2023-02-06 17:57:00

12 files changed, 357 insertions, 170 deletions

diff --git a/source/luametatex/cmake/lua.cmake b/source/luametatex/cmake/lua.cmake
index 7c7eac35d..a31f1c8b0 100644
--- a/source/luametatex/cmake/lua.cmake
+++ b/source/luametatex/cmake/lua.cmake
@@ -82,13 +82,13 @@ if (NOT MSVC)
     )
 endif (NOT MSVC)
 
-if (CMAKE_HOST_APPLE)
-    target_compile_definitions(lua PUBLIC
-        TARGET_OS_IOS=0
-        TARGET_OS_WATCH=0
-        TARGET_OS_TV=0
-    )
-endif (CMAKE_HOST_APPLE)
+# if (CMAKE_HOST_APPLE)
+#     target_compile_definitions(lua PUBLIC
+#         TARGET_OS_IOS=0
+#         TARGET_OS_WATCH=0
+#         TARGET_OS_TV=0
+#     )
+# endif (CMAKE_HOST_APPLE)
 
 # this seems to be ok for mingw default
 #
diff --git a/source/luametatex/source/lua/lmtinterface.h b/source/luametatex/source/lua/lmtinterface.h
index c3ea2a184..59ef808c8 100644
--- a/source/luametatex/source/lua/lmtinterface.h
+++ b/source/luametatex/source/lua/lmtinterface.h
@@ -472,6 +472,7 @@ make_lua_key(L, attributelist);\
 make_lua_key(L, auto);\
 make_lua_key(L, automatic);\
 make_lua_key(L, automaticpenalty);\
+make_lua_key(L, autobase);\
 make_lua_key(L, axis);\
 make_lua_key(L, AxisHeight);\
 make_lua_key(L, baselineskip);\
diff --git a/source/luametatex/source/lua/lmttexlib.c b/source/luametatex/source/lua/lmttexlib.c
index ecc0d63ed..0afd6cdf6 100644
--- a/source/luametatex/source/lua/lmttexlib.c
+++ b/source/luametatex/source/lua/lmttexlib.c
@@ -4829,7 +4829,7 @@ static int texlib_getglyphoptionvalues(lua_State *L)
 
 static int texlib_getnoadoptionvalues(lua_State *L)
 {
-    lua_createtable(L, 2, 32);
+    lua_createtable(L, 2, 34);
     lua_push_key_at_index(L, axis,                   noad_option_axis);
     lua_push_key_at_index(L, noaxis,                 noad_option_no_axis);
     lua_push_key_at_index(L, exact,                  noad_option_exact);
@@ -4865,6 +4865,7 @@ static int texlib_getnoadoptionvalues(lua_State *L)
     lua_push_key_at_index(L, sourceonnucleus,        noad_option_source_on_nucleus);
     lua_push_key_at_index(L, fixedsuperorsubscript,  noad_option_fixed_super_or_sub_script);
     lua_push_key_at_index(L, fixedsuperandsubscript, noad_option_fixed_super_and_sub_script);
+    lua_push_key_at_index(L, autobase,               noad_option_auto_base);
     return 1;
 }
 
diff --git a/source/luametatex/source/luacore/lua54/src/llimits.h b/source/luametatex/source/luacore/lua54/src/llimits.h
index 52a32f92e..251a27021 100644
--- a/source/luametatex/source/luacore/lua54/src/llimits.h
+++ b/source/luametatex/source/luacore/lua54/src/llimits.h
@@ -71,11 +71,24 @@ typedef signed char ls_byte;
 
 
 /*
-** conversion of pointer to unsigned integer:
-** this is for hashing only; there is no problem if the integer
-** cannot hold the whole pointer value
+** conversion of pointer to unsigned integer: this is for hashing only;
+** there is no problem if the integer cannot hold the whole pointer
+** value. (In strict ISO C this may cause undefined behavior, but no
+** actual machine seems to bother.)
 */
-#define point2uint(p)	((unsigned int)((size_t)(p) & UINT_MAX))
+#if !defined(LUA_USE_C89) && defined(__STDC_VERSION__) && \
+    __STDC_VERSION__ >= 199901L
+#include <stdint.h>
+#if defined(UINTPTR_MAX)  /* even in C99 this type is optional */
+#define L_P2I	uintptr_t
+#else  /* no 'intptr'? */
+#define L_P2I	uintmax_t  /* use the largerst available integer */
+#endif
+#else  /* C89 option */
+#define L_P2I	size_t
+#endif
+
+#define point2uint(p)	((unsigned int)((L_P2I)(p) & UINT_MAX))
 
 
 
diff --git a/source/luametatex/source/luacore/lua54/src/loslib.c b/source/luametatex/source/luacore/lua54/src/loslib.c
index 7eb05cafd..89ac06bc4 100644
--- a/source/luametatex/source/luacore/lua54/src/loslib.c
+++ b/source/luametatex/source/luacore/lua54/src/loslib.c
@@ -138,21 +138,14 @@
 /* }================================================================== */
 
