nicematrix (2jan20)

git-svn-id: svn://tug.org/texlive/trunk@53304 c570f23f-e606-0410-a88d-b1316a301751

1 files changed, 1044 insertions, 1042 deletions

diff --git a/Master/texmf-dist/tex/latex/nicematrix/nicematrix.sty b/Master/texmf-dist/tex/latex/nicematrix/nicematrix.sty
index d2940a8e405..fd41a0cf057 100644
--- a/Master/texmf-dist/tex/latex/nicematrix/nicematrix.sty
+++ b/Master/texmf-dist/tex/latex/nicematrix/nicematrix.sty
@@ -18,8 +18,8 @@
 %% and version 1.3 or later is part of all distributions of
 %% LaTeX version 2005/12/01 or later.
 %% 
-\def\myfileversion{3.7}
-\def\myfiledate{2019/11/11}
+\def\myfileversion{3.8}
+\def\myfiledate{2020/01/02}
 \RequirePackage{tikz}
 \usetikzlibrary{fit}
 \RequirePackage{expl3}[2019/07/01]
@@ -29,32 +29,32 @@
   {\myfiledate}
   {\myfileversion}
   {Several features to improve the typesetting of mathematical matrices with TikZ}
-\bool_new:N \c__nm_draft_bool
-\DeclareOption { draft } { \bool_set_true:N \c__nm_draft_bool }
+\bool_new:N \c__nicematrix_draft_bool
+\DeclareOption { draft } { \bool_set_true:N \c__nicematrix_draft_bool }
 \DeclareOption* { }
 \ProcessOptions \relax
 \RequirePackage { array }
 \RequirePackage { amsmath }
 \RequirePackage { xparse } [ 2018-07-01 ]
-\cs_new_protected:Npn \__nm_error:n { \msg_error:nn { nicematrix } }
-\cs_new_protected:Npn \__nm_error:nn { \msg_error:nnn { nicematrix } }
-\cs_new_protected:Npn \__nm_error:nnn { \msg_error:nnnn { nicematrix } }
-\cs_new_protected:Npn \__nm_fatal:n { \msg_fatal:nn { nicematrix } }
-\cs_new_protected:Npn \__nm_fatal:nn { \msg_fatal:nn { nicematrix } }
-\cs_new_protected:Npn \__nm_msg_new:nn { \msg_new:nnn { nicematrix } }
-\cs_new_protected:Npn \__nm_msg_new:nnn { \msg_new:nnnn { nicematrix } }
-\cs_new_protected:Npn \__nm_msg_redirect_name:nn
+\cs_new_protected:Npn \__nicematrix_error:n { \msg_error:nn { nicematrix } }
+\cs_new_protected:Npn \__nicematrix_error:nn { \msg_error:nnn { nicematrix } }
+\cs_new_protected:Npn \__nicematrix_error:nnn { \msg_error:nnnn { nicematrix } }
+\cs_new_protected:Npn \__nicematrix_fatal:n { \msg_fatal:nn { nicematrix } }
+\cs_new_protected:Npn \__nicematrix_fatal:nn { \msg_fatal:nn { nicematrix } }
+\cs_new_protected:Npn \__nicematrix_msg_new:nn { \msg_new:nnn { nicematrix } }
+\cs_new_protected:Npn \__nicematrix_msg_new:nnn { \msg_new:nnnn { nicematrix } }
+\cs_new_protected:Npn \__nicematrix_msg_redirect_name:nn
   { \msg_redirect_name:nnn { nicematrix } }
-\bool_new:N \c__nm_revtex_bool
+\bool_new:N \c__nicematrix_revtex_bool
 \@ifclassloaded { revtex4-1 }
-  { \bool_set_true:N \c__nm_revtex_bool }
+  { \bool_set_true:N \c__nicematrix_revtex_bool }
   { }
 \@ifclassloaded { revtex4-2 }
-  { \bool_set_true:N \c__nm_revtex_bool }
+  { \bool_set_true:N \c__nicematrix_revtex_bool }
   { }
-\__nm_msg_new:nn { Draft~mode }
+\__nicematrix_msg_new:nn { Draft~mode }
   { The~compilation~is~in~draft~mode:~the~dotted~lines~won't~be~drawn. }
