlmode,skiphash)
         else
             done = true
             if trace_contexts then
@@ -2003,7 +1981,7 @@ local function chainrun(head,start,last,dataset,sequence,rlmode,ck,skipsome) --
     return head, start, done
 end
 
-local function chaindisk(head,start,dataset,sequence,rlmode,ck,skipped)
+local function chaindisk(head,start,dataset,sequence,rlmode,skiphash,ck)
 
     if not start then
         return head, start, false
@@ -2233,14 +2211,14 @@ local function chaindisk(head,start,dataset,sequence,rlmode,ck,skipped)
         end
         if not notmatchpre[lookaheaddisc] then
             local ok = false
-            cf, start, ok = chainrun(cf,start,cl,dataset,sequence,rlmode,ck,skipped)
+            cf, start, ok = chainrun(cf,start,cl,dataset,sequence,rlmode,skiphash,ck)
             if ok then
                 done = true
             end
         end
         if not notmatchreplace[lookaheaddisc] then
             local ok = false
-            new, cnew, ok = chainrun(new,cnew,clast,dataset,sequence,rlmode,ck,skipped)
+            new, cnew, ok = chainrun(new,cnew,clast,dataset,sequence,rlmode,skiphash,ck)
             if ok then
                 done = true
             end
@@ -2289,14 +2267,14 @@ local function chaindisk(head,start,dataset,sequence,rlmode,ck,skipped)
         end
         if not notmatchpost[backtrackdisc] then
             local ok = false
-            cf, start, ok = chainrun(cf,start,last,dataset,sequence,rlmode,ck,skipped)
+            cf, start, ok = chainrun(cf,start,last,dataset,sequence,rlmode,skiphash,ck)
             if ok then
                 done = true
             end
         end
         if not notmatchreplace[backtrackdisc] then
             local ok = false
-            new, cnew, ok = chainrun(new,cnew,clast,dataset,sequence,rlmode,ck,skipped)
+            new, cnew, ok = chainrun(new,cnew,clast,dataset,sequence,rlmode,skiphash,ck)
             if ok then
                 done = true
             end
@@ -2323,7 +2301,7 @@ local function chaindisk(head,start,dataset,sequence,rlmode,ck,skipped)
     else
 
         local ok = false
-        head, start, ok = chainrun(head,start,last,dataset,sequence,rlmode,ck,skipped)
+        head, start, ok = chainrun(head,start,last,dataset,sequence,rlmode,skiphash,ck)
         if ok then
             done = true
         end
@@ -2333,7 +2311,7 @@ local function chaindisk(head,start,dataset,sequence,rlmode,ck,skipped)
     return head, start, done
 end
 
-local function chaintrac(head,start,dataset,sequence,rlmode,ck,skipped,match)
+local function chaintrac(head,start,dataset,sequence,rlmode,skiphash,ck,match)
     local rule       = ck[1]
     local lookuptype = ck[8] or ck[2]
     local nofseq     = #ck[3]
@@ -2348,7 +2326,7 @@ end
 -- tests because they have many steps with one context (having multiple contexts makes more sense)
 -- also because we (can) reduce them.
 
--- local function handle_contextchain(head,start,dataset,sequence,contexts,rlmode)
+-- local function handle_contextchain(head,start,dataset,sequence,contexts,rlmode,skiphash)
 --     local sweepnode    = sweepnode
 --     local sweeptype    = sweeptype
 --     local currentfont  = currentfont
@@ -2356,7 +2334,6 @@ end
 --     local checkdisc    = sweeptype and getprev(head)
 --     local flags        = sequence.flags or noflags
 --     local done         = false
---     local skipsome     = sequence.skipsome
 --     local skipped      = false
 --     local startprev,
 --           startnext    = getboth(start)
@@ -2395,7 +2372,7 @@ end
 --                     if last then
 --                         local char, id = ischar(last,currentfont)
 --                         if char then
---                             if skipsome and skipsome[char] then
+--                             if skiphash and skiphash[char] then
 --                                 skipped = true
 --                                 if trace_skips then
 --                                     show_skip(dataset,sequence,char,ck,classes[char])
@@ -2504,7 +2481,7 @@ end
 --                             if prev then
 --                                 local char, id = ischar(prev,currentfont)
 --                                 if char then
---                                     if skipsome and skipsome[char] then
+--                                     if skiphash and skiphash[char] then
 --                                         skipped = true
 --                                         if trace_skips then
 --                                             show_skip(dataset,sequence,char,ck,classes[char])
@@ -2644,7 +2621,7 @@ end
 --                         if current then
 --                             local char, id = ischar(current,currentfont)
 --                             if char then
---                                 if skipsome and skipsome[char] then
+--                                 if skiphash and skiphash[char] then
 --                                     skipped = true
 --                                     if trace_skips then
 --                                         show_skip(dataset,sequence,char,ck,classes[char])
@@ -2761,12 +2738,12 @@ end
 --         end
 --         if match then
 --             if trace_contexts then
---                 chaintrac(head,start,dataset,sequence,rlmode,ck,skipped,true)
+--                 chaintrac(head,start,dataset,sequence,rlmode,skipped and skiphash,ck,true)
 --             end
 --             if diskseen or sweepnode then
---                 head, start, done = chaindisk(head,start,dataset,sequence,rlmode,ck,skipped)
+--                 head, start, done = chaindisk(head,start,dataset,sequence,rlmode,skipped and skiphash,ck)
 --             else
---                 head, start, done = chainrun(head,start,last,dataset,sequence,rlmode,ck,skipped)
+--                 head, start, done = chainrun(head,start,last,dataset,sequence,rlmode,skipped and skiphash,ck)
 --             end
 --             if done then
 --                 break
@@ -2774,7 +2751,7 @@ end
 --                 -- next context
 --             end
 --      -- elseif trace_chains then
---      --     chaintrac(head,start,dataset,sequence,rlmode,ck,skipped,match)
+--      --     chaintrac(head,start,dataset,sequence,rlmode,skipped and skiphash,ck,match)
 --         end
 --     end
 --     if diskseen then
@@ -2789,7 +2766,7 @@ end
 -- "labels" instead. This is one of the cases where it makes th ecode more readable and we might
 -- even gain a bit performance.
 
-local function handle_contextchain(head,start,dataset,sequence,contexts,rlmode)
+local function handle_contextchain(head,start,dataset,sequence,contexts,rlmode,skiphash)
     -- optimizing for rlmode gains nothing
     local sweepnode    = sweepnode
     local sweeptype    = sweeptype
@@ -2810,7 +2787,6 @@ local function handle_contextchain(head,start,dataset,sequence,contexts,rlmode)
     local currentfont  = currentfont
 
     local skipped   -- = false
-    local skipsome     = sequence.skipsome
 
     local startprev,
           startnext    = getboth(start)
@@ -2849,7 +2825,7 @@ local function handle_contextchain(head,start,dataset,sequence,contexts,rlmode)
                     if last then
                         local char, id = ischar(last,currentfont)
                         if char then
-                            if skipsome and skipsome[char] then
+                            if skiphash and skiphash[char] then
                                 skipped = true
                                 if trace_skips then
                                     show_skip(dataset,sequence,char,ck,classes[char])
@@ -2956,7 +2932,7 @@ local function handle_contextchain(head,start,dataset,sequence,contexts,rlmode)
                             if prev then
                                 local char, id = ischar(prev,currentfont)
                                 if char then
-                                    if skipsome and skipsome[char] then
+                                    if skiphash and skiphash[char] then
                                         skipped = true
                                         if trace_skips then
                                             show_skip(dataset,sequence,char,ck,classes[char])
@@ -3082,7 +3058,7 @@ local function handle_contextchain(head,start,dataset,sequence,contexts,rlmode)
                         if current then
                             local char, id = ischar(current,currentfont)
                             if char then
-                                if skipsome and skipsome[char] then
+                                if skiphash and skiphash[char] then
                                     skipped = true
                                     if trace_skips then
                                         show_skip(dataset,sequence,char,ck,classes[char])
@@ -3195,12 +3171,12 @@ local function handle_contextchain(head,start,dataset,sequence,contexts,rlmode)
             end
         end
         if trace_contexts then
-            chaintrac(head,start,dataset,sequence,rlmode,ck,skipped,true)
+            chaintrac(head,start,dataset,sequence,rlmode,skipped and skiphash,ck,true)
         end
         if diskseen or sweepnode then
-            head, start, done = chaindisk(head,start,dataset,sequence,rlmode,ck,skipped)
+            head, start, done = chaindisk(head,start,dataset,sequence,rlmode,skipped and skiphash,ck)
         else
-            head, start, done = chainrun(head,start,last,dataset,sequence,rlmode,ck,skipped)
+            head, start, done = chainrun(head,start,last,dataset,sequence,rlmode,skipped and skiphash,ck)
         end
         if done then
             break
@@ -3209,7 +3185,7 @@ local function handle_contextchain(head,start,dataset,sequence,contexts,rlmode)
         end
         ::next::
      -- if trace_chains then
-     --     chaintrac(head,start,dataset,sequence,rlmode,ck,skipped,match)
+     --     chaintrac(head,start,dataset,sequence,rlmode,skipped and skiphash,ck,false)
      -- end
     end
     if diskseen then
@@ -3228,13 +3204,13 @@ handlers.gpos_context             = handle_contextchain
 