 
-/*
-** Despite claiming to be ISO, the C library in some Apple platforms
-** does not implement 'system'.
-*/
-#if !defined(l_system) && defined(__APPLE__)	/* { */
-#include "TargetConditionals.h"
-#if TARGET_OS_IOS || TARGET_OS_WATCH || TARGET_OS_TV
-#define l_system(cmd) ((cmd) == NULL ? 0 : -1)
-#endif
-#endif						/* } */
-
 #if !defined(l_system)
+#if defined(LUA_USE_IOS)
+/* Despite claiming to be ISO C, iOS does not implement 'system'. */
+#define l_system(cmd) ((cmd) == NULL ? 0 : -1)
+#else
 #define l_system(cmd)	system(cmd)  /* default definition */
 #endif
-
+#endif
 
 
 static int os_execute (lua_State *L) {
diff --git a/source/luametatex/source/luacore/lua54/src/luaconf.h b/source/luametatex/source/luacore/lua54/src/luaconf.h
index e4650fbce..137103ede 100644
--- a/source/luametatex/source/luacore/lua54/src/luaconf.h
+++ b/source/luametatex/source/luacore/lua54/src/luaconf.h
@@ -70,6 +70,12 @@
 #endif
 
 
+#if defined(LUA_USE_IOS)
+#define LUA_USE_POSIX
+#define LUA_USE_DLOPEN
+#endif
+
+
 /*
 @@ LUAI_IS32INT is true iff 'int' has (at least) 32 bits.
 */
diff --git a/source/luametatex/source/tex/texalign.c b/source/luametatex/source/tex/texalign.c
index 4ea4879c2..7a1045fea 100644
--- a/source/luametatex/source/tex/texalign.c
+++ b/source/luametatex/source/tex/texalign.c
@@ -971,7 +971,7 @@ void tex_run_alignment_initialize(void)
             token_link(current) = null;
             while (1) {
                 tex_aux_get_preamble_token();
-                if (cur_cmd == parameter_cmd || (cur_cmd == alignment_cmd && cur_chr == align_content_code)) {
+                if ((cur_cmd == alignment_cmd && cur_chr == align_content_code) || cur_cmd == parameter_cmd) {
                     break;
                 } else if ((cur_cmd == alignment_cmd || cur_cmd == alignment_tab_cmd) && (lmt_input_state.align_state == -1000000)) {
                     if ((current == lmt_alignment_state.hold_token_head) && (! lmt_alignment_state.cur_loop) && (cur_cmd == alignment_tab_cmd)) {
@@ -1004,7 +1004,7 @@ void tex_run_alignment_initialize(void)
                 tex_aux_get_preamble_token();
                 if ((cur_cmd == alignment_cmd || cur_cmd == alignment_tab_cmd) && (lmt_input_state.align_state == -1000000)) {
                     break;
-                } else if (cur_cmd == parameter_cmd || (cur_cmd == alignment_cmd && cur_chr == align_content_code)) {
+                } else if ((cur_cmd == alignment_cmd && cur_chr == align_content_code) || cur_cmd == parameter_cmd) {
                     tex_handle_error(
                         normal_error_type,
                         "Only one # is allowed per tab",
diff --git a/source/luametatex/source/tex/texcommands.c b/source/luametatex/source/tex/texcommands.c
index eaf2c7bbd..e52825b33 100644
--- a/source/luametatex/source/tex/texcommands.c
+++ b/source/luametatex/source/tex/texcommands.c
@@ -1056,8 +1056,8 @@ void tex_initialize_commands(void)
         tex_primitive(tex_command,    "unvcopy",                        un_vbox_cmd,            copy_code,                                0);
         tex_primitive(luatex_command, "unvpack",                        un_vbox_cmd,            unpack_code,                              0);
 
-        tex_primitive(etex_command,   "pagediscards",                   un_vbox_cmd,            page_discards_code,                            0);
-        tex_primitive(etex_command,   "splitdiscards",                  un_vbox_cmd,            split_discards_code,                              0);
+        tex_primitive(etex_command,   "pagediscards",                   un_vbox_cmd,            page_discards_code,                       0);
+        tex_primitive(etex_command,   "splitdiscards",                  un_vbox_cmd,            split_discards_code,                      0);
 
         tex_primitive(luatex_command, "insertunbox",                    un_vbox_cmd,            insert_box_code,                          0);
         tex_primitive(luatex_command, "insertuncopy",                   un_vbox_cmd,            insert_copy_code,                         0);
diff --git a/source/luametatex/source/tex/texmaincontrol.c b/source/luametatex/source/tex/texmaincontrol.c
index c15704129..783de2b8b 100644
--- a/source/luametatex/source/tex/texmaincontrol.c
+++ b/source/luametatex/source/tex/texmaincontrol.c
@@ -4558,8 +4558,8 @@ static void tex_aux_set_def(int a, int force)
         if (is_constant(a)) {
             /* todo: check if already defined or just accept a leak */
             set_token_reference(t, max_token_reference);
-        } else if (! token_link(t)) { 
-            t = lmt_token_state.empty; /* maybe in tex_define */
+     // } else if (! token_link(t)) { 
+     //     t = lmt_token_state.empty; /* leaks */
         }
         tex_define(a, p, tex_flags_to_cmd(a), t);
     }
diff --git a/source/luametatex/source/tex/texmath.c b/source/luametatex/source/tex/texmath.c
index 4979c1a23..0820b2405 100644
--- a/source/luametatex/source/tex/texmath.c
+++ b/source/luametatex/source/tex/texmath.c
@@ -2876,6 +2876,132 @@ void tex_finish_math_radical(void)
     }
 }
 
