nicematrix (31mar18)

git-svn-id: svn://tug.org/texlive/trunk@47232 c570f23f-e606-0410-a88d-b1316a301751

1 files changed, 513 insertions, 245 deletions

diff --git a/Master/texmf-dist/source/latex/nicematrix/nicematrix.dtx b/Master/texmf-dist/source/latex/nicematrix/nicematrix.dtx
index 257e1e03a69..c6f81ecfd46 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{1.2}
-\def\myfiledate{2018/03/11}
+\def\myfileversion{1.3}
+\def\myfiledate{2018/03/31}
 %
 %
 %<*batchfile>
@@ -69,15 +69,14 @@ version 2005/12/01 or later.
 % \maketitle
 %
 % \begin{abstract}
-% The LaTeX package \pkg{nicematrix} provides environments |{NiceArray}| and |{NiceMatrix}| similar to the
-% classical environments |{array}| and |{matrix}| but with the possibility to draw continuous ellipsis dots between
-% the cells of the array.
+% The LaTeX package \pkg{nicematrix} provides new environments similar to the classical environments |{array}| and
+% |{matrix}| but with some additional features. Among these features is the possibility to draw continuous ellipsis
+% dots between the cells of the array.
 % \end{abstract}
 %
 % \vspace{1cm}
 % \section{Presentation}
 %
-%       
 %
 % This package can be used with |xelatex|, |lualatex|, |pdflatex| but also by the classical workflow
 % |latex|-|dvips|-|ps2pdf| (or Adobe Distiller). Two compilations may be necessary. This package requires the
@@ -108,11 +107,11 @@ version 2005/12/01 or later.
 % \end{Verbatim}
 % 
 % \medskip 
-% If we load the package \pkg{nicematrix} with the option |Transparent|, the same code will give the
+% If we load the package \pkg{nicematrix} with the option |transparent|, the same code will give the
 % following result:
 % 
 % \begin{scope}
-% \NiceMatrixOptions{Transparent}
+% \NiceMatrixOptions{transparent}
 % \[A = \begin{pmatrix}
 % 1      & \cdots & \cdots & 1      \\
 % 0      & \ddots &        & \vdots \\
@@ -123,33 +122,26 @@ version 2005/12/01 or later.
 %
 % \medskip
 % The dotted lines are drawn with Tikz. Two compilations may be necessary.
+% 
+% \medskip
+% A command |\NiceMatrixOptions| is provided to fix the options (the scope of the options fixed by this command is
+% the current TeX group).
 %
 %
-% \section{How to use nicematrix for new code}
-%
-% \subsection{The environments NiceArray, NiceMatrix and their variants} 
-%
-% The package \pkg{nicematrix} provides new environments |{NiceArray}|, |{NiceMatrix}|, |{pNiceMatrix}|,
-% |{bNiceMatrix}|, |{BNiceMatrix}|, |{vNiceMatrix}| and |{VNiceMatrix}|. 
-%
-% The environment |{NiceArray}| is similar to the environment |{array}| defined in LaTeX and redefined in the package
-% \pkg{array}. The environments |{NiceMatrix}|, |{pNiceMatrix}|, etc. are similar to the environments |{matrix}|,
-% |{pmatrix}|, etc. of \pkg{amsmath} (and \pkg{mathtools}).
+% \section{How to use \{NiceMatrix\} for new code}
 %
-% The environment |{NiceMatrix}| has the same syntax that the environment |{matrix}| (idem for the variants).
-% However, for the environment |{NiceArray}|, there is a difference: in the preamble of |{NiceArray}|, the user
-% must use the letters |L|, |C| and |R|\footnote{The column types |L|, |C| and |R| are defined locally inside
-% |{NiceArray}| with |\newcolumntype| of \pkg{array}. This definition overrides an eventual previous definition.}
-% instead of |l|, |c| and |r|. It's possible to use the constructions \verb+|+, |>{...}|, |<{...}|, |@{...}|,
-% |!{...}| and |*{n}{...}| but the letters |p|, |m| and |b| should not be used.
+% \subsection{The environment \{NiceMatrix\} and its variants} 
 % 
+% The package \pkg{nicematrix} provides new environments |{NiceMatrix}|, |{pNiceMatrix}|, |{bNiceMatrix}|,
+% |{BNiceMatrix}|, |{vNiceMatrix}| and |{VNiceMatrix}|. By default, these environments behave almost exactly as the
+% corresponding environments of \pkg{amsmath} (and \pkg{mathtools}): |{matrix}|, |{pmatrix}|, |{bmatrix}|,
+% |{Bmatrix}|, |{vmatrix}| and |{Vmatrix}|.
+%
 % \smallskip
-% Inside the new environments defined by the package \pkg{nicematrix}, five commands are defined: |\Ldots|,
-% |\Cdots|, |\Vdots|, |\Ddots| and |\Iddots|. These commands are intended to be used in place of |\dots|, |\cdots|,
-% |\vdots|, |\ddots| and |\iddots|.\footnote{The command |\iddots|, defined in \pkg{nicematrix}, is a variant of
-% |\ddots| with dots going forward: \smash{$\iddots$}. If the command |\iddots| is already defined (for example if
-% \pkg{mathdots} is loaded), the previous definition is not overwritten. Note that the package \pkg{yhmath}
-% provides a command |\adots| similar to |\iddots|.}
+% Inside these environments, five new commands are defined: |\Ldots|, |\Cdots|, |\Vdots|, |\Ddots| and |\Iddots|.
+% These commands are intended to be used in place of |\dots|, |\cdots|, |\vdots|, |\ddots| and
+% |\iddots|.\footnote{The command |\iddots|, defined in \pkg{nicematrix}, is a variant of 
+% |\ddots| with dots going forward: \smash{$\iddots$}. If |mathdots| is loaded, the version of |mathdots| is used.}
 %
 % \smallskip
 % Each of them must be used alone in the cell of the array and it draws a dotted line between the first non-empty
@@ -274,7 +266,7 @@ version 2005/12/01 or later.
 % \end{bNiceMatrix}$
 % 
 % \vskip1cm
-% \subsection{The option NullifyDots}
+% \subsection{The option nullify-dots}
 %
 % Consider the following matrix composed classicaly with the environment |{pmatrix}|.\par\nobreak
 % \medskip
@@ -345,12 +337,11 @@ version 2005/12/01 or later.
 %
 % \bigskip
 % However, one may prefer the geometry of the first matrix $A$ and would like to have such a geometry with a dotted
-% line in the second column. It's possible by using the option |NullifyDots| (and only one instruction |\Vdots| is
+% line in the second column. It's possible by using the option |nullify-dots| (and only one instruction |\Vdots| is
 % necessary).\par\nobreak
 % \medskip
 % \begin{BVerbatim}[baseline=c,boxwidth=7cm]
-% ~emphase#\NiceMatrixOptions{NullifyDots}@
-% $D = \begin{pNiceMatrix}
+% $D = \begin{pNiceMatrix}[~emphase#nullify-dots@]
 % a_0 & b      \\
 % a_1 & \Vdots \\
 % a_2 &        \\
@@ -359,48 +350,47 @@ version 2005/12/01 or later.
 % a_5 & b
 % \end{pNiceMatrix}$
 % \end{BVerbatim}
-% {\NiceMatrixOptions{NullifyDots}
-% $D = \begin{pNiceMatrix}
+% $D = \begin{pNiceMatrix}[nullify-dots]
 % a_0 & b      \\
 % a_1 & \Vdots \\
 % a_2 &        \\
 % a_3 &        \\
 % a_4 &        \\
 % a_5 & b
-% \end{pNiceMatrix}$}
+% \end{pNiceMatrix}$
 %
 % \medskip
-% The option |NullifyDots| smashes the instructions |\Ldots| (and the variants) vertically but also horizontally.
+% The option |nullify-dots| smashes the instructions |\Ldots| (and the variants) vertically but also horizontally.
 %
 % \section{How to use nicematrix for existing code}
 %
-% The package \pkg{nicematrix} provides an option called |Transparent| for using existing code transparently in the
-% environments |{matrix}| (not in the environments |{array}|). This option can be set as option of |\usepackage| or
-% with the dedicated command called |\NiceMatrixOptions|.
+% The package \pkg{nicematrix} provides an option called |transparent| for using existing code transparently in the
+% environments |{matrix}|. This option can be set as option of |\usepackage| or with the command
+% |\NiceMatrixOptions|.
 % 
 %
-% In fact, this option is an alias for the conjonction of two options: |RenewDots| and |RenewMatrix|.
+% In fact, this option is an alias for the conjonction of two options: |renew-dots| and |renew-matrix|.