 -- this needs testing
 
-local function chained_contextchain(head,start,stop,dataset,sequence,currentlookup,rlmode)
+local function chained_contextchain(head,start,stop,dataset,sequence,currentlookup,rlmode,skiphash)
     local steps    = currentlookup.steps
     local nofsteps = currentlookup.nofsteps
     if nofsteps > 1 then
         reportmoresteps(dataset,sequence)
     end
-    return handle_contextchain(head,start,dataset,sequence,currentlookup,rlmode)
+    return handle_contextchain(head,start,dataset,sequence,currentlookup,rlmode,skiphash)
 end
 
 chainprocs.gsub_context             = chained_contextchain
@@ -3249,12 +3225,12 @@ chainprocs.gpos_context             = chained_contextchain
 --
 -- function otf.registerchainproc(name,f)
 --  -- chainprocs[name] = f
---     chainprocs[name] = function(head,start,stop,dataset,sequence,currentlookup,rlmode)
+--     chainprocs[name] = function(head,start,stop,dataset,sequence,currentlookup,rlmode,skiphash)
 --         local done = currentlookup.nofsteps > 0
 --         if not done then
 --             reportzerosteps(dataset,sequence)
 --         else
---             head, start, done = f(head,start,stop,dataset,sequence,currentlookup,rlmode)
+--             head, start, done = f(head,start,stop,dataset,sequence,currentlookup,rlmode,skiphash)
 --             if not head or not start then
 --                 reportbadsteps(dataset,sequence)
 --             end
@@ -3665,7 +3641,7 @@ end
 
 local nesting = 0
 
-local function c_run_single(head,font,attr,lookupcache,step,dataset,sequence,rlmode,handler)
+local function c_run_single(head,font,attr,lookupcache,step,dataset,sequence,rlmode,skiphash,handler)
     local done  = false
     local sweep = sweephead[head]
     if sweep then
@@ -3686,7 +3662,7 @@ local function c_run_single(head,font,attr,lookupcache,step,dataset,sequence,rlm
                 local lookupmatch = lookupcache[char]
                 if lookupmatch then
                     local ok
-                    head, start, ok = handler(head,start,dataset,sequence,lookupmatch,rlmode,step,1)
+                    head, start, ok = handler(head,start,dataset,sequence,lookupmatch,rlmode,skiphash,step)
                     if ok then
                         done = true
                     end
@@ -3787,7 +3763,7 @@ local function t_run_single(start,stop,font,attr,lookupcache)
     return 0
 end
 
-local function k_run_single(sub,injection,last,font,attr,lookupcache,step,dataset,sequence,rlmode,handler)
+local function k_run_single(sub,injection,last,font,attr,lookupcache,step,dataset,sequence,rlmode,skiphash,handler)
     local a -- happens often so no assignment is faster
     if attr then
         a = getattr(sub,0)
@@ -3801,7 +3777,7 @@ local function k_run_single(sub,injection,last,font,attr,lookupcache,step,datase
             if char then
                 local lookupmatch = lookupcache[char]
                 if lookupmatch then
-                    local h, d, ok = handler(sub,n,dataset,sequence,lookupmatch,rlmode,step,1,injection)
+                    local h, d, ok = handler(sub,n,dataset,sequence,lookupmatch,rlmode,skiphash,step,injection)
                     if ok then
                         return true
                     end
@@ -3811,7 +3787,7 @@ local function k_run_single(sub,injection,last,font,attr,lookupcache,step,datase
     end
 end
 
-local function c_run_multiple(head,font,attr,steps,nofsteps,dataset,sequence,rlmode,handler)
+local function c_run_multiple(head,font,attr,steps,nofsteps,dataset,sequence,rlmode,skiphash,handler)
     local done  = false
     local sweep = sweephead[head]
     if sweep then
@@ -3836,7 +3812,7 @@ local function c_run_multiple(head,font,attr,steps,nofsteps,dataset,sequence,rlm
                     if lookupmatch then
                         -- we could move all code inline but that makes things even more unreadable
                         local ok
-                        head, start, ok = handler(head,start,dataset,sequence,lookupmatch,rlmode,step,i)
+                        head, start, ok = handler(head,start,dataset,sequence,lookupmatch,rlmode,skiphash,step)
                         if ok then
                             done = true
                             break
@@ -3947,7 +3923,7 @@ local function t_run_multiple(start,stop,font,attr,steps,nofsteps)
     return 0
 end
 
-local function k_run_multiple(sub,injection,last,font,attr,steps,nofsteps,dataset,sequence,rlmode,handler)
+local function k_run_multiple(sub,injection,last,font,attr,steps,nofsteps,dataset,sequence,rlmode,skiphash,handler)
     local a -- happens often so no assignment is faster
     if attr then
         a = getattr(sub,0)
@@ -3964,7 +3940,7 @@ local function k_run_multiple(sub,injection,last,font,attr,steps,nofsteps,datase
                     local lookupcache = step.coverage
                     local lookupmatch = lookupcache[char]
                     if lookupmatch then
-                        local h, d, ok = handler(sub,n,dataset,sequence,lookupmatch,rlmode,step,i,injection) -- sub was head
+                        local h, d, ok = handler(sub,n,dataset,sequence,lookupmatch,rlmode,skiphash,step,injection) -- sub was head
                         if ok then
                             return true
                         end
@@ -4148,16 +4124,18 @@ do
             local handler      = handlers[typ] -- store in dataset
             local steps        = sequence.steps
             local nofsteps     = sequence.nofsteps
-            local skipsome     = sequence.skipsome
+            local skiphash     = sequence.skiphash
 
