From 241082cbe6f4fe8c38e91c38418ca828ac8d2f7c Mon Sep 17 00:00:00 2001
From: Norbert Preining <norbert@preining.info>
Date: Wed, 25 Oct 2023 03:01:25 +0000
Subject: CTAN sync 202310250301

---
 .../latex/contrib/nicematrix/nicematrix-code.dtx   | 1224 ++++++++++++--------
 1 file changed, 731 insertions(+), 493 deletions(-)

(limited to 'macros/latex/contrib/nicematrix/nicematrix-code.dtx')

diff --git a/macros/latex/contrib/nicematrix/nicematrix-code.dtx b/macros/latex/contrib/nicematrix/nicematrix-code.dtx
index 8246cffbd8..4605970134 100644
--- a/macros/latex/contrib/nicematrix/nicematrix-code.dtx
+++ b/macros/latex/contrib/nicematrix/nicematrix-code.dtx
@@ -17,8 +17,8 @@
 %
 % \fi
 % \iffalse
-\def\myfileversion{6.24}
-\def\myfiledate{2023/09/28}
+\def\myfileversion{6.25}
+\def\myfiledate{2023/10/24}
 %
 %
 %<*batchfile>  
@@ -62,6 +62,9 @@ version 2005/12/01 or later.
 \def\interitem{\vspace{7mm plus 2 mm minus 3mm}}          
 
 \fvset{commandchars=\~\#\@,formatcom=\color{gray}}
+
+\usepackage{upquote}
+
 \usepackage{titlesec}
 \titlespacing*{\section}{0pt}{6.5ex plus 1ex minus .2ex}{4.3ex plus .2ex}
 \titlespacing*{\subsection}{0pt}{4.5ex plus 1ex minus .2ex}{2ex plus .2ex}
@@ -166,7 +169,7 @@ version 2005/12/01 or later.
 \cs_new_protected:Npn \@@_error:n { \msg_error:nn { nicematrix } }
 \cs_new_protected:Npn \@@_warning:n { \msg_warning:nn { nicematrix } }
 \cs_new_protected:Npn \@@_error:nn { \msg_error:nnn { nicematrix } }
-\cs_generate_variant:Nn \@@_error:nn { n x } 
+\cs_generate_variant:Nn \@@_error:nn { n e } 
 \cs_new_protected:Npn \@@_error:nnn { \msg_error:nnnn { nicematrix } }
 \cs_new_protected:Npn \@@_fatal:n { \msg_fatal:nn { nicematrix } }
 \cs_new_protected:Npn \@@_fatal:nn { \msg_fatal:nnn { nicematrix } }
@@ -376,7 +379,6 @@ version 2005/12/01 or later.
 % 
 %   \begin{macrocode}
 \cs_generate_variant:Nn \seq_set_split:Nnn { N V n }
-\cs_generate_variant:Nn \keys_define:nn { n x }
 \cs_generate_variant:Nn \str_lowercase:n { V }
 %    \end{macrocode}
 %
@@ -412,14 +414,14 @@ version 2005/12/01 or later.
 % 
 % We test whether the current class is \cls{revtex4-1} (deprecated) or
 % \cls{revtex4-2} because these classes redefines |\array| (of \pkg{array}) in a
-% way incompatible with our programmation. At the date March 2023, the current
-% version \cls{revtex4-2} is 4.2e (compatible with \pkg{booktabs}).
+% way incompatible with our programmation. At the date May 2023, the current
+% version \cls{revtex4-2} is 4.2f (compatible with \pkg{booktabs}).
 %
 %    \begin{macrocode}
-\@ifclassloaded { revtex4-1 }
+\IfClassLoadedTF { revtex4-1 }
   { \bool_const:Nn \c_@@_revtex_bool \c_true_bool }
   {
-    \@ifclassloaded { revtex4-2 }
+    \IfClassLoadedTF { revtex4-2 }
       { \bool_const:Nn \c_@@_revtex_bool \c_true_bool }
       {
 %    \end{macrocode}
@@ -438,12 +440,6 @@ version 2005/12/01 or later.
 \cs_generate_variant:Nn \tl_if_single_token_p:n { V }
 %    \end{macrocode}
 %
-% \bigskip
-% The following regex will be used to modify the preamble of the array when the
-% key |color-inside| is used.
-%    \begin{macrocode}
-\regex_const:Nn \c_@@_columncolor_regex { \c { columncolor } } 
-%    \end{macrocode}
 % 
 % \bigskip
 % If the final user uses \pkg{nicematrix}, PGF/Tikz will write instruction
@@ -573,7 +569,7 @@ version 2005/12/01 or later.
 \cs_set:Npn \@@_standard_cline #1 { \@@_standard_cline:w #1 \q_stop }
 \cs_set:Npn \@@_standard_cline:w #1-#2 \q_stop
   {
-    \int_compare:nNnT \l_@@_first_col_int = 0 { \omit & }
+    \int_if_zero:nT \l_@@_first_col_int { \omit & }
     \int_compare:nNnT { #1 } > 1 { \multispan { \int_eval:n { #1 - 1 } } & }
     \multispan { \int_eval:n { #2 - #1 + 1 } } 
     { 
@@ -722,6 +718,98 @@ version 2005/12/01 or later.
 %    \end{macrocode}
 %
 % \bigskip
+% Since we will do ourself the expansion of the preamble of the array, we will
+% modify |\@mkpream| of \pkg{array} in order to skip the operation of expansion
+% done by |\@mkpream|.
+%    \begin{macrocode}
+\cs_set_eq:NN \@@_old_mkpream: \@mkpream
+\cs_set_protected:Npn \@@_mkpream: #1
+  {
+%    \end{macrocode}
+% The command |\@@_mkpream_colortbl:| will be empty when \pkg{colortbl} is not loaded.
+%    \begin{macrocode}
+    \@@_mkpream_colortbl:
+    \gdef\@preamble{} \@lastchclass 4 \@firstamptrue
+    \let\@sharp\relax
+    \def\@startpbox##1{\unexpanded\expandafter{\expandafter
+                       \@startpbox\expandafter{##1}}}\let\@endpbox\relax
+    \let\do@row@strut\relax
+    \let\ar@align@mcell\relax
+    \@temptokena{#1} % \@tempswatrue
+    % \@whilesw\if@tempswa\fi{\@tempswafalse\the\NC@list}%
+    \count@\m@ne
+    \let\the@toks\relax
+    \prepnext@tok
+%    \end{macrocode}
+% We have slightly modified the code of the original version of |\@mkpream| in
+% order to have something compatible with |\ExplSyntaxOn|.
+%    \begin{macrocode}
+    \exp_args:NV \tl_map_variable:NNn \@temptokena \@nextchar
+    {\@testpach
+    \ifcase \@chclass \@classz \or \@classi \or \@classii
+      \or \save@decl \or \or \@classv \or \@classvi
+      \or \@classvii \or \@classviii
+      \or \@classx
+      \or \@classx \fi
+    \@lastchclass\@chclass}%
+    \ifcase\@lastchclass
+    \@acol \or
+    \or
+    \@acol \or
+    \@preamerr \thr@@ \or
+    \@preamerr \tw@ \@addtopreamble\@sharp \or
+    \or
+    \else  \@preamerr \@ne \fi
+    \def\the@toks{\the\toks}
+%    \end{macrocode}
+% After an utilisation of the modified version of |\@mkpream|, we come back to
+% the original version because there may be occurrences of the classical
+% |{array}| in the cells of our array (of \pkg{nicematrix}). 
+%    \begin{macrocode}
+    \cs_gset_eq:NN \@mkpream \@@_old_mkpream: 
+  }
+%    \end{macrocode}
+% The classes of REVTeX do their own redefinition of |\array| and that's why the
+% previous mechanisme is not compatible with REVTeX. However, it would probably
+% be possible to do something similar for REVTeX...
+%    \begin{macrocode}
+\bool_if:NTF \c_@@_revtex_bool
+  { \cs_new_protected:Npn \@@_redefine_mkpream: { } }
+  {
+    \cs_new_protected:Npn \@@_redefine_mkpream:
+      { \cs_set_eq:NN \@mkpream \@@_mkpream: }
+  }
+%    \end{macrocode}
+% 
+% \bigskip
+%    \begin{macrocode}
+\cs_new_protected:Npn \@@_mkpream_colortbl: { }
+\hook_gput_code:nnn { begindocument } { . }
+  { 
+    \IfPackageLoadedTF { colortbl }
+      {
+        \cs_set_protected:Npn \@@_mkpream_colortbl:
+          {
+%    \end{macrocode}
+% The following lines are a patch added to |\@mkpream| by \pkg{colortbl} (by
+% storing the version of |\@mkpream| provided by \pkg{array} in
+% |\@mkpreamarray|). Since you do a redefinition of |\@mkpream|, you have to add
+% the following lines in our redefinition when \pkg{colortbl} is loaded.
+%    \begin{macrocode}
+            \cs_set_eq:NN \CT@setup \relax
+            \cs_set_eq:NN \CT@color \relax
+            \cs_set_eq:NN \CT@do@color \relax
+            \cs_set_eq:NN \color \relax
+            \cs_set_eq:NN \CT@column@color \relax
+            \cs_set_eq:NN \CT@row@color \relax
+            \cs_set_eq:NN \CT@cell@color \relax
+          }  
+      }
+      { }
+  }
+%    \end{macrocode}
+%
+% \bigskip
 % \section{Parameters}
 %
 % \bigskip 
@@ -779,7 +867,7 @@ version 2005/12/01 or later.
 %
 % \medskip
 % The following boolean will be equal to |true| in the environments which have
-% an environment (provided by the final user): |{NiceTabular}|, |{NiceArray}|,
+% a preamble (provided by the final user): |{NiceTabular}|, |{NiceArray}|,
 % |{pNiceArray}|, etc. 
 %    \begin{macrocode}
 \bool_new:N \l_@@_preamble_bool
@@ -979,7 +1067,7 @@ version 2005/12/01 or later.
 %    \end{macrocode}
 %
 % \bigskip
-% In particuler, in that |aux| file, there will, for each environment of
+% In particuler, in that |aux| file, there will be, for each environment of
 % \pkg{nicematrix}, an affectation for the the following sequence that will
 % contain informations about the size of the array.
 %    \begin{macrocode}
@@ -1029,6 +1117,13 @@ version 2005/12/01 or later.
 %    \end{macrocode}
 % 
 % \bigskip
+% We will store in the following sequence informations provided by the
+% instructions |\rowlistcolors| in the main array (not in the |\CodeBefore|). 
+%    \begin{macrocode}
+\seq_new:N \g_@@_rowlistcolors_seq
+%    \end{macrocode}
+%
+% \bigskip
 %    \begin{macrocode}
 \cs_new_protected:Npn \@@_test_if_math_mode:
   { 
@@ -1038,12 +1133,6 @@ version 2005/12/01 or later.
   }
 %    \end{macrocode}
 %
-% \bigskip
-% The letter used for the vlines which will be drawn only in the sub-matrices.
-% |vlism| stands for \emph{vertical lines in sub-matrices}.
-%    \begin{macrocode}
-\tl_new:N \l_@@_letter_vlism_tl
-%    \end{macrocode} 
 % 
 % The list of the columns where vertical lines in sub-matrices (vlism) must be
 % drawn. Of course, the actual value of this sequence will be known after the
@@ -1579,7 +1668,8 @@ version 2005/12/01 or later.
 % but we don't know its value because the user has used the option |last-col|
 % without value. A value of $0$ means that the option |last-col| has been used
 % in an environment with preamble (like |{pNiceArray}|): in this case, the key
-% was necessary without argument.
+% was necessary without argument. The command |\NiceMatrixOptions| also sets
+% |\l_@@_last_col_int| to~$0$.
 %    \begin{macrocode}
 \int_new:N \l_@@_last_col_int
 \int_set:Nn \l_@@_last_col_int { -2 }
@@ -1882,10 +1972,10 @@ version 2005/12/01 or later.
                 \seq_map_break: 
               }
           }
-        \int_compare:nNnF \l_tmpa_int = \c_zero_int 
+        \int_if_zero:nF \l_tmpa_int 
           { \int_add:Nn \l_tmpa_int \g_@@_notes_caption_int }
       }
-    \int_compare:nNnT \l_tmpa_int = \c_zero_int
+    \int_if_zero:nT \l_tmpa_int 
       {
         \seq_gput_right:Nn \g_@@_notes_seq { { #1 } { #2 } } 
         \tl_if_novalue:nT { #1 } { \int_gincr:N \c@tabularnote }
@@ -1898,7 +1988,7 @@ version 2005/12/01 or later.
               {
                 \int_eval:n 
                   { 
-                    \int_compare:nNnTF \l_tmpa_int = \c_zero_int
+                    \int_if_zero:nTF \l_tmpa_int 
                       \c@tabularnote 
                       \l_tmpa_int  
                   }
@@ -2478,7 +2568,15 @@ version 2005/12/01 or later.
     vlines-in-sub-matrix .code:n = 
       {
         \tl_if_single_token:nTF { #1 }
-          { \tl_set:Nn \l_@@_letter_vlism_tl { #1 } }
+          { 
+            \tl_if_in:NnTF \c_@@_forbidden_letters_tl { #1 }
+              { \@@_error:nn { Forbidden~letter } { #1 } }
+%    \end{macrocode}
+% We write directly a command for the automata which reads the preamble provided
+% by the final user.
+%    \begin{macrocode}
+              { \cs_set_eq:cN { @@ _ #1 } \@@_make_preamble_vlism:n }
+          }
           { \@@_error:n { One~letter~allowed } } 
       } ,
     vlines-in-sub-matrix .value_required:n = true ,
@@ -2596,13 +2694,11 @@ version 2005/12/01 or later.
     code-after .value_required:n = true ,
     bottomrule .bool_set:N = \l_@@_notes_bottomrule_bool ,
     bottomrule .default:n = true ,
-    style .code:n = \cs_set:Nn \@@_notes_style:n { #1 } ,
+    style .cs_set:Np = \@@_notes_style:n #1 , 
     style .value_required:n = true ,
-    label-in-tabular .code:n = 
-      \cs_set:Nn \@@_notes_label_in_tabular:n { #1 } ,
+    label-in-tabular .cs_set:Np = \@@_notes_label_in_tabular:n #1 ,
     label-in-tabular .value_required:n = true ,
-    label-in-list .code:n = 
-      \cs_set:Nn \@@_notes_label_in_list:n { #1 } , 
+    label-in-list .cs_set:Np = \@@_notes_label_in_list:n #1 , 
     label-in-list .value_required:n = true ,
     enumitem-keys .code:n = 
       { 
@@ -2702,7 +2798,7 @@ version 2005/12/01 or later.
     delimiters / max-width .default:n = true ,
     delimiters .code:n = \keys_set:nn { NiceMatrix / delimiters } { #1 } , 
     delimiters .value_required:n = true , 
-    width .code:n = \dim_set:Nn \l_@@_width_dim { #1 } ,
+    width .dim_set:N = \l_@@_width_dim ,
     width .value_required:n = true ,
     last-col .code:n = 
       \tl_if_empty:nF { #1 }
@@ -2780,7 +2876,7 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
 \keys_define:nn { NiceMatrix / NiceMatrix }
   { 
-    last-col .code:n = \tl_if_empty:nTF {#1}
+    last-col .code:n = \tl_if_empty:nTF { #1 }
                          {  
                            \bool_set_true:N \l_@@_last_col_without_value_bool
                            \int_set:Nn \l_@@_last_col_int { -1 }
@@ -2968,7 +3064,7 @@ version 2005/12/01 or later.