 %
 % \smallskip
 %
 % \begin{itemize}
-% \item The option |RenewDots|\par\nobreak
+% \item The option |renew-dots|\par\nobreak
 % With this option, the commands |\ldots|, |\cdots|, |\vdots|, |\ddots| and |\iddots|\footnote{The command
 % |\iddots| is not a command of LaTeX but is defined by the package \pkg{nicematrix}. If |mathdots| is loaded, the
-% version of |mathdots| is used.} are redefined within the environments |{NiceArray}|, |{NiceMatrix}| and its
-% variants and behave like |\Ldots|, |\Cdots|, |\Vdots|, |\Ddots| and |\Iddots|; the command |\dots| (``automatic
+% version of |mathdots| is used.} are redefined within the environments provided by \pkg{nicematrix} 
+% and behave like |\Ldots|, |\Cdots|, |\Vdots|, |\Ddots| and |\Iddots|; the command |\dots| (``automatic
 % dots'' of |amsmath| --- and |mathtools|) is also redefined to behave like |\Ldots|.
 %
-% \item  The option |RenewMatrix|\par\nobreak
+% \item  The option |renew-matrix|\par\nobreak
 % With this option, the environment |{matrix}| is redefined and behave like |{NiceMatrix}|, and so on for the five
 % variants.
 % \end{itemize}
 %
 % \bigskip 
-% Therefore, with the option |Transparent|, a classical code gives directly the ouput of \pkg{nicematrix}.\par\nobreak
+% Therefore, with the option |transparent|, a classical code gives directly the ouput of \pkg{nicematrix}.\par\nobreak
 % \bigskip
 % \begin{BVerbatim}[baseline=c]
-% ~emphase#\NiceMatrixOptions{Transparent}@
+% ~emphase#\NiceMatrixOptions{transparent}@
 % \begin{pmatrix}
 % 1      & \cdots & \cdots & 1      \\
 % 0      & \ddots &        & \vdots \\
@@ -410,7 +400,7 @@ version 2005/12/01 or later.
 % \end{BVerbatim}
 % \hspace{2cm}
 % \begin{scope}
-% \NiceMatrixOptions{Transparent}
+% \NiceMatrixOptions{transparent}
 % $\begin{pmatrix}
 % 1      & \cdots & \cdots & 1      \\
 % 0      & \ddots &        & \vdots \\
@@ -419,14 +409,141 @@ version 2005/12/01 or later.
 % \end{pmatrix}$
 % \end{scope}
 %
+%
+% \section{The environment \{NiceArray\}}
+%
+% In fact, the environment |{NiceMatrix}| relies upon an environment |{NiceArray}| defined in the package
+% \pkg{nicematrix}.
+%
+% \medskip
+% This environment |{NiceArray}| itself relies upon the environment |{array}| of the package \pkg{array}.\footnote{The
+% environment |{array}| is defined in standard LaTeX but is redefined in the package \pkg{array} (loaded by
+% \pkg{nicematrix}).} 
+% 
+% \medskip
+% The differences between |{NiceArray}| and |{array}| are as follow.
+% \begin{itemize}
+% \item The commands |\Cdots| and its variants are available in the environment |{NiceArray}|.
+% \item The environment |{NiceArray}| accepts (between brackets) the options |t|, |c| and |b| as the classical
+% |{array}| but also the following options defined by \pkg{nicematrix}: |renew-dots|, |nullify-dots|,
+% |exterior-arraycolsep| and |parallelize-diags| (these last two options are technical options described further).
+% \item For technical reasons, in the preamble of |{NiceArray}|, the user
+% must use the letters |L|, |C| and |R|\footnote{The column types |L|, |C| and |R| are defined locally inside
+% |{NiceArray}| with |\newcolumntype| of \pkg{array}. This definition overrides an eventual previous definition.}
+% instead of |l|, |c| and |r|. It's possible to use the constructions \verb+|+, |>{...}|, |<{...}|, |@{...}|,
+% |!{...}| and |*{n}{...}| but the letters |p|, |m| and |b| should not be used.
+% \end{itemize}
+%
+% 
+% \vspace{1cm}
+% An example with a linear system (we need |{NiceArray}| for the vertical rule):
+%
+% \bigskip
+% \begin{BVerbatim}[baseline=c]
+% $\left[\begin{NiceArray}{CCCC|C}
+% a_1    & ?      & \Cdots & ?       & ?     \\
+% 0      &        & \Ddots & \Vdots  & \Vdots\\
+% \Vdots & \Ddots & \Ddots & ? \\ 
+% 0      & \Cdots & 0      & a_n     & ?     \\
+% \end{NiceArray}\right]$
+% \end{BVerbatim}
+% \hspace{2.5cm}
+% $\left[\begin{NiceArray}{CCCC|C}
+% a_1    & ?      & \Cdots & ?       & ?     \\
+% 0      &        & \Ddots & \Vdots  & \Vdots\\
+% \Vdots & \Ddots & \Ddots & ? \\ 
+% 0      & \Cdots & 0      & a_n     & ?     \\
+% \end{NiceArray}\right]$
+%
+% \vspace{1cm}
+% An example where we use |{NiceArray}| because we want to use the types |L| and |R| for the columns:
+%
+% \bigskip
+% \begin{BVerbatim}[baseline=c]
+% $\left(\begin{NiceArray}{LCR}
+% a_{11}    & \Cdots & a_{1n} \\
+% a_{21}    &        & a_{2n} \\
+% \Vdots    &        & \Vdots \\
+% a_{n-1,1} & \Cdots & a_{n-1,n} \\
+% \end{NiceArray}\right)$
+% \end{BVerbatim}
+% \hspace{4cm}
+% $\left(\begin{NiceArray}{LCR}
+% a_{11}    & \Cdots & a_{1n} \\
+% a_{21}    &        & a_{2n} \\
+% \Vdots    &        & \Vdots \\
+% a_{n-1,1} & \Cdots & a_{n-1,n} \\
+% \end{NiceArray}\right)$
+%
+%
+% \section{The environment \{pNiceArrayC\} and its variants}
+%
+% The package \pkg{nicematrix} provides also environments to compose matrices with an exterior column, that is to
+% say on the right of the closing delimiter. These environments are |{pNiceArrayC}|, |{vNiceArrayC}|,
+% |{VNiceArrayC}|, |{bNiceArrayC}| and |{BNiceArrayC}| (there is no environment |{NiceArrayC}| since such an
+% environment would logically be equivalent to |{NiceArray}|).
+% 
+% All these environments have the same characteristics even if, for sake of simplicity, we will speak only of
+% |{pNiceArrayC}|.
+%
+% \medskip
+% \begin{itemize}
+% \item The command |\Cdots| and its variants are available in |{pNiceArrayC}|.
+% \item The environment |{pNiceArrayC}| takes a mandatory argument which is the preamble of the array. The types
+% of columns available are the same as for the environment |{NiceArray}|. \emph{However, no specification must be
+% given for the last column:} it will automatically (and necessarily) be a column~|L|. 
+% \item The options available are |renew-dots|, |nullify-dots|, |parallelize-diags| (this technical option is
+% described further) and |code-for-last-col|. This last option specifies tokens that will be inserted before each
+% cell of the last column, \emph{before} the symbol |$| of the math mode.
+% \end{itemize}
+% 
+% 
+% \bigskip
+% \begin{BVerbatim}[baseline=c]
+% \begin{pNiceArrayC}{RRRR|R}[~emphase#code-for-last-col={\small\color{blue}}@]
+% 1&  2&  2& 3& -2                      \\
+% 0&  0& -1& 5& -5 & L_2 \gets 2L_1-L_2 \\
+% 0& -1& -3& 3& -7 & L_3 \gets L_1-L_3  
+% \end{pNiceArrayC}
+% \end{BVerbatim}
+%
+% \smallskip
+% \[\begin{pNiceArrayC}{RRRR|R}[code-for-last-col={\small\color{blue}}]
+% 1&  2&  2& 3& -2                      \\
+% 0&  0& -1& 5& -5 & L_2 \gets 2L_1-L_2 \\
+% 0& -1& -3& 3& -7 & L_3 \gets L_1-L_3  
+% \end{pNiceArrayC}\]
+%
+% \bigskip
+%
+% \begin{Verbatim}
+% $\begin{pNiceArrayC}{*6C|C}[nullify-dots,code-for-last-col={\small}]
+% 1      & 1 & 1 &\Cdots &   & 1      & 0      & \\
+% 0      & 1 & 0 &\Cdots &   & 0      &        & L_2 \gets L_2-L_1 \\
+% 0      & 0 & 1 &\Ddots &   & \Vdots &        & L_3 \gets L_3-L_1 \\
+%        &   &   &\Ddots &   &        & \Vdots & \Vdots \\
+% \Vdots &   &   &\Ddots &   & 0      & \\
+% 0      &   &   &\Cdots & 0 & 1      & 0      & L_n \gets L_n-L_1 
+% \end{pNiceArrayC}$
+% \end{Verbatim}
+% 
+% \[\begin{pNiceArrayC}{*6C|C}[nullify-dots,code-for-last-col={\small}]
+% 1      & 1 & 1 &\Cdots &   & 1      & 0      & \\
+% 0      & 1 & 0 &\Cdots &   & 0      &        & L_2 \gets L_2-L_1 \\
+% 0      & 0 & 1 &\Ddots &   & \Vdots &        & L_3 \gets L_3-L_1 \\
+%        &   &   &\Ddots &   &        & \Vdots & \Vdots \\
+% \Vdots &   &   &\Ddots &   & 0      & \\
+% 0      &   &   &\Cdots & 0 & 1      & 0      & L_n \gets L_n-L_1 
+% \end{pNiceArrayC}\]
+% 
 % 
 % \section{Technical remarks}
 %
 % \subsection{Diagonal lines} 
 %
-% By default, all the diagonal lines of a same matrix are ``parallelized''. That means that the first diagonal line
+% By default, all the diagonal lines of a same array are ``parallelized''. That means that the first diagonal line
 % is drawn and, then, the other lines are drawn parallel to the first one (by rotation around the left-most
-% extremity of the line). That's why the position of the instructions |\Ddots| in the matrix can have a marked
+% extremity of the line). That's why the position of the instructions |\Ddots| in the array can have a marked
 % effect on the final result.
