nicematrix (23nov20)

git-svn-id: svn://tug.org/texlive/trunk@56990 c570f23f-e606-0410-a88d-b1316a301751

5 files changed, 657 insertions, 251 deletions

diff --git a/Master/texmf-dist/doc/latex/nicematrix/nicematrix-french.pdf b/Master/texmf-dist/doc/latex/nicematrix/nicematrix-french.pdf
index d2425b4bb20..6ce7fd41b2e 100644
--- a/Master/texmf-dist/doc/latex/nicematrix/nicematrix-french.pdf
+++ b/Master/texmf-dist/doc/latex/nicematrix/nicematrix-french.pdf
diff --git a/Master/texmf-dist/doc/latex/nicematrix/nicematrix-french.tex b/Master/texmf-dist/doc/latex/nicematrix/nicematrix-french.tex
index 52949c1d76a..d634e3ff1e3 100644
--- a/Master/texmf-dist/doc/latex/nicematrix/nicematrix-french.tex
+++ b/Master/texmf-dist/doc/latex/nicematrix/nicematrix-french.tex
@@ -419,7 +419,7 @@ avec deux arguments.
 \item Le premier argument est la taille de ce bloc avec la syntaxe $i$-$j$ où
 $i$ est le nombre de rangées et $j$ le nombre de colonnes du bloc.
 
-\colorbox{yellow!50}{\bfseries Nouveau 5.6}\enskip Si cet argument est laissé
+\colorbox{yellow!30}{Nouveau 5.6}\enskip Si cet argument est laissé
 blanc, la valeur par défaut est |1-1|. Si le nombre de rangées n'est pas
 indiqué, le bloc s'étend jusqu'à la dernière rangée (idem pour les colonnes).
 
@@ -518,7 +518,8 @@ construction |wc{...}| de \pkg{array}).
 \begin{BVerbatim}
 \begin{NiceTabular}~emphase#{cwc{2cm}wc{3cm}c}@
 rose      & tulipe & marguerite & dahlia \\
-violette  & \Block{2-2}{\LARGE\color{blue}De très jolies fleurs}  & & souci \\
+violette  
+& \Block[draw=red,fill=red!15]{2-2}{\LARGE De très jolies fleurs}  & & souci \\
 pervenche & & & lys \\
 arum      & iris & jacinthe & muguet 
 \end{NiceTabular}
@@ -529,12 +530,18 @@ arum      & iris & jacinthe & muguet
 \begin{center}
 \begin{NiceTabular}{cwc{2cm}wc{3cm}c}
 rose      & tulipe & marguerite & dahlia \\
-violette  & \Block{2-2}{\LARGE\color{blue}De très jolies fleurs}  & & souci \\
+violette  & \Block[draw=red,fill=red!15]{2-2}{\LARGE De très jolies fleurs} & & souci \\
 pervenche & & & lys \\
 arum      & iris & jacinthe & muguet 
 \end{NiceTabular}
 \end{center}
 
+\medskip
+\colorbox{yellow!50}{\bfseries Nouveau 5.7}\enskip Comme on le voit sur cet
+exemple, on peut fixer la couleur de fond avec la clé |fill| et la couleur du
+cadre avec la clé |draw|\footnote{Si la clé |draw| est utilisée sans valeur,
+c'est la couleur par défaut des filets de tableaux qui est utilisée.}. On peut
+aussi fixer l'épaisseur du trait avec la clé |line-width|.
 
 
 
@@ -590,7 +597,7 @@ Henri                  & 14 \\ \hline
 
 \subsection{Les blocs mono-rangée}
 
-\colorbox{yellow!50}{\textbf{Nouveau 5.6}}\enskip Pour les blocs mono-rangée, la
+\colorbox{yellow!30}{Nouveau 5.6}\enskip Pour les blocs mono-rangée, la
 hauteur (\emph{height}) et la profondeur (\emph{depth}) naturelles sont prises en
 compte pour la hauteur et la largeur de la rangée en cours (comme le fait la
 commande standard |\multicolumn| de LaTeX).
@@ -598,20 +605,26 @@ commande standard |\multicolumn| de LaTeX).
 
 
 
-\subsection{Les blocs mono-cellule}
+\subsection{Les blocs mono-case}
 
-Les blocs mono-cellule héritent des caractéristiques des blocs mono-colonne et
+Les blocs mono-case héritent des caractéristiques des blocs mono-colonne et
 des blocs mono-rangée.
 
 \medskip
-Il y a deux raisons à l'utilisation d'un bloc mono-cellule.
+On pourrait penser que des blocs d'une seule case n'ont aucune utilité mais, en
+fait, il y a plusieurs situations où leur utilisation peut présenter des avantages.
 
 \begin{itemize}
-\item Un bloc mono-cellule permet d'utiliser la commande |\\| pour composer le
+\item Un bloc mono-case permet d'utiliser la commande |\\| pour composer le
 bloc sur plusieurs lignes.
 
 \item On peut utiliser l'option d'alignement horizontal du bloc pour déroger à
 la consigne générale donnée dans le préambule pour cette colonne.
+
+\item On peut tracer un cadre autour du bloc avec la clé |draw| de la commande
+|\Block|.\footnote{Pour colorier le fond d'une case, il n'est pas besoin
+  d'utiliser un bloc mono-case : on peut utiliser la commande |\cellcolor| si la
+  clé |colortbl-like| est utilisée : voir p.~\pageref{colortbl-like}.}
 \end{itemize}
 
 \medskip
@@ -638,8 +651,8 @@ Balzac & 1799 \\
 \end{NiceTabular}
 
 \medskip
-On rappelle que si le premier argument obligatoire de |\Block| est laisssé
-blanc, alors le bloc est mono-cellule\footnote{On peut considérer que la valeur par
+On rappelle que si le premier argument obligatoire de |\Block| est laissé
+blanc, alors le bloc est mono-case\footnote{On peut considérer que la valeur par
 défaut de ce premier argument obligatoire est |1-1|.}.
 
 
@@ -908,13 +921,14 @@ $\begin{pNiceMatrix}[vlines,rules/width=0.2pt]
 
 La clé |hvlines| demande le tracé de tous les filets horizontaux et verticaux
 (sauf dans les blocs et dans les blocs virtuels déterminés par des
-lignes en pointillés).
+lignes en pointillés et sauf les filets correspondants à des clés |draw| de
+commandes |\Block|, filets qui sont tracés avec leurs caractéristiques).
 
 \medskip
 \begin{Verbatim}
 \begin{NiceTabular}{cccc}[~emphase#hvlines@,rules/color=blue,rules/width=1pt]
 rose      & tulipe & marguerite & dahlia \\
-violette  & \Block{2-2}{\LARGE\color{blue} fleurs}  & & souci \\
+violette  & \Block[~emphase#draw=red@]{2-2}{\LARGE fleurs}  & & souci \\
 pervenche & & & lys \\
 arum      & iris & jacinthe & muguet 
 \end{NiceTabular}
@@ -923,7 +937,7 @@ arum      & iris & jacinthe & muguet
 \begin{center}
 \begin{NiceTabular}{cccc}[hvlines,rules/color=blue,rules/width=1pt]
 rose      & tulipe & marguerite & dahlia \\
-violette  & \Block{2-2}{\LARGE\color{blue} fleurs}  & & souci \\
+violette  & \Block[draw=red]{2-2}{\LARGE fleurs}  & & souci \\
 pervenche & & & lys \\
 arum      & iris & jacinthe & muguet 
 \end{NiceTabular}
@@ -1119,10 +1133,10 @@ tracés postérieurement (conformément à l'esprit du «modèle du peintre» de
 PostScript et PDF). De ce point de vue, MuPDF (qui est utilisé par exemple par
 SumatraPDF) donne de meilleurs résultats que Adobe Reader.
 
-\item Une fine ligne blanche semble apparaître entre deux cellules de même
-couleur. Ce phénomène se produit quand chaque cellule est coloriée avec sa
+\item Une fine ligne blanche semble apparaître entre deux cases de même
+couleur. Ce phénomène se produit quand chaque case est coloriée avec sa
 propre instruction |fill| (opérateur |fill| de PostScript noté |f| en PDF).
-C'est le cas avec \pkg{colortbl} avec lequel chaque cellule est coloriée
+C'est le cas avec \pkg{colortbl} avec lequel chaque case est coloriée
 individuellement même si on utilise |\columncolor| ou |\rowcolor|.
 
 Concernant ce phénomène, Adobe Reader donne de meilleurs résultats que
@@ -1409,6 +1423,8 @@ On a utilisé le type de colonne |S| de \pkg{siunitx}.
 
 \subsection{Outils de coloriage avec la syntaxe de colortbl}
 
+\label{colortbl-like}
+
 On peut accéder aux outils de coloriage précédents avec une syntaxe proche de
 celle proposée par \pkg{colortbl}. On doit pour cela utiliser la clé
 |colortbl-like| dans l'environnement concerné.\footnote{Pour le moment, cette
@@ -2334,8 +2350,8 @@ Pour améliorer la lisibilité du code, une syntaxe alternative est proposée :
 peut spécifier les instructions du |code-after| à la fin de l'environnement,
 après le mot-clé |\CodeAfter|\footnote{Dans certaines circonstances, on doit
   mettre |\omit \CodeAfter|, |\omit| étant un mot-clé de TeX qui annule le motif
-  de la cellule courante.} (pour un exemple, voir page
-\pageref{exemple-CodeAfter}). \colorbox{yellow!50}{\textbf{Nouveau 5.5}}\enskip
+  de la case courante.} (pour un exemple, voir page
+\pageref{exemple-CodeAfter}). \colorbox{yellow!30}{Nouveau 5.5}\enskip
 Avant la version 5.5, il fallait parfois mettre le mot-clé |\omit| devant
 |\CodeAfter| dans certaines circonstances. Depuis la version 5.5, on ne doit
 \emph{jamais} mettre |\omit|.
@@ -2457,7 +2473,7 @@ titre inséré par |\caption| dans un environnement |{table}| de LaTeX.
 séparés par une virgule (comme avec l'option |multiple| de \pkg{footmisc} pour
 les notes de pied de page).
 
-\item Si une commande |\tabularnote{...}| se trouve exactement à la fin d'une cellule
+\item Si une commande |\tabularnote{...}| se trouve exactement à la fin d'une case
 (sans aucun espace après), l'appel de note est composé en débordement vers la
 droite (cela peut permettre de mieux conserver l'alignement des contenus d'une
 colonne).
@@ -2946,6 +2962,25 @@ d'éléments en verbatim (avec par exemple la commande
   environnement de LaTeX qui se contente d'insérer des commandes avant et
   après.}
 
+\subsection{Couleur des délimiteurs}
+
+Pour les environnements avec délimiteurs (|{pNiceArray}|, |{pNiceMatrix}|,
+etc.), il est possible de changer la couleur des délimiteurs avec la clé
+|delimiters-color|. 
+
+\medskip
+\begin{BVerbatim}[boxwidth=12cm,baseline=c]
+$\begin{bNiceMatrix}[delimiters-color=red]
+1 & 2 \\
+3 & 4 
+\end{bNiceMatrix}$
+\end{BVerbatim}
+$\begin{bNiceMatrix}[delimiters-color=red]
+1 & 2 \\
+3 & 4 
+\end{bNiceMatrix}$
+
+
 \subsection{L'environnement \{NiceArrayWithDelims\}}
 
 En fait, l'environnement |{pNiceArray}| et ses variantes sont fondés sur un
@@ -2989,7 +3024,7 @@ lignes en pointillés entre les cases du tableau.
 \textbf{Attention} : Par défaut, aucun nœud n'est créé dans une case vide. 
 