 % The codes |\l_@@_code_for_first_row_tl| and \emph{al} don't apply in the
 % corners of the matrix.
 %    \begin{macrocode}
-    \int_compare:nNnTF \c@iRow = 0 
+    \int_if_zero:nTF \c@iRow 
       { 
         \int_compare:nNnT \c@jCol > 0 
           { 
@@ -3023,7 +3119,7 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
 \cs_new_protected:Npn \@@_update_for_first_and_last_row:
   {
-    \int_compare:nNnTF \c@iRow = 0
+    \int_if_zero:nTF \c@iRow 
       { 
         \dim_gset:Nn \g_@@_dp_row_zero_dim
           { \dim_max:nn \g_@@_dp_row_zero_dim { \box_dp:N \l_@@_cell_box } }
@@ -3126,8 +3222,7 @@ version 2005/12/01 or later.
 % of the array (except the cells of the ``first column'' and the ``last
 % column''). 
 %    \begin{macrocode}
-    \dim_gset:Nn \g_@@_max_cell_width_dim
-      { \dim_max:nn \g_@@_max_cell_width_dim { \box_wd:N \l_@@_cell_box } }
+    \@@_update_max_cell_width:
 %    \end{macrocode}
 %
 % The following computations are for the ``first row'' and the ``last row''.
@@ -3178,6 +3273,16 @@ version 2005/12/01 or later.
 %    \end{macrocode}
 %
 % \bigskip
+% The following command will be nullified in our redefinition of |\multicolumn|. 
+%    \begin{macrocode}
+\cs_new_protected:Npn \@@_update_max_cell_width:
+  {
+    \dim_gset:Nn \g_@@_max_cell_width_dim
+      { \dim_max:nn \g_@@_max_cell_width_dim { \box_wd:N \l_@@_cell_box } }
+  }
+%    \end{macrocode}
+% 
+% \bigskip
 % The following variant of |\@@_cell_end:| is only for the columns of type
 % |w{s}{...}| or |W{s}{...}| (which use the horizontal alignement key |s| of
 % |\makebox|). 
@@ -3343,11 +3448,17 @@ version 2005/12/01 or later.
   }  
 %    \end{macrocode}
 %
-%
+% \bigskip
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_array:n
+\cs_new_protected:Npn \@@_array:
   {
-    % modified 05-08-23
+%    \end{macrocode}
+% The following line is only a speed-up: it's a redefinition of |\@mkpream|
+% of \pkg{array} in order to speed up the compilation by deleting one line of
+% code in |\@mkpream| (the expansion of the preamble). In the classes of REVTeX,
+% that command |\@@_redefine_mkpream:| will be nullified (no speed-up).
+%    \begin{macrocode}
+    \@@_redefine_mkpream:
     \dim_set:Nn \col@sep
       { \bool_if:NTF \l_@@_tabular_bool \tabcolsep \arraycolsep }
     \dim_compare:nNnTF \l_@@_tabular_width_dim = \c_zero_dim
@@ -3366,7 +3477,6 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
     [ \str_if_eq:VnTF \l_@@_baseline_tl c c t ]
   }
-\cs_generate_variant:Nn \@@_array:n { V }
 %    \end{macrocode}
 %
 % \medskip
@@ -3448,7 +3558,7 @@ version 2005/12/01 or later.
           {
             \tl_if_eq:NnF \l_@@_hlines_clist { all } 
               { 
-                \exp_args:NNx
+                \exp_args:NNe
                   \clist_if_in:NnT 
                   \l_@@_hlines_clist 
                   { \int_eval:n { \c@iRow + 1 } }
@@ -3493,19 +3603,63 @@ version 2005/12/01 or later.
   }
 %    \end{macrocode}
 %
+%
+%    \begin{macrocode}
+\cs_new_protected:Npn \@@_test_color_inside: 
+  { 
+    \bool_if:NF \l_@@_color_inside_bool
+      { 
+%    \end{macrocode}
+% We will issue an error only during the first run.
+%    \begin{macrocode}
+        \bool_if:NF \g_@@_aux_found_bool
+          { \@@_error:n { without~color-inside } }
+      }
+  }
+%    \end{macrocode}
+% 
 % \bigskip
-% When the key |color-inside| is used, the following code will be executed.
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_colortbl_like:
+\cs_new_protected:Npn \@@_redefine_everycr: { \everycr { \@@_everycr: } } 
+\hook_gput_code:nnn { begindocument } { . }
   {
-    \cs_set_eq:NN \cellcolor \@@_cellcolor_tabular
-    \cs_set_eq:NN \rowcolor \@@_rowcolor_tabular
-    \cs_set_eq:NN \columncolor \@@_columncolor_preamble
-    \cs_set_eq:NN \rowcolors \@@_rowcolors_tabular
-    \cs_set_eq:NN \rowlistcolors \@@_rowlistcolors_tabular
+    \IfPackageLoadedTF { colortbl }
+      {
+        \cs_set_protected:Npn \@@_redefine_everycr:
+          {
+            \CT@everycr 
+              { 
+                \noalign { \cs_gset_eq:NN \CT@row@color \prg_do_nothing: }
+                \@@_everycr:
+              }
+          }
+      }
+      { } 
   }
 %    \end{macrocode}
 % 
+% If \pkg{booktabs} is loaded, we have to patch the macro |\@BTnormal| which is
+% a macro of \pkg{booktabs}. The macro |\@BTnormal| draws an horizontal rule but
+% it occurs after a vertical skip done by a low level TeX command. When this
+% macro |\@BTnormal| occurs, the |row| node has yet been inserted by
+% \pkg{nicematrix} \emph{before} the vertical skip (and thus, at a wrong place).
+% That why we decide to create a new |row| node (for the same row). We patch the
+% macro |\@BTnormal| to create this |row| node. This new |row| node will
+% overwrite the previous definition of that |row| node and we have managed to
+% avoid the error messages of that redefinition
+% \footnote{cf. |\nicematrix@redefine@check@rerun|}.
+%    \begin{macrocode}
+\hook_gput_code:nnn { begindocument } { . }
+  {
+    \IfPackageLoadedTF { booktabs }
+      { 
+        \cs_new_protected:Npn \@@_patch_booktabs: 
+          { \tl_put_left:Nn \@BTnormal \@@_create_row_node_i: }
+      }
+      { \cs_new_protected:Npn \@@_patch_booktabs: { } }
+  }
+%    \end{macrocode}
+%
 % \bigskip
 % The following code |\@@_pre_array_ii:| is used in |{NiceArrayWithDelims}|. It
 % exists as a standalone macro only for legibility.
@@ -3523,22 +3677,7 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
     \@@_expand_clist:N \l_@@_hlines_clist
     \@@_expand_clist:N \l_@@_vlines_clist
-%    \end{macrocode}
-% 
-% If \pkg{booktabs} is loaded, we have to patch the macro |\@BTnormal| which is
-% a macro of \pkg{booktabs}. The macro |\@BTnormal| draws an horizontal rule but
-% it occurs after a vertical skip done by a low level TeX command. When this
-% macro |\@BTnormal| occurs, the |row| node has yet been inserted by
-% \pkg{nicematrix} \emph{before} the vertical skip (and thus, at a wrong place).
-% That why we decide to create a new |row| node (for the same row). We patch the
-% macro |\@BTnormal| to create this |row| node. This new |row| node will
-% overwrite the previous definition of that |row| node and we have managed to
-% avoid the error messages of that redefinition
-% \footnote{cf. |\nicematrix@redefine@check@rerun|}.
-%    \begin{macrocode}
-    \IfPackageLoadedTF { booktabs }
-      { \tl_put_left:Nn \@BTnormal \@@_create_row_node_i: }
-      { }
+    \@@_patch_booktabs:
     \box_clear_new:N \l_@@_cell_box
     \normalbaselines
 %    \end{macrocode}
@@ -3575,15 +3714,7 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
     \cs_set_nopar:Npn \ialign 
       { 
-        \IfPackageLoadedTF { colortbl }
-          {
-            \CT@everycr 
-              { 
-                \noalign { \cs_gset_eq:NN \CT@row@color \prg_do_nothing: }
-                \@@_everycr:
-              }
-          }
-          { \everycr { \@@_everycr: } }
+        \@@_redefine_everycr:
         \tabskip = \c_zero_skip
 %    \end{macrocode}
 %
@@ -3651,7 +3782,10 @@ version 2005/12/01 or later.
     \cs_set_eq:NN \RowStyle \@@_RowStyle:n
     \seq_map_inline:Nn \l_@@_custom_line_commands_seq
       { \cs_set_eq:cc { ##1 } { nicematrix - ##1 } } 
-    \bool_if:NT \l_@@_color_inside_bool \@@_colortbl_like:
+    \cs_set_eq:NN \cellcolor \@@_cellcolor_tabular
+    \cs_set_eq:NN \rowcolor \@@_rowcolor_tabular
+    \cs_set_eq:NN \rowcolors \@@_rowcolors_tabular
+    \cs_set_eq:NN \rowlistcolors \@@_rowlistcolors_tabular
     \bool_if:NT \l_@@_renew_dots_bool \@@_renew_dots:
 %    \end{macrocode}
 % We redefine |\multicolumn| and, since we want |\multicolumn| to be available
@@ -3863,7 +3997,6 @@ version 2005/12/01 or later.
         \dim_set:Nn \l_@@_right_delim_dim { \box_wd:N \l_tmpa_box }
       }
       { 
-        % modified 05-08-23
         \dim_gset:Nn \l_@@_left_delim_dim 
            { 2 \bool_if:NTF \l_@@_tabular_bool \tabcolsep \arraycolsep }
         \dim_gset_eq:NN \l_@@_right_delim_dim \l_@@_left_delim_dim 
@@ -4315,7 +4448,7 @@ version 2005/12/01 or later.
 % Now, we prepare the token list for the instructions that we will have to write
 % on the |aux| file at the end of the environment.
 %    \begin{macrocode}
-    \tl_gclear:N \g_@@_aux_tl
+    \tl_build_gbegin:N \g_@@_aux_tl
 %    \end{macrocode}
 % 
 %    \begin{macrocode}
@@ -4374,7 +4507,7 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
     \bool_if:NT \l_@@_width_used_bool
       {
-        \int_compare:nNnT \g_@@_total_X_weight_int = 0 
+        \int_if_zero:nT \g_@@_total_X_weight_int  
           { \@@_error_or_warning:n { width~without~X~columns } }
       }
 %    \end{macrocode}
@@ -4388,7 +4521,7 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
     \int_compare:nNnT \g_@@_total_X_weight_int > 0 
       { 
-        \tl_gput_right:Nx \g_@@_aux_tl
+        \tl_build_gput_right:Nx \g_@@_aux_tl
           {
             \bool_set_true:N \l_@@_X_columns_aux_bool
             \dim_set:Nn \l_@@_X_columns_dim 
@@ -4462,7 +4595,7 @@ version 2005/12/01 or later.
 % computed its width in |\g_@@_width_first_col_dim|: see
 % p.~\pageref{overlap-left}). 
 %    \begin{macrocode}
-    \int_compare:nNnT \l_@@_first_col_int = 0
+    \int_if_zero:nT \l_@@_first_col_int
       { 
         % \skip_horizontal:N \col@sep % 05-08-23
         \skip_horizontal:N \g_@@_width_first_col_dim
@@ -4488,7 +4621,7 @@ version 2005/12/01 or later.
 % |first-row| is used).
 %    \begin{macrocode}
       {
-        \int_compare:nNnTF \l_@@_first_row_int = 0
+        \int_if_zero:nTF \l_@@_first_row_int
           { 
             \dim_set_eq:NN \l_tmpa_dim \g_@@_dp_row_zero_dim 
             \dim_add:Nn \l_tmpa_dim \g_@@_ht_row_zero_dim 
@@ -4592,6 +4725,7 @@ version 2005/12/01 or later.
 % We write on the |aux| file all the informations corresponding to the
 % current environment.
 %    \begin{macrocode}
+    \tl_build_gend:N \g_@@_aux_tl
     \iow_now:Nn \@mainaux { \ExplSyntaxOn }
     \iow_now:Nn \@mainaux { \char_set_catcode_space:n { 32 }  }
     \iow_now:Nx \@mainaux 
@@ -4631,7 +4765,6 @@ version 2005/12/01 or later.
 \cs_new_protected:Npn \@@_transform_preamble_i:
   {
     \int_gzero:N \c@jCol
-    \group_begin:
 %    \end{macrocode}
 % The sequence |\g_@@_cols_vlsim_seq| will contain the numbers of the columns
 % where you will to have to draw vertical lines in the potential sub-matrices
@@ -4668,29 +4801,40 @@ version 2005/12/01 or later.
           }
       }
 %    \end{macrocode}
+% 
+% \bigskip
 % Now, we actually make the preamble (which will be given to |{array}|). It will
 % be stored in |\g_@@_array_preamble_tl|.
 %    \begin{macrocode}
-    \exp_last_unbraced:NV \@@_make_preamble:n \g_@@_user_preamble_tl \q_stop
+    \exp_last_unbraced:NV \@@_rec_preamble:n \g_@@_user_preamble_tl \stop
     \int_gset_eq:NN \g_@@_static_num_of_col_int \c@jCol
 %    \end{macrocode}
 %
 % \medskip
-% Now, we replace |\columncolor| by |\@@_columncolor_preamble|.
 %    \begin{macrocode}
-    \bool_if:NT \l_@@_color_inside_bool
-      {
-        \regex_replace_all:NnN 
-          \c_@@_columncolor_regex
-          { \c { @@_columncolor_preamble } }  
-          \g_@@_array_preamble_tl
-      }
+    \@@_replace_columncolor: 
+  }
 %    \end{macrocode}
 %
-% \medskip
-% We are not sure that the following TeX group is still necessary.
+% \bigskip
 %    \begin{macrocode}
-    \group_end:
+\hook_gput_code:nnn { begindocument } { . }
+  {
+    \IfPackageLoadedTF { colortbl } 
+      {
+        \regex_const:Nn \c_@@_columncolor_regex { \c { columncolor } } 
+        \cs_new_protected:Npn \@@_replace_columncolor:
+          {
+            \regex_replace_all:NnN 
+              \c_@@_columncolor_regex
+              { \c { @@_columncolor_preamble } }  
+              \g_@@_array_preamble_tl
+          }  
+      }
+      { 
+        \cs_new_protected:Npn \@@_replace_columncolor: 
+          { \cs_set_eq:NN \columncolor \@@_columncolor_preamble }
+      }
   }
 %    \end{macrocode}
 % 
@@ -4701,7 +4845,7 @@ version 2005/12/01 or later.