 %
 % \medskip
@@ -453,7 +570,7 @@ version 2005/12/01 or later.
 % \end{pNiceMatrix}$
 % 
 % \bigskip
-% \NiceMatrixOptions{ParallelizeDiagonals=true}%
+% \NiceMatrixOptions{parallelize-diags=true}%
 % \begin{minipage}{9.5cm}
 % % \begin{Verbatim}
 % $A = \begin{pNiceMatrix}
@@ -472,13 +589,12 @@ version 2005/12/01 or later.
 % \end{pNiceMatrix}$
 %
 % \bigskip
-% It's possible to turn off the parallelization with the option |ParallelizeDiagonals| set to |false|: \par\nobreak 
+% It's possible to turn off the parallelization with the option |parallelize-diags| set to |false|: \par\nobreak 
 %
 % \medskip
-% \NiceMatrixOptions{ParallelizeDiagonals=false}%
+% \NiceMatrixOptions{parallelize-diags=false}%
 % \begin{minipage}{9.5cm}
-% The same example without parallelization:\\
-% |\NiceMatrixOptions{ParallelizeDiagonals=false}|. 
+% The same example without parallelization:
 % \end{minipage}
 % $A = \begin{pNiceMatrix}
 % 1      & \Cdots  &     & 1      \\
@@ -495,7 +611,7 @@ version 2005/12/01 or later.
 % 
 % An instruction like |\Ldots|, |\Cdots|, etc. tries to determine the first non-empty cell on both
 % sides\footnote{If \pkg{nicematrix} can't find theses cells, an error |Imposible instruction| is raised. Nevertheless,
-% with the option |Silent|, these instructions are discarded silently.}. However, a empty cell is not necessarily a
+% with the option |silent|, these instructions are discarded silently.}. However, a empty cell is not necessarily a
 % cell with no TeX content (that is to say a cell with no token between the two ampersands~|&|). Indeed, a cell
 % with contents |\hspace*{1cm}| may be considered as empty.
 %
@@ -523,32 +639,32 @@ version 2005/12/01 or later.
 %
 % \medskip
 % \item A cell with a command |\Hspace| (or |\Hspace*|) is empty. This command |\Hspace| is a command defined by
-% the package \pkg{nicematrix} with the same meaning that |\hspace| except that the cell where it is used is
+% the package \pkg{nicematrix} with the same meaning as |\hspace| except that the cell where it is used is
 % considered as empty. This command can be used to fix the width of some columns of the matrix without interfering
 % with \pkg{nicematrix}.
 % % \end{itemize}
 %
 % \interitem
 % A dotted line must be delimited by two non-empty cells. If it's not possible to find one of these cells whitin
-% the boudaries of the matrix, an error is issued and the instruction is ignored.
+% the boundaries of the matrix, an error is issued and the instruction is ignored.
 %
 % \vspace{1cm}
 % \subsection{The option exterior-arraycolsep}
 % 
 % The environment |{array}| inserts un horizontal space equal to |\arraycolsep| before and after each column. In
 % particular, there is a space equal to |\arraycolsep| before and after the array. This feature of the environment
-% |{array}| was probably not a good idea.\footnote{In the documentation of |{amsmath}|, we can read: \itshape The
+% |{array}| was probably not a good idea.\footnote{In the documentation of |{amsmath}|, we can read: {\itshape The
 % extra space of |\arraycolsep| that \pkg{array} adds on each side is a waste so we remove it [in |{matrix}|]
-% (perhaps we should instead remove it from array in general, but that's a harder task).}
+% (perhaps we should instead remove it from array in general, but that's a harder task).} It's possible to suppress
+% these spaces for a given environment |{array}| with a construction like |\begin{array}{@{}ccccc@{}}|.}
 %
 % The environment |{matrix}| and its variants (|{pmatrix}|, |{vmatrix}|, etc.) of \pkg{amsmath} and \pkg{mathtools}
 % prefer to delete these spaces with explicit instructions |\hskip -\arraycolsep| and |{NiceArray}| does likewise.
 %
-% However, the user can change this behaviour with the boolean option |exterior-arraycolsep|. With this option
-% \footnote{The option |exterior-arraycolsep| can be set globally with |\NiceMatrixOptions| but also locally as an
-% option of a given environment |{NiceArray}|. In this case, it's also possible to give the traditionnal option
-% |t|, |c| or |b| of a environment |{array}|: |\begin{NiceArray}[exterior-arraycolsep,t]...|}, the environment
-% |{NiceArray}| will insert the sames horizontal spaces as the environment |{array}| of LaTeX and \pkg{array}.
+% However, the user can change this behaviour with the boolean option |exterior-arraycolsep|. With this option,
+% |{NiceArray}| will insert the same horizontal spaces as the environment |{array}|. This
+% option can be set as an option of an environment |{NiceArray}| (between square brackets) or with the command
+% |\NiceMatrixOptions|. 
 %
 %
 % \section{Examples}
@@ -558,8 +674,7 @@ version 2005/12/01 or later.
 % 
 % \bigskip
 % \begin{BVerbatim}[baseline=c]
-% \NiceMatrixOptions{NullifyDots}
-% $\begin{pNiceMatrix}
+% $\begin{pNiceMatrix}[nullify-dots]
 % a      & b      & 0      &        & \Cdots & 0      \\ 
 % b      & a      & b      & \Ddots &        & \Vdots \\
 % 0      & b      & a      & \Ddots &        &        \\
@@ -569,9 +684,7 @@ version 2005/12/01 or later.
 % \end{pNiceMatrix}$
 % \end{BVerbatim}
 % \hspace{1.5cm}
-% \begin{scope}
-% \NiceMatrixOptions{NullifyDots}
-% $\begin{pNiceMatrix}
+% $\begin{pNiceMatrix}[nullify-dots]
 % a      & b      & 0      &        & \Cdots & 0      \\ 
 % b      & a      & b      & \Ddots &        & \Vdots \\
 % 0      & b      & a      & \Ddots &        &        \\
@@ -579,7 +692,6 @@ version 2005/12/01 or later.
 % \Vdots &        &        &        &        & b      \\
 % 0      & \Cdots &        & 0      & b      & a
 % \end{pNiceMatrix}$
-% \end{scope}
 %
 % \vspace{2cm}
 %
@@ -628,87 +740,27 @@ version 2005/12/01 or later.
