2023-01-24 13:50:00

12 files changed, 205 insertions, 213 deletions

diff --git a/source/luametatex/source/libraries/miniz/miniz.c b/source/luametatex/source/libraries/miniz/miniz.c
index c197c181c..8d0032f9e 100644
--- a/source/luametatex/source/libraries/miniz/miniz.c
+++ b/source/luametatex/source/libraries/miniz/miniz.c
@@ -3068,7 +3068,7 @@ static WCHAR* mz_utf8z_to_widechar(const char* str)
 {
   int reqChars = MultiByteToWideChar(CP_UTF8, 0, str, -1, NULL, 0);
   WCHAR* wStr = (WCHAR*)malloc(reqChars * sizeof(WCHAR));
-  MultiByteToWideChar(CP_UTF8, 0, str, -1, wStr, sizeof(WCHAR) * reqChars);
+  MultiByteToWideChar(CP_UTF8, 0, str, -1, wStr, reqChars);
   return wStr;
 }
 
diff --git a/source/luametatex/source/lua/lmtinterface.h b/source/luametatex/source/lua/lmtinterface.h
index f5fd10900..c3ea2a184 100644
--- a/source/luametatex/source/lua/lmtinterface.h
+++ b/source/luametatex/source/lua/lmtinterface.h
@@ -488,18 +488,7 @@ make_lua_key(L, bend_tolerance);\
 make_lua_key(L, bestinsert);\
 make_lua_key(L, bestpagebreak);\
 make_lua_key(L, bestsize);\
-make_lua_key(L, bin);\
-make_lua_key(L, binbinspacing);\
-make_lua_key(L, binclosespacing);\
-make_lua_key(L, binfracspacing);\
-make_lua_key(L, bininnerspacing);\
-make_lua_key(L, binmiddlespacing);\
-make_lua_key(L, binopenspacing);\
-make_lua_key(L, binopspacing);\
-make_lua_key(L, binordspacing);\
-make_lua_key(L, binpunctspacing);\
-make_lua_key(L, binradspacing);\
-make_lua_key(L, binrelspacing);\
+make_lua_key(L, binary);\
 make_lua_key(L, boolean);\
 make_lua_key(L, bothflexible);\
 make_lua_key(L, bottom);\
@@ -536,17 +525,6 @@ make_lua_key(L, choice);\
 make_lua_key(L, class);\
 make_lua_key(L, cleaders);\
 make_lua_key(L, close);\
-make_lua_key(L, closebinspacing);\
-make_lua_key(L, closeclosespacing);\
-make_lua_key(L, closefracspacing);\
-make_lua_key(L, closeinnerspacing);\
-make_lua_key(L, closemiddlespacing);\
-make_lua_key(L, closeopenspacing);\
-make_lua_key(L, closeopspacing);\
-make_lua_key(L, closeordspacing);\
-make_lua_key(L, closepunctspacing);\
-make_lua_key(L, closeradspacing);\
-make_lua_key(L, closerelspacing);\
 make_lua_key(L, clubpenalties);\
 make_lua_key(L, clubpenalty);\
 make_lua_key(L, cmd);\
@@ -697,17 +675,6 @@ make_lua_key(L, force);\
 make_lua_key(L, forcecheck);\
 make_lua_key(L, forcehandler);\
 make_lua_key(L, forcerulethickness);\
-make_lua_key(L, fracbinspacing);\
-make_lua_key(L, fracclosespacing);\
-make_lua_key(L, fracfracspacing);\
-make_lua_key(L, fracinnerspacing);\
-make_lua_key(L, fracmiddlespacing);\
-make_lua_key(L, fracopenspacing);\
-make_lua_key(L, fracopspacing);\
-make_lua_key(L, fracordspacing);\
-make_lua_key(L, fracpunctspacing);\
-make_lua_key(L, fracradspacing);\
-make_lua_key(L, fracrelspacing);\
 make_lua_key(L, fraction);\
 make_lua_key(L, FractionDelimiterDisplayStyleSize);\
 make_lua_key(L, FractionDelimiterSize);\
@@ -782,18 +749,7 @@ make_lua_key(L, index);\
 make_lua_key(L, info);\
 make_lua_key(L, Info);\
 make_lua_key(L, inner);\
-make_lua_key(L, innerbinspacing);\
-make_lua_key(L, innerclosespacing);\
-make_lua_key(L, innerfracspacing);\
-make_lua_key(L, innerinnerspacing);\
 make_lua_key(L, innerlocation);\
-make_lua_key(L, innermiddlespacing);\
-make_lua_key(L, inneropenspacing);\
-make_lua_key(L, inneropspacing);\
-make_lua_key(L, innerordspacing);\
-make_lua_key(L, innerpunctspacing);\
-make_lua_key(L, innerradspacing);\
-make_lua_key(L, innerrelspacing);\
 make_lua_key(L, innerxoffset);\
 make_lua_key(L, inneryoffset);\
 make_lua_key(L, input);\
@@ -931,18 +887,7 @@ make_lua_key(L, mathtextchar);\
 make_lua_key(L, medmuskip);\
 make_lua_key(L, message);\
 make_lua_key(L, middle);\
-make_lua_key(L, middlebinspacing);\
 make_lua_key(L, middlebox);\
-make_lua_key(L, middleclosespacing);\
-make_lua_key(L, middlefracspacing);\
-make_lua_key(L, middleinnerspacing);\
-make_lua_key(L, middlemiddlespacing);\
-make_lua_key(L, middleopenspacing);\
-make_lua_key(L, middleopspacing);\
-make_lua_key(L, middleordspacing);\
-make_lua_key(L, middlepunctspacing);\
-make_lua_key(L, middleradspacing);\
-make_lua_key(L, middlerelspacing);\
 make_lua_key(L, MinConnectorOverlap);\
 make_lua_key(L, mirror);\
 make_lua_key(L, mkern);\
@@ -991,47 +936,13 @@ make_lua_key(L, nucleus);\
 make_lua_key(L, number);\