 %    \end{macrocode}
 % 
 % \medskip
-% If there was delimiters at the beginning or at the end of the preamble, the
+% If there were delimiters at the beginning or at the end of the preamble, the
 % environment |{NiceArray}| is transformed into an environment |{xNiceMatrix}|.
 %    \begin{macrocode}
     \bool_lazy_or:nnT 
@@ -4719,7 +4863,7 @@ version 2005/12/01 or later.
 % \bigskip
 % We complete the preamble with the potential ``exterior columns'' (on both sides).
 %    \begin{macrocode}
-    \int_compare:nNnTF \l_@@_first_col_int = 0
+    \int_if_zero:nTF \l_@@_first_col_int 
       { \tl_gput_left:NV \g_@@_array_preamble_tl \c_@@_preamble_first_col_tl }
       {
         \bool_lazy_all:nT 
@@ -4758,97 +4902,47 @@ version 2005/12/01 or later.
 %    \end{macrocode}
 %
 % \bigskip
-% The command |\@@_make_preamble:n| is the main function for the creation
-% of the preamble. It is recursive.
+% The preamble provided by the final user will be read by a finite
+% automata. The following function |\@@_rec_preamble:n| will read that preamble
+% (usually letter by letter) in a recursive way (hence the name of that function). 
+% in the preamble and 
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble:n #1
+\cs_new_protected:Npn \@@_rec_preamble:n #1
   {
-    \str_if_eq:nnF { #1 } { \q_stop }
-      {
-        \cs_if_exist:cTF { @@ \token_to_str:N #1 }
-          { \use:c { @@ \token_to_str:N #1 } { #1 } }
-          { 
-            \str_if_eq:nVTF { #1 } \l_@@_letter_vlism_tl 
-              { 
-                \seq_gput_right:Nx \g_@@_cols_vlism_seq 
-                  { \int_eval:n { \c@jCol + 1 } }
-                \tl_gput_right:Nx \g_@@_array_preamble_tl
-                  { \exp_not:N ! { \skip_horizontal:N \arrayrulewidth } }
-                \@@_make_preamble:n
-              }
 %    \end{macrocode}
-% Now the case of a letter set by the final user for a customized rule. Such
-% customized rule is defined by using the key |custom-line| in
-% |\NiceMatrixOptions|. That key takes in as value a list of \textsl{key=value}
-% pairs. Among the keys avalaible in that list, there is the key |letter|. All
-% the letters defined by this way by the final user for such customized rules
-% are added in the set of keys |{NiceMatrix/ColumnTypes}|. That set of keys is
-% used to store the characteristics of those types of rules for convenience: the
-% keys of that set of keys won't never be used as keys by the final user (he
-% will use, instead, letters in the preamble of its array).
+% For the majority of the letters, we will trigger the corresponding action by
+% calling directly a function in the main hashtable of TeX (thanks to the
+% mechanism |\csname...\endcsname|. Be careful: all these functions take in as
+% first argument the letter (or token) itself.\footnote{We do that because it's
+% a easy way to insert the letter at some places in the code that we will add to
+% |\g_@@_array_preamble_tl|.}
 %    \begin{macrocode}
-              { 
-                \keys_if_exist:nnTF { NiceMatrix / ColumnTypes } { #1 } 
-                  {
-                    \keys_set:nn { NiceMatrix / ColumnTypes } { #1 } 
-                    \@@_make_preamble:n 
-                  }
-                  { 
-                    \cs_if_exist:cTF { NC @ find @ #1 }
-                      {
-                        \tl_set_eq:Nc \l_tmpb_tl { NC @ rewrite @ #1 }
-                        \exp_last_unbraced:NV \@@_make_preamble:n \l_tmpb_tl
-                      }
-                      { 
-                        \tl_if_eq:nnT { #1 } { S }
-                          { \@@_fatal:n { unknown~column~type~S } }
-                          { \@@_fatal:nn { unknown~column~type } { #1 } }
-                      }
-                  }
-              }
+    \cs_if_exist:cTF { @@ _ \token_to_str:N #1 }
+      { \use:c { @@ _ \token_to_str:N #1 } { #1 } }
+      { 
+%    \end{macrocode}
+% Now, the columns defined by |\newcolumntype| of \pkg{array}.
+%    \begin{macrocode}
+        \cs_if_exist:cTF { NC @ find @ #1 }
+          {
+            \tl_set_eq:Nc \l_tmpb_tl { NC @ rewrite @ #1 }
+            \exp_last_unbraced:NV \@@_rec_preamble:n \l_tmpb_tl
+          }
+          { 
+            \tl_if_eq:nnT { #1 } { S }
+              { \@@_fatal:n { unknown~column~type~S } }
+              { \@@_fatal:nn { unknown~column~type } { #1 } }
           }
       }
   }
 %    \end{macrocode}
 %
-% \bigskip
-% Now, we will list all the auxiliary functions for the different types of
-% entries in the preamble of the array.
-%    \begin{macrocode}
-\cs_new:cpn { @@ \string c }        { \@@_make_preamble_i:n }
-\cs_new:cpn { @@ \string l }        { \@@_make_preamble_i:n }
-\cs_new:cpn { @@ \string r }        { \@@_make_preamble_i:n }
-\cs_new:cpn { @@ \string > }        { \@@_make_preamble_xiv:nn }
-\cs_new:cpn { @@ \string ! }        { \@@_make_preamble_ii:nn }
-\cs_new:cpn { @@ \string @ }        { \@@_make_preamble_ii:nn }
-\cs_new:cpn { @@ \string | }        { \@@_make_preamble_iii:n }
-\cs_new:cpn { @@ \string p }        { \@@_make_preamble_iv:n }
-\cs_new:cpn { @@ \string b }        { \@@_make_preamble_iv:n }
-\cs_new:cpn { @@ \string m }        { \@@_make_preamble_iv:n }
-\cs_new:cpn { @@ \string V }        { \@@_make_preamble_v:nn } 
-\cs_new:cpn { @@ \string w }        { \@@_make_preamble_vi:nnnn { } } 
-\cs_new:cpn { @@ \string W }        { \@@_make_preamble_vi:nnnn { \@@_special_W: } } 
-\cs_new:cpn { @@ \string S }        { \@@_make_preamble_vii:nn }
-\cs_new:cpn { @@ \string ( }        { \@@_make_preamble_viii:nn }
-\cs_new:cpn { @@ \string [ }        { \@@_make_preamble_viii:nn }
-\cs_new:cpn { @@ \string \{ }       { \@@_make_preamble_viii:nn }
-\cs_new:cpn { @@ \string \left }    { \@@_make_preamble_viii_ii:n }
-\cs_new:cpn { @@ \string ) }        { \@@_make_preamble_ix:nn }       
-\cs_new:cpn { @@ \string ] }        { \@@_make_preamble_ix:nn }       
-\cs_new:cpn { @@ \string \} }       { \@@_make_preamble_ix:nn }       
-\cs_new:cpn { @@ \string \right }   { \@@_make_preamble_ix_ii:n }
-\cs_new:cpn { @@ \string X }        { \@@_make_preamble_x:nn }
-\cs_new:cpn { @@ \string * }        { \@@_make_preamble_xvi:nnn }
-\cs_new:cpn { @@ \string \NC@find } { \@@_make_preamble_xx:n }
-%    \end{macrocode}
-% The token |\NC@find| is at the head of the definition of the columns type done
-% by |\newcolumntype|. We wan't that token to be no-op here.
 %
 % 
 % \bigskip
 % For |c|, |l| and |r|
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_i:n #1
+\cs_new:Npn \@@_c #1
   { 
     \tl_gput_right:NV \g_@@_array_preamble_tl \g_@@_pre_cell_tl 
     \tl_gclear:N \g_@@_pre_cell_tl
@@ -4863,56 +4957,59 @@ version 2005/12/01 or later.
 % We increment the counter of columns and then we test for the presence of a |<|.
 %    \begin{macrocode}
     \int_gincr:N \c@jCol
-    \@@_make_preamble_xi:n
+    \@@_rec_preamble_after_col:n
   }
+\cs_set_eq:NN \@@_l \@@_c
+\cs_set_eq:NN \@@_r \@@_c
 %    \end{macrocode}
 % 
 % \medskip
-% For |>|, |!| and |@|
+% For |!| and |@|
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_ii:nn #1 #2
+\cs_new:cpn { @@ _ \token_to_str:N ! } #1 #2
   {  
     \tl_gput_right:Nn \g_@@_array_preamble_tl { #1 { #2 } }
-    \@@_make_preamble:n
+    \@@_rec_preamble:n
   }
+\cs_set_eq:cc { @@ _ \token_to_str:N @ } { @@ _ \token_to_str:N ! }
 %    \end{macrocode}
 %
 % 
 % \medskip
 % For \verb+|+
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_iii:n #1
+\cs_new:cpn { @@ _ | } #1
   { 
 %    \end{macrocode}
 % |\l_tmpa_int| is the number of successive occurrences of \verb+|+
 %    \begin{macrocode}
     \int_incr:N \l_tmpa_int 
-    \@@_make_preamble_iii_i:n
+    \@@_make_preamble_i_i:n
   }
 %    \end{macrocode}
 % 
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_iii_i:n #1
+\cs_new_protected:Npn \@@_make_preamble_i_i:n #1
   {
     \str_if_eq:nnTF { #1 } | 
       { \@@_make_preamble_iii:n | }
-      { \@@_make_preamble_iii_ii:nn { } #1 }
+      { \@@_make_preamble_i_ii:nn { } #1 }
   }
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_iii_ii:nn #1 #2
+\cs_new_protected:Npn \@@_make_preamble_i_ii:nn #1 #2
   {
     \str_if_eq:nnTF { #2 } [
-      { \@@_make_preamble_iii_ii:nw { #1 } [ }
-      { \@@_make_preamble_iii_iii:nn { #2 } { #1 } }
+      { \@@_make_preamble_i_ii:nw { #1 } [ }
+      { \@@_make_preamble_i_iii:nn { #2 } { #1 } }
   }
-\cs_new_protected:Npn \@@_make_preamble_iii_ii:nw #1 [ #2 ]  
-  { \@@_make_preamble_iii_ii:nn { #1 , #2 } }
+\cs_new_protected:Npn \@@_make_preamble_i_ii:nw #1 [ #2 ]  
+  { \@@_make_preamble_i_ii:nn { #1 , #2 } }
 %    \end{macrocode}
 % 
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_iii_iii:nn #1 #2
+\cs_new_protected:Npn \@@_make_preamble_i_iii:nn #1 #2
   {
     \@@_compute_rule_width:n { multiplicity = \l_tmpa_int , #2 }
     \tl_gput_right:Nx \g_@@_array_preamble_tl
@@ -4938,16 +5035,17 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
       }
     \int_zero:N \l_tmpa_int
-    \str_if_eq:nnT { #1 } { \q_stop } { \bool_gset_true:N \g_tmpb_bool } 
-    \@@_make_preamble:n #1 
+    \str_if_eq:nnT { #1 } { \stop } { \bool_gset_true:N \g_tmpb_bool } 
+    \@@_rec_preamble:n #1 
   }
 %    \end{macrocode}
 % 
+% \bigskip
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_xiv:nn #1 #2
+\cs_new:cpn { @@ _  > } #1 #2
   { 
     \tl_gput_right:Nn \g_@@_pre_cell_tl { > { #2 } } 
-    \@@_make_preamble:n 
+    \@@_rec_preamble:n 
   }
 %    \end{macrocode}
 % 
@@ -5006,31 +5104,33 @@ version 2005/12/01 or later.
 % 
 % 
 % \medskip
-% For |p|, |b| and |m|. The argument |#1| is that value : |p|, |b| or |m|.
+% For |p|, |b| and |m|. 
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_iv:n #1
+\cs_new:Npn \@@_p #1
   { 
     \str_set:Nn \l_@@_vpos_col_str { #1 }
 %    \end{macrocode}
 % Now, you look for a potential character |[| after the letter of the specifier
 % (for the options).
 %    \begin{macrocode}
-    \@@_make_preamble_iv_i:n 
+    \@@_make_preamble_ii_i:n 
   }
+\cs_set_eq:NN \@@_b \@@_p
+\cs_set_eq:NN \@@_m \@@_p
 %    \end{macrocode}
 % 
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_iv_i:n #1
+\cs_new_protected:Npn \@@_make_preamble_ii_i:n #1
   {
     \str_if_eq:nnTF { #1 } { [ }
-      { \@@_make_preamble_iv_ii:w [ }
-      { \@@_make_preamble_iv_ii:w [ ] { #1 } }
+      { \@@_make_preamble_ii_ii:w [ }
+      { \@@_make_preamble_ii_ii:w [ ] { #1 } }
   }
 %    \end{macrocode}
 % 
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_iv_ii:w [ #1 ]
-  { \@@_make_preamble_iv_iii:nn { #1 } }
+\cs_new_protected:Npn \@@_make_preamble_ii_ii:w [ #1 ]
+  { \@@_make_preamble_ii_iii:nn { #1 } }
 %    \end{macrocode}
 % 
 % \medskip
@@ -5039,7 +5139,7 @@ version 2005/12/01 or later.
 %
 % |#2| is the mandatory argument of the specifier: the width of the column.
 %    \begin{macrocode}  
-\cs_new_protected:Npn \@@_make_preamble_iv_iii:nn #1 #2 
+\cs_new_protected:Npn \@@_make_preamble_ii_iii:nn #1 #2 
   {  
 %    \end{macrocode}
 % The possible values of |\l_@@_hpos_col_str| are |j| (for \emph{justified} which is
@@ -5049,7 +5149,7 @@ version 2005/12/01 or later.
     \str_set:Nn \l_@@_hpos_col_str { j }
     \tl_set:Nn \l_tmpa_tl { #1 }
     \@@_keys_p_column:V \l_tmpa_tl 
-    \@@_make_preamble_iv_iv:nn { #2 } { minipage }
+    \@@_make_preamble_ii_iv:nn { #2 } { minipage }
   }
 %    \end{macrocode}
 %
@@ -5063,11 +5163,11 @@ version 2005/12/01 or later.
 % The first argument is the width of the column. The second is the type of
 % environment: |minipage| or |varwidth|. 
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_iv_iv:nn #1 #2
+\cs_new_protected:Npn \@@_make_preamble_ii_iv:nn #1 #2
   {
-    \use:x 
+    \use:e 
       { 
-        \@@_make_preamble_iv_v:nnnnnnnn
+        \@@_make_preamble_ii_v:nnnnnnnn
           { \str_if_eq:VnTF \l_@@_vpos_col_str { p } { t } { b } }
           { \dim_eval:n { #1 } }
           {
@@ -5114,7 +5214,7 @@ version 2005/12/01 or later.
