2017-09-05 15:17:00

1 files changed, 80 insertions, 78 deletions

diff --git a/tex/context/base/mkiv/math-tag.lua b/tex/context/base/mkiv/math-tag.lua
index a967ed3e8..3b717af15 100644
--- a/tex/context/base/mkiv/math-tag.lua
+++ b/tex/context/base/mkiv/math-tag.lua
@@ -251,93 +251,95 @@ process = function(start) -- we cannot use the processor as we have no finalizer
                 -- keep an eye on math_box_code and see what ends up in there
                 local attr = getattr(start,a_tagged)
                 local specification = taglist[attr]
-                local tag = specification.tagname
-                if tag == "formulacaption" then
-                    -- skip
-                elseif tag == "mstacker" then
-                    local list = getlist(start)
-                    if list then
-                        process(list)
-                    end
-                else
-                    if tag ~= "mstackertop" and tag ~= "mstackermid" and tag ~= "mstackerbot" then
-                        tag = "mtext"
-                    end
-                    local text = start_tagged(tag)
-                    setattr(start,a_tagged,text)
-                    local list = getlist(start)
-                    if not list then
-                        -- empty list
-                    elseif not attr then
-                        -- box comes from strange place
-                        set_attributes(list,a_tagged,text) -- only the first node ?
+                if specification then
+                    local tag = specification.tagname
+                    if tag == "formulacaption" then
+                        -- skip
+                    elseif tag == "mstacker" then
+                        local list = getlist(start)
+                        if list then
+                            process(list)
+                        end
                     else
-                        -- Beware, the first node in list is the actual list so we definitely
-                        -- need to nest. This approach is a hack, maybe I'll make a proper
-                        -- nesting feature to deal with this at another level. Here we just
-                        -- fake structure by enforcing the inner one.
-                        --
-                        -- todo: have a local list with local tags that then get appended
-                        --
-                        local tagdata = specification.taglist
-                        local common = #tagdata + 1
-                        local function runner(list,depth) -- quite inefficient
-                            local cache = { } -- we can have nested unboxed mess so best local to runner
-                            local keep = nil
-                         -- local keep = { } -- win case we might need to move keep outside
-                            for n in traverse_nodes(list) do
-                                local id = getid(n)
-                                local mth = id == math_code and getsubtype(n)
-                                if mth == 0 then
-                                 -- insert(keep,text)
-                                    keep = text
-                                    text = start_tagged("mrow")
-                                    common = common + 1
-                                end
-                                local aa = getattr(n,a_tagged)
-                                if aa then
-                                    local ac = cache[aa]
-                                    if not ac then
-                                        local tagdata = taglist[aa].taglist
-                                        local extra = #tagdata
-                                        if common <= extra then
-                                            for i=common,extra do
-                                                ac = restart_tagged(tagdata[i]) -- can be made faster
-                                            end
-                                            for i=common,extra do
-                                                stop_tagged() -- can be made faster
+                        if tag ~= "mstackertop" and tag ~= "mstackermid" and tag ~= "mstackerbot" then
+                            tag = "mtext"
+                        end
+                        local text = start_tagged(tag)
+                        setattr(start,a_tagged,text)
+                        local list = getlist(start)
+                        if not list then
+                            -- empty list
+                        elseif not attr then
+                            -- box comes from strange place
+                            set_attributes(list,a_tagged,text) -- only the first node ?
+                        else
+                            -- Beware, the first node in list is the actual list so we definitely
+                            -- need to nest. This approach is a hack, maybe I'll make a proper
+                            -- nesting feature to deal with this at another level. Here we just
+                            -- fake structure by enforcing the inner one.
+                            --
+                            -- todo: have a local list with local tags that then get appended
+                            --
+                            local tagdata = specification.taglist
+                            local common = #tagdata + 1
+                            local function runner(list,depth) -- quite inefficient
+                                local cache = { } -- we can have nested unboxed mess so best local to runner
+                                local keep = nil
+                             -- local keep = { } -- win case we might need to move keep outside
+                                for n in traverse_nodes(list) do
+                                    local id = getid(n)
+                                    local mth = id == math_code and getsubtype(n)
+                                    if mth == 0 then
+                                     -- insert(keep,text)
+                                        keep = text
+                                        text = start_tagged("mrow")
+                                        common = common + 1
+                                    end
+                                    local aa = getattr(n,a_tagged)
+                                    if aa then
+                                        local ac = cache[aa]
+                                        if not ac then
+                                            local tagdata = taglist[aa].taglist
+                                            local extra = #tagdata
+                                            if common <= extra then
+                                                for i=common,extra do
+                                                    ac = restart_tagged(tagdata[i]) -- can be made faster
+                                                end
+                                                for i=common,extra do
+                                                    stop_tagged() -- can be made faster
+                                                end
+                                            else
+                                                ac = text
                                             end
-                                        else
-                                            ac = text
+                                            cache[aa] = ac
                                         end
-                                        cache[aa] = ac
+                                        setattr(n,a_tagged,ac)
+                                    else
+                                        setattr(n,a_tagged,text)
                                     end
-                                    setattr(n,a_tagged,ac)
-                                else
-                                    setattr(n,a_tagged,text)
-                                end
 
-                                if id == hlist_code or id == vlist_code then
-                                    runner(getlist(n),depth+1)
-                                elseif id == glyph_code then
-                                    runner(getcomponents(n),depth+1) -- this should not be needed
-                                elseif id == disc_code then
-                                    local pre, post, replace = getdisc(n)
-                                    runner(pre,depth+1)     -- idem
-                                    runner(post,depth+1)    -- idem
-                                    runner(replace,depth+1) -- idem
-                                end
-                                if mth == 1 then
-                                    stop_tagged()
-                                 -- text = remove(keep)
-                                    text = keep
-                                    common = common - 1
+                                    if id == hlist_code or id == vlist_code then
+                                        runner(getlist(n),depth+1)
+                                    elseif id == glyph_code then
+                                        runner(getcomponents(n),depth+1) -- this should not be needed
+                                    elseif id == disc_code then
+                                        local pre, post, replace = getdisc(n)
+                                        runner(pre,depth+1)     -- idem
+                                        runner(post,depth+1)    -- idem
+                                        runner(replace,depth+1) -- idem
+                                    end
+                                    if mth == 1 then
+                                        stop_tagged()
+                                     -- text = remove(keep)
+                                        text = keep
+                                        common = common - 1
+                                    end
                                 end
                             end
+                            runner(list,0)
                         end
-                        runner(list,0)
+                        stop_tagged()
                     end
-                    stop_tagged()
                 end
             elseif id == math_sub_code then -- normally a hbox
                 local list = getlist(start)