 \smallskip
-\colorbox{yellow!50}{\textbf{Nouveau 5.6}}\enskip 
+\colorbox{yellow!30}{Nouveau 5.6}\enskip 
 Néanmoins, on peut forcer la création d'un nœud avec la commande
 |\NotEmpty|.\footnote{Il faut toutefois remarquer qu'avec cette commande, la
   case est considérée comme non vide, ce qui a des conséquences sur le tracé des
@@ -3396,9 +3431,9 @@ L'extension \pkg{nicematrix} fournit deux variables internes mais publiques\foot
 
 \medskip
 Ces variables constituent le code du «|code-before|» et du «|code-after|». Le
-développeur peut donc les utiliser pour y ajouter du code à partir d'une cellule
+développeur peut donc les utiliser pour y ajouter du code à partir d'une case
 du tableau (l'affectation devra être globale, ce qui permettra de sortir de la
-cellule, qui est un groupe au sens de TeX).
+case, qui est un groupe au sens de TeX).
 
 \medskip
 On remarquera que l'utilisation de |\g_nicematrix_code_before_tl| nécessite une
@@ -3407,7 +3442,7 @@ compilation supplémentaire (car les instructions sont écrites dans le fichier
 
 \bigskip
 \emph{Example} : On souhaite écrire une commande |\hatchcell| pour hachurer la
-cellule courante (avec un argument optionnel entre crochets pour la couleur des
+case courante (avec un argument optionnel entre crochets pour la couleur des
 hachures). Il est possible de programmer une telle commande |\hatchcell| comme
 suit, en utilisant explicitement la variable publique
 |\g_nicematrix_code_before_tl| (ce code nécessite le chargement préalable de la
@@ -4072,67 +4107,35 @@ $\begin{pNiceArray}{cccc:c}
 \end{multicols}
 
 
-\subsection{Comment surligner les cases}
+\subsection{Comment surligner les cases d'une matrice}
 
 \label{highlight}
 
 \medskip
-Les exemples suivants nécessitent d'avoir chargé Tikz (\pkg{nicematrix} ne
-charge que \textsc{pgf}) ainsi que la bibliothèque Tikz |fit|, ce qui peut se
-faire avec les deux instructions suivantes dans le préambule du document :
-
-\begin{verbatim}
-\usepackage{tikz}
-\usetikzlibrary{fit}
-\end{verbatim}
-
-
-
-\medskip
-Pour mettre en évidence une case, il est possible de «dessiner» l'un des nœuds
-(le «nœud normal», le «nœud moyen» ou le «nœud large»). Dans l'exemple suivant,
-on utilise les «nœuds larges» de la diagonale de la matrice (avec la clé de Tikz
-«|name suffix|», il est facile d'utiliser les «nœuds larges»).
-
-Nous redessinons les nœuds avec de nouveaux nœuds en utilisant la bibliothèque
-\pkg{fit} de Tikz. Comme nous voulons recréer des nœuds identiques aux premiers,
-nous devons fixer |inner sep = 0pt| (si on ne fait pas cela, les nouveaux nœuds
-seront plus grands que les nœuds d'origine créés par \pkg{nicematrix}).
+Pour mettre en évidence une case d'une matrice, il est possible de «dessiner»
+cette case avec la clé |draw| de la commande |\Block| (c'est l'un des usages des
+blocs mono-case\footnote{On rappelle que si le premier argument obligatoire de
+la commande |\Block| est laissé vide, le bloc est considéré comme mono-case}).
 
 \label{exemple-CodeAfter}
 
 \begin{Verbatim}
-$\begin{pNiceArray}{>{\strut}cccc}[create-large-nodes,margin,extra-margin = 2pt]
-  a_{11} & a_{12} & a_{13} & a_{14} \\
-  a_{21} & a_{22} & a_{23} & a_{24} \\
-  a_{31} & a_{32} & a_{33} & a_{34} \\
-  a_{41} & a_{42} & a_{43} & a_{44} \\
-\CodeAfter
-  \begin{tikzpicture}[~emphase#name suffix = -large@,
-                      every node/.style = {draw,~emphase#inner sep = 0 pt@}]
-     \node [fit = (1-1)] {} ; 
-     \node [fit = (2-2)] {} ; 
-     \node [fit = (3-3)] {} ; 
-     \node [fit = (4-4)] {} ; 
-  \end{tikzpicture}
+$\begin{pNiceArray}{>{\strut}cccc}[margin,rules/color=blue]
+~emphase#\Block[draw]{}{a_{11}}@ & a_{12} & a_{13} & a_{14} \\
+a_{21} & \Block[draw]{}{a_{22}} & a_{23} & a_{24} \\
+a_{31} & a_{32} & \Block[draw]{}{a_{33}} & a_{34} \\
+a_{41} & a_{42} & a_{43} & \Block[draw]{}{a_{44}} \\
 \end{pNiceArray}$
 \end{Verbatim}
 %
-\[\begin{pNiceArray}{>{\strut}cccc}[create-large-nodes,margin,extra-margin = 2pt]
-a_{11} & a_{12} & a_{13} & a_{14} \\
-a_{21} & a_{22} & a_{23} & a_{24} \\
-a_{31} & a_{32} & a_{33} & a_{34} \\
-a_{41} & a_{42} & a_{43} & a_{44} \\
-\CodeAfter
-\begin{tikzpicture}[name suffix = -large,
-                    every node/.style = {draw,inner sep = 0 pt}]
-   \node [fit = (1-1)] {} ; 
-   \node [fit = (2-2)] {} ; 
-   \node [fit = (3-3)] {} ; 
-   \node [fit = (4-4)] {} ; 
-\end{tikzpicture}
+\[\begin{pNiceArray}{>{\strut}cccc}[margin,rules/color=blue]
+\Block[draw]{}{a_{11}} & a_{12} & a_{13} & a_{14} \\
+a_{21} & \Block[draw]{}{a_{22}} & a_{23} & a_{24} \\
+a_{31} & a_{32} & \Block[draw]{}{a_{33}} & a_{34} \\
+a_{41} & a_{42} & a_{43} & \Block[draw]{}{a_{44}} \\
 \end{pNiceArray}\]
 
+
 On remarquera que les traits que l'on vient de tracer sont dessinés \emph{après}
 la matrice sans modifier la position des composantes de celle-ci. En revanche,
 les traits tracés par |\hline|, le spécificateur «\verb+|+» ou les options
@@ -4140,15 +4143,29 @@ les traits tracés par |\hline|, le spécificateur «\verb+|+» ou les options
 matrice.\footnote{Pour la commande |\cline|, voir la remarque
   p.~\pageref{remark-cline}.}
 
-\vspace{1cm} Il est possible de colorier une rangée avec |\rowcolor| dans le
-|code-before| (ou avec |\rowcolor| dans la première case de la
-rangée). Les possibilités de réglages sont néanmoins limitées. C'est pourquoi
-nous présentons ici une autre méthode pour surligner une rangée de la matrice.
-Nous créons un nœud Tikz rectangulaire qui englobe les nœuds de la deuxième
-rangée en utilisant les outils de la bibliothèque Tikz \pkg{fit}. Ce nœud est
-rempli après la construction de la matrice. Pour que l'on puisse voir le texte
-\emph{sous} le nœud, nous devons utiliser la transparence avec le |blend mode|
-égal à |multiply|.
+\vspace{1cm} 
+Il est possible de colorier une rangée avec |\rowcolor| dans le |code-before|
+(ou avec |\rowcolor| dans la première case de la rangée si on utilise la clé
+|colortbl-like|). Les possibilités de réglages sont néanmoins limitées. C'est
+pourquoi nous présentons ici une autre méthode pour surligner une rangée d'une
+matrice. 
+
+\medskip
+Cet exemple et les suivants nécessitent d'avoir chargé Tikz (\pkg{nicematrix} ne
+charge que \textsc{pgf}) ainsi que la bibliothèque Tikz |fit|, ce qui peut se
+faire avec les deux instructions suivantes dans le préambule du document :
+
+\begin{verbatim}
+\usepackage{tikz}
+\usetikzlibrary{fit}
+\end{verbatim}
+
+\medskip
+Nous créons un nœud Tikz rectangulaire qui englobe les nœuds de la
+deuxième rangée en utilisant les outils de la bibliothèque Tikz \pkg{fit}. Ce
+nœud est rempli après la construction de la matrice. Pour que l'on puisse voir
+le texte \emph{sous} le nœud, nous devons utiliser la transparence avec le
+|blend mode| égal à |multiply|.
 
 
 \tikzset{highlight/.style={rectangle,
@@ -4167,17 +4184,19 @@ rempli après la construction de la matrice. Pour que l'on puisse voir le texte
                            inner sep=1pt,
                            fit=~#1}}
 
-$\begin{bNiceMatrix}[~emphase#code-after = {\tikz \node [highlight = (2-1) (2-3)] {} ;}@]
+$\begin{bNiceMatrix}
 0 & \Cdots & 0 \\
 1 & \Cdots & 1 \\
-0 & \Cdots & 0 
+0 & \Cdots & 0 \\
+~emphase#\CodeAfter \tikz \node [highlight = (2-1) (2-3)] {} ;@
 \end{bNiceMatrix}$
 \end{Verbatim}
 
-\[\begin{bNiceMatrix}[code-after = {\tikz \node [highlight = (2-1) (2-3)] {} ;}]
+\[\begin{bNiceMatrix}
 0 & \Cdots & 0 \\
 1 & \Cdots & 1 \\
-0 & \Cdots & 0 
+0 & \Cdots & 0 \\
+\CodeAfter \tikz \node [highlight = (2-1) (2-3)] {} ; 
 \end{bNiceMatrix}\]
 