             if not steps then
-                -- this permits injection, watch the different arguments
-                local h, d, ok = handler(head,head,dataset,sequence,nil,nil,nil,0,font,attr)
+                -- This permits injection, watch the different arguments. Watch out, the arguments passed
+                -- are not frozen as we might extend or change this. Is this used at all apart from some
+                -- experiments?
+                local h, ok = handler(head,dataset,sequence,initialrl,font,attr) -- less arguments now
                 if ok then
                     done = true
-                    if h then
-                        head = h
-                    end
+                end
+                if h and h ~= head then
+                    head = h
                 end
             elseif typ == "gsub_reversecontextchain" then
                 --
@@ -4185,9 +4163,8 @@ do
                                     local lookupcache = step.coverage
                                     local lookupmatch = lookupcache[char]
                                     if lookupmatch then
-                                        -- todo: disc?
                                         local ok
-                                        head, start, ok = handler(head,start,dataset,sequence,lookupmatch,rlmode,step,i)
+                                        head, start, ok = handler(head,start,dataset,sequence,lookupmatch,rlmode,skiphash,step)
                                         if ok then
                                             done = true
                                             break
@@ -4216,7 +4193,7 @@ do
                     while start do
                         local char, id = ischar(start,font)
                         if char then
-                            if skipsome and skipsome[char] then -- we never needed it here but let's try
+                            if skiphash and skiphash[char] then -- we never needed it here but let's try
                                 start = getnext(start)
                             else
                                 local lookupmatch = lookupcache[char]
@@ -4231,7 +4208,7 @@ do
                                     end
                                     if a then
                                         local ok
-                                        head, start, ok = handler(head,start,dataset,sequence,lookupmatch,rlmode,step,1)
+                                        head, start, ok = handler(head,start,dataset,sequence,lookupmatch,rlmode,skiphash,step)
                                         if ok then
                                             done = true
                                         end
@@ -4252,11 +4229,11 @@ do
                             if not discs or discs[start] == true then
                                 local ok
                                 if gpossing then
-                                    start, ok = kernrun(start,k_run_single,             font,attr,lookupcache,step,dataset,sequence,rlmode,handler)
+                                    start, ok = kernrun(start,k_run_single,             font,attr,lookupcache,step,dataset,sequence,rlmode,skiphash,handler)
                                 elseif typ == "gsub_ligature" then
-                                    start, ok = testrun(start,t_run_single,c_run_single,font,attr,lookupcache,step,dataset,sequence,rlmode,handler)
+                                    start, ok = testrun(start,t_run_single,c_run_single,font,attr,lookupcache,step,dataset,sequence,rlmode,skiphash,handler)
                                 else
-                                    start, ok = comprun(start,c_run_single,             font,attr,lookupcache,step,dataset,sequence,rlmode,handler)
+                                    start, ok = comprun(start,c_run_single,             font,attr,lookupcache,step,dataset,sequence,rlmode,skiphash,handler)
                                 end
                                 if ok then
                                     done = true
@@ -4281,7 +4258,7 @@ do
                         if char then
                             local m = merged[char]
                             if m then
-                                if skipsome and skipsome[char] then -- we never needed it here but let's try
+                                if skiphash and skiphash[char] then -- we never needed it here but let's try
                                     start = getnext(start)
                                 else
                                     local a -- happens often so no assignment is faster
@@ -4302,7 +4279,7 @@ do
                                             if lookupmatch then
                                                 -- we could move all code inline but that makes things even more unreadable
                                                 local ok
-                                                head, start, ok = handler(head,start,dataset,sequence,lookupmatch,rlmode,step,i)
+                                                head, start, ok = handler(head,start,dataset,sequence,lookupmatch,rlmode,skiphash,step)
                                                 if ok then
                                                     done = true
                                                     break
@@ -4329,11 +4306,11 @@ do
                             if not discs or discs[start] == true then
                                 local ok
                                 if gpossing then
-                                    start, ok = kernrun(start,k_run_multiple,               font,attr,steps,nofsteps,dataset,sequence,rlmode,handler)
+                                    start, ok = kernrun(start,k_run_multiple,               font,attr,steps,nofsteps,dataset,sequence,rlmode,skiphash,handler)
                                 elseif typ == "gsub_ligature" then
-                                    start, ok = testrun(start,t_run_multiple,c_run_multiple,font,attr,steps,nofsteps,dataset,sequence,rlmode,handler)
+                                    start, ok = testrun(start,t_run_multiple,c_run_multiple,font,attr,steps,nofsteps,dataset,sequence,rlmode,skiphash,handler)
                                 else
-                                    start, ok = comprun(start,c_run_multiple,               font,attr,steps,nofsteps,dataset,sequence,rlmode,handler)
+                                    start, ok = comprun(start,c_run_multiple,               font,attr,steps,nofsteps,dataset,sequence,rlmode,skiphash,handler)
                                 end
                                 if ok then
                                     done = true
@@ -4419,7 +4396,7 @@ do
                 position = position + 1
                 local m = merged[char]
                 if m then
-                    if skipsome and skipsome[char] then -- we never needed it here but let's try
+                    if skiphash and skiphash[char] then -- we never needed it here but let's try
                         start = getnext(start)
                     else
                         for i=m[1],m[2] do
@@ -4428,7 +4405,7 @@ do
                             local lookupmatch = lookupcache[char]
                             if lookupmatch then
                                 local ok
-                                head, start, ok = handler(head,start,dataset,sequence,lookupmatch,rlmode,step,i)
+                                head, start, ok = handler(head,start,dataset,sequence,lookupmatch,rlmode,skiphash,step)
                                 if ok then
                                  -- if matches then
                                  --     matches[position] = i
@@ -4526,27 +4503,35 @@ otf.handlers = handlers -- used in devanagari
 
 local setspacekerns = nodes.injections.setspacekerns if not setspacekerns then os.exit() end
 
+-- This pseudo feature has no steps, so it gets called as:
+--
+--   function(head,dataset,sequence,initialrl,font,attr)
+--       return head, done
+--   end
+--
+-- Also see (!!).
+
 if fontfeatures then
 
-    function otf.handlers.trigger_space_kerns(head,start,dataset,sequence,_,_,_,_,font,attr)
+    function handlers.trigger_space_kerns(head,dataset,sequence,initialrl,font,attr)
         local features = fontfeatures[font]
         local enabled  = features and features.spacekern and features.kern
         if enabled then
             setspacekerns(font,sequence)
         end
-        return head, start, enabled
+        return head, enabled
     end
 
 else -- generic (no hashes)
 
-    function otf.handlers.trigger_space_kerns(head,start,dataset,sequence,_,_,_,_,font,attr)
+    function handlers.trigger_space_kerns(head,dataset,sequence,initialrl,font,attr)
         local shared   = fontdata[font].shared
         local features = shared and shared.features
         local enabled  = features and features.spacekern and features.kern
         if enabled then
             setspacekerns(font,sequence)
         end
-        return head, start, enabled
+        return head, enabled
     end
 
 end
@@ -4676,6 +4661,7 @@ local function spaceinitializer(tfmdata,value) -- attr
                 }
                 if last > 0 then
                     local triggersequence = {
+                        -- no steps, see (!!)
                         features = { kern = feat or { dflt = { dflt = true, } } },
                         flags    = noflags,
                         name     = "trigger_space_kerns",
diff --git a/tex/context/base/mkiv/font-oup.lua b/tex/context/base/mkiv/font-oup.lua
index dab746125..c67662844 100644
--- a/tex/context/base/mkiv/font-oup.lua
+++ b/tex/context/base/mkiv/font-oup.lua
@@ -2534,8 +2534,15 @@ local function mergesteps(t,k)
     end
 end
 
+local function checkmerge(sequence)
+    local steps = sequence.steps
+    if steps then
+        setmetatableindex(steps,mergesteps)
+    end
+end
+
 local function checkflags(sequence,resources)
-    if not sequence.skipsome then
+    if not sequence.skiphash then
         local flags = sequence.flags
         if flags then
             local skipmark     = flags[1]
@@ -2544,24 +2551,38 @@ local function checkflags(sequence,resources)
             local markclass    = sequence.markclass
             local skipsome     = skipmark or skipligature or skipbase or markclass or false
             if skipsome then
-                sequence.skipsome = setmetatableindex(function(t,k)
+                sequence.skiphash = setmetatableindex(function(t,k)
                     local c = resources.classes[k] -- delayed table
                     local v = c == skipmark or (markclass and c == "mark" and not markclass[k]) or c == skipligature or c == skipbase
+-- local v = (skipmark     and c == "mark")
+--        or (markclass    and c == "mark" and not markclass[k])
+--        or (skipligature and c == "ligature")
+--        or (skipbase     and c == "base")
                     t[k] = v or false
                     return v
                 end)
             else
-                sequence.skipsome = false
+                sequence.skiphash = false
             end
         else
-            sequence.skipsome = false
+            sequence.skiphash = false
+        end
+    end
+end
+
+local function checksteps(sequence)
+    local steps = sequence.steps
+    if steps then
+        for i=1,#steps do
+            steps[i].index = i
         end
     end
 end
 
 if fonts.helpers then
-    fonts.helpers.mergesteps = mergesteps
+    fonts.helpers.checkmerge = checkmerge
     fonts.helpers.checkflags = checkflags
+    fonts.helpers.checksteps = checksteps -- has to happen last
 end
 
 function readers.expand(data)
@@ -2619,8 +2640,6 @@ function readers.expand(data)
                 if steps then
                     local nofsteps = sequence.nofsteps
 
-                    setmetatableindex(steps,mergesteps)
-
                     local kind = sequence.type
                     local markclass = sequence.markclass
                     if markclass then
@@ -2632,7 +2651,9 @@ function readers.expand(data)
                         end
                     end
 
+                    checkmerge(sequence)
                     checkflags(sequence,resources)
+                    checksteps(sequence)
 
                     for i=1,nofsteps do
                         local step = steps[i]
diff --git a/tex/context/base/mkiv/font-tra.mkiv b/tex/context/base/mkiv/font-tra.mkiv
index 8ca4bf3e4..07a28b7ab 100644
--- a/tex/context/base/mkiv/font-tra.mkiv
+++ b/tex/context/base/mkiv/font-tra.mkiv
@@ -198,6 +198,41 @@
 %       \blank}%
 %    \endgroup}
 