 % \end{pNiceMatrix}$
 %
 %
-% 
-% 
-% \vspace{2cm}
-% An example with a linear system (we need |{NiceArray}| for the vertical line):
-%
-% \bigskip
-% \begin{BVerbatim}[baseline=c]
-% $\left[\begin{NiceArray}{CCCC|C}
-% a_1    & ?      & \Cdots & ?       & ?     \\
-% 0      &        & \Ddots & \Vdots  & \Vdots\\
-% \Vdots & \Ddots & \Ddots & ? \\ 
-% 0      & \Cdots & 0      & a_n     & ?     \\
-% \end{NiceArray}\right]$
-% \end{BVerbatim}
-% \hspace{2.5cm}
-% $\left[\begin{NiceArray}{CCCC|C}
-% a_1    & ?      & \Cdots & ?       & ?     \\
-% 0      &        & \Ddots & \Vdots  & \Vdots\\
-% \Vdots & \Ddots & \Ddots & ? \\ 
-% 0      & \Cdots & 0      & a_n     & ?     \\
-% \end{NiceArray}\right]$
-%
-% \vspace{2cm} 
-% An example where we use |{NiceArray}| because we want to use the types |L| and |R| for the columns:
-%
-% \bigskip
-% \begin{BVerbatim}[baseline=c]
-% $\left(\begin{NiceArray}{LCR}
-% a_{11}    & \Cdots & a_{1n} \\
-% a_{21}    &        & a_{2n} \\
-% \Vdots    &        & \Vdots \\
-% a_{n-1,1} & \Cdots & a_{n-1,n} \\
-% \end{NiceArray}\right)$
-% \end{BVerbatim}
-% \hspace{4cm}
-% $\left(\begin{NiceArray}{LCR}
-% a_{11}    & \Cdots & a_{1n} \\
-% a_{21}    &        & a_{2n} \\
-% \Vdots    &        & \Vdots \\
-% a_{n-1,1} & \Cdots & a_{n-1,n} \\
-% \end{NiceArray}\right)$
-%
-%
-% \vspace{2cm}
-%
-% Another example with |{NiceArray}|: 
 %
-% \begin{Verbatim}
-% \left(\begin{~emphase#NiceArray@}{*4{C}|*4{C}}
-% 1     &\Cdots&      &1     &2     &\Cdots&      &2     \\
-% \Vdots&      &      &      &      &      &      &\Vdots\\
-%       &      &      &\Vdots&\Vdots&      &      &      \\
-% 1     &      &\Cdots&1     &      &      &      &      \\
-% \cline{1-4}
-% 0     &\Cdots&      &0     &      &      &      &      \\
-% \Vdots&      &      &      &      &      &      &      \\
-%       &      &      &\Vdots&\Vdots&      &      &      \\
-% 0     &      &\Cdots&0     &2     &      &\Cdots&2     
-% \end{~emphase#NiceArray@}\right)
-% \end{Verbatim}
-% 
 % 
-%\[A=\left(\begin{NiceArray}{*4{C}|*4{C}}
-% 1     &\Cdots&      &1     &2     &\Cdots&      &2     \\
-% \Vdots&      &      &      &      &      &      &\Vdots\\
-%       &      &      &\Vdots&\Vdots&      &      &      \\
-% 1     &      &\Cdots&1     &      &      &      &      \\
-% \cline{1-4}
-% 0     &\Cdots&      &0     &      &      &      &      \\
-% \Vdots&      &      &      &      &      &      &      \\
-%       &      &      &\Vdots&\Vdots&      &      &      \\
-% 0     &      &\Cdots&0     &2     &      &\Cdots&2     
-% \end{NiceArray}\right)\]
+% \vspace{1cm}
 %
+% \section{Implementation}
 %
+% By default, the package \pkg{nicematrix} doesn't patch any existing code.
 %
-% 
-% 
-% \vspace{1cm}
+% \smallskip
+% However, when the option |renew-dots| is used, the commands |\cdots|, |\ldots|, |\dots|, |\vdots|, |\ddots| and
+% |\iddots| are redefined in the environments provided by \pkg{nicematrix} as explained previously. In the same way,
+% if the option |renew-matrix| is used, the environment |{matrix}| of \pkg{amsmath} (and \pkg{mathtools}) is
+% redefined.
 %
-% \section{Implementation}
+% \smallskip
+% On the other hand, the environnement |{array}| is never redefined.
+%
+% \smallskip
+% Of course, the package \pkg{nicematrix} uses the features of the package \pkg{array}. It tries to be independant of its
+% implementation. Unfortunately, it was not possible to be strictly independant: the package \pkg{nicematrix} relies upon the
+% fact that the package |{array}| uses |\ialign| to begin the |\halign|.
 %
 % \subsection{Declaration of the package and extensions loaded}
 %
@@ -763,12 +815,12 @@ version 2005/12/01 or later.
 %
 % \bigskip
 % In the environment |{NiceMatrix}|, the command |\multicolumn| will be linked to the following command
-% |\@@_multicolumn:| but only if the option |RenewMatrix| is not set. Indeed, if the option |RenewMatrix| is used,
+% |\@@_multicolumn:| but only if the option |renew-matrix| is not set. Indeed, if the option |renew-matrix| is used,
 % we want to let the possibility to the user to use |\multicolumn| (or |\hdotsfor| of \pkg{amsmath}) in some
 % matrices without dotted lines and to have the automatic dotted lines of \pkg{nicematrix} in other matrices.
 %    \begin{macrocode}
 \cs_new_protected:Nn \@@_multicolumn:nn
-       {\msg_error:nn {nicematrix} {multicolumn~forbidden}}
+       {\msg_error:nn {nicematrix} {Multicolumn~forbidden}}
 %    \end{macrocode}
 % This command |\@@_multicolumn:nn| takes two arguments, and therefore, the first two arguments of |\column| will
 % be gobbled.
@@ -783,9 +835,18 @@ version 2005/12/01 or later.
 % \bigskip
 % \subsection{The options}
 %
+% The token list |\l_@@_pos_env_tl| will contains one of the three values |t|, |c| or |b| and will indicate to
+% position of the environment as in the option of the environment |{array}|. For the environment |{NiceMatrix}|
+% (and its variants) and |{pNiceArrayC}| (and its variants), the value will programmatically be fixed to |c|. For the
+% environment |{NiceArray}|, however, the three values |t|, |c| and |b| are possible.
+%    \begin{macrocode}
+\tl_new:N \l_@@_pos_env_tl 
+\tl_set:Nn \l_@@_pos_env_tl c
+%    \end{macrocode}
+% 
 % The boolean |\l_@@_exterior_arraycolsep_bool| corresponds to the option |exterior-arraycolsep|. If this option is
-% set, a space equal to |\arraycolsep| will be put on both sides of an environment |{NiceArray}| (but not for
-% |{NiceMatrix}| and its variants).
+% set, a space equal to |\arraycolsep| will be put on both sides of an environment |{NiceArray}| (but neither for
+% |{NiceMatrix}| and its variants nor |{pNiceArrayC}| and its variants even if these environments relies upon |{NiceArray}|).
 %    \begin{macrocode}
 \bool_new:N \l_@@_exterior_arraycolsep_bool
 %    \end{macrocode}
@@ -799,7 +860,7 @@ version 2005/12/01 or later.
 %    \end{macrocode}
 %
 % \bigskip
-% The flag |\l_@@_nullify_dots_bool| corresponds to the option |NullifyDots|. When the flag is down, the
+% The flag |\l_@@_nullify_dots_bool| corresponds to the option |nullify-dots|. When the flag is down, the
 % instructions like |\vdots| are inserted within a |\hphantom| (and so the constructed matrix has exactly the same
 % size as a matrix constructed with the classical |{matrix}| and |\ldots|, |\vdots|, etc.)
 %    \begin{macrocode}
@@ -807,76 +868,140 @@ version 2005/12/01 or later.
 %    \end{macrocode}
 %
 % \bigskip
-% The flag |\l_@@_renew_matrix_bool| will be raised if the option |RenewMatrix| is used.
+% The flag |\l_@@_renew_matrix_bool| will be raised if the option |renew-matrix| is used.
 %    \begin{macrocode}
 \bool_new:N \l_@@_renew_matrix_bool
 %    \end{macrocode}
 %
 % \bigskip
-% We define a set of options which will be used with the command |NiceMatrixOptions|.
+% The token list |\l_@@_code_for_last_col_tl| will contains code inserted at the beginning of each cell\footnote{At
+% the beginning of each cell but before the character |$| of the mathematical mode.} of the last
+% column in the environment |{pNiceArrayC}| (and its variants). It corresponds to the option |code-for-last-col|.
+%    \begin{macrocode}
+\tl_new:N \l_@@_code_for_last_col_tl
+%    \end{macrocode}
+% 
+% \bigskip
+% We define a set of options which will be used with the command |NiceMatrixOptions|.\footnote{Before the version
+% 1.3, the names of the options were in ``caml style'' (like |ParallelizeDiagonals|) which was not a good idea. In
+% version 1.4, the names are converted in lowercase with hyphens (like |parallelize-diags|). For compatibility, the
+% old names are conversed.}
 %    \begin{macrocode}
-\keys_define:nn {NiceMatrix}
-     {ParallelizeDiagonals .bool_set:N = \l_@@_parallelize_diags_bool,
-      ParallelizeDiagonals .default:n  = true,
+\keys_define:nn {NiceMatrix/NiceMatrixOptions}
+     {parallelize-diags    .bool_set:N = \l_@@_parallelize_diags_bool,
+      parallelize-diags    .default:n  = true,
+      ParallelizeDiagonals .meta:n = parallelize-diags,
 %    \end{macrocode}
 %
 % \bigskip
-% With the option |RenewDots|, the command |\cdots|, |\ldots|, |\vdots| and |\ddots| are redefined and behave like the
+% With the option |renew-dots|, the command |\cdots|, |\ldots|, |\vdots| and |\ddots| are redefined and behave like the
 % commands |\Cdots|, |\Ldots|, |\Vdots| and |\Ddots|.
 %    \begin{macrocode}
-      RenewDots            .bool_set:N = \l_@@_renew_dots_bool,
-      RenewDots            .default:n  = true,
+      renew-dots        .bool_set:N = \l_@@_renew_dots_bool,
+      renew-dots        .default:n  = true,
+      RenewDots         .meta:n = renew-dots,
 %    \end{macrocode}
 %
 % \bigskip
-% With the option |RenewMatrix|, the environment |{matrix}| of \pkg{amsmath} and its variants are redefined to
+% With the option |renew-matrix|, the environment |{matrix}| of \pkg{amsmath} and its variants are redefined to
 % behave like the environment |{NiceMatrix}| and its variants.