 
diff --git a/Master/texmf-dist/doc/latex/nicematrix/nicematrix.pdf b/Master/texmf-dist/doc/latex/nicematrix/nicematrix.pdf
index c8e2b90a5cb..3f0097097d4 100644
--- a/Master/texmf-dist/doc/latex/nicematrix/nicematrix.pdf
+++ b/Master/texmf-dist/doc/latex/nicematrix/nicematrix.pdf
diff --git a/Master/texmf-dist/source/latex/nicematrix/nicematrix.dtx b/Master/texmf-dist/source/latex/nicematrix/nicematrix.dtx
index a8427171e27..b485a9139d3 100644
--- a/Master/texmf-dist/source/latex/nicematrix/nicematrix.dtx
+++ b/Master/texmf-dist/source/latex/nicematrix/nicematrix.dtx
@@ -15,8 +15,8 @@
 %
 % \fi
 % \iffalse
-\def\myfileversion{5.6}
-\def\myfiledate{2020/11/08}
+\def\myfileversion{5.7}
+\def\myfiledate{2020/11/23}
 %
 %
 %<*batchfile>
@@ -459,7 +459,7 @@ version 2005/12/01 or later.
 % $i$\verb|-|$j$ where $i$ is the number of rows of the block and $j$ its number
 % of columns. 
 %
-% \colorbox{yellow!50}{\bfseries New 5.6}\enskip If this argument is empty, its
+% \colorbox{yellow!30}{New 5.6}\enskip If this argument is empty, its
 % default value is |1-1|. If the number of rows is not specified, the block
 % extends until the last row (idem for the columns).
 %
@@ -558,7 +558,8 @@ version 2005/12/01 or later.
 % \begin{BVerbatim}
 % \begin{NiceTabular}~emphase#{cwc{2cm}wc{3cm}c}@
 % rose      & tulipe & marguerite & dahlia \\
-% violette  & \Block{2-2}{\LARGE\color{blue}De très jolies fleurs}  & & souci \\
+% violette  
+% & \Block[draw=red,fill=red!15]{2-2}{\LARGE De très jolies fleurs}  & & souci \\
 % pervenche & & & lys \\
 % arum      & iris & jacinthe & muguet 
 % \end{NiceTabular}
@@ -569,12 +570,18 @@ version 2005/12/01 or later.
 % \begin{center}
 % \begin{NiceTabular}{cwc{2cm}wc{3cm}c}
 % rose      & tulipe & marguerite & dahlia \\
-% violette  & \Block{2-2}{\LARGE\color{blue}De très jolies fleurs}  & & souci \\
+% violette  & 
+% \Block[draw=red,fill=red!15]{2-2}{\LARGE De très jolies fleurs}  & & souci \\
 % pervenche & & & lys \\
 % arum      & iris & jacinthe & muguet 
 % \end{NiceTabular}
 % \end{center}
 %
+% \colorbox{yellow!50}{\bfseries New 5.7}\enskip As we can see on this example,
+% it's possible to fill the block by using the key |fill| and to draw the frame
+% with the key |draw|\footnote{If the key |draw| is used without value, the
+% default color the rules of the tabulars is used}. It's also possible to change
+% the width (thickness) of that rules with the key |line-width|.
 %
 % \subsection{The mono-column blocks}
 %
@@ -628,7 +635,7 @@ version 2005/12/01 or later.
 % 
 % \subsection{The mono-row blocks}
 %
-% \colorbox{yellow!50}{\textbf{New 5.6}}\enskip For the mono-row blocks, the
+% \colorbox{yellow!30}{New 5.6}\enskip For the mono-row blocks, the
 % natural height and depth are taken into account for the height and depth of
 % the current row (as does a standard |\multicolumn| of LaTeX).
 %
@@ -638,12 +645,18 @@ version 2005/12/01 or later.
 % mono-column blocks.
 %
 % \medskip
-% There are two reasons to use a mono-column block:
+% At first sight, one may think that there is no point using a mono-cell block.
+% However, there are some good reasons to use such a block.
 % \begin{itemize}
 % \item It's possible to use the command |\\| in a (mono-cell) block.
 %
 % \item It's possible to use the option of horizontal alignment of the block in
 % derogation of the type of column given in the preamble of the array.
+%
+% \item It's possible do draw a frame around the cell with the key |draw| of the
+% command |\Block|.\footnote{If one wishes to color the background of a unique
+% celle, there is no point using the command |\Block|: it's possible to use the
+% command |\cellcolor| (when the key |colortbl-like| is used).}
 % \end{itemize}
 % 
 % \bigskip
@@ -669,7 +682,7 @@ version 2005/12/01 or later.
 % \medskip
 % We recall that if the first mandatory argument of |\Block| is left blank, the
 % block is mono-cell.\footnote{One may consider that the default value of the
-% first mandatory argument of |\Block| is |1-1|}
+% first mandatory argument of |\Block| is |1-1|.}
 % 
 % 
 %
@@ -920,15 +933,17 @@ version 2005/12/01 or later.
 % \subsection{The key hvlines}
 % \label{hvlines}
 %
-% The key |hvlines| draws all the vertical and horizontal rules excepted
-% in the blocks (and the virtual blocks determined by dotted lines).
+% The key |hvlines| draws all the vertical and horizontal rules (excepted
+% in the blocks and the virtual blocks determined by dotted lines and excepted
+% the rules corresponding of the frame of the blocks using the key |draw| which
+% are drawn with their own characteristics).
 %
 % \medskip
 % \begin{Verbatim}
 % \setlength{\arrayrulewidth}{1pt}
 % \begin{NiceTabular}{cccc}[~emphase#hvlines@,rules/color=blue]
 % rose      & tulipe & marguerite & dahlia \\
-% violette  & \Block{2-2}{\LARGE\color{blue} fleurs}  & & souci \\
+% violette  & \Block[draw=red]{2-2}{\LARGE fleurs}  & & souci \\
 % pervenche & & & lys \\
 % arum      & iris & jacinthe & muguet 
 % \end{NiceTabular}
@@ -938,7 +953,7 @@ version 2005/12/01 or later.
 % \setlength{\arrayrulewidth}{1pt}
 % \begin{NiceTabular}{cccc}[hvlines,rules/color=blue]
 % rose      & tulipe & marguerite & dahlia \\
-% violette  & \Block{2-2}{\LARGE\color{blue} fleurs}  & & souci \\
+% violette  & \Block[draw=red]{2-2}{\LARGE fleurs}  & & souci \\
 % pervenche & & & lys \\
 % arum      & iris & jacinthe & muguet 
 % \end{NiceTabular}
@@ -2074,9 +2089,9 @@ version 2005/12/01 or later.
 % \Vdots & \Ddots & \Vdots & \Hdotsfor{1} & \Vdots & \Ddots & \Vdots \\ 
 % C[a_n^{(p)},a_1] & \Cdots & C[a_n^{(p)},a_n] & & C[a_n^{(p)},a_1^{(p)}] & \Cdots & C[a_n^{(p)},a_n^{(p)}]
 % \end{bNiceMatrix}\]
-
-
-
+%
+%
+%
 % 
 % \subsection{How to generate the continuous dotted lines transparently}
 %
@@ -2314,7 +2329,7 @@ version 2005/12/01 or later.
 % For the legibility of the code, an alternative syntax is provided: it's
 % possible to give the instructions of the |\code-after| at the end of the
 % environment, after the keyword |\CodeAfter| (for an example, cf.
-% p.~\pageref{example-CodeAfter}). \colorbox{yellow!50}{\textbf{New 5.5}}\enskip
+% p.~\pageref{example-CodeAfter}). \colorbox{yellow!30}{New 5.5}\enskip
 % Before the version 5.5, it was necessary, in some circonstancies, to put the
 % keyword |\omit| before |\CodeAfter|. Since version~5.5, one must never put~|\omit|.
 %
@@ -2889,9 +2904,6 @@ version 2005/12/01 or later.
 % TeX world, the spaces after a control sequence are discarded and the elements
 % between curly braces are considered as a whole.
 %
-% \bigskip
-% The following example has been composed with XeLaTeX with \pkg{unicode-math},
-% which allows the use of greek letters directly in the TeX source.
 %
 % \medskip
 % \begin{scope}
@@ -2922,6 +2934,24 @@ version 2005/12/01 or later.
 % environment of LaTeX which only put TeX commands before and after the content.}
 % 
 %
+% \subsection{Color of the delimiters}
+%
+% For the environements with delimiters (|{pNiceArray}|, |{pNiceMatrix}|, etc.),
+% it's possible to change the color of the delimiters with the key
+% |delimiters-color|.
+%
+% \medskip
+% \begin{BVerbatim}[boxwidth=12cm,baseline=c]
+% $\begin{bNiceMatrix}[delimiters-color=red]
+% 1 & 2 \\
+% 3 & 4 
+% \end{bNiceMatrix}$
+% \end{BVerbatim}
+% $\begin{bNiceMatrix}[delimiters-color=red]
+% 1 & 2 \\
+% 3 & 4 
+% \end{bNiceMatrix}$
+%
 %
 % \subsection{The environment \{NiceArrayWithDelims\}}
 %
@@ -2963,7 +2993,7 @@ version 2005/12/01 or later.
 % \textbf{Caution} : By default, no node is created in a empty cell.
 %
 % \smallskip
-% \colorbox{yellow!50}{\textbf{New 5.6}}\enskip 
+% \colorbox{yellow!30}{New 5.6}\enskip 
 % However, it's possible to impose the creation of a node with the command |\NotEmpty|.
 % \footnote{One should note that, with that command, the cell is considered as
 % non-empty, which has consequencies for the continuous dotted lines (cf.
@@ -4026,64 +4056,34 @@ version 2005/12/01 or later.
 % \end{multicols}
 %
 % 
-% \subsection{How to highlight cells of the matrix}
+% \subsection{How to highlight cells of a matrix}
 %
 %
 % \label{highlight}
-% The following examples require Tikz (by default, \pkg{nicematrix} only loads
-% \textsc{pgf}) and the Tikz library |fit|. The following lines in the preamble
-% of your document do the job:
-% \begin{verbatim}
-% \usepackage{tikz}
-% \usetikzlibrary{fit}
-% \end{verbatim}
 % 
 % \medskip
-% In order to highlight a cell of a matrix, it's possible to ``draw'' one of the
-% correspondant nodes (the ``normal node'', the ``medium node'' or the ``large
-% node''). In the following example, we use the ``large nodes'' of the diagonal
-% of the matrix (with the Tikz key ``|name suffix|'', it's easy to use the
-% ``large nodes''). 
-%
-% We redraw the nodes with other nodes by using the Tikz library |fit|. Since we
-% want to redraw the nodes exactly, we have to set |inner sep = 0 pt| (if we
-% don't do that, the new nodes will be larger that the nodes created by
-% \pkg{nicematrix}). 
+% In order to highlight a cell of a matrix, it's possible to ``draw'' that cell
+% with the key |draw| of the command |\Block| (this is one of the uses of a
+% mono-cell block\footnote{We recall that, if the first mandatory argument of
+% the command |\Block| is left empty, that means that the block is a mono-cell block}).
 %
 % \label{example-CodeAfter}
 %
+%
 % \begin{Verbatim}
-% $\begin{pNiceArray}{>{\strut}cccc}[create-large-nodes,margin,extra-margin = 2pt]