+\newconstant\showotfstepsmode  \showotfstepsmode\plusfour
+
+\unexpanded\def\showotfsteps_n
+  {\blank
+   \begingroup
+     \advance\leftskip6\emwidth
+     \showotfstepmessages\recurselevel
+     \par
+   \endgroup
+   \blank
+   \dontleavehmode
+   \hbox to \hsize \bgroup
+     \hbox to 6\emwidth \bgroup
+       \bf
+       \ifnum\recurselevel=\scratchcounter result\else step \recurselevel\fi
+       \hss
+     \egroup
+     \vtop \bgroup
+       \hsize\dimexpr\hsize-6\emwidth\relax
+       \resetallattributes
+       \pardir TLT\textdir TLT\relax
+       \dontleavehmode
+       \ifnum\recurselevel=\scratchcounter
+         \ruledhbox{\box\otfcompositionbox}%
+       \else
+         \ruledhbox{\showotfstepglyphs\recurselevel}%
+       \fi
+       \quad
+       \showotfstepchars\recurselevel
+       \hfill
+       \par
+     \egroup
+   \egroup
+   \blank}
+
 \unexpanded\def\showotfsteps
   {\begingroup
    \veryraggedright
@@ -226,37 +261,24 @@
    \blank
    \scratchcounter\otfnoffeaturesteps\relax
    \dorecurse\scratchcounter
-     {\blank
-      \begingroup
-        \advance\leftskip6\emwidth
-        \showotfstepmessages\recurselevel
-        \par
-      \endgroup
-      \blank
-      \dontleavehmode
-      \hbox to \hsize \bgroup
-        \hbox to 6\emwidth \bgroup
-          \bf
-          \ifnum\recurselevel=\scratchcounter result\else step \recurselevel\fi
-          \hss
-        \egroup
-        \vtop \bgroup
-          \hsize\dimexpr\hsize-6\emwidth\relax
-          \resetallattributes
-          \pardir TLT\textdir TLT\relax
-          \dontleavehmode
-          \ifnum\recurselevel=\scratchcounter
-            \ruledhbox{\box\otfcompositionbox}%
-          \else
-            \ruledhbox{\showotfstepglyphs\recurselevel}%
-          \fi
-          \quad
-          \showotfstepchars\recurselevel
-          \hfill
-          \par
-        \egroup
-      \egroup
-      \blank}%
+     {\ifcase\showotfstepsmode
+      \or % 1 = only first
+        \ifnum\recurselevel=\plusone
+          \showotfsteps_n
+        \fi
+      \or % 2 = only last
+        \ifnum\recurselevel=\scratchcounter
+          \showotfsteps_n
+        \fi
+      \or % 3 = first and last
+        \ifnum\recurselevel=\plusone
+          \showotfsteps_n
+        \else\ifnum\recurselevel=\scratchcounter
+          \showotfsteps_n
+        \fi\fi
+      \else % everything
+        \showotfsteps_n
+      \fi}%
    \endgroup}
 
 \unexpanded\def\startotfsample
diff --git a/tex/context/base/mkiv/node-res.lua b/tex/context/base/mkiv/node-res.lua
index 85c71a64d..d6f988e0b 100644
--- a/tex/context/base/mkiv/node-res.lua
+++ b/tex/context/base/mkiv/node-res.lua
@@ -430,11 +430,10 @@ function nutpool.temp()
 end
 
 function nutpool.noad()         return copy_nut(noad)         end
-function nutpool.delimiter()    return copy_nut(delimiter)    end
+function nutpool.delimiter()    return copy_nut(delimiter)    end  nutpool.delim = nutpool.delimiter
 function nutpool.fence()        return copy_nut(fence)        end
 function nutpool.submlist()     return copy_nut(submlist)     end
 function nutpool.noad()         return copy_nut(noad)         end
-function nutpool.delimiter()    return copy_nut(delim)        end   nutpool.delim = nutpool.delimiter
 function nutpool.fence()        return copy_nut(fence)        end
 function nutpool.accent()       return copy_nut(accent)       end
 function nutpool.radical()      return copy_nut(radical)      end
diff --git a/tex/context/base/mkiv/status-files.pdf b/tex/context/base/mkiv/status-files.pdf
index 0e42f2f01..40f20e02d 100644
Binary files a/tex/context/base/mkiv/status-files.pdf and b/tex/context/base/mkiv/status-files.pdf differ
diff --git a/tex/context/base/mkiv/status-lua.pdf b/tex/context/base/mkiv/status-lua.pdf
index 7545fe7af..a0f467fa3 100644
Binary files a/tex/context/base/mkiv/status-lua.pdf and b/tex/context/base/mkiv/status-lua.pdf differ
diff --git a/tex/context/interface/mkii/keys-cs.xml b/tex/context/interface/mkii/keys-cs.xml
index 9ce2a779a..727f8e9aa 100644
--- a/tex/context/interface/mkii/keys-cs.xml
+++ b/tex/context/interface/mkii/keys-cs.xml
@@ -693,6 +693,7 @@
 		<cd:constant name='bottomoffset' value='offsetspodku'/>
 		<cd:constant name='bottomspace' value='bottomspace'/>
 		<cd:constant name='bottomstate' value='statusspodku'/>
+		<cd:constant name='break' value='break'/>
 		<cd:constant name='buffer' value='buffer'/>
 		<cd:constant name='cache' value='cache'/>
 		<cd:constant name='calculate' value='pocitat'/>
diff --git a/tex/context/interface/mkiv/i-context.pdf b/tex/context/interface/mkiv/i-context.pdf
index 10cdcdabd..54eef5bcd 100644
Binary files a/tex/context/interface/mkiv/i-context.pdf and b/tex/context/interface/mkiv/i-context.pdf differ
diff --git a/tex/context/interface/mkiv/i-readme.pdf b/tex/context/interface/mkiv/i-readme.pdf
index 5636448f9..16621d972 100644
Binary files a/tex/context/interface/mkiv/i-readme.pdf and b/tex/context/interface/mkiv/i-readme.pdf differ
diff --git a/tex/context/modules/mkiv/s-fnt-20.mkiv b/tex/context/modules/mkiv/s-fnt-20.mkiv
index 99f5eba69..b61caaef6 100644
--- a/tex/context/modules/mkiv/s-fnt-20.mkiv
+++ b/tex/context/modules/mkiv/s-fnt-20.mkiv
@@ -39,21 +39,15 @@
    liga=yes,dlig=yes,rlig=yes,clig=yes,
    mark=yes,mkmk=yes,kern=yes,curs=yes]
 
-% \definefontfeature
-%   [otftracker-husayni]
-%   [analyze=yes,mode=node,
-%    language=dflt,script=arab,ccmp=yes,
-%    init=yes,medi=yes,fina=yes,isol=yes,
-%    calt=yes,
-%    mark=yes,mkmk=yes,kern=yes,curs=yes]
-
 \definefontfeature
-  [otftracker-husayni]
+  [otftracker-husayni-default]
   [analyze=yes,mode=node,
    language=dflt,script=arab,
    init=yes,medi=yes,fina=yes,
+   calt=yes,
    rlig=yes,
    ccmp=yes,
+   salt=yes,
    ss01=yes, % full Allah, Muhammad, Allahumma
    ss05=yes, % full Jiim stacking
    ss09=yes, % full Haa stacking
@@ -77,6 +71,10 @@
    ss41=yes, % initial alternates
    mark=yes,mkmk=yes,kern=yes,curs=yes]
 