+// void tex_run_math_accent(void)
+// {
+//     mathcodeval t = tex_no_math_code();
+//     mathcodeval b = tex_no_math_code();
+//     mathcodeval o = tex_no_math_code();
+//     halfword code = cur_chr;
+//     halfword accent = tex_new_node(accent_noad, bothflexible_accent_subtype);
+//     quarterword subtype = ordinary_noad_subtype;
+//     halfword attrlist = null;
+//     if (cur_cmd == accent_cmd) {
+//         tex_handle_error(
+//             normal_error_type,
+//             "Please use \\mathaccent for accents in math mode",
+//             "I'm changing \\accent to \\mathaccent here; wish me luck. (Accents are not the\n"
+//             "same in formulas as they are in text.)" );
+//     }
+//     tex_tail_append(accent);
+//     switch (code) {
+//         case math_accent_code:
+//             /*tex |\mathaccent| */
+//             t = tex_scan_mathchar(tex_mathcode);
+//             break;
+//         case math_uaccent_code:
+//             /*tex |\Umathaccent| */
+//             while (1) {
+//                 switch (tex_scan_character("abnsfABNSF", 0, 1, 0)) {
+//                     case 'a': case 'A':
+//                         if (tex_scan_mandate_keyword("attr", 1)) {
+//                             attrlist = tex_scan_attribute(attrlist);
+//                         }
+//                         break;
+//                     case 's': case 'S':
+//                         if (tex_scan_mandate_keyword("source", 1)) {
+//                             noad_source(accent) = tex_scan_int(0, NULL);
+//                         }
+//                         break;
+//                     case 'f': case 'F':
+//                         if (tex_scan_mandate_keyword("fraction", 1)) {
+//                             accent_fraction(accent) = tex_scan_int(0, NULL);
+//                         }
+//                         break;
+//                     case 'n': case 'N':
+//                         if (tex_scan_mandate_keyword("nooverflow", 1)) {
+//                             /*tex 
+//                                 Actually there never is an overflow but for consistency we do 
+//                                 accept this key. Mayebe in the future it will be used. 
+//                             */
+//                             noad_options(accent) |= noad_option_no_overflow;
+//                         }
+//                         break;
+//                     case 'b': case 'B':
+//                         if (tex_scan_mandate_keyword("base", 1)) {
+//                             noad_options(accent) |= noad_option_auto_base;
+//                         }
+//                         break;
+//                     default:
+//                         goto DONE;
+//                 }
+//             }
+//           DONE:
+//             /* todo: integrate in the above */
+//             if (tex_scan_keyword("fixed")) {
+//                 /*tex top */
+//                 node_subtype(accent) = fixedtop_accent_subtype;
+//                 t = tex_scan_mathchar(umath_mathcode);
+//             } else if (tex_scan_keyword("both")) {
+//                 /*tex top bottom */
+//                 if (tex_scan_keyword("fixed")) {
+//                     node_subtype(accent) = fixedtop_accent_subtype;
+//                 }
+//                 t = tex_scan_mathchar(umath_mathcode);
+//                 if (tex_scan_keyword("fixed")) {
+//                     node_subtype(accent) = fixedboth_accent_subtype;
+//                 }
+//                 b = tex_scan_mathchar(umath_mathcode);
+//             } else if (tex_scan_keyword("bottom")) {
+//                 /*tex bottom */
+//                 if (tex_scan_keyword("fixed")) {
+//                     node_subtype(accent) = fixedbottom_accent_subtype;
+//                 }
+//                 b = tex_scan_mathchar(umath_mathcode);
+//             } else if (tex_scan_keyword("top")) {
+//                 /*tex top */
+//                 if (tex_scan_keyword("fixed")) {
+//                     node_subtype(accent) = fixedtop_accent_subtype;
+//                 }
+//                 t = tex_scan_mathchar(umath_mathcode);
+//             } else if (tex_scan_keyword("overlay")) {
+//                 /* overlay */
+//                 if (tex_scan_keyword("fixed")) {
+//                     node_subtype(accent) = fixedtop_accent_subtype;
+//                 }
+//                 o = tex_scan_mathchar(umath_mathcode);
+//             } else {
+//                 /*tex top */
+//                 t = tex_scan_mathchar(umath_mathcode);
+//             }
+//             break;
+//         default:
+//             tex_confusion("scan math accent");
+//     }
+//     if (attrlist) {
+//         tex_attach_attribute_list_attribute(accent, attrlist);
+//     }
+//     if (! (t.character_value == 0 && t.family_value == 0)) {
+//         halfword n = tex_new_node(math_char_node, 0);
+//         subtype = tex_aux_set_math_char(n, &t, NULL);
+//         accent_top_character(accent) = n;
+//     }
+//     if (! (b.character_value == 0 && b.family_value == 0)) {
+//         halfword n = tex_new_node(math_char_node, 0);
+//         subtype = tex_aux_set_math_char(n, &b, NULL);
+//         accent_bottom_character(accent) = n;
+//     }
+//     if (! (o.character_value == 0 && o.family_value == 0)) {
+//         halfword n = tex_new_node(math_char_node, 0);
+//         subtype = tex_aux_set_math_char(n, &o, NULL);
+//         accent_middle_character(accent) = n;
+//     }
+//     {
+//         halfword n = tex_new_node(math_char_node, subtype);
+//         noad_nucleus(accent) = n;
+//         tex_aux_scan_math(n, tex_math_style_variant(cur_list.math_style, math_parameter_accent_variant), 0, 0, 0, 0, unset_noad_class, unset_noad_class);
+//     }
+// }
+
 void tex_run_math_accent(void)
 {
     mathcodeval t = tex_no_math_code();
@@ -2901,7 +3027,7 @@ void tex_run_math_accent(void)
         case math_uaccent_code:
             /*tex |\Umathaccent| */
             while (1) {
-                switch (tex_scan_character("ansfASFN", 0, 1, 0)) {
+                switch (tex_scan_character("abnsftoABNSFTO", 0, 1, 0)) {
                     case 'a': case 'A':
                         if (tex_scan_mandate_keyword("attr", 1)) {
                             attrlist = tex_scan_attribute(attrlist);
@@ -2913,10 +3039,23 @@ void tex_run_math_accent(void)
                         }
                         break;
                     case 'f': case 'F':
-                        if (tex_scan_mandate_keyword("fraction", 1)) {
-                            accent_fraction(accent) = tex_scan_int(0, NULL);