-\bool_if:NT \c__nm_draft_bool
+\bool_if:NT \c__nicematrix_draft_bool
   { \msg_warning:nn { nicematrix }  { Draft~mode } }
 \ProvideDocumentCommand \iddots { }
   {
@@ -68,58 +68,58 @@
         \raise 7 \p@ \vbox { \kern 7 pt \hbox:n { . } } \mkern 1 mu
       }
   }
-\int_new:N \g__nm_env_int
-\int_new:N \g__nm_NiceMatrixBlock_int
-\dim_new:N \l__nm_columns_width_dim
-\seq_new:N \g__nm_names_seq
+\int_new:N \g__nicematrix_env_int
+\int_new:N \g__nicematrix_NiceMatrixBlock_int
+\dim_new:N \l__nicematrix_columns_width_dim
+\seq_new:N \g__nicematrix_names_seq
 
-\bool_new:N \l__nm_in_env_bool
-\bool_new:N \l__nm_NiceArray_bool
-\cs_new_protected:Npn \__nm_test_if_math_mode:
+\bool_new:N \l__nicematrix_in_env_bool
+\bool_new:N \l__nicematrix_NiceArray_bool
+\cs_new_protected:Npn \__nicematrix_test_if_math_mode:
   {
     \if_mode_math: \else:
-      \__nm_fatal:n { Outside~math~mode }
+      \__nicematrix_fatal:n { Outside~math~mode }
     \fi:
   }
-\bool_new:N \l__nm_impossible_line_bool
-\bool_new:N \c__nm_colortbl_loaded_bool
+\bool_new:N \l__nicematrix_impossible_line_bool
+\bool_new:N \c__nicematrix_colortbl_loaded_bool
 \AtBeginDocument
   {
     \@ifpackageloaded { colortbl }
       {
-        \bool_set_true:N \c__nm_colortbl_loaded_bool
-        \cs_set_protected:Npn \__nm_vline_i: { { \CT@arc@ \vline } }
+        \bool_set_true:N \c__nicematrix_colortbl_loaded_bool
+        \cs_set_protected:Npn \__nicematrix_vline_i: { { \CT@arc@ \vline } }
       }
       { }
   }
-\dim_new:N \l__nm_inter_dots_dim
-\dim_set:Nn \l__nm_inter_dots_dim { 0.45 em }
-\dim_new:N \l__nm_radius_dim
-\dim_set:Nn \l__nm_radius_dim { 0.53 pt }
-\str_new:N \g__nm_type_env_str
-\tl_new:N \g__nm_code_after_tl
-\int_new:N \l__nm_save_iRow_int
-\int_new:N \l__nm_save_jCol_int
-\int_new:N \l__nm_first_row_int
-\int_set:Nn \l__nm_first_row_int 1
-\int_new:N \l__nm_first_col_int
-\int_set:Nn \l__nm_first_col_int 1
-\int_new:N \l__nm_last_row_int
-\int_set:Nn \l__nm_last_row_int { -2 }
-\bool_new:N \l__nm_last_row_without_value_bool
-\int_new:N \l__nm_last_col_int
-\int_set:Nn \l__nm_last_col_int { -1 }
-\bool_new:N \g__nm_last_col_found_bool
-\bool_new:N \c__nm_siunitx_loaded_bool
+\dim_new:N \l__nicematrix_inter_dots_dim
+\dim_set:Nn \l__nicematrix_inter_dots_dim { 0.45 em }
+\dim_new:N \l__nicematrix_radius_dim
+\dim_set:Nn \l__nicematrix_radius_dim { 0.53 pt }
+\str_new:N \g__nicematrix_type_env_str
+\tl_new:N \g__nicematrix_code_after_tl
+\int_new:N \l__nicematrix_save_iRow_int
+\int_new:N \l__nicematrix_save_jCol_int
+\int_new:N \l__nicematrix_first_row_int
+\int_set:Nn \l__nicematrix_first_row_int 1
+\int_new:N \l__nicematrix_first_col_int
+\int_set:Nn \l__nicematrix_first_col_int 1
+\int_new:N \l__nicematrix_last_row_int
+\int_set:Nn \l__nicematrix_last_row_int { -2 }
+\bool_new:N \l__nicematrix_last_row_without_value_bool
+\int_new:N \l__nicematrix_last_col_int