 %    \begin{macrocode}
-      RenewMatrix          .code:n     = {\cs_set_eq:NN \env@matrix \NiceMatrix
-                                          \bool_set_true:N \l_@@_renew_matrix_bool}, 
-      RenewMatrix          .default:n  = true,
-      Transparent          .meta:n     = {RenewDots,RenewMatrix},
-      Transparent          .value_forbidden:n = true,
+      renew-matrix      .code:n     = {\cs_set_eq:NN \env@matrix \NiceMatrix
+                                      \bool_set_true:N \l_@@_renew_matrix_bool}, 
+      renew-matrix      .value_forbidden:n = true,
+      RenewMatrix       .meta:n     = renew-matrix,
+      transparent       .meta:n     = {renew-dots,renew-matrix},
+      transparent       .value_forbidden:n = true,
+      Transparent       .meta:n     = transparent,
 %    \end{macrocode}
 %
 % \bigskip
-% Without the option |NullifyDots|, the instructions like |\vdots| are inserted within a
+% Without the option |nullify-dots|, the instructions like |\vdots| are inserted within a
 % |\hphantom| (and so the constructed matrix has exactly the same size as a matrix constructed with the
 % classical |{matrix}| and |\ldots|, |\vdots|, etc.). This option is set by default.
 %    \begin{macrocode}
-      NullifyDots          .bool_set:N = \l_@@_nullify_dots_bool ,
-      NullifyDots          .default:n  = true,
+      nullify-dots      .bool_set:N = \l_@@_nullify_dots_bool ,
+      nullify-dots      .default:n  = true,
+      NullifyDots       .meta:n     = nullify-dots,
 %    \end{macrocode}
 %
 % \bigskip
-% With the option |Silent|, no error is generated for the impossible instructions. This option can be useful when
+% With the option |silent|, no error is generated for the impossible instructions. This option can be useful when
 % adapting an existing code. 
 %    \begin{macrocode}
-      Silent               .code:n  = {\msg_redirect_name:nnn {nicematrix} 
-                                                              {Impossible~instruction}
-                                                              {none}} , 
-      Silent               .value_forbidden:n = true}
+      silent            .code:n  = {\msg_redirect_name:nnn {nicematrix} 
+                                                           {Impossible~instruction}
+                                                           {none}} , 
+      silent            .value_forbidden:n = true,
+      Silent            .meta:n            = silent,
+%    \end{macrocode}
+% 
+% \bigskip
+% The following option is only for the environment |{pNiceArrayC}| and its variants. It will contains code inserted
+% at the beginning of each cell of the last column.\footnote{In an environment |{pNiceArrayC}|, the last column is
+% composed outside the parentheses of the array.}
+%    \begin{macrocode}
+      code-for-last-col  .tl_set:N         = \l_@@_code_for_last_col_tl,
+      code-for-last-col  .value_required:n = true,
+%    \end{macrocode}  
+% 
+% \bigskip
+% The option |exterior-arraycolsep| will have effect only in |{NiceArray}| for those who want to have for
+% |{NiceArray}| the same behaviour as |{array}|.
+%    \begin{macrocode}
+      exterior-arraycolsep .bool_set:N = \l_@@_exterior_arraycolsep_bool ,
+      exterior-arraycolsep .default:n  = true,
+      unknown .code:n  = \msg_error:nn {nicematrix} {Option~unknown}}
 %    \end{macrocode}
 % 
 % \bigskip
 % |\NiceMatrixOptions| is the command of the \pkg{nicematrix} package to fix options at the document level. The
-% scope of these specification is the current TeX group.
+% scope of these specifications is the current TeX group.
 %    \begin{macrocode}
 \NewDocumentCommand \NiceMatrixOptions {m}
-    {\keys_set:nn {NiceMatrix} {#1}}
+    {\keys_set:nn {NiceMatrix/NiceMatrixOptions} {#1}}
 %    \end{macrocode}
 %
+% 
+% \bigskip
+%    \begin{macrocode}
+\keys_define:nn {NiceMatrix/NiceMatrix}
+     {parallelize-diags .bool_set:N = \l_@@_parallelize_diags_bool,
+      parallelize-diags .default:n  = true,
+      renew-dots        .bool_set:N = \l_@@_renew_dots_bool,
+      renew-dots        .default:n  = true,
+      nullify-dots      .bool_set:N = \l_@@_nullify_dots_bool ,
+      nullify-dots      .default:n  = true,
+      unknown .code:n  = \msg_error:nn {nicematrix} {Option~unknown}}
+%    \end{macrocode}
+% 
 % \bigskip
-% \subsection{The environments NiceArray and NiceMatrix}
-%
-% First, we define a set of keys named |{NiceArray}|.
 %    \begin{macrocode}
-\keys_define:nn {NiceArray}
-                {exterior-arraycolsep .bool_set:N = \l_@@_exterior_arraycolsep_bool ,
-                 exterior-arraycolsep .default:n  = true}
+\keys_define:nn {NiceMatrix/NiceArray}
+     {parallelize-diags    .bool_set:N = \l_@@_parallelize_diags_bool,
+      parallelize-diags    .default:n  = true,
+      renew-dots           .bool_set:N = \l_@@_renew_dots_bool,
+      renew-dots           .default:n  = true,
+      nullify-dots         .bool_set:N = \l_@@_nullify_dots_bool ,
+      nullify-dots         .default:n  = true,
+      exterior-arraycolsep .bool_set:N = \l_@@_exterior_arraycolsep_bool ,
+      exterior-arraycolsep .default:n  = true,
+%    \end{macrocode}
+% 
+% \bigskip
+% The options |c|, |t| and |b| of the environment |{NiceArray}| have the same meaning as the option of the classical
+% environment |{array}|.
+%    \begin{macrocode}
+      c .code:n = \tl_set:Nn \l_@@_pos_env_tl c,
+      t .code:n = \tl_set:Nn \l_@@_pos_env_tl t,
+      b .code:n = \tl_set:Nn \l_@@_pos_env_tl b,
+      unknown .code:n  = \msg_error:nn {nicematrix} {Option~unknown}}
 %    \end{macrocode}
 %
+% 
 % \bigskip
+% \subsection{The environments \{NiceArray\} and \{NiceMatrix\}}
+%
 % The pseudo-environment |\@@_Cell:n|--|\@@_end_Cell:| will be used to format the cells of the array. In the code,
 % the affectations are global because this pseudo-environment will be used in the cells of a |\halign| (via an
 % environment |{array}|).
@@ -897,7 +1022,7 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
     \tikz[remember~picture, inner~sep = 0pt, minimum~width = 0pt, baseline]
        \node [anchor=base] (nm-\int_use:N \g_@@_env_int-
-                               \int_use:N \g_@@_line_int-
+                               \int_use:N \g_@@_row_int-
                                \int_use:N \g_@@_column_int)
        \bgroup $} % $
 %    \end{macrocode}
@@ -913,7 +1038,7 @@ version 2005/12/01 or later.
 % In order to clarify the explanations, we will first give the definition of the environment |{NiceMatrix}|.
 %
 % Our environment |{NiceMatrix}| must have the same second part as the environment |{matrix}| of \pkg{amsmath}
-% (because of the programmation of the option |RenewMatrix|). Hence, this second part is the following:
+% (because of the programmation of the option |renew-matrix|). Hence, this second part is the following:
 % 
 % \begin{Verbatim}
 %          \endarray
@@ -926,8 +1051,10 @@ version 2005/12/01 or later.
 % \medskip
 % Here's the definition of |{NiceMatrix}|:
 %    \begin{macrocode}
-\NewDocumentEnvironment {NiceMatrix} {}
-    {\bool_set_false:N \l_@@_exterior_arraycolsep_bool
+\NewDocumentEnvironment {NiceMatrix} {O{}}
+    {\keys_set:nn {NiceMatrix/NiceMatrix} {#1}
+     \tl_set:Nn \l_@@_pos_env_tl c
+     \bool_set_false:N \l_@@_exterior_arraycolsep_bool
      \NiceArray{*\c@MaxMatrixCols{C}}}
     {\endarray
      \skip_horizontal:n {-\arraycolsep}}
@@ -942,28 +1069,24 @@ version 2005/12/01 or later.
 % \end{itemize}
 %               
 %    \begin{macrocode}
-\NewDocumentEnvironment {NiceArray} {O{} m}
+\NewDocumentEnvironment {NiceArray} {O{} m O{}}
     {\aftergroup \@@_draw_lines:
-%    \end{macrocode}
-% First, we test wether there is the option |exterior-arraycolsep|. The other options (|t|, |c| or |b|) will be
-% stored in |\l_tmpa_tl| and passed to |\array| (see below).