+                        switch (tex_scan_character("frFR", 0, 0, 0)) {
+                            case 'r': case 'R':
+                                if (tex_scan_mandate_keyword("fraction", 2)) {
+                                    accent_fraction(accent) = tex_scan_int(0, NULL);
+                                }
+                                break;
+                            case 'f': case 'F':
+                                /*tex fixed <char> */
+                                if (tex_scan_mandate_keyword("fixed", 2)) {
+                                    node_subtype(accent) = fixedtop_accent_subtype;
+                                    t = tex_scan_mathchar(umath_mathcode);
+                                }
+                                goto DONE;
+                            default:
+                                tex_aux_show_keyword_error("fraction|fixed");
+                                goto DONE;
                         }
-                        break;
                     case 'n': case 'N':
                         if (tex_scan_mandate_keyword("nooverflow", 1)) {
                             /*tex 
@@ -2926,52 +3065,79 @@ void tex_run_math_accent(void)
                             noad_options(accent) |= noad_option_no_overflow;
                         }
                         break;
+                    case 'b': case 'B':
+                        switch (tex_scan_character("aoAo", 0, 0, 0)) {
+                            case 'a': case 'A':
+                                if (tex_scan_mandate_keyword("base", 2)) {
+                                    noad_options(accent) |= noad_option_auto_base;
+                                }
+                                break;
+                            case 'o': case 'O':
+                                /*tex bottom [fixed] <char> */
+                                /*tex both [fixed] <char> [fixed] <char> */
+                                if (tex_scan_character("t", 0, 0, 0)) {
+                                     switch (tex_scan_character("thTH", 0, 0, 0)) {
+                                         case 'h': case 'H':
+                                             if (tex_scan_mandate_keyword("both", 4)) {
+                                                  /*tex top bottom */
+                                                  if (tex_scan_keyword("fixed")) {
+                                                      node_subtype(accent) = fixedtop_accent_subtype;
+                                                  }
+                                                  t = tex_scan_mathchar(umath_mathcode);
+                                                  if (tex_scan_keyword("fixed")) {
+                                                      node_subtype(accent) = fixedboth_accent_subtype;
+                                                  }
+                                                  b = tex_scan_mathchar(umath_mathcode);
+                                             }
+                                            goto DONE;
+                                         case 't': case 'T':
+                                             if (tex_scan_mandate_keyword("bottom", 4)) {
+                                                /*tex bottom */
+                                                if (tex_scan_keyword("fixed")) {
+                                                    node_subtype(accent) = fixedbottom_accent_subtype;
+                                                }
+                                                b = tex_scan_mathchar(umath_mathcode);
+                                             }
+                                            goto DONE;
+                                        default:
+                                            tex_aux_show_keyword_error("both|bottom");
+                                            goto DONE;
+                                     }
+                                }
+                                goto DONE;
+                            default:
+                                tex_aux_show_keyword_error("base|both|bottom");
+                                goto DONE;
+                        }
+                        break;
+                    case 't': case 'T':
+                        /*tex top [fixed] <char> */
+                        if (tex_scan_mandate_keyword("top", 1)) {
+                            if (tex_scan_keyword("fixed")) {
+                                node_subtype(accent) = fixedtop_accent_subtype;
+                            }
+                            t = tex_scan_mathchar(umath_mathcode);
+                        }
+                        goto DONE;
+                    case 'o': case 'O':
+                        /*tex overlay [fixed] <char> */
+                        if (tex_scan_mandate_keyword("overlay", 1)) {
+                            if (tex_scan_keyword("fixed")) {
+                                node_subtype(accent) = fixedtop_accent_subtype;
+                            }
+                            o = tex_scan_mathchar(umath_mathcode);
+                        }
+                        goto DONE;
                     default:
+                        /*tex top <char> */
+                        t = tex_scan_mathchar(umath_mathcode);
                         goto DONE;
                 }
             }
-          DONE:
-            /* todo: integrate in the above */
-            if (tex_scan_keyword("fixed")) {
-                /*tex top */
-                node_subtype(accent) = fixedtop_accent_subtype;
-                t = tex_scan_mathchar(umath_mathcode);
-            } else if (tex_scan_keyword("both")) {
-                /*tex top bottom */
-                if (tex_scan_keyword("fixed")) {
-                    node_subtype(accent) = fixedtop_accent_subtype;
-                }
-                t = tex_scan_mathchar(umath_mathcode);
-                if (tex_scan_keyword("fixed")) {
-                    node_subtype(accent) = fixedboth_accent_subtype;
-                }
-                b = tex_scan_mathchar(umath_mathcode);
-            } else if (tex_scan_keyword("bottom")) {
-                /*tex bottom */
-                if (tex_scan_keyword("fixed")) {
-                    node_subtype(accent) = fixedbottom_accent_subtype;
-                }
-                b = tex_scan_mathchar(umath_mathcode);
-            } else if (tex_scan_keyword("top")) {
-                /*tex top */
-                if (tex_scan_keyword("fixed")) {
-                    node_subtype(accent) = fixedtop_accent_subtype;
-                }