 make_lua_key(L, numerator);\
 make_lua_key(L, numeratorvariant);\
-make_lua_key(L, op);\
-make_lua_key(L, opbinspacing);\
-make_lua_key(L, opclosespacing);\
 make_lua_key(L, open);\
-make_lua_key(L, openbinspacing);\
-make_lua_key(L, openclosespacing);\
-make_lua_key(L, openfracspacing);\
-make_lua_key(L, openinnerspacing);\
-make_lua_key(L, openmiddlespacing);\
-make_lua_key(L, openopenspacing);\
-make_lua_key(L, openopspacing);\
-make_lua_key(L, openordspacing);\
-make_lua_key(L, openpunctspacing);\
-make_lua_key(L, openradspacing);\
-make_lua_key(L, openrelspacing);\
 make_lua_key(L, openupdepth);\
 make_lua_key(L, openupheight);\
 make_lua_key(L, operator);\
 make_lua_key(L, operatorsize);\
-make_lua_key(L, opfracspacing);\
-make_lua_key(L, opinnerspacing);\
-make_lua_key(L, opmiddlespacing);\
-make_lua_key(L, opopenspacing);\
-make_lua_key(L, opopspacing);\
-make_lua_key(L, opordspacing);\
-make_lua_key(L, oppunctspacing);\
-make_lua_key(L, opradspacing);\
-make_lua_key(L, oprelspacing);\
 make_lua_key(L, options);\
-make_lua_key(L, ord);\
-make_lua_key(L, ordbinspacing);\
-make_lua_key(L, ordclosespacing);\
-make_lua_key(L, ordfracspacing);\
-make_lua_key(L, ordinnerspacing);\
-make_lua_key(L, ordmiddlespacing);\
-make_lua_key(L, ordopenspacing);\
-make_lua_key(L, ordopspacing);\
-make_lua_key(L, ordordspacing);\
-make_lua_key(L, ordpunctspacing);\
-make_lua_key(L, ordradspacing);\
-make_lua_key(L, ordrelspacing);\
+make_lua_key(L, ordinary);\
 make_lua_key(L, orientation);\
 make_lua_key(L, original);\
 make_lua_key(L, orphanpenalties);\
@@ -1134,22 +1045,8 @@ make_lua_key(L, semi_protected_call);\
 make_lua_key(L, protrudechars);\
 make_lua_key(L, protrusion);\
 make_lua_key(L, ptr);\
-make_lua_key(L, punct);\
-make_lua_key(L, punctbinspacing);\
-make_lua_key(L, punctclosespacing);\
-make_lua_key(L, punctfracspacing);\
-make_lua_key(L, punctinnerspacing);\
-make_lua_key(L, punctmiddlespacing);\
-make_lua_key(L, punctopenspacing);\
-make_lua_key(L, punctopspacing);\
-make_lua_key(L, punctordspacing);\
-make_lua_key(L, punctpunctspacing);\
-make_lua_key(L, punctradspacing);\
-make_lua_key(L, punctrelspacing);\
+make_lua_key(L, punctuation);\
 make_lua_key(L, quad);\
-make_lua_key(L, radbinspacing);\
-make_lua_key(L, radclosespacing);\
-make_lua_key(L, radfracspacing);\
 make_lua_key(L, radical);\
 make_lua_key(L, radicaldegreeafter);\
 make_lua_key(L, radicaldegreebefore);\
@@ -1169,14 +1066,6 @@ make_lua_key(L, RadicalRuleThickness);\
 make_lua_key(L, radicalvariant);\
 make_lua_key(L, RadicalVerticalGap);\
 make_lua_key(L, radicalvgap);\
-make_lua_key(L, radinnerspacing);\
-make_lua_key(L, radmiddlespacing);\
-make_lua_key(L, radopenspacing);\
-make_lua_key(L, radopspacing);\
-make_lua_key(L, radordspacing);\
-make_lua_key(L, radpunctspacing);\
-make_lua_key(L, radradspacing);\
-make_lua_key(L, radrelspacing);\
 make_lua_key(L, reader);\
 make_lua_key(L, register);\
 make_lua_key(L, register_attribute);\
@@ -1198,19 +1087,8 @@ make_lua_key(L, registergluespec);\
 make_lua_key(L, registerinteger);\
 make_lua_key(L, registermugluespec);\
 make_lua_key(L, regular);\
-make_lua_key(L, rel);\
+make_lua_key(L, relation);\
 make_lua_key(L, relax);\
-make_lua_key(L, relbinspacing);\
-make_lua_key(L, relclosespacing);\
-make_lua_key(L, relfracspacing);\
-make_lua_key(L, relinnerspacing);\
-make_lua_key(L, relmiddlespacing);\
-make_lua_key(L, relopenspacing);\
-make_lua_key(L, relopspacing);\
-make_lua_key(L, relordspacing);\
-make_lua_key(L, relpunctspacing);\
-make_lua_key(L, relradspacing);\
-make_lua_key(L, relrelspacing);\
 make_lua_key(L, remove_item);\
 make_lua_key(L, repeat);\
 make_lua_key(L, replace);\
@@ -1450,6 +1328,7 @@ make_lua_key(L, vertical);\
 make_lua_key(L, verticalmathkern);\
 make_lua_key(L, vextensible);\
 make_lua_key(L, vextensiblevariant);\
+make_lua_key(L, virtual);\
 make_lua_key(L, vlist);\
 make_lua_key(L, vmode);\
 make_lua_key(L, vmodepar);\
diff --git a/source/luametatex/source/lua/lmtnodelib.c b/source/luametatex/source/lua/lmtnodelib.c
index 116860f85..6a07e3454 100644
--- a/source/luametatex/source/lua/lmtnodelib.c
+++ b/source/luametatex/source/lua/lmtnodelib.c
@@ -2902,6 +2902,27 @@ static int nodelib_direct_getlistdimensions(lua_State *L)
     return 0;
 }
 