-%    \begin{macrocode}           
-      \keys_set_known:nnN {NiceArray} {#1} \l_tmpa_tl
+     \keys_set:nn {NiceMatrix/NiceArray} {#1,#3} 
 %    \end{macrocode}
 % The environment |{array}| uses internally the command |\ialign| and, in particular, this command |\ialign| sets
-% |\everycr| to |{}|. However, we want to use |\everycr| in our array (in particular to increment |\g_@@_line_int|).
+% |\everycr| to |{}|. However, we want to use |\everycr| in our array (in particular to increment |\g_@@_row_int|).
 % The solution is to give to |\ialign| a new definition (giving to |\everycr| the value we want)
 % that will revert automatically to its default definition after the first utilisation.\footnote{With this programmation, we will
 % have, in the cells of the array, a clean version of |\ialign|. That's necessary: the user will probably not employ directly 
 % |\ialign| in the array...  but more likely environments that utilize |\ialign| internally (e.g.: |{substack}|)}
 %    \begin{macrocode}
      \cs_set:Npn \ialign 
-          {\everycr{\noalign{\int_gincr:N \g_@@_line_int
+          {\everycr{\noalign{\int_gincr:N \g_@@_row_int
                              \int_gzero:N \g_@@_column_int
 %    \end{macrocode}
-% We want to have the preamble of the array in |\g_@@_preamble_tl| at the end of the array. However, some lines of the array
-% may be shorter (that is to say without all the ampersands) and it's not possible to known which line will be the
-% longest. That's why, during the construction of a line, we retrieve the corresponding preamble in
+% We want to have the preamble of the array in |\g_@@_preamble_tl| at the end of the array. However, some rows of the array
+% may be shorter (that is to say without all the ampersands) and it's not possible to known which row will be the
+% longest. That's why, during the construction of a row, we retrieve the corresponding preamble in
 % |\g_@@_preamble_aux_tl|. At the end of the array, we are sure that the longest value will be the real preamble of
 % the array (stored in |\g_@@_preamble_tl|).
 %    \begin{macrocode}                                                                                  
@@ -1005,64 +1128,63 @@ version 2005/12/01 or later.
 % 
 % We increment the counter |\g_@@_env_int| which counts the environments |{NiceArray}|.
 %    \begin{macrocode}
-    \int_gincr:N \g_@@_env_int
+     \int_gincr:N \g_@@_env_int
 %    \end{macrocode}
 %
 % We have to remind the types of the columns (|l|, |c| or |r|) because we will use this information when we will
 % draw the vertical dotted lines. That's why we store the types of the columns in |\g_@@_preamble_tl| (for example,
-% if the preamble of |{NiceArray}| is |L*4{C}R|, the final value of |\g_@@_preamble_tl| will be |lccccr|).
+% if the preamble of |{NiceArray}| is |L*4{C}R|, the final value of |\g_@@_preamble_tl| will be |lccccr| if the
+% user really uses the six columns).
 %    \begin{macrocode}
      \tl_clear_new:N \g_@@_preamble_tl
      \tl_clear_new:N \g_@@_preamble_aux_tl
 %    \end{macrocode}
 %
 % The sequence |\g_@@_empty_cells_seq| will contains a list of ``empty'' cells (not all the empty cells of the
-% matrix). If we want to indicate that the cell in line~$i$ and line~$j$ must be considered as empty, the token
+% matrix). If we want to indicate that the cell in row~$i$ and column~$j$ must be considered as empty, the token
 % list ``|i-j|'' will be put in this sequence.
 %    \begin{macrocode}
-    \seq_gclear_new:N  \g_@@_empty_cells_seq
+     \seq_gclear_new:N  \g_@@_empty_cells_seq
 %    \end{macrocode}
 %
 % The counter |\g_@@_instruction_int| will count the instructions (|\Cdots|, |\Vdots|, |\Ddots|, etc.) in the matrix.
 %    \begin{macrocode}
-    \int_gzero_new:N \g_@@_instruction_int
+     \int_gzero_new:N \g_@@_instruction_int
 %    \end{macrocode}
 %
-% The counter |\g_@@_line_int| will be used to count the lines of the array (its incrementation will be in
-% |\everycr|). At the end of the environment |{array}|, this counter will give the total number of lines of the matrix.
+% The counter |\g_@@_row_int| will be used to count the rows of the array (its incrementation will be in
+% |\everycr|). At the end of the environment |{array}|, this counter will give the total number of rows of the matrix.
 %    \begin{macrocode}
-    \int_gzero_new:N \g_@@_line_int 
+     \int_gzero_new:N \g_@@_row_int 
 %    \end{macrocode}
 %
 % The counter |\g_@@_column_int| will be used to count the columns of the array (it will be set to zero in
 % |\everycr|). This counter is updated in the command |\@@_Cell:n| executed at the beginning of each cell. At the
 % end of the array (in the beginning of |\@@_draw_lines:|), it will be set to the total number of columns of the array.
 %    \begin{macrocode}
-    \int_gzero_new:N \g_@@_column_int 
-    \cs_set_eq:NN \@ifnextchar \new@ifnextchar
+     \int_gzero_new:N \g_@@_column_int 
+     \cs_set_eq:NN \@ifnextchar \new@ifnextchar
 %    \end{macrocode}
 %
 % The extra horizontal spaces on both sides of an environment |{array}| should be considered as a bad idea of
 % standard LaTeX. In the environment |{matrix}| the package  \pkg{amsmath} prefers to suppress these spaces with
-% intructions ``|\hskip -\arraycolsep|''. In the same way, we decide to suppress them in |{NiceArray}|. However, for better
+% instructions ``|\hskip -\arraycolsep|''. In the same way, we decide to suppress them in |{NiceArray}|. However, for better
 % compatibility, we give an option |exterior-arraycolsep| to control this feature.
 %    \begin{macrocode}
-      \bool_if:NF \l_@@_exterior_arraycolsep_bool
+     \bool_if:NF \l_@@_exterior_arraycolsep_bool
          {\skip_horizontal:n {-\arraycolsep}}
 %    \end{macrocode}
 % 
-% Eventually, the environment |{NiceArray}| is defined upon the environment |{array}|. As said previously, we must
-% use |\array| and not |\begin{array}|. The token list |\l_tmpa_tl| contains the options given to the environment
-% |{NiceArray}| that have not been catched by the set of keys |NiceArray| (|\l_tmpa_tl| should be equal to |t|,
-% |c|, |b| or the empty list).
+% Eventually, the environment |{NiceArray}| is defined upon the environment |{array}|. The token list |l_@@_pos_tl|
+% will contain one of the values |t|, |c| or |b|.
 %    \begin{macrocode}
-      \array[\l_tmpa_tl]{#2}}
+     \array[\l_@@_pos_env_tl]{#2}}
 %    \end{macrocode}
 %
 % \bigskip
 %    \begin{macrocode}
-     {\endarray
-      \bool_if:NF \l_@@_exterior_arraycolsep_bool
+    {\endarray
+     \bool_if:NF \l_@@_exterior_arraycolsep_bool
          {\skip_horizontal:n {-\arraycolsep}}}
 %    \end{macrocode}
 %
@@ -1084,19 +1206,19 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
 \NewDocumentEnvironment {BNiceMatrix} {}
    {\left\{\begin{NiceMatrix}}
-   {\end{BNiceMatrix}\right\}}
+   {\end{NiceMatrix}\right\}}
 %    \end{macrocode}
 %
 %    \begin{macrocode}
 \NewDocumentEnvironment {vNiceMatrix} {}
    {\left\lvert\begin{NiceMatrix}}
-   {\end{BNiceMatrix}\right\rvert}
+   {\end{NiceMatrix}\right\rvert}
 %    \end{macrocode}
 %
 %    \begin{macrocode}
 \NewDocumentEnvironment {VNiceMatrix} {}
    {\left\lVert\begin{NiceMatrix}}
-   {\end{BNiceMatrix}\right\rVert}
+   {\end{NiceMatrix}\right\rVert}
 %    \end{macrocode}
 %
 % \interitem
@@ -1149,7 +1271,7 @@ version 2005/12/01 or later.
 % informations corresponding to the instruction. Such an property list will have three fields:
 % \begin{itemize}
 % \item a field ``type'' with the type of the instruction (|cdots|, |vdots|, |ddots|, etc.);
-% \item a field ``line'' with the number of the line of the matrix where the instruction appeared;
+% \item a field ``row'' with the number of the row of the matrix where the instruction appeared;
 % \item a field ``column'' with the number of the column of the matrix where the instruction appeared.
 % \end{itemize}
 %
@@ -1164,7 +1286,7 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
      {\int_gincr:N \g_@@_instruction_int
       \prop_put:Nnn \l_tmpa_prop {type} {#1}
-      \prop_put:NnV \l_tmpa_prop {line} \g_@@_line_int
+      \prop_put:NnV \l_tmpa_prop {row} \g_@@_row_int
       \prop_put:NnV \l_tmpa_prop {column} \g_@@_column_int
 %    \end{macrocode}
 % The property list has been created in a local variable for convenience. Now, it will be stored in a
@@ -1184,9 +1306,12 @@ version 2005/12/01 or later.