-                t = tex_scan_mathchar(umath_mathcode);
-            } else if (tex_scan_keyword("overlay")) {
-                /* overlay */
-                if (tex_scan_keyword("fixed")) {
-                    node_subtype(accent) = fixedtop_accent_subtype;
-                }
-                o = tex_scan_mathchar(umath_mathcode);
-            } else {
-                /*tex top */
-                t = tex_scan_mathchar(umath_mathcode);
-            }
-            break;
         default:
             tex_confusion("scan math accent");
     }
+  DONE:
     if (attrlist) {
         tex_attach_attribute_list_attribute(accent, attrlist);
     }
diff --git a/source/luametatex/source/tex/texmlist.c b/source/luametatex/source/tex/texmlist.c
index b3f8cf294..d7c37e47a 100644
--- a/source/luametatex/source/tex/texmlist.c
+++ b/source/luametatex/source/tex/texmlist.c
@@ -1136,13 +1136,12 @@ halfword tex_make_extensible(halfword fnt, halfword chr, scaled target, scaled m
                     if (overlap < initial) {
                         initial = overlap;
                     }
-                 // if (advance == 0) {
-                 //     /*tex for tfm fonts (so no need for scaling) */
-                 //     advance = tex_aux_math_x_size_scaled(fnt, tex_char_width_from_font(fnt, e->glyph), size); /* todo: combine */
-                        if (advance <= 0) {
-                            tex_formatted_error("fonts", "bad horizontal extensible character %i in font %i", chr, fnt);
-                        }
-                 // }
+                    if (advance == 0) {
+                        advance = tex_aux_math_x_size_scaled(fnt, tex_char_width_from_font(fnt, e->glyph), size); /* todo: combine */
+                    }
+                    if (advance <= 0) {
+                        tex_formatted_error("fonts", "bad horizontal extensible character %i in font %i", chr, fnt);
+                    }
                     max_natural += advance - initial;
                     overlap = tex_aux_math_x_size_scaled(fnt, e->end_overlap, size);
                 } else {
@@ -1156,13 +1155,12 @@ halfword tex_make_extensible(halfword fnt, halfword chr, scaled target, scaled m
                         if (overlap < initial) {
                             initial = overlap;
                         }
-                     // if (advance == 0) {
-                     //     /*tex for tfm fonts (so no need for scaling) */
-                     //     advance = tex_aux_math_x_size_scaled(fnt, tex_char_width_from_font(fnt, e->glyph), size); /* todo: combine */
-                            if (advance <= 0) {
-                                tex_formatted_error("fonts", "bad horizontal extensible character %i in font %i", chr, fnt);
-                            }
-                     // }
+                        if (advance == 0) {
+                            advance = tex_aux_math_x_size_scaled(fnt, tex_char_width_from_font(fnt, e->glyph), size); /* todo: combine */
+                        }
+                        if (advance <= 0) {
+                            tex_formatted_error("fonts", "bad horizontal extensible character %i in font %i", chr, fnt);
+                        }
                         max_natural += advance - initial;
                         overlap = tex_aux_math_x_size_scaled(fnt, e->end_overlap, size);
                         pieces--;
@@ -1180,12 +1178,12 @@ halfword tex_make_extensible(halfword fnt, halfword chr, scaled target, scaled m
                     if (overlap < initial) {
                         initial = overlap;
                     }
-                 // if (advance == 0) {
-                 //     advance = tex_aux_math_y_size_scaled(fnt, tex_char_total_from_font(fnt, e->glyph), size); /* todo: combine */
-                        if (advance <= 0) {
-                            tex_formatted_error("fonts", "bad vertical extensible character %i in font %i", chr, fnt);
-                        }
-                 // }
+                    if (advance == 0) {
+                        advance = tex_aux_math_y_size_scaled(fnt, tex_char_total_from_font(fnt, e->glyph), size); /* todo: combine */
+                    }
+                    if (advance <= 0) {
+                        tex_formatted_error("fonts", "bad vertical extensible character %i in font %i", chr, fnt);
+                    }
                     max_natural += advance - initial;
                     overlap = tex_aux_math_y_size_scaled(fnt, e->end_overlap, size);
                 } else {
@@ -1199,12 +1197,12 @@ halfword tex_make_extensible(halfword fnt, halfword chr, scaled target, scaled m
                         if (overlap < initial) {
                             initial = overlap;
                         }
-                     // if (advance == 0) {
-                     //     advance = tex_aux_math_y_size_scaled(fnt, tex_char_total_from_font(fnt, e->glyph), size); /* todo: combine */
-                            if (advance <= 0) {
-                                tex_formatted_error("fonts", "bad vertical extensible character %i in font %i", chr, fnt);
-                            }
-                     // }
+                        if (advance == 0) {
+                            advance = tex_aux_math_y_size_scaled(fnt, tex_char_total_from_font(fnt, e->glyph), size); /* todo: combine */
+                        }
+                        if (advance <= 0) {
+                            tex_formatted_error("fonts", "bad vertical extensible character %i in font %i", chr, fnt);
+                        }
                         max_natural += advance - initial;
                         overlap = tex_aux_math_y_size_scaled(fnt, e->end_overlap, size);
                         pieces--;
@@ -1426,10 +1424,13 @@ static halfword tex_aux_make_delimiter(halfword target, halfword delimiter, int
                             }
                         }
                        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;
+                            if (tex_char_has_tag_from_font(curfnt, curchr, horizontal_tag) || tex_char_has_tag_from_font(curfnt, curchr, vertical_tag)) {
+                                /*tex We only check when we are explicit. */
+                                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) {
@@ -2745,7 +2746,7 @@ typedef enum math_accent_location_codes {
     top_accent_code     = 1,
     bot_accent_code     = 2,
     overlay_accent_code = 4,
-    stretch_accent_code = 8,
+    stretch_accent_code = 8, /* reserved, not yet set */
 } math_accent_location_codes;
 