+static int nodelib_direct_getruledimensions(lua_State *L)
+{
+    halfword n = nodelib_valid_direct_from_index(L, 1);
+    if (n && node_type(n) == rule_node) {
+        if (node_subtype(n) == virtual_rule_subtype) {
+            lua_pushinteger(L, rule_data(n));
+            lua_pushinteger(L, rule_left(n));
+            lua_pushinteger(L, rule_right(n));
+            lua_pushboolean(L, 1);
+        } else {
+            lua_pushinteger(L, rule_width(n));
+            lua_pushinteger(L, rule_height(n));
+            lua_pushinteger(L, rule_depth(n));
+            lua_pushboolean(L, 0);
+        }
+        return 4;
+    } else { 
+        return 0;
+    }
+}
+
 /* node.direct.getlist */
 
 static int nodelib_direct_getlist(lua_State *L)
@@ -3541,32 +3562,45 @@ static int nodelib_direct_setlink(lua_State *L)
             and the nodes themselves can have old values for prev and next, so ... only single nodes
             are looked at!
         */
-        if (lua_type(L, i) == LUA_TNUMBER) {
-            halfword c = nodelib_valid_direct_from_index(L, i); /* current node */
-            if (c) {
-                if (c != t) {
-                    if (t) {
-                        node_next(t) = c;
-                        node_prev(c) = t;
-                    } else if (i > 1) {
-                        /* we assume that the first node is a kind of head */
-                        node_prev(c) = null;
-                    }
-                    t = c;
-                    if (! h) {
-                        h = t;
+        switch (lua_type(L, i)) { 
+            case LUA_TNUMBER:
+                {
+                    halfword c = nodelib_valid_direct_from_index(L, i); /* current node */
+                    if (c) {
+                        if (c != t) {
+                            if (t) {
+                                node_next(t) = c;
+                                node_prev(c) = t;
+                            } else if (i > 1) {
+                                /* we assume that the first node is a kind of head */
+                                node_prev(c) = null;
+                            }
+                            t = c;
+                            if (! h) {
+                                h = t;
+                            }
+                        } else {
+                            /* we ignore duplicate nodes which can be tails or the previous */
+                        }
+                    } else {
+                        /* we ignore bad nodes, but we could issue a message */
                     }
-                } else {
-                    /* we ignore duplicate nodes which can be tails or the previous */
                 }
-            } else {
-                /* we ignore bad nodes, but we could issue a message */
-            }
-        } else if (t) {
-            /* safeguard: a nil in the list can be meant as end so we nil the next of tail */
-            node_next(t) = null;
-        } else {
-            /* we just ignore nil nodes and have no tail yet */
+                break;
+            case LUA_TBOOLEAN:
+                if (lua_toboolean(L, i)) {
+                    /*tex Just skip this one. */
+                    break;
+                } else { 
+                    /* fall through */
+                }
+            default:
+                if (t) {
+                    /* safeguard: a nil in the list can be meant as end so we nil the next of tail */
+                    node_next(t) = null;
+                } else { 
+                    /* we just ignore nil nodes and have no tail yet */
+                }
         }
     }
     nodelib_push_direct_or_nil(L, h);
@@ -9758,7 +9792,8 @@ static const struct luaL_Reg nodelib_direct_function_list[] = {
     { "rangedimensions",         nodelib_direct_rangedimensions        }, /* maybe get... */
     { "getglyphdimensions",      nodelib_direct_getglyphdimensions     },
     { "getkerndimension",        nodelib_direct_getkerndimension       },
-    { "getlistdimensions",       nodelib_direct_getlistdimensions       },
+    { "getlistdimensions",       nodelib_direct_getlistdimensions      },
+    { "getruledimensions",       nodelib_direct_getruledimensions      },
     { "patchattributes",         nodelib_direct_patchattributes        },
     { "remove",                  nodelib_direct_remove                 },