 % We increment the counter of columns, and then we test for the presence of a |<|.
 %    \begin{macrocode}
     \int_gincr:N \c@jCol
-    \@@_make_preamble_xi:n
+    \@@_rec_preamble_after_col:n
   }
 %    \end{macrocode}
 % 
@@ -5143,7 +5243,7 @@ version 2005/12/01 or later.
 % |#8| is the letter |c| or |r| or |l| which is the basic specificier of column
 % which is used \emph{in fine}.
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_iv_v:nnnnnnnn #1 #2 #3 #4 #5 #6 #7 #8
+\cs_new_protected:Npn \@@_make_preamble_ii_v:nnnnnnnn #1 #2 #3 #4 #5 #6 #7 #8
   {
     \str_if_eq:VnTF \l_@@_hpos_col_str { si }
       { \tl_gput_right:Nn \g_@@_array_preamble_tl { > { \@@_test_if_empty_for_S: } } }
@@ -5278,31 +5378,35 @@ version 2005/12/01 or later.
 % \medskip
 % For |V| (similar to the |V| of \pkg{varwidth}).
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_v:nn #1 #2
+\cs_new:Npn \@@_V #1 #2
   {
     \str_if_eq:nnTF { #2 } { [ }
-      { \@@_make_preamble_v_i:w [ }
-      { \@@_make_preamble_v_i:w [ ] { #2 } }
+      { \@@_make_preamble_V_i:w [ }
+      { \@@_make_preamble_V_i:w [ ] { #2 } }
   }
-\cs_new_protected:Npn \@@_make_preamble_v_i:w [ #1 ]
-  { \@@_make_preamble_v_ii:nn { #1 } }
-\cs_new_protected:Npn \@@_make_preamble_v_ii:nn #1 #2
+\cs_new_protected:Npn \@@_make_preamble_V_i:w [ #1 ]
+  { \@@_make_preamble_V_ii:nn { #1 } }
+\cs_new_protected:Npn \@@_make_preamble_V_ii:nn #1 #2
   {
     \str_set:Nn \l_@@_vpos_col_str { p }
     \str_set:Nn \l_@@_hpos_col_str { j }
     \tl_set:Nn \l_tmpa_tl { #1 }
     \@@_keys_p_column:V \l_tmpa_tl 
     \IfPackageLoadedTF { varwidth }
-      { \@@_make_preamble_iv_iv:nn { #2 } { varwidth } }
+      { \@@_make_preamble_ii_iv:nn { #2 } { varwidth } }
       { 
         \@@_error_or_warning:n { varwidth~not~loaded }
-        \@@_make_preamble_iv_iv:nn { #2 } { minipage } 
+        \@@_make_preamble_ii_iv:nn { #2 } { minipage } 
       }
   }
 %    \end{macrocode}
 % 
 % \medskip
 % For |w| and |W|
+%    \begin{macrocode}
+\cs_new:Npn \@@_w { \@@_make_preamble_w:nnnn { } } 
+\cs_new:Npn \@@_W { \@@_make_preamble_w:nnnn { \@@_special_W: } } 
+%    \end{macrocode}
 %
 % |#1| is a special argument: empty for |w| and equal to |\@@_special_W:| for |W|;
 %
@@ -5313,11 +5417,11 @@ version 2005/12/01 or later.
 % |#4| is the width of the column.
 %
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_vi:nnnn #1 #2 #3 #4
+\cs_new_protected:Npn \@@_make_preamble_w:nnnn #1 #2 #3 #4
   {  
     \str_if_eq:nnTF { #3 } { s }
-      { \@@_make_preamble_vi_i:nnnn { #1 } { #4 } }
-      { \@@_make_preamble_vi_ii:nnnn { #1 } { #2 } { #3 } { #4 } }
+      { \@@_make_preamble_w_i:nnnn { #1 } { #4 } }
+      { \@@_make_preamble_w_ii:nnnn { #1 } { #2 } { #3 } { #4 } }
   }
 %    \end{macrocode}
 % 
@@ -5329,7 +5433,7 @@ version 2005/12/01 or later.
 %
 % |#2| is the width of the column.
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_vi_i:nnnn #1 #2 
+\cs_new_protected:Npn \@@_make_preamble_w_i:nnnn #1 #2 
   {  
     \tl_gput_right:NV \g_@@_array_preamble_tl \g_@@_pre_cell_tl 
     \tl_gclear:N \g_@@_pre_cell_tl
@@ -5349,7 +5453,7 @@ version 2005/12/01 or later.
           }
       }
     \int_gincr:N \c@jCol
-    \@@_make_preamble_xi:n
+    \@@_rec_preamble_after_col:n
   }
 %    \end{macrocode}
 % 
@@ -5357,7 +5461,7 @@ version 2005/12/01 or later.
 % Then, the most important version, for the horizontal alignments types of |c|,
 % |l| and |r| (and not |s|).
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_vi_ii:nnnn #1 #2 #3 #4
+\cs_new_protected:Npn \@@_make_preamble_w_ii:nnnn #1 #2 #3 #4
   {  
     \tl_gput_right:NV \g_@@_array_preamble_tl \g_@@_pre_cell_tl 
     \tl_gclear:N \g_@@_pre_cell_tl
@@ -5387,7 +5491,7 @@ version 2005/12/01 or later.
 % We increment the counter of columns and then we test for the presence of a |<|.
 %    \begin{macrocode}
     \int_gincr:N \c@jCol
-    \@@_make_preamble_xi:n
+    \@@_rec_preamble_after_col:n
   }
 %    \end{macrocode}
 % 
@@ -5403,43 +5507,39 @@ version 2005/12/01 or later.
 % \medskip
 % For |S| (of \pkg{siunitx}). 
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_vii:nn #1 #2
+\cs_new:Npn \@@_S #1 #2
   {
     \str_if_eq:nnTF { #2 } { [ }
-      { \@@_make_preamble_vii_i:w [ }
-      { \@@_make_preamble_vii_i:w [ ] { #2 } }
+      { \@@_make_preamble_S:w [ }
+      { \@@_make_preamble_S:w [ ] { #2 } }
   }
 %    \end{macrocode}
 % 
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_vii_i:w [ #1 ]
-  { \@@_make_preamble_vii_ii:n { #1 } }
+\cs_new_protected:Npn \@@_make_preamble_S:w [ #1 ]
+  { \@@_make_preamble_S_i:n { #1 } }
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_vii_ii:n #1
+\cs_new_protected:Npn \@@_make_preamble_S_i:n #1
   { 
-    \IfPackageAtLeastTF { siunitx } { 2022/01/01 }
+    \tl_gput_right:NV \g_@@_array_preamble_tl \g_@@_pre_cell_tl 
+    \tl_gclear:N \g_@@_pre_cell_tl
+    \tl_gput_right:Nn \g_@@_array_preamble_tl 
       {
-        \tl_gput_right:NV \g_@@_array_preamble_tl \g_@@_pre_cell_tl 
-        \tl_gclear:N \g_@@_pre_cell_tl
-        \tl_gput_right:Nn \g_@@_array_preamble_tl 
-          {
-            > { 
-                \@@_cell_begin:w 
-                \keys_set:nn { siunitx } { #1 } 
-                \siunitx_cell_begin:w 
-              }
-            c
-            < { \siunitx_cell_end: \@@_cell_end: }
+        > { 
+            \@@_cell_begin:w 
+            \keys_set:nn { siunitx } { #1 } 
+            \siunitx_cell_begin:w 
           }
+        c
+        < { \siunitx_cell_end: \@@_cell_end: }
+      }
 %    \end{macrocode}
 % We increment the counter of columns and then we test for the presence of a |<|.
 %    \begin{macrocode}
-        \int_gincr:N \c@jCol
-        \@@_make_preamble_xi:n
-      } 
-      { \@@_fatal:n { Version~of~siunitx~too~old } }
+    \int_gincr:N \c@jCol
+    \@@_rec_preamble_after_col:n
   }
 %    \end{macrocode}
 %
@@ -5447,14 +5547,14 @@ version 2005/12/01 or later.
 % \medskip
 % For |(|, |[| and |\{|.
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_viii:nn #1 #2
+\cs_new:cpn { @@ _ \token_to_str:N ( } #1 #2
   {
     \bool_if:NT \l_@@_small_bool { \@@_fatal:n { Delimiter~with~small } }
 %    \end{macrocode}
 % If we are before the column 1 and not in |{NiceArray}|, we reserve space for
 % the left delimiter. 
 %    \begin{macrocode}
-    \int_compare:nNnTF \c@jCol = \c_zero_int 
+    \int_if_zero:nTF \c@jCol 
       { 
         \str_if_eq:VnTF \g_@@_left_delim_tl { . }
           { 
@@ -5464,34 +5564,36 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
             \tl_gset:Nn \g_@@_left_delim_tl { #1 } 
             \tl_gset:Nn \g_@@_right_delim_tl { . }
-            \@@_make_preamble:n #2 
+            \@@_rec_preamble:n #2 
           }
           {  
             \tl_gput_right:Nn \g_@@_array_preamble_tl { ! { \enskip } } 
-            \@@_make_preamble_viii_i:nn { #1 } { #2 }
+            \@@_make_preamble_iv:nn { #1 } { #2 }
           }
       }
-      { \@@_make_preamble_viii_i:nn { #1 } { #2 } } 
+      { \@@_make_preamble_iv:nn { #1 } { #2 } } 
   }
+\cs_set_eq:cc { @@ _ \token_to_str:N [ } { @@ _ \token_to_str:N ( } 
+\cs_set_eq:cc { @@ _ \token_to_str:N \{ } { @@ _ \token_to_str:N ( } 
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_viii_i:nn #1 #2
+\cs_new_protected:Npn \@@_make_preamble_iv:nn #1 #2
   {
     \tl_gput_right:Nx \g_@@_pre_code_after_tl
       { \@@_delimiter:nnn #1 { \int_eval:n { \c@jCol + 1 } } \c_true_bool }  
     \tl_if_in:nnTF { ( [ \{ ) ] \} \left \right } { #2 }
       {
         \@@_error:nn { delimiter~after~opening } { #2 } 
-        \@@_make_preamble:n
+        \@@_rec_preamble:n
       }
-      { \@@_make_preamble:n #2 }
+      { \@@_rec_preamble:n #2 }
   }
 %    \end{macrocode}
 %
+% In fact, if would be possible to define |\left| and |\right| as no-op.
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_viii_ii:n #1 
-  { \@@_make_preamble_viii:nn }
+\cs_new:cpn { @@ _ \token_to_str:N \left } #1 { \use:c { @@ _ \token_to_str:N ( } }
 %    \end{macrocode}
 % 
 % \bigskip
@@ -5502,13 +5604,13 @@ version 2005/12/01 or later.
 % considered as the right delimiter of the environment if the environment is
 % |{NiceArray}|). 
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_ix:nn #1 #2 
+\cs_new:cpn { @@ _ \token_to_str:N ) } #1 #2 
   {
     \bool_if:NT \l_@@_small_bool { \@@_fatal:n { Delimiter~with~small } }
     \tl_if_in:nnTF { ) ] \} } { #2 }
-      { \@@_make_preamble_ix_i:nnn #1 #2 }
+      { \@@_make_preamble_v:nnn #1 #2 }
       { 
-        \tl_if_eq:nnTF { \q_stop } { #2 }
+        \tl_if_eq:nnTF { \stop } { #2 }
           {
             \str_if_eq:VnTF \g_@@_right_delim_tl { . }
               { \tl_gset:Nn \g_@@_right_delim_tl { #1 } }
@@ -5516,7 +5618,7 @@ version 2005/12/01 or later.
                 \tl_gput_right:Nn \g_@@_array_preamble_tl { ! { \enskip } } 
                 \tl_gput_right:Nx \g_@@_pre_code_after_tl
                   { \@@_delimiter:nnn #1 { \int_use:N \c@jCol } \c_false_bool }
-                \@@_make_preamble:n #2
+                \@@_rec_preamble:n #2
               }
           }
           {
@@ -5524,16 +5626,18 @@ version 2005/12/01 or later.
               { \tl_gput_right:Nn \g_@@_array_preamble_tl { ! { \enskip } } }
             \tl_gput_right:Nx \g_@@_pre_code_after_tl
               { \@@_delimiter:nnn #1 { \int_use:N \c@jCol } \c_false_bool }
-            \@@_make_preamble:n #2
+            \@@_rec_preamble:n #2
           }
       }
   }
+\cs_set_eq:cc { @@ _ \token_to_str:N ] } { @@ _ \token_to_str:N ] } 
+\cs_set_eq:cc { @@ _ \token_to_str:N \} } { @@ _ \token_to_str:N \} } 
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_ix_i:nnn #1 #2 #3
+\cs_new_protected:Npn \@@_make_preamble_v:nnn #1 #2 #3
   {
-    \tl_if_eq:nnTF { \q_stop } { #3 }
+    \tl_if_eq:nnTF { \stop } { #3 }
       {
         \str_if_eq:VnTF \g_@@_right_delim_tl { . }
           {
@@ -5553,14 +5657,98 @@ version 2005/12/01 or later.
         \tl_gput_right:Nx \g_@@_pre_code_after_tl
           { \@@_delimiter:nnn #1 { \int_use:N \c@jCol } \c_false_bool }
         \@@_error:nn { double~closing~delimiter } { #2 } 
-        \@@_make_preamble:n #3 
+        \@@_rec_preamble:n #3 
+      }
+  }
+%    \end{macrocode}
+%
+% \medskip
+%    \begin{macrocode}
+\cs_new:cpn { @@ _ \token_to_str:N \right } #1 
+    { \use:c { @@ _ \token_to_str:N ) } } 
+%    \end{macrocode}
+%
+% 
+% \bigskip
+% After a specifier of column, we have to test whether there is one or several
+% |<{..}| because, after those potential |<{...}|, we have to insert
+% |!{\skip_horizontal:N ...}| when the key |vlines| is used. In fact, we have
+% also to test whether there is, after the |<{...}|, a |@{...}|.
+%    \begin{macrocode}
+\cs_new_protected:Npn \@@_rec_preamble_after_col:n #1
+  {
+    \str_if_eq:nnTF { #1 } { < }
+      \@@_rec_preamble_after_col_i:n
+      { 
+        \str_if_eq:nnTF { #1 } { @ }
+          \@@_rec_preamble_after_col_ii:n
+          {
+            \tl_if_eq:NnTF \l_@@_vlines_clist { all }
+              { 
+                \tl_gput_right:Nn \g_@@_array_preamble_tl 
+                  { ! { \skip_horizontal:N \arrayrulewidth } }
+              } 
+              { 
+                \exp_args:NNe
+                \clist_if_in:NnT \l_@@_vlines_clist { \int_eval:n { \c@jCol + 1 } }  
+                  { 
+                    \tl_gput_right:Nn \g_@@_array_preamble_tl 
+                      { ! { \skip_horizontal:N \arrayrulewidth } }
+                  } 
+              }
+            \@@_rec_preamble:n { #1 }
+          }
       }
   }
 %    \end{macrocode}
+% 
+%    \begin{macrocode}
+\cs_new_protected:Npn \@@_rec_preamble_after_col_i:n #1
+  {
+    \tl_gput_right:Nn \g_@@_array_preamble_tl { < { #1 } }
+    \@@_rec_preamble_after_col:n
+  }
+%    \end{macrocode}
+%
+% We have to catch a |@{...}| after a specifier of column because, if we have to
+% draw a vertical rule, we have to add in that |@{...}| a |\hskip| corresponding
+% to the width of the vertical rule.