 static int tex_aux_compute_accent_skew(halfword target, int flags, scaled *skew, halfword size)
@@ -2982,8 +2983,11 @@ static void tex_aux_do_make_math_accent(halfword target, halfword accentfnt, hal
                 }
             }
         }
+        if (has_noad_option_auto_base(target)) {
+            b = - box_depth(accent);
+        }
         if (b != undefined_math_parameter) {
-            /* not okay */
+            /* not okay but interesting with negative values */
             delta = baseheight < b ? baseheight : b;
         }
         if (u != undefined_math_parameter) {
diff --git a/source/luametatex/source/tex/texnodes.h b/source/luametatex/source/tex/texnodes.h
index 113de8f40..e19ff933d 100644
--- a/source/luametatex/source/tex/texnodes.h
+++ b/source/luametatex/source/tex/texnodes.h
@@ -1743,46 +1743,47 @@ typedef struct noad_classes {
 // # else 
 typedef enum noad_options {
 // # endif 
-    noad_option_axis                       = 0x000000001,
-    noad_option_no_axis                    = 0x000000002,
-    noad_option_exact                      = 0x000000004,
-    noad_option_left                       = 0x000000008, /* align option for overflown under/over */ /* used ? */
-    noad_option_middle                     = 0x000000010, /* idem */
-    noad_option_right                      = 0x000000020, /* idem */
-    noad_option_adapt_to_left_size         = 0x000000040, /* old trickery, might go away but kind of fun */
-    noad_option_adapt_to_right_size        = 0x000000080, /* idem */
-    noad_option_no_sub_script              = 0x000000100,
-    noad_option_no_super_script            = 0x000000200,
-    noad_option_no_sub_pre_script          = 0x000000400,
-    noad_option_no_super_pre_script        = 0x000000800,
-    noad_option_no_script                  = 0x000001000,
-    noad_option_no_overflow                = 0x000002000, /* keep (middle) extensible widthin target size */
-    noad_option_void                       = 0x000004000, /* wipe and set width to zero */
-    noad_option_phantom                    = 0x000008000, /* wipe */
-    noad_option_openup_height              = 0x000010000,
-    noad_option_openup_depth               = 0x000020000,
-    noad_option_limits                     = 0x000040000, /* traditional modifier */
-    noad_option_no_limits                  = 0x000080000, /* idem */
-    noad_option_prefer_font_thickness      = 0x000100000,
-    noad_option_no_ruling                  = 0x000200000,
-    noad_option_shifted_sub_script         = 0x000400000,
-    noad_option_shifted_super_script       = 0x000800000,
-    noad_option_shifted_sub_pre_script     = 0x001000000,
-    noad_option_shifted_super_pre_script   = 0x002000000,
-    noad_option_unpack_list                = 0x004000000,
-    noad_option_no_check                   = 0x008000000, /* don't check for missing end fence */
-    noad_option_auto                       = 0x010000000,
-    noad_option_unroll_list                = 0x020000000,
-    noad_option_followed_by_space          = 0x040000000,
-    noad_option_proportional               = 0x080000000,
+    noad_option_axis                       = 0x0000000001,
+    noad_option_no_axis                    = 0x0000000002,
+    noad_option_exact                      = 0x0000000004,
+    noad_option_left                       = 0x0000000008, /* align option for overflown under/over */ /* used ? */
+    noad_option_middle                     = 0x0000000010, /* idem */
+    noad_option_right                      = 0x0000000020, /* idem */
+    noad_option_adapt_to_left_size         = 0x0000000040, /* old trickery, might go away but kind of fun */
+    noad_option_adapt_to_right_size        = 0x0000000080, /* idem */
+    noad_option_no_sub_script              = 0x0000000100,
+    noad_option_no_super_script            = 0x0000000200,
+    noad_option_no_sub_pre_script          = 0x0000000400,
+    noad_option_no_super_pre_script        = 0x0000000800,
+    noad_option_no_script                  = 0x0000001000,
+    noad_option_no_overflow                = 0x0000002000, /* keep (middle) extensible widthin target size */
+    noad_option_void                       = 0x0000004000, /* wipe and set width to zero */
+    noad_option_phantom                    = 0x0000008000, /* wipe */
+    noad_option_openup_height              = 0x0000010000,
+    noad_option_openup_depth               = 0x0000020000,
+    noad_option_limits                     = 0x0000040000, /* traditional modifier */
+    noad_option_no_limits                  = 0x0000080000, /* idem */
+    noad_option_prefer_font_thickness      = 0x0000100000,
+    noad_option_no_ruling                  = 0x0000200000,
+    noad_option_shifted_sub_script         = 0x0000400000,
+    noad_option_shifted_super_script       = 0x0000800000,
+    noad_option_shifted_sub_pre_script     = 0x0001000000,
+    noad_option_shifted_super_pre_script   = 0x0002000000,
+    noad_option_unpack_list                = 0x0004000000,
+    noad_option_no_check                   = 0x0008000000, /* don't check for missing end fence */
+    noad_option_auto                       = 0x0010000000,
+    noad_option_unroll_list                = 0x0020000000,
+    noad_option_followed_by_space          = 0x0040000000,
+    noad_option_proportional               = 0x0080000000,
     /*tex Watch out: the following options exceed halfword: |noad_options| are |long long|. */
 } noad_options;
 