     { "removefromlist",          nodelib_direct_remove_from_list       },
diff --git a/source/luametatex/source/luarest/lmtoslibext.c b/source/luametatex/source/luarest/lmtoslibext.c
index 0dc5fb940..e49edd5a5 100644
--- a/source/luametatex/source/luarest/lmtoslibext.c
+++ b/source/luametatex/source/luarest/lmtoslibext.c
@@ -115,15 +115,21 @@ static int oslib_sleep(lua_State *L)
         osver.dwOSVersionInfoSize = sizeof(osver);
         GetSystemInfo(&sysinfo);
         strcpy(uts->sysname, "Windows");
-        /* When |GetVersionEx| becomes obsolete the version and release fields will be set to "". */
-        GetVersionEx(&osver);
-        sprintf(uts->version, "%ld.%02ld", osver.dwMajorVersion, osver.dwMinorVersion);
-        if (osver.szCSDVersion[0] != '\0' && (strlen(osver.szCSDVersion) + strlen(uts->version) + 1) < sizeof(uts->version)) {
-            strcat(uts->version, " ");
-            strcat(uts->version, osver.szCSDVersion);
-        }
-        sprintf(uts->release, "build %ld", osver.dwBuildNumber & 0xFFFF);
-        /* So far for the fragile and actually not that relevant part of |uts|. */
+        /*tex When |GetVersionEx| becomes obsolete the version and release fields will be set to "". */
+     // if (0) {
+     //     GetVersionEx(&osver);
+     //     sprintf(uts->version, "%ld.%02ld", osver.dwMajorVersion, osver.dwMinorVersion);
+     //     if (osver.szCSDVersion[0] != '\0' && (strlen(osver.szCSDVersion) + strlen(uts->version) + 1) < sizeof(uts->version)) {
+     //         strcat(uts->version, " ");
+     //         strcat(uts->version, osver.szCSDVersion);
+     //     }
+     //     sprintf(uts->release, "build %ld", osver.dwBuildNumber & 0xFFFF);
+     // } else { 
+            /*tex I can't motivate myself to figure this out. */
+            strcpy(uts->version, "");
+            strcpy(uts->release, "");
+     // }
+        /*tex So far for the fragile and actually not that relevant part of |uts|. */
         switch (sysinfo.wProcessorArchitecture) {
             case PROCESSOR_ARCHITECTURE_AMD64:
                 strcpy(uts->machine, "x86_64");
diff --git a/source/luametatex/source/mp/mpc/mp.c b/source/luametatex/source/mp/mpc/mp.c
index d171e07a6..2d0320868 100644
--- a/source/luametatex/source/mp/mpc/mp.c
+++ b/source/luametatex/source/mp/mpc/mp.c
@@ -9028,11 +9028,21 @@ static mp_knot mp_path_intersection(MP mp, mp_knot h, mp_knot hh, int path, mp_k
                     number_add(nn, unity_t);
                     ll = pp;
                     pp = mp_next_knot(pp);
+if (pp != hh && mp_knotstate(pp) == mp_end_knot) {
+    number_add(nn, unity_t);
+    ll = pp;
+    pp = mp_next_knot(pp);
+}
                 } while (pp != hh);
             }
             number_add(n, unity_t);
             l = p;
             p = mp_next_knot(p);
+if (p != hh && mp_knotstate(p) == mp_end_knot) {
+    number_add(n, unity_t);
+    l = p;
+    p = mp_next_knot(p);
+}
         } while (p != h);
         mp->tol_step = mp->tol_step + 3;
         if (done) {
diff --git a/source/luametatex/source/mp/mpw/mp.w b/source/luametatex/source/mp/mpw/mp.w
index 5fb24250c..f4bdb58ca 100644
--- a/source/luametatex/source/mp/mpw/mp.w
+++ b/source/luametatex/source/mp/mpw/mp.w
@@ -13827,11 +13827,25 @@ static mp_knot mp_path_intersection(MP mp, mp_knot h, mp_knot hh, int path, mp_k
                     number_add(nn, unity_t);
                     ll = pp;
                     pp = mp_next_knot(pp);
+/* begin experiment HH/MS, maybe a loop  */
+if (pp != hh && mp_knotstate(pp) == mp_end_knot) {
+    number_add(nn, unity_t);
+    ll = pp;
+    pp = mp_next_knot(pp);
+}
+/* end experiment HH/MS */
                 } while (pp != hh);
             }
             number_add(n, unity_t);
             l = p;
             p = mp_next_knot(p);
+/* begin experiment HH/MS, maybe a loop  */
+if (p != hh && mp_knotstate(p) == mp_end_knot) {
+    number_add(n, unity_t);
+    l = p;
+    p = mp_next_knot(p);
+}
+/* end experiment HH/MS */
         } while (p != h);
         mp->tol_step = mp->tol_step + 3;
         if (done) {
diff --git a/source/luametatex/source/tex/texcommands.c b/source/luametatex/source/tex/texcommands.c
index 03bcc34d1..13357a141 100644
--- a/source/luametatex/source/tex/texcommands.c
+++ b/source/luametatex/source/tex/texcommands.c
@@ -495,10 +495,12 @@ void tex_initialize_commands(void)
 