 
 %    \begin{macrocode}
 \cs_new_protected:Nn \@@_draw_lines:
-    {\int_compare:nNnT {\tl_count:N \g_@@_preamble_aux_tl}
-            > {\tl_count:N \g_@@_preamble_tl} 
-              {\tl_set_eq:NN \g_@@_preamble_tl \g_@@_preamble_aux_tl}
+    {
+%    \end{macrocode}
+% The last |\cr| in the array has incremented the counter |\g_@@_row_int|. That's why we decrement it to have the
+% real number of rows.
+%    \begin{macrocode}
+     \int_decr:N \g_@@_row_int
 %    \end{macrocode}
 % The counter |\g_@@_column_int| will now be the total number of columns in the array.                           
 %    \begin{macrocode}
@@ -1203,14 +1328,14 @@ version 2005/12/01 or later.
 % The following variables will be used further.
 %    \begin{macrocode}
      \int_zero_new:N \l_@@_type_int
-     \int_zero_new:N \l_@@_line_int
+     \int_zero_new:N \l_@@_row_int
      \int_zero_new:N \l_@@_column_int
      \int_zero_new:N \l_@@_di_int
      \int_zero_new:N \l_@@_dj_int
 %    \end{macrocode}
 %
 % By befault, the diagonal lines will be parallelized\footnote{It's possible to use the option
-% |ParallelizeDiagonals| to disable this parallelization.}. There are two types of diagonals lines: the $|\Ddots|$
+% |parallelize-diags| to disable this parallelization.}. There are two types of diagonals lines: the $|\Ddots|$
 % diagonals and the |\Iddots| diagonals. We have to count both types in order to known wether a diagonal is the
 % first of its type in the current |{NiceArray}| environment.
 %    \begin{macrocode}
@@ -1245,7 +1370,7 @@ version 2005/12/01 or later.
 %    \end{macrocode}
 %
 % \interitem
-% We extract from the property list of the current instruction the fields ``type'', ``line'' and ``column'' and we
+% We extract from the property list of the current instruction the fields ``type'', ``row'' and ``column'' and we
 % store these values. We have to do a conversion because the components of a property list are token lists (and not
 % integers).
 %    \begin{macrocode}
@@ -1253,8 +1378,8 @@ version 2005/12/01 or later.
                         {type} \l_tmpa_tl
          \int_set:Nn \l_@@_type_int {\l_tmpa_tl}
          \prop_get:cnN {g_@@_instruction_\int_use:N \l_@@_instruction_int _prop}
-                        {line} \l_tmpa_tl
-         \int_set:Nn \l_@@_line_int {\l_tmpa_tl}
+                        {row} \l_tmpa_tl
+         \int_set:Nn \l_@@_row_int {\l_tmpa_tl}
          \prop_get:cnN {g_@@_instruction_\int_use:N \l_@@_instruction_int _prop}
                         {column} \l_tmpa_tl
          \int_set:Nn \l_@@_column_int {\l_tmpa_tl}
@@ -1293,7 +1418,7 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
            \int_zero_new:N  \l_@@_final_i_int
            \int_zero_new:N  \l_@@_final_j_int
-           \int_set:Nn \l_@@_final_i_int \l_@@_line_int
+           \int_set:Nn \l_@@_final_i_int \l_@@_row_int
            \int_set:Nn \l_@@_final_j_int \l_@@_column_int
            \bool_if_exist:NTF \l_@@_stop_loop_bool
                   {\bool_set_false:N \l_@@_stop_loop_bool}
@@ -1305,7 +1430,7 @@ version 2005/12/01 or later.
 % We test if we are still in the matrix. 
 %    \begin{macrocode}
                \bool_if:nTF { \int_compare_p:nNn \l_@@_final_i_int < 1
-                           || \int_compare_p:nNn \l_@@_final_i_int > \g_@@_line_int
+                           || \int_compare_p:nNn \l_@@_final_i_int > \g_@@_row_int
                            || \int_compare_p:nNn \l_@@_final_j_int < 1
                            || \int_compare_p:nNn \l_@@_final_j_int > \g_@@_column_int}
 %    \end{macrocode}
@@ -1328,10 +1453,10 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
            \int_zero_new:N  \l_@@_initial_i_int
            \int_zero_new:N  \l_@@_initial_j_int
-           \int_set:Nn \l_@@_initial_i_int \l_@@_line_int
+           \int_set:Nn \l_@@_initial_i_int \l_@@_row_int
            \int_set:Nn \l_@@_initial_j_int \l_@@_column_int
 %    \end{macrocode}
-% If we known that the instruction is impossible (because it was not possible to found the correct value for 
+% If we know that the instruction is impossible (because it was not possible to found the correct value for 
 % |\l_@@_final_i_int| and |\l_@@_final_j_int|), we don't do this loop.
 %    \begin{macrocode}
            \bool_set_eq:NN \l_@@_stop_loop_bool \l_@@_impossible_instruction_bool
@@ -1340,7 +1465,7 @@ version 2005/12/01 or later.
                \int_sub:Nn \l_@@_initial_j_int \l_@@_dj_int
                \bool_if:nTF 
                        {   \int_compare_p:nNn \l_@@_initial_i_int < 1
-                        || \int_compare_p:nNn \l_@@_initial_i_int > \g_@@_line_int
+                        || \int_compare_p:nNn \l_@@_initial_i_int > \g_@@_row_int
                         || \int_compare_p:nNn \l_@@_initial_j_int < 1
                         || \int_compare_p:nNn \l_@@_initial_j_int > \g_@@_column_int}
                        {\bool_set_true:N \l_@@_impossible_instruction_bool
@@ -1599,10 +1724,10 @@ version 2005/12/01 or later.
 %    \end{macrocode}
 %
 % \bigskip
-% \subsection{User commands available in environments {NiceArray} and {NiceMatrix}}
+% \subsection{User commands available in the new environments}
 %
 % We give new names for the commands |\ldots|, |\cdots|, |\vdots| and |\ddots| because these commands will be
-% redefined (if the option |RenewDots| is used).
+% redefined (if the option |renew-dots| is used).
 %    \begin{macrocode}
 \cs_set_eq:NN \@@_ldots \ldots
 \cs_set_eq:NN \@@_cdots \cdots
@@ -1617,13 +1742,14 @@ version 2005/12/01 or later.
 %    \begin{macrocode}
 \cs_new_protected:Nn \@@_add_to_empty_cells:
     {\seq_gput_right:Nx \g_@@_empty_cells_seq
-          {\int_use:N \g_@@_line_int-
+          {\int_use:N \g_@@_row_int-
            \int_use:N \g_@@_column_int}}
 %    \end{macrocode}
 %
 % \interitem 
 % The commands |\@@_Ldots|, |\@@_Cdots|, |\@@_Vdots|, |\@@_Ddots| and |\@@_Iddots| will be linked to |\Ldots|,
-% |\Cdots|, |\Vdots|, |\Ddots| and |\Iddots| in the environments |{NiceArray}|.
+% |\Cdots|, |\Vdots|, |\Ddots| and |\Iddots| in the environments |{NiceArray}| (the other environments of
+% \pkg{nicematrix} rely upon |{NiceArray}|).
 %    \begin{macrocode}
 \NewDocumentCommand \@@_Ldots {s}
     {\IfBooleanF {#1} {\@@_instruction_of_type:n 0}
@@ -1665,7 +1791,7 @@ version 2005/12/01 or later.
 %
 %
 % \bigskip
-% The command |\@@_Hspace:| will be linked to |\hspace| in the environments |{NiceArray}|.
+% The command |\@@_Hspace:| will be linked to |\hspace| in |{NiceArray}|.
 %    \begin{macrocode}
 \cs_new_protected:Nn \@@_Hspace:
   {\@@_add_to_empty_cells:
@@ -1673,7 +1799,7 @@ version 2005/12/01 or later.
 %    \end{macrocode}
 %
 % \bigskip
-% The command |\@@_NiceMatrixEndPoint:| will be linked to |\NiceMatrixEndPoint| in the environments |{NiceArray}|.
+% The command |\@@_NiceMatrixEndPoint:| will be linked to |\NiceMatrixEndPoint| in |{NiceArray}|.
 %    \begin{macrocode}
 \cs_new_protected:Nn \@@_NiceMatrixEndPoint:
      {\kern 0.5pt}
@@ -1686,7 +1812,7 @@ version 2005/12/01 or later.
 % |\NiceMatrixOptions| instead. 
 %
 % We must process these options after the definition of the environment |{NiceMatrix}| because the option
-% |RenewMatrix| execute the code |\cs_set_eq:NN \env@matrix \NiceMatrix|. 