-%   a_{11} & a_{12} & a_{13} & a_{14} \\
-%   a_{21} & a_{22} & a_{23} & a_{24} \\
-%   a_{31} & a_{32} & a_{33} & a_{34} \\
-%   a_{41} & a_{42} & a_{43} & a_{44} \\
-% \CodeAfter
-%   \begin{tikzpicture}[~emphase#name suffix = -large@,
-%                       every node/.style = {draw,~emphase#inner sep = 0 pt@}]
-%      \node [fit = (1-1)] {} ; 
-%      \node [fit = (2-2)] {} ; 
-%      \node [fit = (3-3)] {} ; 
-%      \node [fit = (4-4)] {} ; 
-%   \end{tikzpicture}
+% $\begin{pNiceArray}{>{\strut}cccc}[margin,rules/color=blue]
+% ~emphase#\Block[draw]{}{a_{11}}@ & a_{12} & a_{13} & a_{14} \\
+% a_{21} & \Block[draw]{}{a_{22}} & a_{23} & a_{24} \\
+% a_{31} & a_{32} & \Block[draw]{}{a_{33}} & a_{34} \\
+% a_{41} & a_{42} & a_{43} & \Block[draw]{}{a_{44}} \\
 % \end{pNiceArray}$
 % \end{Verbatim}
-%
-% \[\begin{pNiceArray}{>{\strut}cccc}[create-large-nodes,margin,extra-margin = 2pt]
-%   a_{11} & a_{12} & a_{13} & a_{14} \\
-%   a_{21} & a_{22} & a_{23} & a_{24} \\
-%   a_{31} & a_{32} & a_{33} & a_{34} \\
-%   a_{41} & a_{42} & a_{43} & a_{44} \\
-% \CodeAfter
-%   \begin{tikzpicture}[name suffix = -large,
-%                       every node/.style = {draw,inner sep = 0 pt}]
-%      \node [fit = (1-1)] {} ; 
-%      \node [fit = (2-2)] {} ; 
-%      \node [fit = (3-3)] {} ; 
-%      \node [fit = (4-4)] {} ; 
-%   \end{tikzpicture}
+% \[\begin{pNiceArray}{>{\strut}cccc}[margin,rules/color=blue]
+% \Block[draw]{}{a_{11}} & a_{12} & a_{13} & a_{14} \\
+% a_{21} & \Block[draw]{}{a_{22}} & a_{23} & a_{24} \\
+% a_{31} & a_{32} & \Block[draw]{}{a_{33}} & a_{34} \\
+% a_{41} & a_{42} & a_{43} & \Block[draw]{}{a_{44}} \\
 % \end{pNiceArray}\]
-%
 % 
 % We should remark that the rules we have drawn are drawn \emph{after} the
 % construction of the array and thus, they don't spread the cells of the array.
@@ -4095,13 +4095,23 @@ version 2005/12/01 or later.
 %
 % \vspace{1cm}
 % It's possible to color a row with |\rowcolor| in the |code-before| (or with
-% |\rowcolor| of \pkg{colortbl} in the first cell of the row). However, it's not
-% possible to do a fine tuning. That's why we describe now method to highlight a
-% row of the matrix. We create a rectangular Tikz node which encompasses the
-% nodes of the second row with the Tikz library \pkg{fit}. This Tikz node is
-% filled after the construction of the matrix. In order to see the text
-% \emph{under} this node, we have to use transparency with the |blend mode|
-% equal to |multiply|.
+% |\rowcolor| in the first cell of the row if the key |colortbl-like| is used).
+% However, it's not possible to do a fine tuning. That's why we describe now a
+% method to highlight a row of the matrix. We create a rectangular Tikz node
+% which encompasses the nodes of the second row with the Tikz library \pkg{fit}.
+% This Tikz node is filled after the construction of the matrix. In order to see
+% the text \emph{under} this node, we have to use transparency with the 
+% |blend mode| equal to |multiply|.
+%
+%
+% \medskip
+% That example and the following ones require Tikz (by default, \pkg{nicematrix}
+% only loads \textsc{pgf}) and the Tikz library |fit|. The following lines in
+% the preamble of your document do the job:
+% \begin{verbatim}
+% \usepackage{tikz}
+% \usetikzlibrary{fit}
+% \end{verbatim}
 %
 % \tikzset{highlight/.style={rectangle,
 %                            fill=red!15,
@@ -4119,19 +4129,21 @@ version 2005/12/01 or later.
 %                            inner sep=1pt,
 %                            fit = ~#1}}
 %
-% $\begin{bNiceMatrix}[~emphase#code-after = {\tikz \node [highlight = (2-1) (2-3)] {} ;}@]
+% 
+% $\begin{bNiceMatrix}
 % 0 & \Cdots & 0 \\
 % 1 & \Cdots & 1 \\
-% 0 & \Cdots & 0 
+% 0 & \Cdots & 0 \\
+% ~emphase#\CodeAfter \tikz \node [highlight = (2-1) (2-3)] {} ;@
 % \end{bNiceMatrix}$
 % \end{Verbatim}
-% 
-% \[\begin{bNiceMatrix}[code-after = {\tikz \node [highlight = (2-1) (2-3)] {} ;}]
+% \[\begin{bNiceMatrix}
 % 0 & \Cdots & 0 \\
 % 1 & \Cdots & 1 \\
-% 0 & \Cdots & 0 
+% 0 & \Cdots & 0 \\
+% \CodeAfter \tikz \node [highlight = (2-1) (2-3)] {} ; 
 % \end{bNiceMatrix}\]
-% 
+%
 %
 %
 % \vspace{1cm} 
@@ -5144,6 +5156,15 @@ version 2005/12/01 or later.
 \tl_new:N \l_@@_rules_color_tl
 %    \end{macrocode}
 %
+% 
+% \bigskip
+% This boolean will be used only to detect in an expandable way whether we are
+% at the beginning of the (potential) column zero, in order to raise an error if
+% |\Hdotsfor| is used in that column.
+%    \begin{macrocode}
+\bool_new:N \g_@@_after_col_zero_bool
+%    \end{macrocode}
+% 
 % \bigskip
 % A kind of false row will be inserted at the end of the array for the
 % construction of the |col| nodes (and also to fix the width of the columns when
@@ -5158,7 +5179,7 @@ version 2005/12/01 or later.
 % \bigskip
 % It's possible to use the command |\NotEmpty| to specify explicitely that a
 % cell must be considered as non empty by \pkg{nicematrix} (the Tikz nodes are
-% constructed only the non empty cells).
+% constructed only in the non empty cells).
 %    \begin{macrocode}
 \bool_new:N \g_@@_not_empty_cell_bool
 %    \end{macrocode}
@@ -5220,7 +5241,7 @@ version 2005/12/01 or later.
 %    \end{macrocode}
 %
 % \bigskip
-% The following sequence will contain the caracteristics of the blocks of the
+% The following sequence will contain the characteristics of the blocks of the
 % array, specified by the command |\Block|. Each block is represented by 6
 % components surrounded by braces:
 %
@@ -5256,6 +5277,17 @@ version 2005/12/01 or later.
 % blocks corresponding to the dotted lines).
 %
 % \medskip
+% The final user may decide to ``stroke'' a block (using, for example, the key
+% |color=red!15| when using the command |\Block|). In that case, the rules
+% specified, for instance, by |hvlines| must not be drawn around the block.
+% That's why we keep the information of all that stroken blocks in the following
+% sequence.
+%    \begin{macrocode}
+\seq_new:N \g_@@_pos_of_stroken_blocks_seq
+%    \end{macrocode}
+% 
+%
+% \medskip
 % We are able to determine the number of columns specified in the preamble (for
 % the environments with explicit preamble, of course and without the potential
 % exterior columns).
@@ -5263,12 +5295,32 @@ version 2005/12/01 or later.
 \int_new:N \g_@@_static_num_of_col_int
 %    \end{macrocode}
 % 
+% \medskip 
+% The following token lists correspond to the keys |fill| and |draw| of
+% a command |\Block|.
+%    \begin{macrocode}
+\tl_new:N \l_@@_fill_tl
+\tl_new:N \l_@@_draw_tl
+%    \end{macrocode}
+% 
 % \medskip
-% Used for the color of the blocks.
+% The following token list correspond to the key |color| of the command
+% |\Block|. However, as of now (v. 5.7 of \pkg{nicematrix}), the key |color|
+% linked to |fill| with an error. We will give to the key |color| of |\Block|
+% its new meaning in a few months (with its new definition, the key |color| will
+% draw the frame with the given color but also color the content of the block
+% (that is to say the text) as does the key |color| of a Tikz node).
 %    \begin{macrocode}
 \tl_new:N \l_@@_color_tl
 %    \end{macrocode}
-%
+% 
+% \medskip
+% Here is the dimension for the width of the rule when a block (created by
+% |\Block|) is stroked.
+%    \begin{macrocode}
+\dim_new:N \l_@@_line_width_dim
+%    \end{macrocode}
+% 
 % \medskip
 % The parameter of position of the label of a block (|c|, |r| or |l|).
 %    \begin{macrocode}
@@ -5844,7 +5896,13 @@ version 2005/12/01 or later.
 \tl_new:N \l_@@_xdots_color_tl
 %    \end{macrocode}
 % 
-% \medskip
+% \bigskip
+% The following token list corresponds to the key |delimiters-color|.
+%    \begin{macrocode}
+\tl_new:N \l_@@_delimiters_color_tl
+%    \end{macrocode}
+% 
+% \bigskip
 % Sometimes, we want to have several arrays vertically juxtaposed in order to
 % have an alignment of the columns of these arrays. To acheive this goal, one
 % may wish to use the same width for all the columns (for example with the
@@ -6143,6 +6201,8 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
 \keys_define:nn { NiceMatrix / NiceMatrixOptions }
   { 
+    delimiters-color .tl_set:N = \l_@@_delimiters_color_tl ,
+    delimiters-color .value_required:n = true ,
     last-col .code:n = \tl_if_empty:nF { #1 }
                          { \@@_error:n { last-col~non~empty~for~NiceMatrixOptions } } 
                        \int_zero:N \l_@@_last_col_int ,
@@ -6247,6 +6307,8 @@ version 2005/12/01 or later.
     r .code:n = \tl_set:Nn \l_@@_type_of_col_tl r ,
     small .bool_set:N = \l_@@_small_bool ,
     small .value_forbidden:n = true ,
+    delimiters-color .tl_set:N = \l_@@_delimiters_color_tl ,
+    delimiters-color .value_required:n = true ,
     unknown .code:n = \@@_error:n { Unknown~option~for~NiceMatrix } 
   }
 %    \end{macrocode}
@@ -6277,6 +6339,8 @@ version 2005/12/01 or later.
     notes / bottomrule .default:n = true ,
     tabularnote .tl_set:N = \l_@@_tabularnote_tl ,
     tabularnote .value_required:n = true ,
+    delimiters-color .tl_set:N = \l_@@_delimiters_color_tl ,
+    delimiters-color .value_required:n = true ,
     unknown .code:n = \@@_error:n { Unknown~option~for~NiceArray } 
   }
 %    \end{macrocode}
@@ -6392,7 +6456,7 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
 \cs_new_protected:Npn \@@_begin_of_row:
   {
-    \int_gincr:N \c@iRow 
+    \refstepcounter { iRow } 
     \dim_gset_eq:NN \g_@@_dp_ante_last_row_dim \g_@@_dp_last_row_dim 