         tex_primitive(tex_command,    "vrule",                          vrule_cmd,              normal_rule_code,                         0);
         tex_primitive(luatex_command, "novrule",                        vrule_cmd,              empty_rule_code,                          0);
+        tex_primitive(luatex_command, "virtualvrule",                   vrule_cmd,              virtual_rule_code,                        0);
         tex_primitive(luatex_command, "srule",                          vrule_cmd,              strut_rule_code,                          0);
 
         tex_primitive(tex_command,    "hrule",                          hrule_cmd,              normal_rule_code,                         0);
         tex_primitive(luatex_command, "nohrule",                        hrule_cmd,              empty_rule_code,                          0);
+        tex_primitive(luatex_command, "virtualhrule",                   hrule_cmd,              virtual_rule_code,                        0);
 
         tex_primitive(tex_command,    "count",                          register_cmd,           int_val_level,                            0);
         tex_primitive(luatex_command, "attribute",                      register_cmd,           attr_val_level,                           0);
diff --git a/source/luametatex/source/tex/texmath.c b/source/luametatex/source/tex/texmath.c
index a9f1a3ed9..4979c1a23 100644
--- a/source/luametatex/source/tex/texmath.c
+++ b/source/luametatex/source/tex/texmath.c
@@ -1691,20 +1691,27 @@ int tex_check_active_math_char(int character)
             case alignment_tab_cmd:              
             case superscript_cmd:                
             case subscript_cmd:                  
-                cur_cmd = code;
-                cur_chr = character;
-                cur_tok = token_val(cur_cmd, cur_chr);
-                if (tracing_commands_par >= 4) {
-                    tex_aux_report_active(4, "control", code, character);
-                }
-                return 1;
             case letter_cmd:                     
             case other_char_cmd:
+            case active_char_cmd:
                 cur_cmd = code;
                 cur_chr = character;
                 cur_tok = token_val(cur_cmd, cur_chr);
                 if (tracing_commands_par >= 4) {
-                    tex_aux_report_active(4, "inject", code, character);
+                    switch (code) {
+                        case alignment_tab_cmd:              
+                        case superscript_cmd:                
+                        case subscript_cmd:                  
+                            tex_aux_report_active(4, "control", code, character);
+                            break;
+                        case letter_cmd:                     
+                        case other_char_cmd:
+                            tex_aux_report_active(4, "inject", code, character);
+                            break;
+                        case active_char_cmd:
+                            tex_aux_report_active(4, "active", code, character);
+                            break;
+                    }
                 }
                 return 1;
             default: 
@@ -1754,6 +1761,21 @@ static int tex_aux_scan_active_math_char(mathcodeval *mval, int where)
                     tex_aux_report_active(where, "inject", code, character);
                 }
                 return 0;
+            case active_char_cmd:
+                /*tex 
+                    We reset the code so that we don't get a loop, whuich means that the macro that 
+                    gets invoked has to set the amcode again if needed. 
+                */
+                tex_set_am_code(character, other_char_cmd, 0);
+                cur_cs = tex_active_to_cs(cur_chr, 1);
+                cur_cmd = eq_type(cur_cs);
+                cur_chr = eq_value(cur_cs);
+                tex_x_token();
+                tex_back_input(cur_tok);
+                if (tracing_commands_par >= 4) {
+                    tex_aux_report_active(where, "active", code, character);
+                }
+                return 1;
             default: 
                 if (tracing_commands_par >= 4) {
                     tex_aux_report_active(where, "ignore", code, character);
@@ -1761,6 +1783,7 @@ static int tex_aux_scan_active_math_char(mathcodeval *mval, int where)
                 return 1;
         }