+% |renew-matrix| execute the code |\cs_set_eq:NN \env@matrix \NiceMatrix|. 
 %
 % Of course, the command |\NiceMatrix| must be defined before such an instruction is executed.
 %    \begin{macrocode}
@@ -1704,18 +1830,18 @@ version 2005/12/01 or later.
                  {0 {\token_to_str:N \Ldots}
                   1 {\token_to_str:N \Cdots}
                   2 {\token_to_str:N \Vdots}
-                  3 {\token_to_str:N \Ddots}}~in~the~line~\int_use:N\l_@@_line_int\ 
+                  3 {\token_to_str:N \Ddots}}~in~the~row~\int_use:N\l_@@_row_int\ 
                ~and~the~column~\int_use:N\l_@@_column_int\space of~the~matrix~
                because~it's~impossible~to~find~one~of~its~extremities~  
                (both~extremities~must~be~non~empty~cells~of~the~matrix).~
                If~you~go~on,~the~instruction~will~be~ignored.}
-              {You~can~specify~a~end~of~line~on~a~empty~cell~
+              {You~can~specify~an~end~of~line~on~a~empty~cell~
                with~\token_to_str:N \NiceMatrixEndPoint.}
 %    \end{macrocode}
 %
 %    \begin{macrocode}
 \msg_new:nnn {nicematrix}
-             {multicolumn~forbidden}
+             {Multicolumn~forbidden}
              {The~command~\token_to_str:N \multicolumn\ 
               is~forbidden~in~the~environment~\{NiceMatrix\}~ 
               and~its~variants.~The~command~\token_to_str:N \hdotsfor\ 
@@ -1724,12 +1850,139 @@ version 2005/12/01 or later.
               probably~be~wrong.}
 %    \end{macrocode}
 %
+%    \begin{macrocode}
+\msg_new:nnn {nicematrix}
+             {Option~unknown}
+             {The~option~"\tl_use:N\l_keys_key_tl"~is~unknown~or~
+              meaningless~in~the~context.~If~you~go~on,~it~will~be~ignored.}
+%    \end{macrocode}
+% 
+% \bigskip
+% \subsection{The environment \{pNiceArrayC\} and its variants}
+% 
+% The code in this section can be removed without affecting the previous code.
 % 
+% \medskip
+% First, we define a set of options for the environment |{pNiceArrayC}| and its variants. This set of keys is named   
+% |NiceMatrix/NiceArrayC| even though there is no environment called |{NiceArrayC}|.
+%
+%    \begin{macrocode}
+\keys_define:nn {NiceMatrix/NiceArrayC}
+     {parallelize-diags    .bool_set:N       = \l_@@_parallelize_diags_bool,
+      parallelize-diags    .default:n        = true,
+      renew-dots           .bool_set:N       = \l_@@_renew_dots_bool,
+      renew-dots           .default:n        = true,
+      nullify-dots         .bool_set:N       = \l_@@_nullify_dots_bool ,
+      nullify-dots         .default:n        = true,
+      code-for-last-col    .tl_set:N         = \l_@@_code_for_last_col_tl,
+      code-for-last-col    .value_required:n = true,
+      unknown .code:n  = \msg_error:nn {nicematrix} {Option~unknown}}
+%    \end{macrocode}
+%
+% \bigskip
+% In the environment |{pNiceArrayC}| (and its variants), the last column is composed with instructions
+% |\hbox_overlap_right:n| (this instruction may be seen as the \pkg{expl3} equivalent of the classical command
+% |\rlap|). After the composition of the array, an horizontal skip is inserted to compensate for these
+% overlapping boxes.
+%
+% \medskip
+% The command |\@@_NiceArrayC:nn| will be used in the environment |{pNiceArrayC}| and its variants.
+%    \begin{macrocode}
+\cs_new_protected:Nn \@@_NiceArrayC:nn
+    {\dim_gzero_new:N \g_@@_width_last_col_dim
+     \keys_set:nn {NiceMatrix/NiceArrayC} {#1}
+     \bool_set_false:N \l_@@_exterior_arraycolsep_bool
+     \tl_set:Nn \l_@@_pos_env_tl c
+     \begin{NiceArray}
+%    \end{macrocode}
+% The beginning of the preamble is the argument of the environment |{pNiceArrayC}|. 
+%    \begin{macrocode}
+             {#2
+%    \end{macrocode}
+% 
+% However, we add a last column with its own specification. For a cell in this last column, the first operation is
+% to store the content of the cell in the box |\l_tmpa_box|. This is allowed in \pkg{expl3} with the construction
+% |\hbox_set:Nw \l_tmpa_box| ... |\hbox_set_end:|.
+%    \begin{macrocode}
+                >{\hbox_set:Nw \l_tmpa_box 
+                  \l_@@_code_for_last_col_tl
+                  \@@_Cell:n l}
+                  l
+                <{\@@_end_Cell:
+                  \hbox_set_end:
+%    \end{macrocode}
+% 
+% We actualize the value of |\g_@@with_last_col_dim| which, at the end of the array, will contains the maximal width
+% of the cells of the last column (thus, it will be equal to the width of the last column).
+%    \begin{macrocode}
+                  \dim_gset:Nn \g_@@_width_last_col_dim
+                     {\dim_max:nn \g_@@_width_last_col_dim
+                                  {\box_wd:N \l_tmpa_box}}
+                  \skip_horizontal:n {-2\arraycolsep}
+%    \end{macrocode}
+% The content of the cell is inserted in a overlapping position.
+%    \begin{macrocode}
+                  \hbox_overlap_right:n 
+                       {\skip_horizontal:n {2\arraycolsep}
+                        \box_use:N \l_tmpa_box}}}}
+%    \end{macrocode}
+% This ends the preamble of the array that will be constructed (a rather long preamble, indeed).
+%
+% \bigskip
+% The command |\@@_after_last_col:| will be used to insert, after the construction of the array (and after the
+% insertion of the right parenthesis, brace, bracket, etc.), an horizontal space in order to compensate for the
+% overlapping boxes.
+%    \begin{macrocode}                       
+\cs_new:Nn \@@_after_last_col:
+    {\dim_compare:nNnF \g_@@_width_last_col_dim = \c_zero_dim
+        {\skip_horizontal:n {\g_@@_width_last_col_dim}{}}}
+%    \end{macrocode}
+%
+% \bigskip
+%    \begin{macrocode}                       
+\NewDocumentEnvironment {pNiceArrayC} {O{} m O{}}
+    {\left(
+     \@@_NiceArrayC:nn {#1,#3} {#2}}
+    {\end{NiceArray}
+     \right)
+     \@@_after_last_col:}
+
+\NewDocumentEnvironment {vNiceArrayC} {O{} m O{}}
+    {\left|
+     \@@_NiceArrayC:nn {#1,#3} {#2}}
+    {\end{NiceArray}
+     \right|
+     \@@_after_last_col:}
+
+\NewDocumentEnvironment {VNiceArrayC} {O{} m O{}}
+    {\left\|
+     \@@_NiceArrayC:nn {#1,#3} {#2}}
+    {\end{NiceArray}
+     \right\|
+     \@@_after_last_col:}
+
+\NewDocumentEnvironment {bNiceArrayC} {O{} m O{}}
+    {\left[
+     \@@_NiceArrayC:nn {#1,#3} {#2}}
+    {\end{NiceArray}
+     \right]
+     \@@_after_last_col:}
+
+\NewDocumentEnvironment {BNiceArrayC} {O{} m O{}}
+    {\left\{
+     \@@_NiceArrayC:nn {#1,#3} {#2}}
+    {\end{NiceArray}
+     \right\}
+     \@@_after_last_col:}
+%    \end{macrocode}
+%
+%
+%                           
 % \section{History}
 %
 % \subsection{Changes between versions 1.0 and 1.1}
 % 
-% Option |Silent| (with this option, the impossible instructions are discarded silently).
+% Option |silent| (with this option, the impossible instructions are discarded silently).
 %
 % The dotted lines are no longer drawn with Tikz nodes but with Tikz circles (for efficiency).
 % 
@@ -1739,6 +1992,21 @@ version 2005/12/01 or later.
 %
 % New environment |{NiceArray}| with column types |L|, |C| and |R|.
 %
+% \subsection{Changes between version 1.2 and 1.3}
+%
+% New environment |{pNiceArrayC}| and its variants.
+%
+% We decrement |\g_@@_row_int| in |\@@_draw_arrows:| to have the exact number of rows.
+% 
+% Correction of a bug in the definition of |{BNiceMatrix}|, |{vNiceMatrix}| and |{VNiceMatrix}| (in fact, it was a
+% typo).
+%
+% Options are now available locally in |{pNiceMatrix}| and its variants. 
+% 
+% The names of the options are changed. The old names were names in ``camel style''. New names are in lowercase and
+% hyphens (but backward compatibility is kept).
+% 
+%
 % \endinput
 % Local Variables:
 % TeX-fold-mode: nil