+\definefontfeature
+  [otftracker-husayni]
+  [otftracker-husayni-default]
+
 \definefontfeature
   [otftracker-simplenaskhi]
   [analyze=yes,mode=node,
diff --git a/tex/generic/context/luatex/luatex-fonts-merged.lua b/tex/generic/context/luatex/luatex-fonts-merged.lua
index 4e0a15bd3..c1bbcd2d0 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 : c:/data/develop/context/sources/luatex-fonts-merged.lua
 -- parent file : c:/data/develop/context/sources/luatex-fonts.lua
--- merge date  : 08/03/17 11:02:54
+-- merge date  : 08/04/17 09:40:52
 
 do -- begin closure to overcome local limits and interference
 
@@ -19501,8 +19501,14 @@ local function mergesteps(t,k)
     return merged
   end
 end
+local function checkmerge(sequence)
+  local steps=sequence.steps
+  if steps then
+    setmetatableindex(steps,mergesteps)
+  end
+end
 local function checkflags(sequence,resources)
-  if not sequence.skipsome then
+  if not sequence.skiphash then
     local flags=sequence.flags
     if flags then
       local skipmark=flags[1]
@@ -19511,23 +19517,32 @@ local function checkflags(sequence,resources)
       local markclass=sequence.markclass
       local skipsome=skipmark or skipligature or skipbase or markclass or false
       if skipsome then
-        sequence.skipsome=setmetatableindex(function(t,k)
+        sequence.skiphash=setmetatableindex(function(t,k)
           local c=resources.classes[k] 
           local v=c==skipmark or (markclass and c=="mark" and not markclass[k]) or c==skipligature or c==skipbase
           t[k]=v or false
           return v
         end)
       else
-        sequence.skipsome=false
+        sequence.skiphash=false
       end
     else
-      sequence.skipsome=false
+      sequence.skiphash=false
+    end
+  end
+end
+local function checksteps(sequence)
+  local steps=sequence.steps
+  if steps then
+    for i=1,#steps do
+      steps[i].index=i
     end
   end
 end
 if fonts.helpers then
-  fonts.helpers.mergesteps=mergesteps
+  fonts.helpers.checkmerge=checkmerge
   fonts.helpers.checkflags=checkflags
+  fonts.helpers.checksteps=checksteps 
 end
 function readers.expand(data)
   if not data or data.expanded then
@@ -19574,7 +19589,6 @@ function readers.expand(data)
         local steps=sequence.steps
         if steps then
           local nofsteps=sequence.nofsteps
-          setmetatableindex(steps,mergesteps)
           local kind=sequence.type
           local markclass=sequence.markclass
           if markclass then
@@ -19585,7 +19599,9 @@ function readers.expand(data)
               sequence.markclass=markclasses[markclass]
             end
           end
+          checkmerge(sequence)
           checkflags(sequence,resources)
+          checksteps(sequence)
           for i=1,nofsteps do
             local step=steps[i]
             local baseclasses=step.baseclasses
@@ -19715,7 +19731,7 @@ local trace_defining=false registertracker("fonts.defining",function(v) trace_de
 local report_otf=logs.reporter("fonts","otf loading")
 local fonts=fonts
 local otf=fonts.handlers.otf
-otf.version=3.101 
+otf.version=3.102 
 otf.cache=containers.define("fonts","otl",otf.version,true)
 otf.svgcache=containers.define("fonts","svg",otf.version,true)
 otf.sbixcache=containers.define("fonts","sbix",otf.version,true)
@@ -21676,6 +21692,9 @@ local function inject_everything(head,where)
     if rightkern then 
       if pn.markdir<0 then
         ox=px-pn.markx-rightkern
+if not pn.markmark then 
+  ox=ox+(pn.leftkern or 0)
+end
       else
         if false then
           local leftkern=pp.leftkern
@@ -23067,7 +23086,7 @@ function handlers.gsub_single(head,start,dataset,sequence,replacement)
   setchar(start,replacement)
   return head,start,true
 end
-function handlers.gsub_alternate(head,start,dataset,sequence,alternative)
+function handlers.gsub_alternate(head,start,dataset,sequence,alternative,rlmode,skiphash)
   local kind=dataset[4]
   local what=dataset[1]
   local value=what==true and tfmdata.shared.features[kind] or what
@@ -23085,13 +23104,13 @@ function handlers.gsub_alternate(head,start,dataset,sequence,alternative)
   end
   return head,start,true
 end
-function handlers.gsub_multiple(head,start,dataset,sequence,multiple)
+function handlers.gsub_multiple(head,start,dataset,sequence,multiple,rlmode,skiphash)
   if trace_multiples then
     logprocess("%s: replacing %s by multiple %s",pref(dataset,sequence),gref(getchar(start)),gref(multiple))
   end
   return multiple_glyphs(head,start,multiple,sequence.flags[1],dataset[1])
 end
-function handlers.gsub_ligature(head,start,dataset,sequence,ligature)
+function handlers.gsub_ligature(head,start,dataset,sequence,ligature,rlmode,skiphash)
   local current=getnext(start)
   if not current then
     return head,start,false,nil
@@ -23201,7 +23220,7 @@ function handlers.gsub_ligature(head,start,dataset,sequence,ligature)
   end
   return head,start,false,discfound
 end
-function handlers.gpos_single(head,start,dataset,sequence,kerns,rlmode,step,i,injection)
+function handlers.gpos_single(head,start,dataset,sequence,kerns,rlmode,skiphash,step,injection)
   local startchar=getchar(start)
   local format=step.format
   if format=="single" or type(kerns)=="table" then 
@@ -23217,7 +23236,7 @@ function handlers.gpos_single(head,start,dataset,sequence,kerns,rlmode,step,i,in
   end
   return head,start,false
 end
-function handlers.gpos_pair(head,start,dataset,sequence,kerns,rlmode,step,i,injection)
+function handlers.gpos_pair(head,start,dataset,sequence,kerns,rlmode,skiphash,step,injection)
   local snext=getnext(start)
   if not snext then
     return head,start,false
@@ -23275,7 +23294,7 @@ function handlers.gpos_pair(head,start,dataset,sequence,kerns,rlmode,step,i,inje
     return head,start,false
   end
 end
-function handlers.gpos_mark2base(head,start,dataset,sequence,markanchors,rlmode)
+function handlers.gpos_mark2base(head,start,dataset,sequence,markanchors,rlmode,skiphash)
   local markchar=getchar(start)
   if marks[markchar] then
     local base=getprev(start) 
@@ -23328,7 +23347,7 @@ function handlers.gpos_mark2base(head,start,dataset,sequence,markanchors,rlmode)
   end
   return head,start,false
 end
-function handlers.gpos_mark2ligature(head,start,dataset,sequence,markanchors,rlmode)
+function handlers.gpos_mark2ligature(head,start,dataset,sequence,markanchors,rlmode,skiphash)
   local markchar=getchar(start)
   if marks[markchar] then
     local base=getprev(start) 
@@ -23391,7 +23410,7 @@ function handlers.gpos_mark2ligature(head,start,dataset,sequence,markanchors,rlm
   end
   return head,start,false
 end
-function handlers.gpos_mark2mark(head,start,dataset,sequence,markanchors,rlmode)
+function handlers.gpos_mark2mark(head,start,dataset,sequence,markanchors,rlmode,skiphash)
   local markchar=getchar(start)
   if marks[markchar] then
     local base=getprev(start) 
@@ -23426,7 +23445,7 @@ function handlers.gpos_mark2mark(head,start,dataset,sequence,markanchors,rlmode)
   end
   return head,start,false
 end
-function handlers.gpos_cursive(head,start,dataset,sequence,exitanchors,rlmode,step,i) 
+function handlers.gpos_cursive(head,start,dataset,sequence,exitanchors,rlmode,skiphash,step) 
   local startchar=getchar(start)
   if marks[startchar] then
     if trace_cursive then
@@ -23476,7 +23495,7 @@ local function logprocess(...)
   report_chain(...)
 end
 local logwarning=report_chain
-local function reversesub(head,start,stop,dataset,sequence,replacements,rlmode)
+local function reversesub(head,start,stop,dataset,sequence,replacements,rlmode,skiphash)
   local char=getchar(start)
   local replacement=replacements[char]
   if replacement then
@@ -23497,7 +23516,7 @@ end
 local function reportmoresteps(dataset,sequence)
   logwarning("%s: more than 1 step",cref(dataset,sequence))
 end
-function chainprocs.gsub_single(head,start,stop,dataset,sequence,currentlookup,chainindex)
+function chainprocs.gsub_single(head,start,stop,dataset,sequence,currentlookup,rlmode,skiphash,chainindex)
   local steps=currentlookup.steps
   local nofsteps=currentlookup.nofsteps
   if nofsteps>1 then
@@ -23681,7 +23700,7 @@ function chainprocs.gsub_ligature(head,start,stop,dataset,sequence,currentlookup