+%    \begin{macrocode}
+\cs_new_protected:Npn \@@_rec_preamble_after_col_ii:n #1
+  {
+    \tl_if_eq:NnTF \l_@@_vlines_clist { all }
+      { 
+        \tl_gput_right:Nn \g_@@_array_preamble_tl 
+          { @ { #1 \skip_horizontal:N \arrayrulewidth } }
+      } 
+      { 
+        \exp_args:NNe
+        \clist_if_in:NnTF \l_@@_vlines_clist { \int_eval:n { \c@jCol + 1 } }  
+          { 
+            \tl_gput_right:Nn \g_@@_array_preamble_tl 
+              { @ { #1 \skip_horizontal:N \arrayrulewidth } }
+          } 
+          { \tl_gput_right:Nn \g_@@_array_preamble_tl { @ { #1 } } }
+      }
+    \@@_rec_preamble:n 
+  }
+%    \end{macrocode}
+% 
+% \bigskip
+%    \begin{macrocode}
+\cs_new:cpn { @@ _ * } #1 #2 #3
+  { 
+    \tl_clear:N \l_tmpa_tl
+    \int_step_inline:nn { #2 } { \tl_put_right:Nn \l_tmpa_tl { #3 } } 
+    \exp_last_unbraced:NV \@@_rec_preamble:n \l_tmpa_tl
+  }
+%    \end{macrocode}
 %
+% \bigskip
+% The token |\NC@find| is at the head of the definition of the columns type done
+% by |\newcolumntype|. We wan't that token to be no-op here.
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_ix_ii:n #1 
-  { \@@_make_preamble_ix:nn }
+\cs_new:cpn { @@ _ \token_to_str:N \NC@find } #1 { \@@_rec_preamble:n }
 %    \end{macrocode}
 % 
 % \bigskip
@@ -5568,17 +5756,17 @@ version 2005/12/01 or later.
 % (between square brackets). That's why we test whether there is a |[| after the
 % letter |X|.
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_x:nn #1 #2
+\cs_new:Npn \@@_X #1 #2
   {
     \str_if_eq:nnTF { #2 } { [ }
-      { \@@_make_preamble_x_i:w [ }
-      { \@@_make_preamble_x_i:w [ ] #2 }
+      { \@@_make_preamble_X:w [ }
+      { \@@_make_preamble_X:w [ ] #2 }
   }
 %    \end{macrocode}
 % 
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_x_i:w [ #1 ]
-  { \@@_make_preamble_x_ii:n { #1 } }
+\cs_new_protected:Npn \@@_make_preamble_X:w [ #1 ]
+  { \@@_make_preamble_X_i:n { #1 } }
 %    \end{macrocode}
 % |#1| is the optional argument of the |X| specifier (a list of
 % \emph{key}-\emph{value} pairs).
@@ -5597,7 +5785,7 @@ version 2005/12/01 or later.
 % \medskip
 % In the following command, |#1| is the list of the options of the specifier |X|.
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_x_ii:n #1
+\cs_new_protected:Npn \@@_make_preamble_X_i:n #1
   {
 %    \end{macrocode}
 % The possible values of |\l_@@_hpos_col_str| are |j| (for \emph{justified} which is
@@ -5638,8 +5826,8 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
     \bool_if:NTF \l_@@_X_columns_aux_bool
       { 
-        \exp_args:Nnx
-        \@@_make_preamble_iv_iv:nn 
+        \exp_args:Nne
+        \@@_make_preamble_ii_iv:nn 
           { \l_@@_weight_int \l_@@_X_columns_dim } 
           { minipage }
       }
@@ -5675,93 +5863,43 @@ version 2005/12/01 or later.
               }
           }  
         \int_gincr:N \c@jCol
-        \@@_make_preamble_xi:n
+        \@@_rec_preamble_after_col:n
       }
   }
 %    \end{macrocode}
 %
-% 
-% \bigskip
-% After a specifier of column, we have to test whether there is one or several
-% |<{..}| because, after those potential |<{...}|, we have to insert
-% |!{\skip_horizontal:N ...}| when the key |vlines| is used. In fact, we have
-% also to test whether there is, after the |<{...}|, a |@{...}|.
-%    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_xi:n #1
-  {
-    \str_if_eq:nnTF { #1 } { < }
-      \@@_make_preamble_xiii:n 
-      { 
-        \str_if_eq:nnTF { #1 } { @ }
-          \@@_make_preamble_xv:n 
-          {
-            \tl_if_eq:NnTF \l_@@_vlines_clist { all }
-              { 
-                \tl_gput_right:Nn \g_@@_array_preamble_tl 
-                  { ! { \skip_horizontal:N \arrayrulewidth } }
-              } 
-              { 
-                \exp_args:NNx 
-                \clist_if_in:NnT \l_@@_vlines_clist { \int_eval:n { \c@jCol + 1 } }  
-                  { 
-                    \tl_gput_right:Nn \g_@@_array_preamble_tl 
-                      { ! { \skip_horizontal:N \arrayrulewidth } }
-                  } 
-              }
-            \@@_make_preamble:n { #1 }
-          }
-      }
-  }
-%    \end{macrocode}
-% 
+% \medskip
+% For the letter set by the user with |vlines-in-sub-matrix| (vlism).
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_xiii:n #1
+\cs_new_protected:Npn \@@_make_preamble_vlism:n #1 
   {
-    \tl_gput_right:Nn \g_@@_array_preamble_tl { < { #1 } }
-    \@@_make_preamble_xi:n
+    \seq_gput_right:Nx \g_@@_cols_vlism_seq 
+      { \int_eval:n { \c@jCol + 1 } }
+    \tl_gput_right:Nx \g_@@_array_preamble_tl
+      { \exp_not:N ! { \skip_horizontal:N \arrayrulewidth } }
+    \@@_rec_preamble:n
   }
 %    \end{macrocode}
 %
-% We have to catch a |@{...}| after a specifier of column because, if we have to
-% draw a vertical rule, we have to add in that |@{...}| a |\hskip| corresponding
-% to the width of the vertical rule.
+%  \medskip
+% The token |\stop| is a marker that we have inserted to mark the end of the
+% preamble (as provided by the final user) that we have inserted in the TeX flow.
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_xv:n #1
-  {
-    \tl_if_eq:NnTF \l_@@_vlines_clist { all }
-      { 
-        \tl_gput_right:Nn \g_@@_array_preamble_tl 
-          { @ { #1 \skip_horizontal:N \arrayrulewidth } }
-      } 
-      { 
-        \exp_args:NNx 
-        \clist_if_in:NnTF \l_@@_vlines_clist { \int_eval:n { \c@jCol + 1 } }  
-          { 
-            \tl_gput_right:Nn \g_@@_array_preamble_tl 
-              { @ { #1 \skip_horizontal:N \arrayrulewidth } }
-          } 
-          { \tl_gput_right:Nn \g_@@_array_preamble_tl { @ { #1 } } }
-      }
-    \@@_make_preamble:n 
-  }
+\cs_set_eq:cN { @@ _ \token_to_str:N \stop } \use_none:n 
 %    \end{macrocode}
 %
+%  \medskip
+% The following lines try to catch some errors (when the final user has
+% forgotten the preamble of its environment). 
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_xx:n #1 { \@@_make_preamble:n }
+\cs_new_protected:cpn { @@ _ \token_to_str:N \hline } 
+  { \@@_fatal:n { Preamble~forgotten } }
+\cs_set_eq:cc { @@ _ \token_to_str:N \Hline } { @@ _ \token_to_str:N \hline } 
+\cs_set_eq:cc { @@ _ \token_to_str:N \toprule } { @@ _ \token_to_str:N \hline } 
+\cs_set_eq:cc { @@ _ \token_to_str:N \CodeBefore } { @@ _ \token_to_str:N \hline } 
 %    \end{macrocode}
 % 
 % \bigskip
-%    \begin{macrocode}
-\cs_new_protected:Npn \@@_make_preamble_xvi:nnn #1 #2 #3
-  { 
-    \tl_clear:N \l_tmpa_tl
-    \int_step_inline:nn { #2 } { \tl_put_right:Nn \l_tmpa_tl { #3 } } 
-    \exp_last_unbraced:NV \@@_make_preamble:n \l_tmpa_tl
-  }
-%    \end{macrocode}
-% 
-% 
-% \bigskip
 % \section{The redefinition of \textbackslash multicolumn}
 %
 % \medskip
@@ -5777,6 +5915,7 @@ version 2005/12/01 or later.
 % |\multicolumn|. 
 %    \begin{macrocode}
     \multispan { #1 }
+    \cs_set_eq:NN \@@_update_max_cell_width: \prg_do_nothing: % added 2023-10-04
     \begingroup
     \cs_set:Npn \@addamp { \if@firstamp \@firstampfalse \else \@preamerr 5 \fi } 
 %    \end{macrocode}
@@ -5799,7 +5938,7 @@ version 2005/12/01 or later.
 %    \end{macrocode}
 %
 % \medskip
-% Now, you do a treatment specific to \pkg{nicematrix} which has no equivalent
+% Now, we do a treatment specific to \pkg{nicematrix} which has no equivalent
 % in the original definition of |\multicolumn|.
 %    \begin{macrocode}
     \int_compare:nNnT { #1 } > 1
@@ -5810,13 +5949,13 @@ version 2005/12/01 or later.
         \seq_gput_right:Nx \g_@@_pos_of_blocks_seq
           { 
             { 
-              \int_compare:nNnTF \c@jCol = 0
+              \int_if_zero:nTF \c@jCol
                 { \int_eval:n { \c@iRow + 1 } }
                 { \int_use:N \c@iRow }
             } 
             { \int_eval:n { \c@jCol + 1 } }
             { 
-              \int_compare:nNnTF \c@jCol = 0
+              \int_if_zero:nTF \c@jCol
                 { \int_eval:n { \c@iRow + 1 } }
                 { \int_use:N \c@iRow }
             } 
@@ -5867,11 +6006,6 @@ version 2005/12/01 or later.
         w { \@@_make_m_preamble_v:nnnn { } #1 } 
         W { \@@_make_m_preamble_v:nnnn { \@@_special_W: } #1 } 
         \q_stop { }
-%    \end{macrocode}
-% The token |\NC@find| is at the head of the definition of the columns type done
-% by |\newcolumntype|. We wan't that token to no-op here.
-%    \begin{macrocode}
-        \NC@find { \@@_make_preamble:n }
       }
       { 
         \cs_if_exist:cTF { NC @ find @ #1 }
@@ -6127,7 +6261,7 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
             \int_compare:nNnT \g_@@_notes_caption_int > 0 
               {
-                \tl_gput_right:Nx \g_@@_aux_tl
+                \tl_build_gput_right:Nx \g_@@_aux_tl
                   {
                     \tl_set:Nn \exp_not:N \l_@@_note_in_caption_tl 
                       { \int_use:N \g_@@_notes_caption_int }
@@ -6337,7 +6471,7 @@ version 2005/12/01 or later.
       \dim_gsub:Nn \g_tmpa_dim \pgf@y
     \endpgfpicture
     \dim_gadd:Nn \g_tmpa_dim \arrayrulewidth 
-    \int_compare:nNnT \l_@@_first_row_int = 0 
+    \int_if_zero:nT \l_@@_first_row_int
       {
         \dim_gadd:Nn \g_tmpa_dim \g_@@_ht_row_zero_dim 
         \dim_gadd:Nn \g_tmpa_dim \g_@@_dp_row_zero_dim 
@@ -6388,7 +6522,7 @@ version 2005/12/01 or later.
     \dim_gsub:Nn \g_tmpa_dim \pgf@y
     \endpgfpicture
     \dim_gadd:Nn \g_tmpa_dim \arrayrulewidth
-    \int_compare:nNnT \l_@@_first_row_int = 0 
+    \int_if_zero:nT \l_@@_first_row_int
       {
         \dim_gadd:Nn \g_tmpa_dim \g_@@_ht_row_zero_dim 
         \dim_gadd:Nn \g_tmpa_dim \g_@@_dp_row_zero_dim 
@@ -6475,10 +6609,10 @@ version 2005/12/01 or later.
           { 
             \@@_transform_preamble:
 %    \end{macrocode}
-% Here is the call to |\array| (we have a dedicated macro |\@@_array:n| because
+% Here is the call to |\array| (we have a dedicated macro |\@@_array:| because
 % of compatibility with the classes \cls{revtex4-1} and \cls{revtex4-2}).
 %    \begin{macrocode}
-            \@@_array:V \g_@@_array_preamble_tl 
+            \exp_args:NV \@@_array: \g_@@_array_preamble_tl 
           }
       }
   }
@@ -6570,11 +6704,10 @@ version 2005/12/01 or later.
 % \bigskip
 % The new value of the body (that is to say after replacement of the separators
 % of rows and columns by |\\| and |&|) of the environment will be stored in 
-% |\l_@@_new_body_tl| (that part of the implementation has been changed in the
-% version 6.11 of \pkg{nicematrix} in order to allow the use of commands such as
+% |\l_@@_new_body_tl| in order to allow the use of commands such as
 % |\hline| or |\hdottedline| with the key |light-syntax|).
 %    \begin{macrocode}
-    \tl_clear_new:N \l_@@_new_body_tl 
+    \tl_build_begin:N \l_@@_new_body_tl
     \int_zero_new:N \l_@@_nb_cols_int
 %    \end{macrocode}
 % First, we treat the first row.
@@ -6587,9 +6720,10 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
     \seq_map_inline:Nn \l_@@_rows_seq 
       { 
-        \tl_put_right:Nn \l_@@_new_body_tl { \\ } 
+        \tl_build_put_right:Nn \l_@@_new_body_tl { \\ } 
         \@@_line_with_light_syntax:n { ##1 } 
       }
+    \tl_build_end:N \l_@@_new_body_tl
 %    \end{macrocode}
 %
 %    \begin{macrocode}
@@ -6606,14 +6740,13 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
     \@@_transform_preamble:
 %    \end{macrocode}
-%
-% 
+% \bigskip
 %
 % The call to |\array| is in the following command (we have a dedicated macro
-% |\@@_array:n| because of compatibility with the classes \cls{revtex4-1} and
+% |\@@_array:| because of compatibility with the classes \cls{revtex4-1} and
 % \cls{revtex4-2}). 