     } else if (mval->class_value == active_math_class_value) {
+        /*tex We might eventually drop tthis feature in favor of the amcode. */
         cur_cs = tex_active_to_cs(cur_chr, 1);
         cur_cmd = eq_type(cur_cs);
         cur_chr = eq_value(cur_cs);
diff --git a/source/luametatex/source/tex/texmlist.c b/source/luametatex/source/tex/texmlist.c
index 79ab490e7..b3f8cf294 100644
--- a/source/luametatex/source/tex/texmlist.c
+++ b/source/luametatex/source/tex/texmlist.c
@@ -1326,14 +1326,14 @@ static halfword register_extensible(halfword fnt, halfword chr, int size, halfwo
 {
     int callback_id = lmt_callback_defined(register_extensible_callback);
     if (callback_id > 0) {
-        halfword b = null;
-        lmt_run_callback(lmt_lua_state.lua_instance, callback_id, "dddN->N", fnt, chr, size, result, &b);
-        if (b) {
-            switch (node_type(b)) {
+        halfword boxed = null;
+        lmt_run_callback(lmt_lua_state.lua_instance, callback_id, "dddN->N", fnt, chr, size, result, &boxed);
+        if (boxed) {
+            switch (node_type(boxed)) {
                 case hlist_node:
                 case vlist_node:
-                    tex_attach_attribute_list_attribute(b, att);
-                    return b;
+                    tex_attach_attribute_list_attribute(boxed, att); /* yes or no */
+                    return boxed;
                 default:
                     tex_formatted_error("fonts", "invalid extensible character %U registered for font %F, [h|v]list expected", chr, fnt);
                     break;
@@ -1425,10 +1425,12 @@ static halfword tex_aux_make_delimiter(halfword target, halfword delimiter, int
                                 goto FOUND;
                             }
                         }
-                        if (tex_char_has_tag_from_font(curfnt, curchr, extensible_tag)) {
-                            fnt = curfnt;
-                            chr = curchr;
-                            do_parts = 1;
+                       if (tex_char_has_tag_from_font(curfnt, curchr, extensible_tag)) {
+                            if (flat ? tex_char_has_tag_from_font(curfnt, curchr, horizontal_tag) : tex_char_has_tag_from_font(curfnt, curchr, vertical_tag)) {
+                                fnt = curfnt;
+                                chr = curchr;
+                                do_parts = 1;
+                            }
                             goto FOUND;
                         } else if (count > 1000) {
                             tex_formatted_warning("fonts", "endless loop in extensible character %U of font %F", curchr, curfnt);
@@ -2142,7 +2144,6 @@ static void tex_aux_make_over(halfword target, halfword style, halfword size, ha
         extensibles. The order is: kern, rule, gap, content.
 
     */
-    halfword result;
     scaled thickness = tex_get_math_y_parameter_checked(style, math_parameter_overbar_rule);
     scaled vgap = tex_get_math_y_parameter_checked(style, math_parameter_overbar_vgap);
     scaled kern = tex_get_math_y_parameter_checked(style, math_parameter_overbar_kern);
@@ -2152,14 +2153,16 @@ static void tex_aux_make_over(halfword target, halfword style, halfword size, ha
             thickness = t;
         }
     }
-    result = tex_aux_overbar(
-        tex_aux_clean_box(noad_nucleus(target), tex_math_style_variant(style, math_parameter_over_line_variant), style, math_nucleus_list, 0, NULL),
-        vgap, thickness, kern,
-        get_attribute_list(noad_nucleus(target)), math_over_rule_subtype, size, fam
-    );
-    node_subtype(result) = math_over_list;
-    kernel_math_list(noad_nucleus(target)) = result;
-    node_type(noad_nucleus(target)) = sub_box_node;
+    {
+        halfword result = tex_aux_overbar(
+            tex_aux_clean_box(noad_nucleus(target), tex_math_style_variant(style, math_parameter_over_line_variant), style, math_nucleus_list, 0, NULL),
+            vgap, thickness, kern,
+            get_attribute_list(noad_nucleus(target)), math_over_rule_subtype, size, fam
+        );
+        node_subtype(result) = math_over_list;
+        kernel_math_list(noad_nucleus(target)) = result;
+        node_type(noad_nucleus(target)) = sub_box_node;
+    }
 }
 
 static void tex_aux_make_under(halfword target, halfword style, halfword size, halfword fam)
@@ -2171,7 +2174,6 @@ static void tex_aux_make_under(halfword target, halfword style, halfword size, h
         rule, kern.
 