 /*tex The Microsoft compiler truncates to int, so: */
 
-# define noad_option_source_on_nucleus          0x100000000
-# define noad_option_fixed_super_or_sub_script  0x200000000
-# define noad_option_fixed_super_and_sub_script 0x400000000
+# define noad_option_source_on_nucleus          0x0100000000
+# define noad_option_fixed_super_or_sub_script  0x0200000000
+# define noad_option_fixed_super_and_sub_script 0x0400000000
+# define noad_option_auto_base                  0x0800000000
 
 # define has_option(a,b)     (((a) & (b)) == (b))
 # define unset_option(a,b)   ((a) & ~(b))
@@ -1809,37 +1810,38 @@ inline static int has_noad_no_script_option(halfword n, halfword option)
 # define has_noad_option_nosubprescript(a) has_noad_no_script_option(a, noad_option_no_sub_pre_script)
 # define has_noad_option_nosupprescript(a) has_noad_no_script_option(a, noad_option_no_super_pre_script)
 
-# define has_noad_option_shiftedsubscript(a)           (has_option(noad_options(a), noad_option_shifted_sub_script))
-# define has_noad_option_shiftedsupscript(a)           (has_option(noad_options(a), noad_option_shifted_super_script))
-# define has_noad_option_shiftedsubprescript(a)        (has_option(noad_options(a), noad_option_shifted_sub_pre_script))
-# define has_noad_option_shiftedsupprescript(a)        (has_option(noad_options(a), noad_option_shifted_super_pre_script))
-# define has_noad_option_axis(a)                       (has_option(noad_options(a), noad_option_axis))
-# define has_noad_option_exact(a)                      (has_option(noad_options(a), noad_option_exact))
-# define has_noad_option_noaxis(a)                     (has_option(noad_options(a), noad_option_no_axis))
-# define has_noad_option_openupheight(a)               (has_option(noad_options(a), noad_option_openup_height))
-# define has_noad_option_openupdepth(a)                (has_option(noad_options(a), noad_option_openup_depth))
-# define has_noad_option_adapttoleft(a)                (has_option(noad_options(a), noad_option_adapt_to_left_size))
-# define has_noad_option_adapttoright(a)               (has_option(noad_options(a), noad_option_adapt_to_right_size))
-# define has_noad_option_limits(a)                     (has_option(noad_options(a), noad_option_limits))
-# define has_noad_option_nolimits(a)                   (has_option(noad_options(a), noad_option_no_limits))
-# define has_noad_option_nooverflow(a)                 (has_option(noad_options(a), noad_option_no_overflow))
-# define has_noad_option_preferfontthickness(a)        (has_option(noad_options(a), noad_option_prefer_font_thickness))
-# define has_noad_option_noruling(a)                   (has_option(noad_options(a), noad_option_no_ruling))
-# define has_noad_option_unpacklist(a)                 (has_option(noad_options(a), noad_option_unpack_list))
-# define has_noad_option_nocheck(a)                    (has_option(noad_options(a), noad_option_no_check))
-# define has_noad_option_exact(a)                      (has_option(noad_options(a), noad_option_exact))
-# define has_noad_option_left(a)                       (has_option(noad_options(a), noad_option_left))
-# define has_noad_option_middle(a)                     (has_option(noad_options(a), noad_option_middle))
-# define has_noad_option_right(a)                      (has_option(noad_options(a), noad_option_right))
-# define has_noad_option_auto(a)                       (has_option(noad_options(a), noad_option_auto))
-# define has_noad_option_phantom(a)                    (has_option(noad_options(a), noad_option_phantom))
-# define has_noad_option_void(a)                       (has_option(noad_options(a), noad_option_void))
-# define has_noad_option_unrolllist(a)                 (has_option(noad_options(a), noad_option_unroll_list))
-# define has_noad_option_followedbyspace(a)            (has_option(noad_options(a), noad_option_followed_by_space))
-# define has_noad_option_proportional(a)               (has_option(noad_options(a), noad_option_proportional))
-# define has_noad_option_source_on_nucleus(a)          (has_option(noad_options(a), noad_option_source_on_nucleus))
