On Sun, Feb 2, 2025 at 9:38 PM Udicoudco <[email protected]> wrote: > > On Sun, Feb 2, 2025 at 7:52 PM Hans Hagen <[email protected]> wrote: > > > > On 2/2/2025 10:56 AM, Udicoudco wrote: > > > > > Even though this change is less disruptive, there might be more > > > concerns about backwards compatibility today than three years ago, if > > > this is the case a new value to \matheqdirmode can be added. > > > > I checked how I'd do it in luametatex and noticed a potential issue > > with the patch: because there can be more than one node (par plus plenty > > dir) you need to flush the list starting with vlink(head), otherwise you > > leak nodes. > > > > (Because pop_nest is kind of dumb that should be enough but in other > > situations one should also set tail to head and the next node of head to > > null.) > > > > (I actually added a bit more clever variant so that i can test some > > scenarios, but right now I can't forecast side effects as i have no clue > > about intended usage in macro packages as we don't need it in context.) > > > > Oh, yes, a total oversight on my part... I intended to > copy what is done in end_graf (which > also suits the current behaviour that tests that > vlink(head)==tail and flushes the tail, so flushing vlink(head) > is the same). > > wrong copy paste that worked for my too simplistic tests. > > I'll test some more and send a new patch with the primitive > and doc in a couple of hours.
I attached the patch with the new primitive, documentation, and the fix pointed by Hans (thanks for catching that early). Udi
From ccdeba54657bf2fd2c825f81c4f4db16d6a7f5d9 Mon Sep 17 00:00:00 2001 From: Udi Fogiel <[email protected]> Date: Mon, 3 Feb 2025 01:35:20 +0200 Subject: [PATCH] add mathemptydisplaymode primitive By default paragraphs created because of interuption of display eqautaion containing dir nodes are never ignored. Changing that could break existing documents, but when you set mathemptydisplaymode to 1 paragraphs containing only dir nodes and a local par node before a display equation will be ignored. --- manual/luatex-modifications.tex | 5 +++ source/texk/web2c/luatexdir/tex/commands.c | 1 + source/texk/web2c/luatexdir/tex/equivalents.h | 6 ++- source/texk/web2c/luatexdir/tex/texmath.c | 40 +++++++++++++------ 4 files changed, 38 insertions(+), 14 deletions(-) diff --git a/manual/luatex-modifications.tex b/manual/luatex-modifications.tex index 8d67d7dfa..261bed895 100644 --- a/manual/luatex-modifications.tex +++ b/manual/luatex-modifications.tex @@ -1164,6 +1164,11 @@ Because \type {\noindent} doesn't inject anything but a \type {\indent} injects an box, paragraphs with only an indent and directions are handled as paragraphs with content. +By default paragraphs created because of interuption of display eqautaion containing +dir nodes are never ignored. Changing that could break existing documents, +but when you set \lpr {mathemptydisplaymode} to~\type {1} empty paragraphs before +a display equation will be ignored. + \stopsubsection \startsubsection[title={Controlling glue with \lpr {breakafterdirmode}}] diff --git a/source/texk/web2c/luatexdir/tex/commands.c b/source/texk/web2c/luatexdir/tex/commands.c index 371626daf..e794bf0f3 100644 --- a/source/texk/web2c/luatexdir/tex/commands.c +++ b/source/texk/web2c/luatexdir/tex/commands.c @@ -180,6 +180,7 @@ void initialize_commands(void) primitive_luatex("mathdefaultsmode", assign_int_cmd, int_base + math_defaults_mode_code, int_base); primitive_luatex("discretionaryligaturemode", assign_int_cmd, int_base + discretionary_ligature_mode_code, int_base); primitive_etex("partokencontext", assign_int_cmd, int_base + partoken_context_code, int_base); + primitive_luatex("mathemptydisplaymode", assign_int_cmd, int_base + math_empty_display_mode_code, int_base); /*tex diff --git a/source/texk/web2c/luatexdir/tex/equivalents.h b/source/texk/web2c/luatexdir/tex/equivalents.h index bf329b3a1..988d7ae39 100644 --- a/source/texk/web2c/luatexdir/tex/equivalents.h +++ b/source/texk/web2c/luatexdir/tex/equivalents.h @@ -318,7 +318,9 @@ the |number_regs| \.{\\dimen} registers. # define ignore_primitive_error_code 125 /*ignore some primitive/engine errors*/ -# define math_option_code 126 +# define math_empty_display_mode_code 126 + +# define math_option_code 127 # define mathoption_int_base_code (math_option_code+1) /* one reserve */ @@ -830,6 +832,8 @@ extern halfword last_cs_name; #define show_stream_par int_par(show_stream_code) +#define math_empty_display_mode_par int_par(math_empty_display_mode_code) + /* */ #define math_use_current_family_code 7 diff --git a/source/texk/web2c/luatexdir/tex/texmath.c b/source/texk/web2c/luatexdir/tex/texmath.c index 4b34c1723..54c5c4817 100644 --- a/source/texk/web2c/luatexdir/tex/texmath.c +++ b/source/texk/web2c/luatexdir/tex/texmath.c @@ -1084,6 +1084,18 @@ static boolean math_and_text_reversed_p(void) */ +static int only_dirs(halfword n) +{ + while (n) { + if (type(n) == local_par_node || type(n) == dir_node) { + n = vlink(n); + } else { + return 0; + } + } + return 1; +} + void enter_display_math(void) { /*tex new or partial |pre_display_size| */ @@ -1101,19 +1113,21 @@ void enter_display_math(void) \.{\$\${ }\$\$} */ - if (head == tail || - (vlink(head) == tail && - type(tail) == local_par_node && vlink(tail) == null)) { - if (vlink(head) == tail) { - /*tex - - |resume_after_display| inserts a |local_par_node|, but if there - is another display immediately following, we have to get rid of - that node. - - */ - flush_node(tail); - } + if (head == tail) { + pop_nest(); + w = -max_dimen; + } else if ((vlink(head) == tail && + type(tail) == local_par_node && vlink(tail) == null) || + ((math_empty_display_mode_par == 1) && (only_dirs(vlink(head))))) { + /*tex + + We ignore |null| paragraphs, that is those that only have a local par node, + for example because |resume_after_display| inserts a |local_par_node|. + If |\mathdisplayemptymode=1| paragraphs caontaining only local par node + and possibly a few dir nodes are ignored as well. + + */ + flush_node(vlink(head)); pop_nest(); w = -max_dimen; } else { -- 2.44.0
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