     \dim_gset:Nn \g_@@_dp_last_row_dim { \box_dp:N \@arstrutbox }
     \dim_gset:Nn \g_@@_ht_last_row_dim { \box_ht:N \@arstrutbox }
@@ -6733,6 +6797,7 @@ version 2005/12/01 or later.
 \cs_new_protected:Npn \@@_everycr_i:
   { 
     \int_gzero:N \c@jCol 
+    \bool_gset_false:N \g_@@_after_col_zero_bool
     \bool_if:NF \g_@@_row_of_col_done_bool
       {
         \@@_create_row_node:
@@ -7073,10 +7138,14 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
     \seq_gclear:N \g_@@_blocks_seq
     \seq_gclear:N \g_@@_pos_of_blocks_seq
-    \seq_gclear:N \g_@@_pos_of_xdots_seq
 %    \end{macrocode}
 % In fact, the sequence |\g_@@_pos_of_blocks_seq| will also contain the
 % positions of the cells with a |\diagbox|.
+%
+%    \begin{macrocode}
+    \seq_gclear:N \g_@@_pos_of_stroken_blocks_seq
+    \seq_gclear:N \g_@@_pos_of_xdots_seq
+%    \end{macrocode}
 % 
 %    \begin{macrocode}
     \tl_if_exist:cT { g_@@_code_before_ \int_use:N \g_@@_env_int _ tl }
@@ -7455,6 +7524,8 @@ version 2005/12/01 or later.
         \hbox_set:Nn \l_tmpa_box
           {
             \c_math_toggle_token
+            \tl_if_empty:NF \l_@@_delimiters_color_tl 
+              { \color { \l_@@_delimiters_color_tl } }
             \left #1
             \vcenter 
               { 
@@ -7688,6 +7759,9 @@ version 2005/12/01 or later.
         \@@_w: { \@@_patch_preamble_v:nnnn { }                          #1 } 
         \@@_W: { \@@_patch_preamble_v:nnnn { \cs_set_eq:NN \hss \hfil } #1 } 
         \@@_true_c: { \@@_patch_preamble_vi:n #1 }
+        C { \@@_error:nn { old~column~type } C }
+        L { \@@_error:nn { old~column~type } L }
+        R { \@@_error:nn { old~column~type } R }
         \q_stop { }
       }
       { 
@@ -7963,7 +8037,7 @@ version 2005/12/01 or later.
 % \bigskip
 % The following command is \emph{always} used by |{NiceArrayWithDelims}| (even
 % if, in fact, there is no tabular notes: in fact, it's not possible to know
-% whether there is or not before the composition of the blocks).
+% whether there is tabular notes or not before the composition of the blocks).
 %    \begin{macrocode}
 \cs_new_protected:Npn \@@_use_arraybox_with_notes_c:
   {
@@ -8511,6 +8585,7 @@ version 2005/12/01 or later.
   {
     > 
       { 
+        \bool_gset_true:N \g_@@_after_col_zero_bool
         \@@_begin_of_row:
 %    \end{macrocode}
 % The contents of the cell is constructed in the box |\l_@@_cell_box| because we
@@ -10381,8 +10456,15 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
 \cs_new:Npn \@@_Hdotsfor:
   {
-    \int_compare:nNnTF \c@jCol = 0
-      { \@@_error:n { Hdotsfor~in~col~0 } }
+    \int_compare:nNnTF \c@jCol = 0 
+      { 
+        \bool_if:NTF \g_@@_after_col_zero_bool 
+          {        
+            \multicolumn { 1 } { c } { }
+            \@@_Hdotsfor_i
+          }
+          { \@@_fatal:n { Hdotsfor~in~col~0 } } 
+      }
       { 
         \multicolumn { 1 } { c } { }
         \@@_Hdotsfor_i
@@ -10416,7 +10498,7 @@ version 2005/12/01 or later.
                 #1 , #3 , 
                 down = \exp_not:n { #4 } , up = \exp_not:n { #5 }
               } 
-          } 
+          }   
         \prg_replicate:nn { #2 - 1 } { & \multicolumn { 1 } { c } { } }
       } 
   }
@@ -11086,6 +11168,9 @@ version 2005/12/01 or later.
       }
   }
 %    \end{macrocode}
+%
+% 
+% 
 % 
 % \bigskip
 % \subsection*{The vertical rules}
@@ -11189,6 +11274,8 @@ version 2005/12/01 or later.
            { \@@_test_if_vline_in_block:nnnn ##1 }
          \seq_map_inline:Nn \g_@@_pos_of_xdots_seq
            { \@@_test_if_vline_in_block:nnnn ##1 }
+         \seq_map_inline:Nn \g_@@_pos_of_stroken_blocks_seq
+           { \@@_test_if_vline_in_stroken_block:nnnn ##1 }
          \clist_if_empty:NF \l_@@_except_corners_clist
            \@@_test_in_corner_v:
          \bool_if:NTF \g_tmpa_bool
@@ -11364,6 +11451,8 @@ version 2005/12/01 or later.
            { \@@_test_if_hline_in_block:nnnn ##1 }
          \seq_map_inline:Nn \g_@@_pos_of_xdots_seq
            { \@@_test_if_hline_in_block:nnnn ##1 }
+         \seq_map_inline:Nn \g_@@_pos_of_stroken_blocks_seq
+           { \@@_test_if_hline_in_stroken_block:nnnn ##1 }
          \clist_if_empty:NF \l_@@_except_corners_clist \@@_test_in_corner_h: 
          \bool_if:NTF \g_tmpa_bool
            { 
@@ -11565,7 +11654,34 @@ version 2005/12/01 or later.
   }
 %    \end{macrocode}
 %
+%    \begin{macrocode}
+\cs_new_protected:Npn \@@_test_if_hline_in_stroken_block:nnnn #1 #2 #3 #4
+  {
+    \bool_lazy_all:nT
+      {
+        { \int_compare_p:nNn \l_tmpa_tl > { #1 - 1 } }
+        { \int_compare_p:nNn \l_tmpa_tl < { #3 + 2 } }
+        { \int_compare_p:nNn \l_tmpb_tl > { #2 - 1 } }
+        { \int_compare_p:nNn \l_tmpb_tl < { #4 + 1 } }
+      }
+      { \bool_gset_false:N \g_tmpa_bool }
+  }
+%    \end{macrocode}
 %
+%    \begin{macrocode}
+\cs_new_protected:Npn \@@_test_if_vline_in_stroken_block:nnnn #1 #2 #3 #4
+  {
+    \bool_lazy_all:nT
+      {
+        { \int_compare_p:nNn \l_tmpa_tl > { #1 - 1 } }
+        { \int_compare_p:nNn \l_tmpa_tl < { #3 + 1 } }
+        { \int_compare_p:nNn \l_tmpb_tl > { #2 - 1 } }
+        { \int_compare_p:nNn \l_tmpb_tl < { #4 + 2 } }
+      }
+      { \bool_gset_false:N \g_tmpa_bool }
+  }
+%    \end{macrocode}
+% 
 % \bigskip
 % \subsubsection*{The key except-corners}
 %
@@ -12400,8 +12516,8 @@ version 2005/12/01 or later.
 %
 % \bigskip
 % The options of the command |\Block| will be analyzed first in the cell of the
-% array (and once again when the block will be put in the array in the
-% |code-after|). Here is the set of keys for the first pass.
+% array (and once again when the block will be put in the array).
+% Here is the set of keys for the first pass.
 %    \begin{macrocode}
 \keys_define:nn { NiceMatrix / Block / FirstPass }
   {
@@ -12411,6 +12527,12 @@ version 2005/12/01 or later.
     r .value_forbidden:n = true ,
     c .code:n = \tl_set:Nn \l_@@_pos_of_block_tl c ,
     c .value_forbidden:n = true ,
+%    \end{macrocode}
+% The two following lines will be uncommented when we will give to the key
+% |color| its new definition.
+%    \begin{macrocode}
+    % color .tl_set:N = \l_@@_color_tl ,
+    % color .value_required:n = true ,
   }
 %    \end{macrocode}
 %
@@ -12418,8 +12540,9 @@ version 2005/12/01 or later.
 % The following command |\@@_Block:| will be linked to |\Block| in the
 % environments of \pkg{nicematrix}. We define it with
 % |\NewExpandableDocumentCommand| because it has an optional argument between
-% |<| and |>| (for TeX instructions put before the math mode of the label). It's
-% mandatory to use an expandable command.
+% |<| and |>| (for TeX instructions put before the math mode of the label and
+% before the beginning of the small array of the block). It's mandatory to use
+% an expandable command.
 %
 %    \begin{macrocode}
 \NewExpandableDocumentCommand \@@_Block: { O { } m D < > { } m }
@@ -12444,17 +12567,21 @@ version 2005/12/01 or later.
 % \medskip
 % Now, the arguments have been extracted: |#1| is $i$ (the number of rows of the
 % block), |#2| is $j$ (the number of columns of the block), |#3| is the list of
-% key-values, |#4| are the tokens to put before the math mode and |#5| is the
-% label of the block.
+% key-values, |#4| are the tokens to put before the math mode and the beginning
+% of the small array of the block and |#5| is the label of the block.
 %    \begin{macrocode}
 \cs_new_protected:Npn \@@_Block_ii:nnnnn #1 #2 #3 #4 #5
   {
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-    \tl_if_empty:NTF \l_@@_cell_type_tl
+    \int_compare:nNnTF { #2 } = 1
+      {
+        \tl_if_empty:NTF \l_@@_cell_type_tl
+          { \tl_set:Nn \l_@@_pos_of_block_tl c }
+          { \tl_set_eq:NN \l_@@_pos_of_block_tl \l_@@_cell_type_tl }
+      }
       { \tl_set:Nn \l_@@_pos_of_block_tl c }
-      { \tl_set_eq:NN \l_@@_pos_of_block_tl \l_@@_cell_type_tl }
 %    \end{macrocode}
 %
 % \medskip
@@ -12488,7 +12615,7 @@ version 2005/12/01 or later.
 %    \end{macrocode}
 % Now, |\l_tmpa_tl|  contains an ``object'' corresponding to the position of the
 % block whith four components, each of them surrounded by curly brackets:
-% 
+%
 % |{|\textsl{imin}|}{|\textsl{jmin}|}{|\textsl{imax}|}{|\textsl{jmax}|}|.
 % 
 % We store this information in the sequence |\g_@@_pos_of_blocks_seq|.
@@ -12553,13 +12680,13 @@ version 2005/12/01 or later.
 % command seems to be bugged: it doesn't work in XeLaTeX when \pkg{fontspec} is
 % loaded.
 %    \begin{macrocode}
-        \int_compare:nNnT { #2 } = 1 \set@color
-        \bool_if:NTF \l_@@_NiceTabular_bool
-          { 
-            \group_begin:
-            \cs_set:Npn \arraystretch { 1 }
-            \dim_set_eq:NN \extrarowheight \c_zero_dim 
-            #4
+        \tl_if_empty:NTF \l_@@_color_tl
+          { \int_compare:nNnT { #2 } = 1 \set@color }
+          { \color { \l_@@_color_tl } }
+        \group_begin:
+        \cs_set:Npn \arraystretch { 1 }
+        \dim_set_eq:NN \extrarowheight \c_zero_dim 
+        #4
 %    \end{macrocode}
 % If the box is rotated (the key |\rotate| may be in the previous |#4|), the
 % tabular used for the content of the cell will be constructed with a format
@@ -12568,29 +12695,23 @@ version 2005/12/01 or later.
 % the tabular is the same as the external alignment of the tabular (that is to
 % say the position of the block in its zone of merged cells).
 %    \begin{macrocode}
-            \bool_if:NT \g_@@_rotate_bool