   end
   return head,start,false,0,false
 end
-function chainprocs.gpos_single(head,start,stop,dataset,sequence,currentlookup,rlmode,chainindex)
+function chainprocs.gpos_single(head,start,stop,dataset,sequence,currentlookup,rlmode,skiphash,chainindex)
   local steps=currentlookup.steps
   local nofsteps=currentlookup.nofsteps
   if nofsteps>1 then
@@ -23711,7 +23730,7 @@ function chainprocs.gpos_single(head,start,stop,dataset,sequence,currentlookup,r
   end
   return head,start,false
 end
-function chainprocs.gpos_pair(head,start,stop,dataset,sequence,currentlookup,rlmode,chainindex) 
+function chainprocs.gpos_pair(head,start,stop,dataset,sequence,currentlookup,rlmode,skiphash,chainindex) 
   local steps=currentlookup.steps
   local nofsteps=currentlookup.nofsteps
   if nofsteps>1 then
@@ -23780,7 +23799,7 @@ function chainprocs.gpos_pair(head,start,stop,dataset,sequence,currentlookup,rlm
   end
   return head,start,false
 end
-function chainprocs.gpos_mark2base(head,start,stop,dataset,sequence,currentlookup,rlmode)
+function chainprocs.gpos_mark2base(head,start,stop,dataset,sequence,currentlookup,rlmode,skiphash)
   local steps=currentlookup.steps
   local nofsteps=currentlookup.nofsteps
   if nofsteps>1 then
@@ -23847,7 +23866,7 @@ function chainprocs.gpos_mark2base(head,start,stop,dataset,sequence,currentlooku
   end
   return head,start,false
 end
-function chainprocs.gpos_mark2ligature(head,start,stop,dataset,sequence,currentlookup,rlmode)
+function chainprocs.gpos_mark2ligature(head,start,stop,dataset,sequence,currentlookup,rlmode,skiphash)
   local steps=currentlookup.steps
   local nofsteps=currentlookup.nofsteps
   if nofsteps>1 then
@@ -23918,7 +23937,7 @@ function chainprocs.gpos_mark2ligature(head,start,stop,dataset,sequence,currentl
   end
   return head,start,false
 end
-function chainprocs.gpos_mark2mark(head,start,stop,dataset,sequence,currentlookup,rlmode)
+function chainprocs.gpos_mark2mark(head,start,stop,dataset,sequence,currentlookup,rlmode,skiphash)
   local steps=currentlookup.steps
   local nofsteps=currentlookup.nofsteps
   if nofsteps>1 then
@@ -23973,7 +23992,7 @@ function chainprocs.gpos_mark2mark(head,start,stop,dataset,sequence,currentlooku
   end
   return head,start,false
 end
-function chainprocs.gpos_cursive(head,start,stop,dataset,sequence,currentlookup,rlmode)
+function chainprocs.gpos_cursive(head,start,stop,dataset,sequence,currentlookup,rlmode,skiphash)
   local steps=currentlookup.steps
   local nofsteps=currentlookup.nofsteps
   if nofsteps>1 then
@@ -24069,7 +24088,7 @@ local function setdiscchecked(d,pre,post,replace)
   setdisc(d,pre,post,replace)
 end
 local noflags={ false,false,false,false }
-local function chainrun(head,start,last,dataset,sequence,rlmode,ck,skipsome) 
+local function chainrun(head,start,last,dataset,sequence,rlmode,skiphash,ck)
   local size=ck[5]-ck[4]+1
   local chainlookups=ck[6]
   local done=false
@@ -24082,7 +24101,7 @@ local function chainrun(head,start,last,dataset,sequence,rlmode,ck,skipsome)
         local chainproc=chainprocs[chainkind]
         if chainproc then
           local ok
-          head,start,ok=chainproc(head,start,last,dataset,sequence,chainstep,rlmode,1)
+          head,start,ok=chainproc(head,start,last,dataset,sequence,chainstep,rlmode,skiphash)
           if ok then
             done=true
           end
@@ -24091,18 +24110,15 @@ local function chainrun(head,start,last,dataset,sequence,rlmode,ck,skipsome)
         end
       end
      else
-      if skipsome then
-        skipsome=sequence.skipsome
-      end
       local i=1
       local laststart=start
       local nofchainlookups=#chainlookups 
       while start do
-        if skipsome then 
+        if skiphash then 
           while start do
             local char=ischar(start,currentfont)
             if char then
-              if skipsome[char] then
+              if skiphash and skiphash[char] then
                 start=getnext(start)
               else
                 break
@@ -24120,7 +24136,7 @@ local function chainrun(head,start,last,dataset,sequence,rlmode,ck,skipsome)
             local chainproc=chainprocs[chainkind]
             if chainproc then
               local ok,n
-              head,start,ok,n=chainproc(head,start,last,dataset,sequence,chainstep,rlmode,i)
+              head,start,ok,n=chainproc(head,start,last,dataset,sequence,chainstep,rlmode,skiphash)
               if ok then
                 done=true
                 if n and n>1 and i+n>nofchainlookups then
@@ -24148,7 +24164,7 @@ local function chainrun(head,start,last,dataset,sequence,rlmode,ck,skipsome)
   else
     local replacements=ck[7]
     if replacements then
-      head,start,done=reversesub(head,start,last,dataset,sequence,replacements,rlmode)
+      head,start,done=reversesub(head,start,last,dataset,sequence,replacements,rlmode,skiphash)
     else
       done=true
       if trace_contexts then
@@ -24158,7 +24174,7 @@ local function chainrun(head,start,last,dataset,sequence,rlmode,ck,skipsome)
   end
   return head,start,done
 end
-local function chaindisk(head,start,dataset,sequence,rlmode,ck,skipped)
+local function chaindisk(head,start,dataset,sequence,rlmode,skiphash,ck)
   if not start then
     return head,start,false
   end
@@ -24371,14 +24387,14 @@ local function chaindisk(head,start,dataset,sequence,rlmode,ck,skipped)
     end
     if not notmatchpre[lookaheaddisc] then
       local ok=false
-      cf,start,ok=chainrun(cf,start,cl,dataset,sequence,rlmode,ck,skipped)
+      cf,start,ok=chainrun(cf,start,cl,dataset,sequence,rlmode,skiphash,ck)
       if ok then
         done=true
       end
     end
     if not notmatchreplace[lookaheaddisc] then
       local ok=false
-      new,cnew,ok=chainrun(new,cnew,clast,dataset,sequence,rlmode,ck,skipped)
+      new,cnew,ok=chainrun(new,cnew,clast,dataset,sequence,rlmode,skiphash,ck)
       if ok then
         done=true
       end
@@ -24424,14 +24440,14 @@ local function chaindisk(head,start,dataset,sequence,rlmode,ck,skipped)
     end
     if not notmatchpost[backtrackdisc] then
       local ok=false
-      cf,start,ok=chainrun(cf,start,last,dataset,sequence,rlmode,ck,skipped)
+      cf,start,ok=chainrun(cf,start,last,dataset,sequence,rlmode,skiphash,ck)
       if ok then
         done=true
       end
     end
     if not notmatchreplace[backtrackdisc] then
       local ok=false
-      new,cnew,ok=chainrun(new,cnew,clast,dataset,sequence,rlmode,ck,skipped)
+      new,cnew,ok=chainrun(new,cnew,clast,dataset,sequence,rlmode,skiphash,ck)
       if ok then
         done=true
       end
@@ -24456,14 +24472,14 @@ local function chaindisk(head,start,dataset,sequence,rlmode,ck,skipped)
     sweephead[replace]=getnext(last) or false
   else
     local ok=false
-    head,start,ok=chainrun(head,start,last,dataset,sequence,rlmode,ck,skipped)
+    head,start,ok=chainrun(head,start,last,dataset,sequence,rlmode,skiphash,ck)
     if ok then
       done=true
     end
   end
   return head,start,done
 end
-local function chaintrac(head,start,dataset,sequence,rlmode,ck,skipped,match)
+local function chaintrac(head,start,dataset,sequence,rlmode,skiphash,ck,match)
   local rule=ck[1]
   local lookuptype=ck[8] or ck[2]
   local nofseq=#ck[3]
@@ -24473,7 +24489,7 @@ local function chaintrac(head,start,dataset,sequence,rlmode,ck,skipped,match)
   logwarning("%s: rule %s %s at char %s for (%s,%s,%s) chars, lookuptype %a",
     cref(dataset,sequence),rule,match and "matches" or "nomatch",gref(char),first-1,last-first+1,nofseq-last,lookuptype)
 end
-local function handle_contextchain(head,start,dataset,sequence,contexts,rlmode)
+local function handle_contextchain(head,start,dataset,sequence,contexts,rlmode,skiphash)
   local sweepnode=sweepnode
   local sweeptype=sweeptype
   local postreplace
@@ -24492,7 +24508,6 @@ local function handle_contextchain(head,start,dataset,sequence,contexts,rlmode)
   end
   local currentfont=currentfont
   local skipped  
-  local skipsome=sequence.skipsome
   local startprev,
      startnext=getboth(start)
   local done   
@@ -24522,7 +24537,7 @@ local function handle_contextchain(head,start,dataset,sequence,contexts,rlmode)
           if last then