 %    \begin{macrocode}
-    \@@_array:V \g_@@_array_preamble_tl \l_@@_new_body_tl
+    \exp_args:NV \@@_array: \g_@@_array_preamble_tl \l_@@_new_body_tl
   }
 %    \end{macrocode}
 %
@@ -6629,9 +6762,9 @@ version 2005/12/01 or later.
           { \seq_count:N \l_@@_cells_seq }
       }
     \seq_pop_left:NN \l_@@_cells_seq \l_tmpa_tl
-    \tl_put_right:NV \l_@@_new_body_tl \l_tmpa_tl
+    \exp_args:NNV \tl_build_put_right:Nn \l_@@_new_body_tl \l_tmpa_tl
     \seq_map_inline:Nn \l_@@_cells_seq 
-      { \tl_put_right:Nn \l_@@_new_body_tl { & ##1 } }
+      { \tl_build_put_right:Nn \l_@@_new_body_tl { & ##1 } }
   }
 \cs_generate_variant:Nn \@@_line_with_light_syntax:n { V }
 %    \end{macrocode}
@@ -6663,7 +6796,7 @@ version 2005/12/01 or later.
 \cs_new:Npn \@@_create_col_nodes:
   {
     \crcr 
-    \int_compare:nNnT \l_@@_first_col_int = 0 
+    \int_if_zero:nT \l_@@_first_col_int 
       { 
         \omit 
         \hbox_overlap_left:n
@@ -6690,7 +6823,7 @@ version 2005/12/01 or later.
 % First, we put a |col| node on the left of the first column (of course, we
 % have to do that \emph{after} the |\omit|).
 %    \begin{macrocode}
-    \int_compare:nNnTF \l_@@_first_col_int = 0 
+    \int_if_zero:nTF \l_@@_first_col_int
       {
         \bool_if:NT \l_@@_code_before_bool
           { 
@@ -7155,6 +7288,12 @@ version 2005/12/01 or later.
       {
         \bool_gset_true:N \g_@@_delims_bool 
         \str_gset:Nn \g_@@_name_env_str { #1 NiceMatrix } 
+        % added 2023/10/01
+        \int_if_zero:nT \l_@@_last_col_int
+          {  
+            \bool_set_true:N \l_@@_last_col_without_value_bool
+            \int_set:Nn \l_@@_last_col_int { -1 }
+          }                
         \keys_set:nn { NiceMatrix / NiceMatrix } { ##1 }
         \@@_begin_of_NiceMatrix:nV { #1 } \l_@@_columns_type_tl 
       }
@@ -7168,6 +7307,12 @@ version 2005/12/01 or later.
 \NewDocumentEnvironment { NiceMatrix } { ! O { } }
   {
     \str_gset:Nn \g_@@_name_env_str { NiceMatrix } 
+    % added 2023/10/01
+    \int_if_zero:nT \l_@@_last_col_int
+      {  
+        \bool_set_true:N \l_@@_last_col_without_value_bool
+        \int_set:Nn \l_@@_last_col_int { -1 }
+      }                
     \keys_set:nn { NiceMatrix / NiceMatrix } { #1 }
     \bool_lazy_or:nnT
       { \clist_if_empty_p:N \l_@@_vlines_clist }
@@ -7244,7 +7389,7 @@ version 2005/12/01 or later.
   }
   { 
     \endNiceArray 
-    \int_compare:nNnT \g_@@_total_X_weight_int = \c_zero_int
+    \int_if_zero:nT \g_@@_total_X_weight_int 
       { \@@_error:n { NiceTabularX~without~X } }
   }
 %    \end{macrocode}
@@ -7334,7 +7479,7 @@ version 2005/12/01 or later.
 % 
 % \medskip
 %    \begin{macrocode}
-    \tl_gput_right:Nx \g_@@_aux_tl
+    \tl_build_gput_right:Nx \g_@@_aux_tl
       { 
         \seq_gset_from_clist:Nn \exp_not:N \g_@@_size_seq 
           { 
@@ -7353,7 +7498,7 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
     \seq_if_empty:NF \g_@@_pos_of_blocks_seq
       {
-        \tl_gput_right:Nx \g_@@_aux_tl
+        \tl_build_gput_right:Nx \g_@@_aux_tl
           { 
             \seq_gset_from_clist:Nn \exp_not:N \g_@@_pos_of_blocks_seq
               { \seq_use:Nnnn \g_@@_pos_of_blocks_seq , , , }
@@ -7361,7 +7506,7 @@ version 2005/12/01 or later.
       } 
     \seq_if_empty:NF \g_@@_multicolumn_cells_seq
       {
-        \tl_gput_right:Nx \g_@@_aux_tl
+        \tl_build_gput_right:Nx \g_@@_aux_tl
           { 
             \seq_gset_from_clist:Nn \exp_not:N \g_@@_multicolumn_cells_seq
               { \seq_use:Nnnn \g_@@_multicolumn_cells_seq , , , }
@@ -7566,9 +7711,10 @@ version 2005/12/01 or later.
 % force). These instructions will be written on the |aux| file to be added to
 % the |code-before| in the next run.
 %    \begin{macrocode}
+    \seq_if_empty:NF \g_@@_rowlistcolors_seq { \@@_clear_rowlistcolors_seq: }
     \tl_if_empty:NF \g_@@_pre_code_before_tl
       {
-        \tl_gput_right:Nx \g_@@_aux_tl
+        \tl_build_gput_right:Nx \g_@@_aux_tl
           {
             \tl_gset:Nn \exp_not:N \g_@@_pre_code_before_tl 
               { \exp_not:V \g_@@_pre_code_before_tl }
@@ -7577,7 +7723,7 @@ version 2005/12/01 or later.
       }
     \tl_if_empty:NF \g_nicematrix_code_before_tl
       {
-        \tl_gput_right:Nx \g_@@_aux_tl
+        \tl_build_gput_right:Nx \g_@@_aux_tl
           {
             \tl_gset:Nn \exp_not:N \g_@@_code_before_tl 
               { \exp_not:V \g_nicematrix_code_before_tl }
@@ -7735,7 +7881,7 @@ version 2005/12/01 or later.
         \pgftransformshift { \pgfpoint \l_tmpa_dim \l_tmpb_dim }
 %    \end{macrocode}
 % Now, |\l_tmpa_dim| and |\l_tmpb_dim| become the width and the height of the
-% node (of shape |@à_diag_node|) that we will construct.
+% node (of shape |@@_diag_node|) that we will construct.
 %    \begin{macrocode}
         \dim_set:Nn \l_tmpa_dim { ( \l_@@_tmpc_dim - \l_tmpa_dim ) / 2 } 
         \dim_set:Nn \l_tmpb_dim { ( \l_@@_tmpd_dim - \l_tmpb_dim ) / 2 } 
@@ -7937,7 +8083,7 @@ version 2005/12/01 or later.
             \int_compare:nNnTF { #3 } = 1
               { \bool_set_true:N \l_@@_initial_open_bool }
               {
-                \int_compare:nNnT \l_@@_initial_j_int = { \l_@@_col_min_int -1 }  
+                \int_compare:nNnT \l_@@_initial_j_int = { \l_@@_col_min_int - 1 }  
                   { \bool_set_true:N \l_@@_initial_open_bool }
               }
           }
@@ -8192,7 +8338,7 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
         \group_begin:
           \@@_open_shorten:
-          \int_compare:nNnTF { #1 } = 0
+          \int_if_zero:nTF { #1 } 
             { \color { nicematrix-first-row } }
             { 
 %    \end{macrocode}
@@ -8287,7 +8433,7 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
         \group_begin:
           \@@_open_shorten:
-          \int_compare:nNnTF { #1 } = 0
+          \int_if_zero:nTF { #1 } 
             { \color { nicematrix-first-row } }
             { 
 %    \end{macrocode}
@@ -8422,7 +8568,7 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
         \group_begin:
           \@@_open_shorten:
-          \int_compare:nNnTF { #2 } = 0 
+          \int_if_zero:nTF { #2 } 
             { \color { nicematrix-first-col } }
             {
               \int_compare:nNnT { #2 } = \l_@@_last_col_int
@@ -8465,7 +8611,7 @@ version 2005/12/01 or later.
       {
         \@@_open_y_initial_dim: 
         \@@_open_y_final_dim: 
-        \int_compare:nNnTF \l_@@_initial_j_int = \c_zero_int
+        \int_if_zero:nTF \l_@@_initial_j_int 
 %    \end{macrocode}
 % We have a dotted line open on both sides in the ``first column''.
 %    \begin{macrocode}
@@ -9142,7 +9288,7 @@ version 2005/12/01 or later.
       { \@@_collect_options:n { \@@_Ldots_i } }
     \exp_args:NNV \NewDocumentCommand \@@_Ldots_i \l_@@_argspec_tl 
       { 
-        \int_compare:nNnTF \c@jCol = 0 
+        \int_if_zero:nTF \c@jCol
           { \@@_error:nn { in~first~col } \Ldots }
           { 
             \int_compare:nNnTF \c@jCol = \l_@@_last_col_int
@@ -9164,7 +9310,7 @@ version 2005/12/01 or later.
       { \@@_collect_options:n { \@@_Cdots_i } }
     \exp_args:NNV \NewDocumentCommand \@@_Cdots_i \l_@@_argspec_tl
       { 
-        \int_compare:nNnTF \c@jCol = 0 
+        \int_if_zero:nTF \c@jCol
           { \@@_error:nn { in~first~col } \Cdots }
           { 
             \int_compare:nNnTF \c@jCol = \l_@@_last_col_int
@@ -9186,7 +9332,7 @@ version 2005/12/01 or later.
       { \@@_collect_options:n { \@@_Vdots_i } }
     \exp_args:NNV \NewDocumentCommand \@@_Vdots_i \l_@@_argspec_tl
       {
-        \int_compare:nNnTF \c@iRow = 0 
+        \int_if_zero:nTF \c@iRow 
           { \@@_error:nn { in~first~row } \Vdots }
           { 
             \int_compare:nNnTF \c@iRow = \l_@@_last_row_int
@@ -9308,8 +9454,8 @@ version 2005/12/01 or later.
 \cs_new:Npn \@@_Hdotsfor:
   {
     \bool_lazy_and:nnTF
-      { \int_compare_p:nNn \c@jCol = 0 }
-      { \int_compare_p:nNn \l_@@_first_col_int = 0 }
+      { \int_if_zero_p:n \c@jCol }
+      { \int_if_zero_p:n \l_@@_first_col_int }
       { 
         \bool_if:NTF \g_@@_after_col_zero_bool 
           {        
@@ -9420,11 +9566,8 @@ version 2005/12/01 or later.
 %
 %    \begin{macrocode}
     \group_begin:
-
     \@@_open_shorten:
-
-
-    \int_compare:nNnTF { #1 } = 0
+    \int_if_zero:nTF { #1 } 
       { \color { nicematrix-first-row } }
       { 
         \int_compare:nNnT { #1 } = \g_@@_row_total_int
@@ -9531,11 +9674,7 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
     \group_begin:
     \@@_open_shorten:
-
-
-
-
-    \int_compare:nNnTF { #2 } = 0
+    \int_if_zero:nTF { #2 } 
       { \color { nicematrix-first-col } }
       { 
         \int_compare:nNnT { #2 } = \g_@@_col_total_int
@@ -9896,7 +10035,7 @@ version 2005/12/01 or later.
         \seq_map_indexed_inline:Nn \g_@@_colors_seq
           { \tl_if_eq:nnT { #1 } { ##2 } { \int_set:Nn \l_tmpa_int { ##1 } } }
       }
-    \int_compare:nNnTF \l_tmpa_int = \c_zero_int
+    \int_if_zero:nTF \l_tmpa_int 
 %    \end{macrocode}
 % First, the case where the color is a \emph{new} color (not in the sequence).
 %    \begin{macrocode}
@@ -9913,8 +10052,8 @@ version 2005/12/01 or later.
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-\cs_generate_variant:Nn \@@_add_to_colors_seq:nn { x n }
-\cs_generate_variant:Nn \@@_add_to_colors_seq:nn { x x }
+\cs_generate_variant:Nn \@@_add_to_colors_seq:nn { e n }
+\cs_generate_variant:Nn \@@_add_to_colors_seq:nn { e e }
 %    \end{macrocode}
 %
 % \bigskip
@@ -10036,7 +10175,7 @@ version 2005/12/01 or later.
     \tl_if_empty:NF \l_tmpa_tl { \exp_args:NV \pgfsetfillopacity \l_tmpa_tl }
     \tl_if_empty:NTF \l_tmpb_tl 
       { \@declaredcolor }
-      { \use:x { \exp_not:N \@undeclaredcolor [ \l_tmpb_tl ] } }
+      { \use:e { \exp_not:N \@undeclaredcolor [ \l_tmpb_tl ] } }
   }
 %    \end{macrocode}
 %
@@ -10067,7 +10206,7 @@ version 2005/12/01 or later.
   { 
     \tl_if_blank:nF { #2 }
       {
-        \@@_add_to_colors_seq:xn 
+        \@@_add_to_colors_seq:en 
           { \tl_if_blank:nF { #1 } { [ #1 ] } { #2 } }
           { \@@_cartesian_color:nn { #3 } { - } }
       }
@@ -10081,7 +10220,7 @@ version 2005/12/01 or later.
   { 
     \tl_if_blank:nF { #2 }
       {
-        \@@_add_to_colors_seq:xn 
+        \@@_add_to_colors_seq:en 
           { \tl_if_blank:nF { #1 } { [ #1 ] } { #2 } }
           { \@@_cartesian_color:nn { - } { #3 } }
       }
@@ -10095,7 +10234,7 @@ version 2005/12/01 or later.
   {
     \tl_if_blank:nF { #2 }
       { 
-        \@@_add_to_colors_seq:xn 
+        \@@_add_to_colors_seq:en 
           { \tl_if_blank:nF { #1 } { [ #1 ] } { #2 } }
           { \@@_rectanglecolor:nnn { #3 } { #4 } { 0 pt } } 
       }
@@ -10109,7 +10248,7 @@ version 2005/12/01 or later.
   {
     \tl_if_blank:nF { #2 }
       { 
-        \@@_add_to_colors_seq:xn 
+        \@@_add_to_colors_seq:en 
           { \tl_if_blank:nF { #1 } { [ #1 ] } { #2 } }
           { \@@_rectanglecolor:nnn { #3 } { #4 } { #5 } } 
       }
@@ -10199,12 +10338,12 @@ version 2005/12/01 or later.
 %
 % Here is an example: |\rowcolors{1}{blue!10}{}[respect-blocks]|.
 %
-% In \pkg{nicematrix}, the commmand |\@@_rowcolors| apperas as a special case of
+% In \pkg{nicematrix}, the commmand |\@@_rowcolors| appears as a special case of
 % |\@@_rowlistcolors|. 
 % 
-% |#1| (optional) is the color space ;
-% |#2| is a list of intervals of rows ;
-% |#3| is the list of colors ;
+% |#1| (optional) is the color space;
+% |#2| is a list of intervals of rows;
+% |#3| is the list of colors;
 % |#4| is for the optional list of pairs \textsl{key=value}.