-              { \tl_set:Nn \l_@@_pos_of_block_tl c }
+        \bool_if:NT \g_@@_rotate_bool { \tl_set:Nn \l_@@_pos_of_block_tl c }  
+        \bool_if:NTF \l_@@_NiceTabular_bool
+          { 
             \exp_args:Nnx \begin { tabular } 
               { @ { } \l_@@_pos_of_block_tl @ { } } 
               #5 
             \end { tabular } 
-            \group_end:
           } 
           { 
-            \group_begin:
-            \cs_set:Npn \arraystretch { 1 }
-            \dim_set_eq:NN \extrarowheight \c_zero_dim 
-            #4 
-            \bool_if:NT \g_@@_rotate_bool
-              { \tl_set:Nn \l_@@_pos_of_block_tl c }
             \c_math_toggle_token
             \exp_args:Nnx \begin { array } 
               { @ { } \l_@@_pos_of_block_tl @ { } } 
               #5 
             \end { array } 
             \c_math_toggle_token 
-            \group_end:
           }
+        \group_end:
       }
     \bool_if:NT \g_@@_rotate_bool
       {
@@ -12721,17 +12842,25 @@ version 2005/12/01 or later.
 % array \emph{after the construction of the array} (by using \textsc{pgf}).
 % 
 % \medskip
-% The key |tikz| is for Tikz options used when the \textsc{pgf} node of the
-% block is created (the ``normal'' block node and not the ``short'' one nor the
-% ``medium'' one). \textbf{In fact, as of now, it is \emph{not} documented}. Is
-% it really a good idea to provide such a key?
 %   \begin{macrocode}
 \keys_define:nn { NiceMatrix / Block / SecondPass }
   {
-    tikz .tl_set:N = \l_@@_tikz_tl ,
-    tikz .value_required:n = true ,
-    color .tl_set:N = \l_@@_color_tl ,
+    fill .tl_set:N = \l_@@_fill_tl ,
+    fill .value_required:n = true ,
+    draw .tl_set:N = \l_@@_draw_tl ,
+    draw .default:n = default ,
+%    \end{macrocode}
+% The following definition for the key |color| will be deleted when we will give
+% to the key |color| of the command |\Block| its new definition. It will be
+% replaced by the line which is commented.
+%    \begin{macrocode}
+    color .code:n = 
+      \@@_error:n { Key~color~for~Block }
+      \tl_set:Nn \l_@@_fill_tl { #1 } ,
+    % color .code:n = \color { #1 } \tl_set:Nn \l_@@_draw_tl { #1 } ,
     color .value_required:n = true ,
+    line-width .dim_set:N = \l_@@_line_width_dim ,
+    line-width .value_required:n = true ,
     l .code:n = \tl_set:Nn \l_@@_pos_of_block_tl l ,
     l .value_forbidden:n = true ,
     r .code:n = \tl_set:Nn \l_@@_pos_of_block_tl r ,
@@ -12762,11 +12891,11 @@ version 2005/12/01 or later.
 % The group is for the keys.
 %    \begin{macrocode}
     \group_begin:
-    \keys_set:nn { NiceMatrix / Block / SecondPass} { #5 }
+    \keys_set:nn { NiceMatrix / Block / SecondPass } { #5 }
 %    \end{macrocode}
 %
 % The integer |\l_@@_last_row_int| will be the last row of the block and
-% |\l_@@_last_col_int| it's last column.
+% |\l_@@_last_col_int| its last column.
 %    \begin{macrocode}
     \int_zero_new:N \l_@@_last_row_int 
     \int_zero_new:N \l_@@_last_col_int 
@@ -12789,12 +12918,29 @@ version 2005/12/01 or later.
 %    \end{macrocode}
 % 
 %    \begin{macrocode}
-    \tl_if_empty:NF \l_@@_color_tl
+    \bool_lazy_or:nnT 
+      { ! \tl_if_empty_p:N \l_@@_draw_tl }
+      { \dim_compare_p:nNn \l_@@_line_width_dim > \c_zero_dim }
+      {
+        \tl_gput_right:Nx \g_nicematrix_code_after_tl
+          { 
+            \@@_stroke_block:nnn
+              { #5 } 
+              { #1 - #2 } 
+              { \int_use:N \l_@@_last_row_int - \int_use:N \l_@@_last_col_int } 
+          }  
+        \seq_gput_right:Nn \g_@@_pos_of_stroken_blocks_seq 
+           { { #1 } { #2 } { #3 } { #4 } }
+      }
+%    \end{macrocode}
+%
+%    \begin{macrocode}
+    \tl_if_empty:NF \l_@@_fill_tl
       {
         \tl_gput_right:Nx \g_nicematrix_code_before_tl
           { 
             \exp_not:N \rectanglecolor 
-              { \l_@@_color_tl } 
+              { \l_@@_fill_tl } 
               { #1 - #2 } 
               { \int_use:N \l_@@_last_row_int - \int_use:N \l_@@_last_col_int } 
           }  
@@ -12897,7 +13043,6 @@ version 2005/12/01 or later.
 % and the four coordinates of two opposite corner points of the rectangle.
 %    \begin{macrocode}
           \begin { pgfscope }
-          \exp_args:Nx \pgfset { \l_@@_tikz_tl }
           \@@_pgf_rect_node:nnnnn
             { \@@_env: - #1 - #2 - block }
             \l_tmpb_dim \l_tmpa_dim \l_tmpd_dim \l_tmpc_dim 
@@ -13036,17 +13181,20 @@ version 2005/12/01 or later.
 %
 % \medskip
 % If the number of rows is different of $1$, we will put the label of the block
-% in using the short node (the label of the block has been composed in
+% by using the short node (the label of the block has been composed in
 % |\l_@@_cell_box|).
 %    \begin{macrocode}
           { 
 %    \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 \c@jCol = 0 
+            \int_compare:nNnT { #2 } = 0 
               { \tl_set:Nn \l_@@_pos_of_block_tl r }
-            \int_compare:nNnT \c@jCol = \l_@@_last_col_int
-              { \tl_set:Nn \l_@@_pos_of_block_tl l }
+            \bool_if:nT \g_@@_last_col_found_bool 
+              {
+                \int_compare:nNnT { #2 } = \g_@@_col_total_int
+                  { \tl_set:Nn \l_@@_pos_of_block_tl l }
+              }
             \pgftransformshift
               {
                 \pgfpointanchor 
@@ -13079,6 +13227,76 @@ version 2005/12/01 or later.
   }
 %    \end{macrocode}
 %
+%
+% % \bigskip
+% The first argument of |\@@_stroke_block:nnn| is a list of options for the
+% rectangle that you will stoke. The second argument is the upper-left cell of
+% the block (with, as usual, the syntex $i$|-|$j$) and the third is the last
+% cell of the block (with the same syntax).
+%    \begin{macrocode}
+\cs_new_protected:Npn \@@_stroke_block:nnn #1 #2 #3
+  {
+    \group_begin:
+    \tl_clear:N \l_@@_draw_tl
+    \dim_set_eq:NN \l_@@_line_width_dim \arrayrulewidth
+    \keys_set_known:nn { NiceMatrix / BlockStroke } { #1 }
+    \pgfpicture
+    \pgfrememberpicturepositiononpagetrue
+    \pgf@relevantforpicturesizefalse
+    \tl_if_empty:NF \l_@@_draw_tl 
+      { 
+%    \end{macrocode}
+% If the user has used the key |color| of the command |\Block| without value,
+% the color fixed by |\arrayrulecolor| is used.
+%    \begin{macrocode}
+        \str_if_eq:VnTF \l_@@_draw_tl { default } 
+          { \CT@arc@ }
+          { \pgfsetstrokecolor { \l_@@_draw_tl } }
+      }
+    \@@_cut_on_hyphen:w #2 \q_stop
+    \bool_lazy_and:nnT 
+      { \int_compare_p:n { \l_tmpa_tl <= \c@iRow } }
+      { \int_compare_p:n { \l_tmpb_tl <= \c@jCol } }
+      {
+        \@@_qpoint:n { row - \l_tmpa_tl } 
+        \dim_set:Nn \l_tmpb_dim { \pgf@y }
+        \@@_qpoint:n { col - \l_tmpb_tl }
+        \dim_set:Nn \l_tmpc_dim { \pgf@x }
+        \@@_cut_on_hyphen:w #3 \q_stop
+        \int_compare:nNnT \l_tmpa_tl > \c@iRow
+          { \tl_set:Nx \l_tmpa_tl { \int_use:N \c@iRow } }
+        \int_compare:nNnT \l_tmpb_tl > \c@jCol
+          { \tl_set:Nx \l_tmpb_tl { \int_use:N \c@jCol } }
+        \@@_qpoint:n { row - \@@_succ:n \l_tmpa_tl }
+        \dim_set:Nn \l_tmpa_dim { \pgf@y } 
+        \@@_qpoint:n { col - \@@_succ:n \l_tmpb_tl }
+        \dim_set:Nn \l_tmpd_dim { \pgf@x }
+        \pgfpathrectanglecorners
+          { \pgfpoint \l_tmpc_dim \l_tmpb_dim }
+          { \pgfpoint \l_tmpd_dim \l_tmpa_dim }
+        \pgfsetlinewidth { 1.1 \l_@@_line_width_dim }
+        \pgfusepathqstroke
+      }
+    \endpgfpicture
+    \group_end:
+  }
+%    \end{macrocode}
+%
+% Here is the set of keys for the command |\@@_stroke_block:nnn|.
+%    \begin{macrocode}
+\keys_define:nn { NiceMatrix / BlockStroke }
+  {
+%    \end{macrocode}
+% We will uncomment the following line when we will give to the key |color| of
+% the command |\Block| its new definition.
+%    \begin{macrocode}
+    % color .tl_set:N = \l_@@_draw_tl ,
+    draw .tl_set:N = \l_@@_draw_tl ,
+    draw .default:n = default ,
+    line-width .dim_set:N = \l_@@_line_width_dim ,
+  }
+%    \end{macrocode}
+% 
 % \bigskip
 % \subsection*{How to draw the dotted lines transparently}
 %    \begin{macrocode}
@@ -13658,6 +13876,16 @@ version 2005/12/01 or later.
 %    \end{macrocode}
 %
 %    \begin{macrocode}
+\@@_msg_new:nn { Key~color~for~Block }
+  {
+    The~key~'color'~for~the~command~\token_to_str:N \Block\ 
+    is~deprecated:~you~should~use~'fill'~instead.\\
+    You~can~go~on~for~this~time~but~remember~that~that~key~
+    will~be~deleted~in~a~future~version.
+  }
+%    \end{macrocode}
+%
+%    \begin{macrocode}
 \@@_msg_new:nn { ampersand~in~light-syntax }
   {
     You~can't~use~an~ampersand~(\token_to_str &)~to~separate~columns~because
@@ -13682,7 +13910,16 @@ version 2005/12/01 or later.
   }
 %    \end{macrocode}
 % 
-%
+%    \begin{macrocode}
+\@@_msg_new:nn { old~column~type } 
+  {
+    The~column~type~'#1'~is~no~longer~defined~in~'nicematrix'.~
+    Since~version~5.0,~you~have~to~use~'l',~'c'~and~'r'~instead~of~'L',~
+    'C'~and~'R'.~You~can~also~use~the~key~'define-L-C-R'.\\
+    This~error~is~fatal.
+  }
+%    \end{macrocode}
+% 
 %    \begin{macrocode}
 \@@_msg_new:nn { bad~value~for~baseline }
   {
@@ -13712,7 +13949,7 @@ version 2005/12/01 or later.
 \@@_msg_new:nn { Hdotsfor~in~col~0 }
   {
     You~can't~use~\token_to_str:N \Hdotsfor\ in~an~exterior~column~of~
-    the~array.~If~you~go~on,~the~corresponding~dotted~line~won't~be~drawn.
+    the~array.~This~error~is~fatal.
   }
 %    \end{macrocode}
 % 