     */
-    halfword result;
     scaled thickness = tex_get_math_y_parameter_checked(style, math_parameter_underbar_rule);
     scaled vgap = tex_get_math_y_parameter_checked(style, math_parameter_underbar_vgap);
     scaled kern = tex_get_math_y_parameter_checked(style, math_parameter_underbar_kern);
@@ -2181,14 +2183,16 @@ static void tex_aux_make_under(halfword target, halfword style, halfword size, h
             thickness = t;
         }
     }
-    result = tex_aux_underbar(
-        tex_aux_clean_box(noad_nucleus(target), tex_math_style_variant(style, math_parameter_under_line_variant), style, math_nucleus_list, 0, NULL),
-        vgap, thickness, kern,
-        get_attribute_list(noad_nucleus(target)), math_under_rule_subtype, size, fam
-    );
-    node_subtype(result) = math_over_list;
-    kernel_math_list(noad_nucleus(target)) = result;
-    node_type(noad_nucleus(target)) = sub_box_node;
+    { 
+        halfword result = tex_aux_underbar(
+            tex_aux_clean_box(noad_nucleus(target), tex_math_style_variant(style, math_parameter_under_line_variant), style, math_nucleus_list, 0, NULL),
+            vgap, thickness, kern,
+            get_attribute_list(noad_nucleus(target)), math_under_rule_subtype, size, fam
+        );
+        node_subtype(result) = math_over_list;
+        kernel_math_list(noad_nucleus(target)) = result;
+        node_type(noad_nucleus(target)) = sub_box_node;
+    }
 }
 
 /*tex
diff --git a/source/luametatex/source/tex/texnodes.c b/source/luametatex/source/tex/texnodes.c
index 27b9520e3..625a4346b 100644
--- a/source/luametatex/source/tex/texnodes.c
+++ b/source/luametatex/source/tex/texnodes.c
@@ -204,6 +204,7 @@ void lmt_nodelib_initialize(void) {
     set_value_entry_key(subtypes_rule, math_radical_rule_subtype,  radical)
     set_value_entry_key(subtypes_rule, box_rule_subtype,           box)
     set_value_entry_key(subtypes_rule, image_rule_subtype,         image)
+    set_value_entry_key(subtypes_rule, virtual_rule_subtype,       virtual)
 
     subtypes_glyph = lmt_aux_allocate_value_info(glyph_math_accent_subtype);
 
@@ -212,13 +213,13 @@ void lmt_nodelib_initialize(void) {
     set_value_entry_key(subtypes_glyph, glyph_ligature_subtype,         ligature)
     set_value_entry_key(subtypes_glyph, glyph_math_delimiter_subtype,   delimiter);
     set_value_entry_key(subtypes_glyph, glyph_math_extensible_subtype,  extensible);
-    set_value_entry_key(subtypes_glyph, glyph_math_ordinary_subtype,    ord);
-    set_value_entry_key(subtypes_glyph, glyph_math_operator_subtype,    op);
-    set_value_entry_key(subtypes_glyph, glyph_math_binary_subtype,      bin);
-    set_value_entry_key(subtypes_glyph, glyph_math_relation_subtype,    rel);
+    set_value_entry_key(subtypes_glyph, glyph_math_ordinary_subtype,    ordinary);
+    set_value_entry_key(subtypes_glyph, glyph_math_operator_subtype,    operator);
+    set_value_entry_key(subtypes_glyph, glyph_math_binary_subtype,      binary);
+    set_value_entry_key(subtypes_glyph, glyph_math_relation_subtype,    relation);
     set_value_entry_key(subtypes_glyph, glyph_math_open_subtype,        open);
     set_value_entry_key(subtypes_glyph, glyph_math_close_subtype,       close);
-    set_value_entry_key(subtypes_glyph, glyph_math_punctuation_subtype, punct);
+    set_value_entry_key(subtypes_glyph, glyph_math_punctuation_subtype, punctuation);
     set_value_entry_key(subtypes_glyph, glyph_math_variable_subtype,    variable);
     set_value_entry_key(subtypes_glyph, glyph_math_active_subtype,      active);
     set_value_entry_key(subtypes_glyph, glyph_math_inner_subtype,       inner);
@@ -307,13 +308,13 @@ void lmt_nodelib_initialize(void) {
 
     subtypes_noad = lmt_aux_allocate_value_info(vcenter_noad_subtype); // last_noad_subtype
 