 %    \begin{macrocode}
 \NewDocumentCommand \@@_rowlistcolors { O { } m m O { } }
@@ -10293,7 +10432,7 @@ version 2005/12/01 or later.
               }
             \tl_if_empty:NF \l_@@_color_tl
               {
-                \@@_add_to_colors_seq:xx
+                \@@_add_to_colors_seq:ee
                   { \tl_if_blank:nF { #1 } { [ #1 ] } { \l_@@_color_tl } }
                   { \@@_cartesian_color:nn { \l_@@_rows_tl } { \l_@@_cols_tl } }
               }
@@ -10321,12 +10460,13 @@ version 2005/12/01 or later.
 % 
 % \bigskip
 % The command |\rowcolors| (available in the |\CodeBefore|) is a specialisation
-% of the most general command |\rowlistcolors|. The last argument, which is a
+% of the more general command |\rowlistcolors|. The last argument, which is a
 % optional argument between square brackets is provided by curryfication.
 %    \begin{macrocode}
 \NewDocumentCommand \@@_rowcolors { O { } m m m }
   { \@@_rowlistcolors [ #1 ] { #2 } { { #3 } , { #4 } } }
 %    \end{macrocode}
+% The braces around |#3| and |#4| are mandatory.
 % 
 % \bigskip 
 %    \begin{macrocode}
@@ -10343,7 +10483,7 @@ version 2005/12/01 or later.
 \prg_new_conditional:Nnn \@@_not_in_exterior:nnnnn p
   {
     \bool_lazy_or:nnTF 
-      { \int_compare_p:nNn { #4 } = \c_zero_int }
+      { \int_if_zero_p:n { #4 } }
       { \int_compare_p:nNn { #2 } = { \int_eval:n { \c@jCol + 1 } } }
       \prg_return_false:
       \prg_return_true:
@@ -10503,6 +10643,7 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
 \NewDocumentCommand \@@_cellcolor_tabular { O { } m }
   {
+    \@@_test_color_inside:
     \tl_gput_right:Nx \g_@@_pre_code_before_tl
       { 
 %    \end{macrocode}
@@ -10523,6 +10664,7 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
 \NewDocumentCommand \@@_rowcolor_tabular { O { } m }
   {
+    \@@_test_color_inside:
     \tl_gput_right:Nx \g_@@_pre_code_before_tl
       { 
         \@@_rectanglecolor [ #1 ] { \exp_not:n { #2 } } 
@@ -10539,8 +10681,9 @@ version 2005/12/01 or later.
 % argument between square brackets is taken by curryfication).
 %    \begin{macrocode}
 \NewDocumentCommand { \@@_rowcolors_tabular } { O { } m m }
-  { \@@_rowlistcolors_tabular [ #1 ] { #2 , #3 } }
+  { \@@_rowlistcolors_tabular [ #1 ] { { #2 } , { #3 } } }
 %    \end{macrocode}
+% The braces around |#2| and |#3| are mandatory.
 %
 % \bigskip
 % When the user uses the key |color-inside|, the following command will
@@ -10548,19 +10691,113 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
 \NewDocumentCommand { \@@_rowlistcolors_tabular } { O { } m O { } }
   {
+    \@@_test_color_inside:
     \peek_remove_spaces:n 
+      { \@@_rowlistcolors_tabular:nnn { #1 } { #2 } { #3 } }
+  }
+%    \end{macrocode}
+%
+% \bigskip
+%    \begin{macrocode}
+\cs_new_protected:Npn \@@_rowlistcolors_tabular:nnn #1 #2 #3 
+  {
+%    \end{macrocode}
+% A use of |\rowlistcolors| in the tabular erases the instructions
+% |\rowlistcolors| which are in force. However, it's possible to put \emph{several}
+% instructions |\rowlistcolors| in the same row of a tabular: it may be useful
+% when those instructions |\rowlistcolors| concerns different columns of the
+% tabular (thanks to the key |cols| of |\rowlistcolors|). That's why we store
+% the different instructions |\rowlistcolors| which are in force in a sequence
+% |\g_@@_rowlistcolors_seq|. Now, we will filter that sequence to keep only the
+% elements which have been issued on the actual row. We will store the elements
+% to keep in the |\g_tmpa_seq|.
+%    \begin{macrocode}
+    \seq_gclear:N \g_tmpa_seq
+    \seq_map_inline:Nn \g_@@_rowlistcolors_seq
+      { \@@_rowlistcolors_tabular_i:nnnn ##1 }
+    \seq_gset_eq:NN \g_@@_rowlistcolors_seq \g_tmpa_seq 
+%    \end{macrocode}
+% Now, we add to the sequence |\g_@@_rowlistcolors_seq| (which is the list of
+% the commands |\rowlistcolors| which are in force) the current instruction
+% |\rowlistcolors|. 
+%    \begin{macrocode}
+    \seq_gput_right:Nx \g_@@_rowlistcolors_seq 
+      {
+        { \int_use:N \c@iRow }
+        { \exp_not:n { #1 } }
+        { \exp_not:n { #2 } }
+        { restart , cols = \int_use:N \c@jCol - , \exp_not:n { #3 } }
+      }
+  }
+%    \end{macrocode}
+%
+% 
+% \bigskip
+% The following command will be applied to each component of
+% |\g_@@_rowlistcolors_seq|. Each component of that sequence is a kind of 4-uple
+% of the form |{#1}{#2}{#3}{#4}|.
+% 
+% |#1| is the number of the row where the command |\rowlistcolors| has been
+% issued.
+% 
+% |#2| is the colorimetric space (optional argument of the |\rowlistcolors|).
+%
+% |#3| is the list of colors (mandatory argument of |\rowlistcolors|). 
+%
+% |#4| is the list of \textsl{key=value} pairs (last optional argument of
+% |\rowlistcolors|). 
+% 
+%    \begin{macrocode}
+\cs_new_protected:Npn \@@_rowlistcolors_tabular_i:nnnn #1 #2 #3 #4
+  {
+    \int_compare:nNnTF { #1 } = \c@iRow 
+%    \end{macrocode}
+% We (temporary) keep in memory in |\g_tmpa_seq| the instructions which will
+% still be in force after the current instruction (because they have been issued
+% in the same row of the tabular).
+%    \begin{macrocode}
+      { \seq_gput_right:Nn \g_tmpa_seq { { #1 } { #2 } { #3 } { #4 } } }
       {
         \tl_gput_right:Nx \g_@@_pre_code_before_tl 
           { 
             \@@_rowlistcolors 
-               [ #1 ] { \int_use:N \c@iRow } { #2 } 
-               [ restart, cols = \int_use:N \c@jCol - , #3 ] 
+               [ \exp_not:n { #2 } ] 
+               { #1 - \int_eval:n { \c@iRow - 1 } } 
+               { \exp_not:n { #3 } } 
+               [ \exp_not:n { #4 } ]
           }
       }
   }
 %    \end{macrocode}
 %
 % \bigskip
+% The following command will be used at the end of the tabular, just before the
+% execution of the |\g_@@_pre_code_before_tl|. It clears the sequence
+% |\g_@@_rowlistcolors_seq| of all the commands |\rowlistcolors| which are
+% (still) in force.
+%    \begin{macrocode}
+\cs_new_protected:Npn \@@_clear_rowlistcolors_seq:
+  {
+    \seq_map_inline:Nn \g_@@_rowlistcolors_seq 
+      { \@@_rowlistcolors_tabular_ii:nnnn ##1 }
+    \seq_gclear:N \g_@@_rowlistcolors_seq
+  }
+%    \end{macrocode}
+% 
+% \medskip
+%    \begin{macrocode}
+\cs_new_protected:Npn \@@_rowlistcolors_tabular_ii:nnnn #1 #2 #3 #4
+  {
+    \tl_gput_right:Nn \g_@@_pre_code_before_tl 
+      { \@@_rowlistcolors [ #2 ] { #1 } { #3 } [ #4 ] }
+  }
+%    \end{macrocode}
+% The first mandatory argument of the command |\@@_rowlistcolors| which is
+% writtent in the pre-|\CodeBefore| is of the form |i|: it means that the
+% command must be applied to all the rows from the row~$i$ until the end of the
+% tabular. 
+% 
+% \bigskip
 %    \begin{macrocode}
 \NewDocumentCommand \@@_columncolor_preamble { O { } m }
   { 
@@ -10618,10 +10855,10 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
 \cs_new_protected:Npn \@@_OnlyMainNiceMatrix:n #1
   { 
-    \int_compare:nNnTF \l_@@_first_col_int = 0 
+    \int_if_zero:nTF \l_@@_first_col_int 
       { \@@_OnlyMainNiceMatrix_i:n { #1 } }
       { 
-        \int_compare:nNnTF \c@jCol = 0
+        \int_if_zero:nTF \c@jCol 
           {
             \int_compare:nNnF \c@iRow = { -1 }
               { \int_compare:nNnF \c@iRow = { \l_@@_last_row_int - 1 } { #1 } }  
@@ -10640,7 +10877,7 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
 \cs_new_protected:Npn \@@_OnlyMainNiceMatrix_i:n #1
   {
-    \int_compare:nNnF \c@iRow = 0
+    \int_if_zero:nF \c@iRow 
       { 
         \int_compare:nNnF \c@iRow = \l_@@_last_row_int 
           { 
@@ -10784,7 +11021,7 @@ version 2005/12/01 or later.
         \clist_if_empty:NF \l_@@_corners_clist \@@_test_in_corner_v:
         \bool_if:NTF \g_tmpa_bool
           { 
-            \int_compare:nNnT \l_@@_local_start_int = 0
+            \int_if_zero:nT \l_@@_local_start_int 
 %    \end{macrocode}
 % We keep in memory that we have a rule to draw. |\l_@@_local_start_int| will be 
 % the starting row of the rule that we will have to draw.
@@ -10962,7 +11199,7 @@ version 2005/12/01 or later.
     \@@_qpoint:n { row - \int_eval:n { \l_@@_local_end_int + 1 } }
     \dim_set_eq:NN \l_@@_tmpc_dim \pgf@y
     \exp_args:NV \tikzset \l_@@_tikz_rule_tl
-    \use:x { \exp_not:N \draw [ \l_@@_tikz_rule_tl ] } 
+    \use:e { \exp_not:N \draw [ \l_@@_tikz_rule_tl ] } 
       ( \l_tmpb_dim , \l_tmpa_dim ) --
       ( \l_tmpb_dim , \l_@@_tmpc_dim ) ;
     \end { tikzpicture }
@@ -11049,7 +11286,7 @@ version 2005/12/01 or later.
          \clist_if_empty:NF \l_@@_corners_clist \@@_test_in_corner_h: 
          \bool_if:NTF \g_tmpa_bool
            { 
-             \int_compare:nNnT \l_@@_local_start_int = 0
+             \int_if_zero:nT \l_@@_local_start_int 
 %    \end{macrocode}
 % We keep in memory that we have a rule to draw. |\l_@@_local_start_int| will be
 % the starting row of the rule that we will have to draw.
@@ -11288,7 +11525,7 @@ version 2005/12/01 or later.
     \@@_qpoint:n { col - \int_eval:n { \l_@@_local_end_int + 1 } }
     \dim_set_eq:NN \l_@@_tmpc_dim \pgf@x
     \exp_args:NV \tikzset \l_@@_tikz_rule_tl
-    \use:x { \exp_not:N \draw [ \l_@@_tikz_rule_tl ] } 
+    \use:e { \exp_not:N \draw [ \l_@@_tikz_rule_tl ] } 
       ( \l_tmpa_dim , \l_tmpb_dim ) --
       ( \l_@@_tmpc_dim , \l_tmpb_dim ) ;
     \end { tikzpicture }
@@ -11378,21 +11615,7 @@ version 2005/12/01 or later.
 % The final user can define a customized rule by using the key |custom-line| in
 % |\NiceMatrixOptions|. That key takes in as value a list of \textsl{key=value}
 % pairs. 
-%
 % 
-% 
-% \medskip
-% Among the keys avalaible in that list, there is the key |letter| to specify a
-% letter that the final user will use in the preamble of the array. All the
-% letters defined by this way by the final user for such customized rules are
-% added in the set of keys |{NiceMatrix / ColumnTypes}|. That set of keys is
-% used to store the characteristics of those types of rules for convenience: the
-% keys of that set of keys won't never be used as keys by the final user (he
-% will use, instead, letters in the preamble of its array).
-%
-%    \begin{macrocode}
-\keys_define:nn { NiceMatrix / ColumnTypes }  { }
-%    \end{macrocode}
 %
 % 
 % \medskip
@@ -11473,21 +11696,18 @@ version 2005/12/01 or later.
           {
             \exp_args:NnV \tl_if_in:NnTF 
               \c_@@_forbidden_letters_str \l_@@_letter_str  
-              { \@@_error:n { Forbidden~letter } }
+              { \@@_error:ne { Forbidden~letter } \l_@@_letter_str }
               { 
 %    \end{macrocode}
-% The final user can, locally, redefine a letter of column type. That's
-% compatible with the use of |\keys_define:nn|: the definition is local and may
-% overwrite a previous definition.
+% During the analyse of the preamble provided by the final user, our automaton,
+% for the letter corresponding at the custom line, will directly use the
+% following command that you define in the main hash table of TeX.
 %    \begin{macrocode}
-                 \keys_define:nx { NiceMatrix / ColumnTypes }
-                   {
-                     \l_@@_letter_str .code:n = 
-                       { \@@_v_custom_line:n { \exp_not:n { #1 }  } }
-                   }
-               } 
-           }
-       }
+                \cs_set:cpn { @@ _ \l_@@_letter_str } ##1 
+                  { \@@_v_custom_line:n { #1 } }
+              } 
+          }
+      }
     \str_if_empty:NF \l_@@_command_str { \@@_h_custom_line:n { #1 } }
     \str_if_empty:NF \l_@@_ccommand_str { \@@_c_custom_line:n { #1 } }
   } 
@@ -11495,6 +11715,7 @@ version 2005/12/01 or later.
 %
 % 
 %    \begin{macrocode}
+\tl_const:Nn \c_@@_forbidden_letters_tl { lcrpmbVX|()[]!@<> }
 \str_const:Nn \c_@@_forbidden_letters_str { lcrpmbVX|()[]!@<> }
 %    \end{macrocode}
 % 
@@ -11668,6 +11889,7 @@ version 2005/12/01 or later.
             total-width = \dim_use:N \l_@@_rule_width_dim 
           } 
       }
+    \@@_rec_preamble:n
   }
 %    \end{macrocode}
 %
@@ -11786,7 +12008,7 @@ version 2005/12/01 or later.
 % commands which color the |rows|, |columns| and |cells| must not color the
 % cells in the corners.