@@ -13882,6 +14119,7 @@ version 2005/12/01 or later.
     create-extra-nodes,~
     create-medium-nodes,~
     create-large-nodes,~
+    delimiters-color,~
     end-of-row,~
     first-col,~
     first-row,~
@@ -13932,6 +14170,7 @@ version 2005/12/01 or later.
     create-extra-nodes,~
     create-medium-nodes,~
     create-large-nodes,~
+    delimiters-color,~
     extra-left-margin,~
     extra-right-margin,~
     first-col,~
@@ -13989,6 +14228,7 @@ version 2005/12/01 or later.
     create-extra-nodes,~
     create-medium-nodes,~
     create-large-nodes,~
+    delimiters-color,~
     extra-left-margin,~
     extra-right-margin,~
     first-col,~
@@ -14486,6 +14726,12 @@ version 2005/12/01 or later.
 % Different behaviour for the mono-row blocks.
 %
 % New command |\NotEmpty|.
+%
+% \subsection*{Changes between versions 5.6 and 5.7}
+%
+% New key |delimiters-color|
+%
+% Keys |fill|, |draw| and |line-width| for the command |\Block|.
 %  
 % \PrintIndex
 % 
diff --git a/Master/texmf-dist/tex/latex/nicematrix/nicematrix.sty b/Master/texmf-dist/tex/latex/nicematrix/nicematrix.sty
index 595260e2658..a43579d0b61 100644
--- a/Master/texmf-dist/tex/latex/nicematrix/nicematrix.sty
+++ b/Master/texmf-dist/tex/latex/nicematrix/nicematrix.sty
@@ -18,9 +18,8 @@
 %% and version 1.3 or later is part of all distributions of
 %% LaTeX version 2005/12/01 or later.
 %% 
-\def\myfileversion{5.6}
-\def\myfiledate{2020/11/08}
-
+\def\myfileversion{5.7}
+\def\myfiledate{2020/11/23}
 \RequirePackage{pgfcore}
 \usepgfmodule{shapes}
 \RequirePackage{l3keys2e}
@@ -283,6 +282,7 @@
 \int_new:N \l__nicematrix_old_iRow_int
 \int_new:N \l__nicematrix_old_jCol_int
 \tl_new:N \l__nicematrix_rules_color_tl
+\bool_new:N \g__nicematrix_after_col_zero_bool
 \bool_new:N \g__nicematrix_row_of_col_done_bool
 \bool_new:N \g__nicematrix_not_empty_cell_bool
 \tl_new:N \l__nicematrix_code_before_tl
@@ -300,8 +300,12 @@
 \seq_new:N \g__nicematrix_blocks_seq
 \seq_new:N \g__nicematrix_pos_of_blocks_seq
 \seq_new:N \g__nicematrix_pos_of_xdots_seq
+\seq_new:N \g__nicematrix_pos_of_stroken_blocks_seq
 \int_new:N \g__nicematrix_static_num_of_col_int
+\tl_new:N \l__nicematrix_fill_tl
+\tl_new:N \l__nicematrix_draw_tl
 \tl_new:N \l__nicematrix_color_tl
+\dim_new:N \l__nicematrix_line_width_dim
 \tl_new:N \l__nicematrix_pos_of_block_tl
 \tl_set:Nn \l__nicematrix_pos_of_block_tl { c }
 \bool_new:N \l__nicematrix_draw_first_bool
@@ -470,6 +474,7 @@
 \tl_new:N \l__nicematrix_end_of_row_tl
 \tl_set:Nn \l__nicematrix_end_of_row_tl { ; }
 \tl_new:N \l__nicematrix_xdots_color_tl
+\tl_new:N \l__nicematrix_delimiters_color_tl
 \bool_new:N \l__nicematrix_max_delimiter_width_bool
 \keys_define:nn { NiceMatrix / xdots }
   {
@@ -687,6 +692,8 @@
   }
 \keys_define:nn { NiceMatrix / NiceMatrixOptions }
   {
+    delimiters-color .tl_set:N = \l__nicematrix_delimiters_color_tl ,
+    delimiters-color .value_required:n = true ,
     last-col .code:n = \tl_if_empty:nF { #1 }
                          { \__nicematrix_error:n { last-col~non~empty~for~NiceMatrixOptions } }
                        \int_zero:N \l__nicematrix_last_col_int ,
@@ -731,6 +738,8 @@
     r .code:n = \tl_set:Nn \l__nicematrix_type_of_col_tl r ,
     small .bool_set:N = \l__nicematrix_small_bool ,
     small .value_forbidden:n = true ,
+    delimiters-color .tl_set:N = \l__nicematrix_delimiters_color_tl ,
+    delimiters-color .value_required:n = true ,
     unknown .code:n = \__nicematrix_error:n { Unknown~option~for~NiceMatrix }
   }
 \keys_define:nn { NiceMatrix / NiceArray }
@@ -746,6 +755,8 @@
     notes / bottomrule .default:n = true ,
     tabularnote .tl_set:N = \l__nicematrix_tabularnote_tl ,
     tabularnote .value_required:n = true ,
+    delimiters-color .tl_set:N = \l__nicematrix_delimiters_color_tl ,
+    delimiters-color .value_required:n = true ,
     unknown .code:n = \__nicematrix_error:n { Unknown~option~for~NiceArray }
   }
 \keys_define:nn { NiceMatrix / pNiceArray }
@@ -803,7 +814,7 @@
   }
 \cs_new_protected:Npn \__nicematrix_begin_of_row:
   {
-    \int_gincr:N \c@iRow
+    \refstepcounter { iRow }
     \dim_gset_eq:NN \g__nicematrix_dp_ante_last_row_dim \g__nicematrix_dp_last_row_dim
     \dim_gset:Nn \g__nicematrix_dp_last_row_dim { \box_dp:N \@arstrutbox }
     \dim_gset:Nn \g__nicematrix_ht_last_row_dim { \box_ht:N \@arstrutbox }
@@ -986,6 +997,7 @@
 \cs_new_protected:Npn \__nicematrix_everycr_i:
   {
     \int_gzero:N \c@jCol
+    \bool_gset_false:N \g__nicematrix_after_col_zero_bool
     \bool_if:NF \g__nicematrix_row_of_col_done_bool
       {
         \__nicematrix_create_row_node:
@@ -1140,6 +1152,7 @@
       { \dim_gzero_new:N \g__nicematrix_max_cell_width_dim }
     \seq_gclear:N \g__nicematrix_blocks_seq
     \seq_gclear:N \g__nicematrix_pos_of_blocks_seq
+    \seq_gclear:N \g__nicematrix_pos_of_stroken_blocks_seq
     \seq_gclear:N \g__nicematrix_pos_of_xdots_seq
     \tl_if_exist:cT { g__nicematrix_code_before_ \int_use:N \g__nicematrix_env_int _ tl }
       {
@@ -1343,6 +1356,8 @@
         \hbox_set:Nn \l_tmpa_box
           {
             \c_math_toggle_token
+            \tl_if_empty:NF \l__nicematrix_delimiters_color_tl
+              { \color { \l__nicematrix_delimiters_color_tl } }
             \left #1
             \vcenter
               {
@@ -1455,6 +1470,9 @@
         \__nicematrix_w: { \__nicematrix_patch_preamble_v:nnnn { }                          #1 }
         \__nicematrix_W: { \__nicematrix_patch_preamble_v:nnnn { \cs_set_eq:NN \hss \hfil } #1 }
         \__nicematrix_true_c: { \__nicematrix_patch_preamble_vi:n #1 }
+        C { \__nicematrix_error:nn { old~column~type } C }
+        L { \__nicematrix_error:nn { old~column~type } L }
+        R { \__nicematrix_error:nn { old~column~type } R }
         \q_stop { }
       }
       {
@@ -1972,6 +1990,7 @@
   {
     >
       {
+        \bool_gset_true:N \g__nicematrix_after_col_zero_bool
         \__nicematrix_begin_of_row:
         \hbox_set:Nw \l__nicematrix_cell_box
         \__nicematrix_math_toggle_token:
@@ -3107,7 +3126,14 @@
 \cs_new:Npn \__nicematrix_Hdotsfor:
   {
     \int_compare:nNnTF \c@jCol = 0
-      { \__nicematrix_error:n { Hdotsfor~in~col~0 } }
+      {
+        \bool_if:NTF \g__nicematrix_after_col_zero_bool
+          {
+            \multicolumn { 1 } { c } { }
+            \__nicematrix_Hdotsfor_i
+          }
+          { \__nicematrix_fatal:n { Hdotsfor~in~col~0 } }
+      }
       {
         \multicolumn { 1 } { c } { }
         \__nicematrix_Hdotsfor_i
@@ -3614,6 +3640,8 @@
            { \__nicematrix_test_if_vline_in_block:nnnn ##1 }
          \seq_map_inline:Nn \g__nicematrix_pos_of_xdots_seq
            { \__nicematrix_test_if_vline_in_block:nnnn ##1 }
+         \seq_map_inline:Nn \g__nicematrix_pos_of_stroken_blocks_seq
+           { \__nicematrix_test_if_vline_in_stroken_block:nnnn ##1 }
          \clist_if_empty:NF \l__nicematrix_except_corners_clist
            \__nicematrix_test_in_corner_v:
          \bool_if:NTF \g_tmpa_bool
@@ -3734,6 +3762,8 @@
            { \__nicematrix_test_if_hline_in_block:nnnn ##1 }
          \seq_map_inline:Nn \g__nicematrix_pos_of_xdots_seq
            { \__nicematrix_test_if_hline_in_block:nnnn ##1 }
+         \seq_map_inline:Nn \g__nicematrix_pos_of_stroken_blocks_seq
+           { \__nicematrix_test_if_hline_in_stroken_block:nnnn ##1 }
          \clist_if_empty:NF \l__nicematrix_except_corners_clist \__nicematrix_test_in_corner_h:
          \bool_if:NTF \g_tmpa_bool
            {
@@ -3875,6 +3905,28 @@
       }
       { \bool_gset_false:N \g_tmpa_bool }
   }
+\cs_new_protected:Npn \__nicematrix_test_if_hline_in_stroken_block:nnnn #1 #2 #3 #4
+  {
+    \bool_lazy_all:nT
+      {
+        { \int_compare_p:nNn \l_tmpa_tl > { #1 - 1 } }
+        { \int_compare_p:nNn \l_tmpa_tl < { #3 + 2 } }
+        { \int_compare_p:nNn \l_tmpb_tl > { #2 - 1 } }
+        { \int_compare_p:nNn \l_tmpb_tl < { #4 + 1 } }
+      }
+      { \bool_gset_false:N \g_tmpa_bool }
+  }
+\cs_new_protected:Npn \__nicematrix_test_if_vline_in_stroken_block:nnnn #1 #2 #3 #4
+  {
+    \bool_lazy_all:nT
+      {
+        { \int_compare_p:nNn \l_tmpa_tl > { #1 - 1 } }
+        { \int_compare_p:nNn \l_tmpa_tl < { #3 + 1 } }
+        { \int_compare_p:nNn \l_tmpb_tl > { #2 - 1 } }
+        { \int_compare_p:nNn \l_tmpb_tl < { #4 + 2 } }
+      }
+      { \bool_gset_false:N \g_tmpa_bool }
+  }
 \cs_new_protected:Npn \__nicematrix_compute_corners:
   {
     \seq_clear_new:N \l__nicematrix_empty_corner_cells_seq
@@ -4299,6 +4351,8 @@
     r .value_forbidden:n = true ,
     c .code:n = \tl_set:Nn \l__nicematrix_pos_of_block_tl c ,
     c .value_forbidden:n = true ,
+    % color .tl_set:N = \l__nicematrix_color_tl ,
+    % color .value_required:n = true ,
   }
 \NewExpandableDocumentCommand \__nicematrix_Block: { O { } m D < > { } m }
   {
@@ -4308,9 +4362,13 @@
 \cs_new:Npn \__nicematrix_Block_i #1-#2 \q_stop { \__nicematrix_Block_ii:nnnnn { #1 } { #2 } }
 \cs_new_protected:Npn \__nicematrix_Block_ii:nnnnn #1 #2 #3 #4 #5
   {
-    \tl_if_empty:NTF \l__nicematrix_cell_type_tl
+    \int_compare:nNnTF { #2 } = 1
+      {
+        \tl_if_empty:NTF \l__nicematrix_cell_type_tl
+          { \tl_set:Nn \l__nicematrix_pos_of_block_tl c }
+          { \tl_set_eq:NN \l__nicematrix_pos_of_block_tl \l__nicematrix_cell_type_tl }
+      }
       { \tl_set:Nn \l__nicematrix_pos_of_block_tl c }
-      { \tl_set_eq:NN \l__nicematrix_pos_of_block_tl \l__nicematrix_cell_type_tl }