-    set_value_entry_key(subtypes_noad, ordinary_noad_subtype,    ord)
-    set_value_entry_key(subtypes_noad, operator_noad_subtype,    op)
-    set_value_entry_key(subtypes_noad, binary_noad_subtype,      bin)
-    set_value_entry_key(subtypes_noad, relation_noad_subtype,    rel)
+    set_value_entry_key(subtypes_noad, ordinary_noad_subtype,    ordinary)
+    set_value_entry_key(subtypes_noad, operator_noad_subtype,    operator)
+    set_value_entry_key(subtypes_noad, binary_noad_subtype,      binary)
+    set_value_entry_key(subtypes_noad, relation_noad_subtype,    relation)
     set_value_entry_key(subtypes_noad, open_noad_subtype,        open)
     set_value_entry_key(subtypes_noad, close_noad_subtype,       close)
-    set_value_entry_key(subtypes_noad, punctuation_noad_subtype, punct)
+    set_value_entry_key(subtypes_noad, punctuation_noad_subtype, punctuation)
     set_value_entry_key(subtypes_noad, variable_noad_subtype,    variable)
     set_value_entry_key(subtypes_noad, active_noad_subtype,      active)
     set_value_entry_key(subtypes_noad, inner_noad_subtype,       inner)
diff --git a/source/luametatex/source/tex/texnodes.h b/source/luametatex/source/tex/texnodes.h
index 093978c4e..113de8f40 100644
--- a/source/luametatex/source/tex/texnodes.h
+++ b/source/luametatex/source/tex/texnodes.h
@@ -79,6 +79,13 @@
     - radical
     - boundary
 
+    Before we went on with \LUAMETATEX\ already quite a bit was added to \LUATEX\ (granularity in 
+    subtypes, more of them, etc.) but here we add more. Some day I might make a list of difference
+    just for historic reasons. Don't assume equivalence: some in \LUATEX\ was sort of experimental 
+    and improved over time and maybe should not have been added to \LUATEX\ at all and been delayed
+    for \LUAMETATEX\ instead (as it's probably not used), so that core \LUATEX\ stayed closer the 
+    other engines. 
+
 */
 
 typedef enum node_types {
@@ -966,6 +973,7 @@ typedef enum rule_subtypes {
     empty_rule_subtype,
     strut_rule_subtype,
     outline_rule_subtype,
+    virtual_rule_subtype,
     user_rule_subtype,
     math_over_rule_subtype,
     math_under_rule_subtype,
@@ -978,7 +986,8 @@ typedef enum rule_subtypes {
 typedef enum rule_codes {
     normal_rule_code,
     empty_rule_code,
-    strut_rule_code,
+    virtual_rule_code,
+    strut_rule_code
 } rule_codes;
 
 # define last_rule_subtype image_rule_subtype
diff --git a/source/luametatex/source/tex/texrules.c b/source/luametatex/source/tex/texrules.c
index b3d069ad3..db993585b 100644
--- a/source/luametatex/source/tex/texrules.c
+++ b/source/luametatex/source/tex/texrules.c
@@ -4,19 +4,19 @@
 
 # include "luametatex.h"
 
-halfword tex_aux_scan_rule_spec(rule_types t, halfword s)
+halfword tex_aux_scan_rule_spec(rule_types type, halfword code)
 {
     /*tex |width|, |depth|, and |height| all equal |null_flag| now */
-    halfword rule = tex_new_rule_node((quarterword) s);
+    halfword rule = tex_new_rule_node((quarterword) code);
     halfword attr = node_attr(rule);
-    switch (t) {
+    switch (type) {
         case h_rule_type:
             rule_height(rule) = default_rule;
             rule_depth(rule) = 0;
             break;
         case v_rule_type:
         case m_rule_type:
-            if (s == strut_rule_code) {
+            if (code == strut_rule_code) {
                 rule_width(rule) = 0;
                 node_subtype(rule) = strut_rule_subtype;
             } else {
@@ -124,9 +124,18 @@ halfword tex_aux_scan_rule_spec(rule_types t, halfword s)
     }
   DONE:
     node_attr(rule) = attr;
-    if (t == v_rule_type && s == strut_rule_code) {
+    if (type == v_rule_type && code == strut_rule_code) {
         tex_aux_check_text_strut_rule(rule, text_style);
     }
+    if (code == virtual_rule_code) { 
+        rule_data(rule) = rule_width(rule);
+        rule_left(rule) = rule_height(rule);
+        rule_right(rule) = rule_depth(rule);
+        rule_width(rule) = 0;
+        rule_height(rule) = 0;
+        rule_depth(rule) = 0;
+        node_subtype(rule) = virtual_rule_subtype;
+    }
     return rule;
 }