 %    \begin{macrocode}
-        \tl_gput_right:Nx \g_@@_aux_tl
+        \tl_build_gput_right:Nx \g_@@_aux_tl
           {
             \seq_set_from_clist:Nn \exp_not:N \l_@@_corners_cells_seq 
               { \seq_use:Nnnn \l_@@_corners_cells_seq , , , }
@@ -11968,7 +12190,8 @@ version 2005/12/01 or later.
         \cs_if_exist:cT 
           { @@_max_cell_width_ \int_use:N \g_@@_NiceMatrixBlock_int }
           {
-            \exp_args:NNx \dim_set:Nn \l_@@_columns_width_dim
+           % is \exp_args:NNe mandatory?
+            \exp_args:NNe \dim_set:Nn \l_@@_columns_width_dim
               { 
                 \use:c 
                   { @@_max_cell_width _ \int_use:N \g_@@_NiceMatrixBlock_int }
@@ -12550,8 +12773,8 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
         && ! \l_@@_X_column_bool 
       }
-      { \exp_args:Nxx \@@_Block_iv:nnnnn }
-      { \exp_args:Nxx \@@_Block_v:nnnnn }
+      { \exp_args:Nee \@@_Block_iv:nnnnn }
+      { \exp_args:Nee \@@_Block_v:nnnnn }
     { \l_tmpa_int } { \l_tmpb_int } { #3 } { #4 } { #5 } 
   }
 %    \end{macrocode}
@@ -12616,7 +12839,7 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
         \int_compare:nNnT { #1 } = 1 
           {
-            \int_compare:nNnTF \c@iRow = 0 
+            \int_if_zero:nTF \c@iRow 
               \l_@@_code_for_first_row_tl
               {
                 \int_compare:nNnT \c@iRow = \l_@@_last_row_int 
@@ -12664,7 +12887,7 @@ version 2005/12/01 or later.
 % use a |{minipage}|.
 %    \begin{macrocode}
               { 
-                \use:x
+                \use:e
                   {
                     \exp_not:N \begin { minipage }%
                       [ \str_lowercase:V { \l_@@_vpos_of_block_str } ] 
@@ -12679,7 +12902,7 @@ version 2005/12/01 or later.
 % In the other cases, we use a |{tabular}|.
 %    \begin{macrocode}
               { 
-                \use:x 
+                \use:e 
                   { 
                     \exp_not:N \begin { tabular }%
                       [ \str_lowercase:V { \l_@@_vpos_of_block_str } ] 
@@ -12695,7 +12918,7 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
           { 
             \c_math_toggle_token
-            \use:x 
+            \use:e 
               { 
                 \exp_not:N \begin { array }% 
                   [ \str_lowercase:V { \l_@@_vpos_of_block_str } ] 
@@ -12883,7 +13106,7 @@ version 2005/12/01 or later.
 % say the position of the block in its zone of merged cells).
 %    \begin{macrocode}
                    % \@@_adjust_hpos_rotate:
-                   \use:x 
+                   \use:e 
                      { 
                        \exp_not:N \begin { tabular } [ \l_@@_vpos_of_block_str ] 
                        { @ { } \l_@@_hpos_block_str @ { } } 
@@ -12906,7 +13129,7 @@ version 2005/12/01 or later.
                   #4 
                   % \@@_adjust_hpos_rotate:
                   \c_math_toggle_token    % :n c 
-                  \use:x 
+                  \use:e 
                     { 
                       \exp_not:N \begin { array } [ \l_@@_vpos_of_block_str ]
                       { @ { } \l_@@_hpos_block_str @ { } }
@@ -13037,8 +13260,12 @@ version 2005/12/01 or later.
       { \int_set:Nn \l_@@_last_col_int { #4 } }
     \int_compare:nNnTF \l_@@_last_col_int > \g_@@_col_total_int 
       {
-        \int_compare:nTF 
-          { \l_@@_last_col_int <= \g_@@_static_num_of_col_int }
+        \bool_lazy_and:nnTF
+          \l_@@_preamble_bool
+          { 
+            \int_compare_p:n 
+              { \l_@@_last_col_int <= \g_@@_static_num_of_col_int }
+          }
           { 
             \msg_error:nnnn { nicematrix } { Block~too~large~2 } { #1 } { #2 } 
             \@@_msg_redirect_name:nn { Block~too~large~2 } { none }
@@ -13239,9 +13466,10 @@ version 2005/12/01 or later.
 %                            inner sep=0pt,
 %                            fit = #1}}
 %
-% \begin{tabular}{c!{\hspace{1cm}}c}
+% \begin{tabular}{c@{\hspace{1cm}}c}
 % We highlight the node |1-1-block| 
-% & We highlight the node |1-1-block-short| \\[2mm]
+% & 
+% We highlight the node |1-1-block-short| \\[2mm]
 % \begin{NiceTabular}{cc!{\hspace{1cm}}c}
 % \Block{2-2}{our block} &      & one    \\
 %                        &      & two    \\
@@ -13260,7 +13488,7 @@ version 2005/12/01 or later.
 % \tikz \node [highlight = (1-1-block-short)] { } ;
 % \end{NiceTabular} 
 % \end{tabular}
-%
+%   
 %
 % \bigskip
 % The construction of the node corresponding to the merged cells.
@@ -13406,7 +13634,7 @@ version 2005/12/01 or later.
 %    \end{macrocode}
 % If we are in the first column, we must put the block as if it was with the key~|r|.
 %    \begin{macrocode}
-        \int_compare:nNnT { #2 } = 0 { \str_set:Nn \l_@@_hpos_block_str r }
+        \int_if_zero:nT { #2 } { \str_set:Nn \l_@@_hpos_block_str r }
 %    \end{macrocode}
 % If we are in the last column, we must put the block as if it was with the key~|l|.
 %    \begin{macrocode}
@@ -13599,7 +13827,7 @@ version 2005/12/01 or later.
   {
     color .tl_set:N = \l_@@_draw_tl ,
     draw .code:n = 
-      \exp_args:Nx \tl_if_empty:nF { #1 } { \tl_set:Nn \l_@@_draw_tl { #1 } } ,
+      \exp_args:Ne \tl_if_empty:nF { #1 } { \tl_set:Nn \l_@@_draw_tl { #1 } } ,
     draw .default:n = default ,
     line-width .dim_set:N = \l_@@_line_width_dim ,
     rounded-corners .dim_set:N = \l_@@_rounded_corners_dim ,
@@ -13626,14 +13854,14 @@ version 2005/12/01 or later.
     \tl_set:Nx \l_tmpb_tl { \int_eval:n { \l_tmpb_tl + 1 } }
     \int_step_inline:nnn \l_@@_tmpd_tl \l_tmpb_tl
       { 
-        \use:x 
+        \use:e 
           { 
             \@@_vline:n
               { 
                 position = ##1 ,
                 start = \l_@@_tmpc_tl ,
                 end = \int_eval:n { \l_tmpa_tl - 1 } ,
-                total-width = \dim_use:N \l_@@_line_width_dim % added 2022-08-06
+                total-width = \dim_use:N \l_@@_line_width_dim 
               }
           } 
       }
@@ -13650,7 +13878,7 @@ version 2005/12/01 or later.
     \tl_set:Nx \l_tmpb_tl { \int_eval:n { \l_tmpb_tl + 1 } }
     \int_step_inline:nnn \l_@@_tmpc_tl \l_tmpa_tl
       { 
-        \use:x 
+        \use:e 
           { 
             \@@_hline:n 
               { 
@@ -13757,7 +13985,7 @@ version 2005/12/01 or later.
         \pgfusepathqstroke
       }
       {
-        \use:x { \exp_not:N \draw [ \l_@@_borders_tikz_tl ] }
+        \use:e { \exp_not:N \draw [ \l_@@_borders_tikz_tl ] }
           ( \pgf@x , \l_tmpb_dim ) -- ( \pgf@x , \l_@@_tmpc_dim ) ; 
       }
   }
@@ -13783,7 +14011,7 @@ version 2005/12/01 or later.
         \pgfusepathqstroke
       }
       {
-        \use:x { \exp_not:N \draw [ \l_@@_borders_tikz_tl ] }
+        \use:e { \exp_not:N \draw [ \l_@@_borders_tikz_tl ] }
           ( \l_tmpa_dim , \pgf@y ) -- ( \l_tmpb_dim , \pgf@y ) ; 
       }
   }
@@ -13817,7 +14045,7 @@ version 2005/12/01 or later.
     \clist_map_inline:nn { #5 }
       {
         \keys_set_known:nnN { NiceMatrix / SpecialOffset } { ##1 } \l_tmpa_tl
-        \use:x { \exp_not:N \path [ \l_tmpa_tl ] }
+        \use:e { \exp_not:N \path [ \l_tmpa_tl ] }
               ( 
                 [ 
                   xshift = \dim_use:N \l_@@_offset_dim , 
@@ -13916,21 +14144,21 @@ version 2005/12/01 or later.
 % yet nicematrix-ready).
 %    \begin{macrocode}
     % \bool_set_false:N \l_@@_preamble_bool 
-    \use:x 
+    \use:e 
       {
         \exp_not:N \begin { NiceArrayWithDelims } { #1 } { #2 } 
           { * { #4 } { \exp_not:V \l_@@_columns_type_tl } }  
           [ \exp_not:V \l_tmpa_tl ] 
       }
-    \int_compare:nNnT \l_@@_first_row_int = 0
+    \int_if_zero:nT \l_@@_first_row_int 
       { 
-        \int_compare:nNnT \l_@@_first_col_int = 0 { & } 
+        \int_if_zero:nT \l_@@_first_col_int { & } 
         \prg_replicate:nn { #4 - 1 } { & } 
         \int_compare:nNnT \l_@@_last_col_int > { -1 } { & } \\ 
       }
     \prg_replicate:nn { #3 }
       { 
-        \int_compare:nNnT \l_@@_first_col_int = 0 { & }
+        \int_if_zero:nT \l_@@_first_col_int { & }
 %    \end{macrocode}
 % We put |{ }| before |#6| to avoid a hasty expansion of a potential
 % |\arabic{iRow}| at the beginning of the row which would result in an incorrect
@@ -13942,7 +14170,7 @@ version 2005/12/01 or later.
       }
     \int_compare:nNnT \l_@@_last_row_int > { -2 }
       { 
-        \int_compare:nNnT \l_@@_first_col_int = 0 { & }
+        \int_if_zero:nT \l_@@_first_col_int { & }
         \prg_replicate:nn { #4 - 1 } { & } 
         \int_compare:nNnT \l_@@_last_col_int > { -1 } { & } \\  
       }
@@ -15098,8 +15326,6 @@ version 2005/12/01 or later.
 % \section{The command TikzEveryCell}
 %
 %    \begin{macrocode}
-
-
 \bool_new:N \l_@@_not_empty_bool 
 \bool_new:N \l_@@_empty_bool 
 
@@ -15129,7 +15355,11 @@ version 2005/12/01 or later.
       {
         \group_begin:
         \keys_set:nn { NiceMatrix / TikzEveryCell } { #1 }
-        \tl_set:Nn \l_tmpa_tl { #2 }
+%    \end{macrocode}
+% The inner pair of braces in the following line is mandatory because, the last
+% argument of |\@@_tikz:nnnnn| is \emph{a list of lists} of TikZ keys.
+%    \begin{macrocode}
+        \tl_set:Nn \l_tmpa_tl { { #2 } }
         \seq_map_inline:Nn \g_@@_pos_of_blocks_seq 
           { \@@_for_a_block:nnnnn ##1 }  
         \@@_all_the_cells:
@@ -15149,7 +15379,7 @@ version 2005/12/01 or later.
           { 
             \cs_if_exist:cF { cell - \@@_i_tl - \@@_j_tl } 
               {
-                \exp_args:NNx \seq_if_in:NnF \l_@@_corners_cells_seq 
+                \exp_args:NNe \seq_if_in:NnF \l_@@_corners_cells_seq 
                   { \@@_i_tl - \@@_j_tl }
                   {
                     \bool_set_false:N \l_tmpa_bool
@@ -15192,8 +15422,6 @@ version 2005/12/01 or later.
           { \cs_set:cpn { cell - ##1 - ####1 } { } }
       }
   }
-
-
 %    \end{macrocode}
 % 
 % 
@@ -15922,7 +16150,7 @@ version 2005/12/01 or later.
   {
     Problem~with~'not-empty'\\
     For~technical~reasons,~you~must~activate~
-    'recreate-cell-nodes'~in~\token_to_str:N \CodeBefore\ 
+    'create-cell-nodes'~in~\token_to_str:N \CodeBefore\ 
     in~order~to~use~the~key~'\l_keys_key_str'.\\
     That~key~will~be~ignored.
   }
@@ -16020,7 +16248,7 @@ version 2005/12/01 or later.
 \@@_msg_new:nn { Forbidden~letter }
   {
     Forbidden~letter.\\
-    You~can't~use~the~letter~'\l_@@_letter_str'~for~a~customized~line.\\
+    You~can't~use~the~letter~'#1'~for~a~customized~line.\\
     It~will~be~ignored.
   }
 %    \end{macrocode}
@@ -16283,6 +16511,17 @@ version 2005/12/01 or later.
 %    \end{macrocode}
 %
 %    \begin{macrocode}
+\@@_msg_new:nn { without~color-inside } 
+  {
+    If~order~to~use~\token_to_str:N \cellcolor,~\token_to_str:N \rowcolor,~
+    \token_to_str:N \rowcolors\ or~\token_to_str:N \rowlistcolors\ 
+    outside~\token_to_str:N \CodeBefore,~you~
+    should~have~used~the~key~'color-inside'~in~your~\@@_full_name_env:.\\
+    You~can~go~on~but~you~may~need~more~compilations.
+  }
+%    \end{macrocode}
+% 
+%    \begin{macrocode}
 \@@_msg_new:nn { color~in~custom-line~with~tikz }
   {
     Erroneous~use.\\
@@ -16385,17 +16624,6 @@ version 2005/12/01 or later.
     respect-arraystretch,~t,~T,~tikz,~transparent~and~vlines.  
   }
 %    \end{macrocode}
-%
-%    \begin{macrocode}
-\@@_msg_new:nn { Version~of~siunitx~too~old }
-  {
-    siunitx~too~old.\\
-    You~can't~use~'S'~columns~because~your~version~of~'siunitx'~
-    is~too~old.~You~need~at~least~v~3.0.38~and~your~log~file~says:~"siunitx,~ 
-    \use:c { ver @ siunitx.sty }". \\
-    This~error~is~fatal.
-  }
-%    \end{macrocode}
 % 
 %
 %    \begin{macrocode}
@@ -16794,6 +17022,16 @@ version 2005/12/01 or later.
     However,~you~can~go~on.
   }
 %    \end{macrocode}
+%
+%    \begin{macrocode}
+\@@_msg_new:nn { Preamble~forgotten }
+  {
+    Preamble~forgotten.\\
+    You~have~probably~forgotten~the~preamble~of~your~
+    \@@_full_name_env:. \\
+    This~error~is~fatal.
+  }
+%    \end{macrocode}
 % 
 % \newpage
 % \tableofcontents
-- 
cgit v1.2.3