             local char,id=ischar(last,currentfont)
             if char then
-              if skipsome and skipsome[char] then
+              if skiphash and skiphash[char] then
                 skipped=true
                 if trace_skips then
                   show_skip(dataset,sequence,char,ck,classes[char])
@@ -24624,7 +24639,7 @@ local function handle_contextchain(head,start,dataset,sequence,contexts,rlmode)
               if prev then
                 local char,id=ischar(prev,currentfont)
                 if char then
-                  if skipsome and skipsome[char] then
+                  if skiphash and skiphash[char] then
                     skipped=true
                     if trace_skips then
                       show_skip(dataset,sequence,char,ck,classes[char])
@@ -24742,7 +24757,7 @@ local function handle_contextchain(head,start,dataset,sequence,contexts,rlmode)
             if current then
               local char,id=ischar(current,currentfont)
               if char then
-                if skipsome and skipsome[char] then
+                if skiphash and skiphash[char] then
                   skipped=true
                   if trace_skips then
                     show_skip(dataset,sequence,char,ck,classes[char])
@@ -24847,12 +24862,12 @@ local function handle_contextchain(head,start,dataset,sequence,contexts,rlmode)
       end
     end
     if trace_contexts then
-      chaintrac(head,start,dataset,sequence,rlmode,ck,skipped,true)
+      chaintrac(head,start,dataset,sequence,rlmode,skipped and skiphash,ck,true)
     end
     if diskseen or sweepnode then
-      head,start,done=chaindisk(head,start,dataset,sequence,rlmode,ck,skipped)
+      head,start,done=chaindisk(head,start,dataset,sequence,rlmode,skipped and skiphash,ck)
     else
-      head,start,done=chainrun(head,start,last,dataset,sequence,rlmode,ck,skipped)
+      head,start,done=chainrun(head,start,last,dataset,sequence,rlmode,skipped and skiphash,ck)
     end
     if done then
       break
@@ -24871,13 +24886,13 @@ handlers.gsub_contextchain=handle_contextchain
 handlers.gsub_reversecontextchain=handle_contextchain
 handlers.gpos_contextchain=handle_contextchain
 handlers.gpos_context=handle_contextchain
-local function chained_contextchain(head,start,stop,dataset,sequence,currentlookup,rlmode)
+local function chained_contextchain(head,start,stop,dataset,sequence,currentlookup,rlmode,skiphash)
   local steps=currentlookup.steps
   local nofsteps=currentlookup.nofsteps
   if nofsteps>1 then
     reportmoresteps(dataset,sequence)
   end
-  return handle_contextchain(head,start,dataset,sequence,currentlookup,rlmode)
+  return handle_contextchain(head,start,dataset,sequence,currentlookup,rlmode,skiphash)
 end
 chainprocs.gsub_context=chained_contextchain
 chainprocs.gsub_contextchain=chained_contextchain
@@ -25197,7 +25212,7 @@ local function testrun(disc,t_run,c_run,...)
   end
 end
 local nesting=0
-local function c_run_single(head,font,attr,lookupcache,step,dataset,sequence,rlmode,handler)
+local function c_run_single(head,font,attr,lookupcache,step,dataset,sequence,rlmode,skiphash,handler)
   local done=false
   local sweep=sweephead[head]
   if sweep then
@@ -25217,7 +25232,7 @@ local function c_run_single(head,font,attr,lookupcache,step,dataset,sequence,rlm
         local lookupmatch=lookupcache[char]
         if lookupmatch then
           local ok
-          head,start,ok=handler(head,start,dataset,sequence,lookupmatch,rlmode,step,1)
+          head,start,ok=handler(head,start,dataset,sequence,lookupmatch,rlmode,skiphash,step)
           if ok then
             done=true
           end
@@ -25311,7 +25326,7 @@ local function t_run_single(start,stop,font,attr,lookupcache)
   end
   return 0
 end
-local function k_run_single(sub,injection,last,font,attr,lookupcache,step,dataset,sequence,rlmode,handler)
+local function k_run_single(sub,injection,last,font,attr,lookupcache,step,dataset,sequence,rlmode,skiphash,handler)
   local a 
   if attr then
     a=getattr(sub,0)
@@ -25325,7 +25340,7 @@ local function k_run_single(sub,injection,last,font,attr,lookupcache,step,datase
       if char then
         local lookupmatch=lookupcache[char]
         if lookupmatch then
-          local h,d,ok=handler(sub,n,dataset,sequence,lookupmatch,rlmode,step,1,injection)
+          local h,d,ok=handler(sub,n,dataset,sequence,lookupmatch,rlmode,skiphash,step,injection)
           if ok then
             return true
           end
@@ -25334,7 +25349,7 @@ local function k_run_single(sub,injection,last,font,attr,lookupcache,step,datase
     end
   end
 end
-local function c_run_multiple(head,font,attr,steps,nofsteps,dataset,sequence,rlmode,handler)
+local function c_run_multiple(head,font,attr,steps,nofsteps,dataset,sequence,rlmode,skiphash,handler)
   local done=false
   local sweep=sweephead[head]
   if sweep then
@@ -25357,7 +25372,7 @@ local function c_run_multiple(head,font,attr,steps,nofsteps,dataset,sequence,rlm
           local lookupmatch=lookupcache[char]
           if lookupmatch then
             local ok
-            head,start,ok=handler(head,start,dataset,sequence,lookupmatch,rlmode,step,i)
+            head,start,ok=handler(head,start,dataset,sequence,lookupmatch,rlmode,skiphash,step)
             if ok then
               done=true
               break
@@ -25459,7 +25474,7 @@ local function t_run_multiple(start,stop,font,attr,steps,nofsteps)
   end
   return 0
 end
-local function k_run_multiple(sub,injection,last,font,attr,steps,nofsteps,dataset,sequence,rlmode,handler)
+local function k_run_multiple(sub,injection,last,font,attr,steps,nofsteps,dataset,sequence,rlmode,skiphash,handler)
   local a 
   if attr then
     a=getattr(sub,0)
@@ -25476,7 +25491,7 @@ local function k_run_multiple(sub,injection,last,font,attr,steps,nofsteps,datase
           local lookupcache=step.coverage
           local lookupmatch=lookupcache[char]
           if lookupmatch then
-            local h,d,ok=handler(sub,n,dataset,sequence,lookupmatch,rlmode,step,i,injection) 
+            local h,d,ok=handler(sub,n,dataset,sequence,lookupmatch,rlmode,skiphash,step,injection) 
             if ok then
               return true
             end
@@ -25583,14 +25598,14 @@ do
       local handler=handlers[typ] 
       local steps=sequence.steps
       local nofsteps=sequence.nofsteps
-      local skipsome=sequence.skipsome
+      local skiphash=sequence.skiphash
       if not steps then
-        local h,d,ok=handler(head,head,dataset,sequence,nil,nil,nil,0,font,attr)
+        local h,ok=handler(head,dataset,sequence,initialrl,font,attr) 
         if ok then
           done=true
-          if h then
-            head=h
-          end
+        end
+        if h and h~=head then
+          head=h
         end
       elseif typ=="gsub_reversecontextchain" then
         local start=find_node_tail(head)
@@ -25612,7 +25627,7 @@ do
                   local lookupmatch=lookupcache[char]
                   if lookupmatch then
                     local ok
-                    head,start,ok=handler(head,start,dataset,sequence,lookupmatch,rlmode,step,i)
+                    head,start,ok=handler(head,start,dataset,sequence,lookupmatch,rlmode,skiphash,step)
                     if ok then
                       done=true
                       break
@@ -25641,7 +25656,7 @@ do
           while start do
             local char,id=ischar(start,font)
             if char then
-              if skipsome and skipsome[char] then 
+              if skiphash and skiphash[char] then 
                 start=getnext(start)
               else
                 local lookupmatch=lookupcache[char]
@@ -25656,7 +25671,7 @@ do
                   end
                   if a then
                     local ok
-                    head,start,ok=handler(head,start,dataset,sequence,lookupmatch,rlmode,step,1)
+                    head,start,ok=handler(head,start,dataset,sequence,lookupmatch,rlmode,skiphash,step)
                     if ok then
                       done=true
                     end
@@ -25676,11 +25691,11 @@ do
               if not discs or discs[start]==true then
                 local ok
                 if gpossing then