     \keys_set_known:nn { NiceMatrix / Block / FirstPass } { #3 }
     \tl_if_empty:nTF { #1 }
       { \int_set:Nn \l_tmpa_int { 100 } }
@@ -4353,36 +4411,30 @@
     \hbox_gset:cn
       { g__nicematrix_ block _ box _ \int_use:N \g__nicematrix_block_box_int _ box }
       {
-        \int_compare:nNnT { #2 } = 1 \set@color
+        \tl_if_empty:NTF \l__nicematrix_color_tl
+          { \int_compare:nNnT { #2 } = 1 \set@color }
+          { \color { \l__nicematrix_color_tl } }
+        \group_begin:
+        \cs_set:Npn \arraystretch { 1 }
+        \dim_set_eq:NN \extrarowheight \c_zero_dim
+        #4
+        \bool_if:NT \g__nicematrix_rotate_bool { \tl_set:Nn \l__nicematrix_pos_of_block_tl c }
         \bool_if:NTF \l__nicematrix_NiceTabular_bool
           {
-            \group_begin:
-            \cs_set:Npn \arraystretch { 1 }
-            \dim_set_eq:NN \extrarowheight \c_zero_dim
-            #4
-            \bool_if:NT \g__nicematrix_rotate_bool
-              { \tl_set:Nn \l__nicematrix_pos_of_block_tl c }
             \exp_args:Nnx \begin { tabular }
               { @ { } \l__nicematrix_pos_of_block_tl @ { } }
               #5
             \end { tabular }
-            \group_end:
           }
           {
-            \group_begin:
-            \cs_set:Npn \arraystretch { 1 }
-            \dim_set_eq:NN \extrarowheight \c_zero_dim
-            #4
-            \bool_if:NT \g__nicematrix_rotate_bool
-              { \tl_set:Nn \l__nicematrix_pos_of_block_tl c }
             \c_math_toggle_token
             \exp_args:Nnx \begin { array }
               { @ { } \l__nicematrix_pos_of_block_tl @ { } }
               #5
             \end { array }
             \c_math_toggle_token
-            \group_end:
           }
+        \group_end:
       }
     \bool_if:NT \g__nicematrix_rotate_bool
       {
@@ -4476,10 +4528,17 @@
   }
 \keys_define:nn { NiceMatrix / Block / SecondPass }
   {
-    tikz .tl_set:N = \l__nicematrix_tikz_tl ,
-    tikz .value_required:n = true ,
-    color .tl_set:N = \l__nicematrix_color_tl ,
+    fill .tl_set:N = \l__nicematrix_fill_tl ,
+    fill .value_required:n = true ,
+    draw .tl_set:N = \l__nicematrix_draw_tl ,
+    draw .default:n = default ,
+    color .code:n =
+      \__nicematrix_error:n { Key~color~for~Block }
+      \tl_set:Nn \l__nicematrix_fill_tl { #1 } ,
+    % color .code:n = \color { #1 } \tl_set:Nn \l__nicematrix_draw_tl { #1 } ,
     color .value_required:n = true ,
+    line-width .dim_set:N = \l__nicematrix_line_width_dim ,
+    line-width .value_required:n = true ,
     l .code:n = \tl_set:Nn \l__nicematrix_pos_of_block_tl l ,
     l .value_forbidden:n = true ,
     r .code:n = \tl_set:Nn \l__nicematrix_pos_of_block_tl r ,
@@ -4496,7 +4555,7 @@
 \cs_new_protected:Npn \__nicematrix_Block_iii:nnnnnn #1 #2 #3 #4 #5 #6
   {
     \group_begin:
-    \keys_set:nn { NiceMatrix / Block / SecondPass} { #5 }
+    \keys_set:nn { NiceMatrix / Block / SecondPass } { #5 }
     \int_zero_new:N \l__nicematrix_last_row_int
     \int_zero_new:N \l__nicematrix_last_col_int
     \int_compare:nNnTF { #3 } > { 99 }
@@ -4505,12 +4564,26 @@
     \int_compare:nNnTF { #4 } > { 99 }
       { \int_set_eq:NN \l__nicematrix_last_col_int \c@jCol }
       { \int_set:Nn \l__nicematrix_last_col_int { #4 } }
-    \tl_if_empty:NF \l__nicematrix_color_tl
+    \bool_lazy_or:nnT
+      { ! \tl_if_empty_p:N \l__nicematrix_draw_tl }
+      { \dim_compare_p:nNn \l__nicematrix_line_width_dim > \c_zero_dim }
+      {
+        \tl_gput_right:Nx \g_nicematrix_code_after_tl
+          {
+            \__nicematrix_stroke_block:nnn
+              { #5 }
+              { #1 - #2 }
+              { \int_use:N \l__nicematrix_last_row_int - \int_use:N \l__nicematrix_last_col_int }
+          }
+        \seq_gput_right:Nn \g__nicematrix_pos_of_stroken_blocks_seq
+           { { #1 } { #2 } { #3 } { #4 } }
+      }
+    \tl_if_empty:NF \l__nicematrix_fill_tl
       {
         \tl_gput_right:Nx \g_nicematrix_code_before_tl
           {
             \exp_not:N \rectanglecolor
-              { \l__nicematrix_color_tl }
+              { \l__nicematrix_fill_tl }
               { #1 - #2 }
               { \int_use:N \l__nicematrix_last_row_int - \int_use:N \l__nicematrix_last_col_int }
           }
@@ -4546,7 +4619,6 @@
           \__nicematrix_qpoint:n { col - \__nicematrix_succ:n { \l__nicematrix_last_col_int } }
           \dim_set_eq:NN \l_tmpd_dim \pgf@x
           \begin { pgfscope }
-          \exp_args:Nx \pgfset { \l__nicematrix_tikz_tl }
           \__nicematrix_pgf_rect_node:nnnnn
             { \__nicematrix_env: - #1 - #2 - block }
             \l_tmpb_dim \l_tmpa_dim \l_tmpd_dim \l_tmpc_dim
@@ -4640,10 +4712,13 @@
               { \box_use_drop:N \l__nicematrix_cell_box } { } { }
           }
           {
-            \int_compare:nNnT \c@jCol = 0
+            \int_compare:nNnT { #2 } = 0
               { \tl_set:Nn \l__nicematrix_pos_of_block_tl r }
-            \int_compare:nNnT \c@jCol = \l__nicematrix_last_col_int
-              { \tl_set:Nn \l__nicematrix_pos_of_block_tl l }
+            \bool_if:nT \g__nicematrix_last_col_found_bool
+              {
+                \int_compare:nNnT { #2 } = \g__nicematrix_col_total_int
+                  { \tl_set:Nn \l__nicematrix_pos_of_block_tl l }
+              }
             \pgftransformshift
               {
                 \pgfpointanchor
@@ -4674,6 +4749,55 @@
       }
     \group_end:
   }
+\cs_new_protected:Npn \__nicematrix_stroke_block:nnn #1 #2 #3
+  {
+    \group_begin:
+    \tl_clear:N \l__nicematrix_draw_tl
+    \dim_set_eq:NN \l__nicematrix_line_width_dim \arrayrulewidth
+    \keys_set_known:nn { NiceMatrix / BlockStroke } { #1 }
+    \pgfpicture
+    \pgfrememberpicturepositiononpagetrue
+    \pgf@relevantforpicturesizefalse
+    \tl_if_empty:NF \l__nicematrix_draw_tl
+      {
+        \str_if_eq:VnTF \l__nicematrix_draw_tl { default }
+          { \CT@arc@ }
+          { \pgfsetstrokecolor { \l__nicematrix_draw_tl } }
+      }
+    \__nicematrix_cut_on_hyphen:w #2 \q_stop
+    \bool_lazy_and:nnT
+      { \int_compare_p:n { \l_tmpa_tl <= \c@iRow } }
+      { \int_compare_p:n { \l_tmpb_tl <= \c@jCol } }
+      {
+        \__nicematrix_qpoint:n { row - \l_tmpa_tl }
+        \dim_set:Nn \l_tmpb_dim { \pgf@y }
+        \__nicematrix_qpoint:n { col - \l_tmpb_tl }
+        \dim_set:Nn \l_tmpc_dim { \pgf@x }
+        \__nicematrix_cut_on_hyphen:w #3 \q_stop
+        \int_compare:nNnT \l_tmpa_tl > \c@iRow
+          { \tl_set:Nx \l_tmpa_tl { \int_use:N \c@iRow } }
+        \int_compare:nNnT \l_tmpb_tl > \c@jCol
+          { \tl_set:Nx \l_tmpb_tl { \int_use:N \c@jCol } }
+        \__nicematrix_qpoint:n { row - \__nicematrix_succ:n \l_tmpa_tl }
+        \dim_set:Nn \l_tmpa_dim { \pgf@y }
+        \__nicematrix_qpoint:n { col - \__nicematrix_succ:n \l_tmpb_tl }
+        \dim_set:Nn \l_tmpd_dim { \pgf@x }
+        \pgfpathrectanglecorners
+          { \pgfpoint \l_tmpc_dim \l_tmpb_dim }
+          { \pgfpoint \l_tmpd_dim \l_tmpa_dim }
+        \pgfsetlinewidth { 1.1 \l__nicematrix_line_width_dim }
+        \pgfusepathqstroke
+      }
+    \endpgfpicture
+    \group_end:
+  }
+\keys_define:nn { NiceMatrix / BlockStroke }
+  {
+    % color .tl_set:N = \l__nicematrix_draw_tl ,
+    draw .tl_set:N = \l__nicematrix_draw_tl ,
+    draw .default:n = default ,
+    line-width .dim_set:N = \l__nicematrix_line_width_dim ,
+  }
 \cs_set_protected:Npn \__nicematrix_renew_matrix:
   {
     \RenewDocumentEnvironment { pmatrix } { }
@@ -5003,6 +5127,13 @@
     (and~you~try~to~use~'\l_keys_key_tl').~If~you~go~on,~
     this~option~will~be~ignored.
   }
+\__nicematrix_msg_new:nn { Key~color~for~Block }
+  {
+    The~key~'color'~for~the~command~\token_to_str:N \Block\
+    is~deprecated:~you~should~use~'fill'~instead.\\
+    You~can~go~on~for~this~time~but~remember~that~that~key~
+    will~be~deleted~in~a~future~version.
+  }
 \__nicematrix_msg_new:nn { ampersand~in~light-syntax }
   {
     You~can't~use~an~ampersand~(\token_to_str &)~to~separate~columns~because
@@ -5019,6 +5150,13 @@
     The~key~'standard-cline'~is~available~only~in~the~preamble.\\
     If~you~go~on~this~command~will~be~ignored.
   }
+\__nicematrix_msg_new:nn { old~column~type }
+  {
+    The~column~type~'#1'~is~no~longer~defined~in~'nicematrix'.~
+    Since~version~5.0,~you~have~to~use~'l',~'c'~and~'r'~instead~of~'L',~
+    'C'~and~'R'.~You~can~also~use~the~key~'define-L-C-R'.\\
+    This~error~is~fatal.
+  }
 \__nicematrix_msg_new:nn { bad~value~for~baseline }
   {
     The~value~given~to~'baseline'~(\int_use:N \l_tmpa_int)~is~not~
@@ -5037,7 +5175,7 @@
 \__nicematrix_msg_new:nn { Hdotsfor~in~col~0 }
   {
     You~can't~use~\token_to_str:N \Hdotsfor\ in~an~exterior~column~of~
-    the~array.~If~you~go~on,~the~corresponding~dotted~line~won't~be~drawn.
+    the~array.~This~error~is~fatal.
   }
 \__nicematrix_msg_new:nn { bad~corner }
   {
@@ -5158,6 +5296,7 @@
     create-extra-nodes,~
     create-medium-nodes,~
     create-large-nodes,~
+    delimiters-color,~
     end-of-row,~
     first-col,~
     first-row,~
@@ -5205,6 +5344,7 @@
     create-extra-nodes,~
     create-medium-nodes,~
     create-large-nodes,~
+    delimiters-color,~
     extra-left-margin,~
     extra-right-margin,~
     first-col,~
@@ -5255,6 +5395,7 @@
     create-extra-nodes,~
     create-medium-nodes,~
     create-large-nodes,~
+    delimiters-color,~
     extra-left-margin,~
     extra-right-margin,~
     first-col,~