+# define has_noad_option_shiftedsubscript(a)            (has_option(noad_options(a), noad_option_shifted_sub_script))
+# define has_noad_option_shiftedsupscript(a)            (has_option(noad_options(a), noad_option_shifted_super_script))
+# define has_noad_option_shiftedsubprescript(a)         (has_option(noad_options(a), noad_option_shifted_sub_pre_script))
+# define has_noad_option_shiftedsupprescript(a)         (has_option(noad_options(a), noad_option_shifted_super_pre_script))
+# define has_noad_option_axis(a)                        (has_option(noad_options(a), noad_option_axis))
+# define has_noad_option_exact(a)                       (has_option(noad_options(a), noad_option_exact))
+# define has_noad_option_noaxis(a)                      (has_option(noad_options(a), noad_option_no_axis))
+# define has_noad_option_openupheight(a)                (has_option(noad_options(a), noad_option_openup_height))
+# define has_noad_option_openupdepth(a)                 (has_option(noad_options(a), noad_option_openup_depth))
+# define has_noad_option_adapttoleft(a)                 (has_option(noad_options(a), noad_option_adapt_to_left_size))
+# define has_noad_option_adapttoright(a)                (has_option(noad_options(a), noad_option_adapt_to_right_size))
+# define has_noad_option_limits(a)                      (has_option(noad_options(a), noad_option_limits))
+# define has_noad_option_nolimits(a)                    (has_option(noad_options(a), noad_option_no_limits))
+# define has_noad_option_nooverflow(a)                  (has_option(noad_options(a), noad_option_no_overflow))
+# define has_noad_option_preferfontthickness(a)         (has_option(noad_options(a), noad_option_prefer_font_thickness))
+# define has_noad_option_noruling(a)                    (has_option(noad_options(a), noad_option_no_ruling))
+# define has_noad_option_unpacklist(a)                  (has_option(noad_options(a), noad_option_unpack_list))
+# define has_noad_option_nocheck(a)                     (has_option(noad_options(a), noad_option_no_check))
+# define has_noad_option_exact(a)                       (has_option(noad_options(a), noad_option_exact))
+# define has_noad_option_left(a)                        (has_option(noad_options(a), noad_option_left))
+# define has_noad_option_middle(a)                      (has_option(noad_options(a), noad_option_middle))
+# define has_noad_option_right(a)                       (has_option(noad_options(a), noad_option_right))
+# define has_noad_option_auto(a)                        (has_option(noad_options(a), noad_option_auto))
+# define has_noad_option_phantom(a)                     (has_option(noad_options(a), noad_option_phantom))
+# define has_noad_option_void(a)                        (has_option(noad_options(a), noad_option_void))
+# define has_noad_option_unrolllist(a)                  (has_option(noad_options(a), noad_option_unroll_list))
+# define has_noad_option_followedbyspace(a)             (has_option(noad_options(a), noad_option_followed_by_space))
+# define has_noad_option_proportional(a)                (has_option(noad_options(a), noad_option_proportional))
+# define has_noad_option_source_on_nucleus(a)           (has_option(noad_options(a), noad_option_source_on_nucleus))
 # define has_noad_option_fixed_super_or_sub_script(a)   (has_option(noad_options(a), noad_option_fixed_super_or_sub_script))
 # define has_noad_option_fixed_super_and_sub_script(a)  (has_option(noad_options(a), noad_option_fixed_super_and_sub_script))
+# define has_noad_option_auto_base(a)                   (has_option(noad_options(a), noad_option_auto_base))
 
 /*tex
     In the meantime the codes and subtypes are in sync. The variable component does not really
@@ -1928,7 +1930,8 @@ typedef enum math_modifier_types {
 # define accent_top_overshoot    noad_extra_5
 # define accent_bot_overshoot    noad_extra_6
 
-typedef enum math_accent_subtypes {
+typedef enum math_accent_subtypes { 
+    /* we can be more specific: todo fixedoverlay_accent_subtype */
     bothflexible_accent_subtype,
     fixedtop_accent_subtype,
     fixedbottom_accent_subtype,