-                  start,ok=kernrun(start,k_run_single,font,attr,lookupcache,step,dataset,sequence,rlmode,handler)
+                  start,ok=kernrun(start,k_run_single,font,attr,lookupcache,step,dataset,sequence,rlmode,skiphash,handler)
                 elseif typ=="gsub_ligature" then
-                  start,ok=testrun(start,t_run_single,c_run_single,font,attr,lookupcache,step,dataset,sequence,rlmode,handler)
+                  start,ok=testrun(start,t_run_single,c_run_single,font,attr,lookupcache,step,dataset,sequence,rlmode,skiphash,handler)
                 else
-                  start,ok=comprun(start,c_run_single,font,attr,lookupcache,step,dataset,sequence,rlmode,handler)
+                  start,ok=comprun(start,c_run_single,font,attr,lookupcache,step,dataset,sequence,rlmode,skiphash,handler)
                 end
                 if ok then
                   done=true
@@ -25705,7 +25720,7 @@ do
             if char then
               local m=merged[char]
               if m then
-                if skipsome and skipsome[char] then 
+                if skiphash and skiphash[char] then 
                   start=getnext(start)
                 else
                   local a 
@@ -25723,7 +25738,7 @@ do
                       local lookupmatch=lookupcache[char]
                       if lookupmatch then
                         local ok
-                        head,start,ok=handler(head,start,dataset,sequence,lookupmatch,rlmode,step,i)
+                        head,start,ok=handler(head,start,dataset,sequence,lookupmatch,rlmode,skiphash,step)
                         if ok then
                           done=true
                           break
@@ -25748,11 +25763,11 @@ do
               if not discs or discs[start]==true then
                 local ok
                 if gpossing then
-                  start,ok=kernrun(start,k_run_multiple,font,attr,steps,nofsteps,dataset,sequence,rlmode,handler)
+                  start,ok=kernrun(start,k_run_multiple,font,attr,steps,nofsteps,dataset,sequence,rlmode,skiphash,handler)
                 elseif typ=="gsub_ligature" then
-                  start,ok=testrun(start,t_run_multiple,c_run_multiple,font,attr,steps,nofsteps,dataset,sequence,rlmode,handler)
+                  start,ok=testrun(start,t_run_multiple,c_run_multiple,font,attr,steps,nofsteps,dataset,sequence,rlmode,skiphash,handler)
                 else
-                  start,ok=comprun(start,c_run_multiple,font,attr,steps,nofsteps,dataset,sequence,rlmode,handler)
+                  start,ok=comprun(start,c_run_multiple,font,attr,steps,nofsteps,dataset,sequence,rlmode,skiphash,handler)
                 end
                 if ok then
                   done=true
@@ -25815,7 +25830,7 @@ do
         position=position+1
         local m=merged[char]
         if m then
-          if skipsome and skipsome[char] then 
+          if skiphash and skiphash[char] then 
             start=getnext(start)
           else
             for i=m[1],m[2] do
@@ -25824,7 +25839,7 @@ do
               local lookupmatch=lookupcache[char]
               if lookupmatch then
                 local ok
-                head,start,ok=handler(head,start,dataset,sequence,lookupmatch,rlmode,step,i)
+                head,start,ok=handler(head,start,dataset,sequence,lookupmatch,rlmode,skiphash,step)
                 if ok then
                   break
                 elseif not start then
@@ -25897,23 +25912,23 @@ registerotffeature {
 otf.handlers=handlers
 local setspacekerns=nodes.injections.setspacekerns if not setspacekerns then os.exit() end
 if fontfeatures then
-  function otf.handlers.trigger_space_kerns(head,start,dataset,sequence,_,_,_,_,font,attr)
+  function handlers.trigger_space_kerns(head,dataset,sequence,initialrl,font,attr)
     local features=fontfeatures[font]
     local enabled=features and features.spacekern and features.kern
     if enabled then
       setspacekerns(font,sequence)
     end
-    return head,start,enabled
+    return head,enabled
   end
 else 
-  function otf.handlers.trigger_space_kerns(head,start,dataset,sequence,_,_,_,_,font,attr)
+  function handlers.trigger_space_kerns(head,dataset,sequence,initialrl,font,attr)
     local shared=fontdata[font].shared
     local features=shared and shared.features
     local enabled=features and features.spacekern and features.kern
     if enabled then
       setspacekerns(font,sequence)
     end
-    return head,start,enabled
+    return head,enabled
   end
 end
 local function hasspacekerns(data)
@@ -26350,7 +26365,6 @@ local sequence_reorder_matras={
   nofsteps=1,
   steps={
     {
-      osdstep=true,
       coverage=pre_mark,
     }
   }
@@ -26364,7 +26378,6 @@ local sequence_reorder_reph={
   nofsteps=1,
   steps={
     {
-      osdstep=true,
       coverage={},
     }
   }
@@ -26378,7 +26391,6 @@ local sequence_reorder_pre_base_reordering_consonants={
   nofsteps=1,
   steps={
     {
-      osdstep=true,
       coverage={},
     }
   }
@@ -26391,7 +26403,7 @@ local sequence_remove_joiners={
   type="devanagari_remove_joiners",
   nofsteps=1,
   steps={
-    { osdstep=true,
+    {
       coverage=both_joiners_true,
     },
   }
@@ -26500,24 +26512,21 @@ local function initializedevanagi(tfmdata)
               if coverage then
                 local reph=false
                 if kind=="rphf" then
-                  if true then
-                    for k,v in next,ra do
-                      local r=coverage[k]
-                      if r then
-                        local h=false
-                        for k,v in next,halant do
-                          local h=r[k]
-                          if h then
-                            reph=h.ligature or false
-                            break
-                          end
-                        end
-                        if reph then
+                  for k,v in next,ra do
+                    local r=coverage[k]
+                    if r then
+                      local h=false
+                      for k,v in next,halant do
+                        local h=r[k]
+                        if h then
+                          reph=h.ligature or false
                           break
                         end
                       end
+                      if reph then
+                        break
+                      end
                     end
-                  else
                   end
                 end
                 seqsubset[#seqsubset+1]={ kind,coverage,reph }
@@ -28499,8 +28508,9 @@ local fonts=fonts
 local otf=fonts.handlers.otf
 local registerotffeature=otf.features.register
 local setmetatableindex=table.setmetatableindex
-local mergesteps=fonts.helpers.mergesteps
+local checkmerge=fonts.helpers.checkmerge
 local checkflags=fonts.helpers.checkflags
+local checksteps=fonts.helpers.checksteps
 local normalized={
   substitution="substitution",
   single="substitution",
@@ -29076,7 +29086,8 @@ local function addfeature(data,feature,specifications)
               steps[nofsteps]=register(coverage,featuretype,format,feature,nofsteps,descriptions,resources)
             end
           end
-          setmetatableindex(steps,mergesteps)
+          checkmerge(specification)
+          checksteps(specification)
           s[i]={
             [stepkey]=steps,
             nofsteps=nofsteps,
@@ -29135,7 +29146,6 @@ local function addfeature(data,feature,specifications)
             askedfeatures[k]=tohash(v)
           end
         end
-        setmetatableindex(steps,mergesteps)
         if featureflags[1] then featureflags[1]="mark" end
         if featureflags[2] then featureflags[2]="ligature" end
         if featureflags[3] then featureflags[3]="base" end
@@ -29151,6 +29161,8 @@ local function addfeature(data,feature,specifications)
           type=steptype,
         }
         checkflags(sequence,resources)
+        checkmerge(sequence)
+        checksteps(sequence)
         local first,last=getrange(sequences,category)
         inject(specification,sequences,sequence,first,last,category,feature)
         local features=fontfeatures[category]
-- 
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