+\int_set:Nn \l__nicematrix_last_col_int { -1 }
+\bool_new:N \g__nicematrix_last_col_found_bool
+\bool_new:N \c__nicematrix_siunitx_loaded_bool
 \AtBeginDocument
   {
     \@ifpackageloaded { siunitx }
-      { \bool_set_true:N \c__nm_siunitx_loaded_bool }
+      { \bool_set_true:N \c__nicematrix_siunitx_loaded_bool }
       { }
   }
-\cs_set_protected:Npn \__nm_adapt_S_column:
+\cs_set_protected:Npn \__nicematrix_adapt_S_column:
   {
-    \bool_if:NT \c__nm_siunitx_loaded_bool
+    \bool_if:NT \c__nicematrix_siunitx_loaded_bool
       {
         \group_begin:
         \@temptokena = { }
@@ -127,70 +127,66 @@
         \NC@rewrite@S { }
         \tl_gset:NV \g_tmpa_tl \@temptokena
         \group_end:
-        \tl_new:N \c__nm_table_collect_begin_tl
+        \tl_new:N \c__nicematrix_table_collect_begin_tl
         \tl_set:Nx \l_tmpa_tl { \tl_item:Nn \g_tmpa_tl 2 }
-        \tl_gset:Nx \c__nm_table_collect_begin_tl { \tl_item:Nn \l_tmpa_tl 1 }
-        \tl_new:N \c__nm_table_print_tl
-        \tl_gset:Nx \c__nm_table_print_tl { \tl_item:Nn \g_tmpa_tl { -1 } }
-        \cs_gset_eq:NN \__nm_adapt_S_column: \prg_do_nothing:
+        \tl_gset:Nx \c__nicematrix_table_collect_begin_tl { \tl_item:Nn \l_tmpa_tl 1 }
+        \tl_new:N \c__nicematrix_table_print_tl
+        \tl_gset:Nx \c__nicematrix_table_print_tl { \tl_item:Nn \g_tmpa_tl { -1 } }
+        \cs_gset_eq:NN \__nicematrix_adapt_S_column: \prg_do_nothing:
       }
   }
-\cs_new_protected:Npn \__nm_renew_NC@rewrite@S:
+\cs_new_protected:Npn \__nicematrix_renew_NC@rewrite@S:
   {
     \renewcommand*{\NC@rewrite@S}[1][]
       {
         \@temptokena \exp_after:wN
           {
             \tex_the:D \@temptokena
-            > { \__nm_Cell: \c__nm_table_collect_begin_tl S {##1} }
+            > { \__nicematrix_Cell: \c__nicematrix_table_collect_begin_tl S {##1} }
             c
-            < { \c__nm_table_print_tl \__nm_end_Cell: }
+            < { \c__nicematrix_table_print_tl \__nicematrix_end_Cell: }
           }
         \NC@find
       }
   }
-\str_new:N \l__nm_pos_env_str
-\str_set:Nn \l__nm_pos_env_str c
-\bool_new:N \l__nm_exterior_arraycolsep_bool
-\bool_new:N \l__nm_parallelize_diags_bool
-\bool_set_true:N \l__nm_parallelize_diags_bool
-\bool_new:N \l__nm_hlines_bool
-\bool_new:N \l__nm_nullify_dots_bool
-\bool_new:N \l__nm_auto_columns_width_bool
-\str_new:N \l__nm_name_str
-\bool_new:N \l__nm_extra_nodes_bool
-\bool_new:N \g__nm_extra_nodes_bool
-\dim_new:N \l__nm_left_margin_dim
-\dim_new:N \l__nm_right_margin_dim
-\dim_new:N \g__nm_width_last_col_dim
-\dim_new:N \g__nm_width_first_col_dim
-\dim_new:N \l__nm_extra_left_margin_dim
-\dim_new:N \l__nm_extra_right_margin_dim
+\str_new:N \l__nicematrix_pos_env_str
+\str_set:Nn \l__nicematrix_pos_env_str c
+\bool_new:N \l__nicematrix_exterior_arraycolsep_bool
+\bool_new:N \l__nicematrix_parallelize_diags_bool
+\bool_set_true:N \l__nicematrix_parallelize_diags_bool
+\bool_new:N \l__nicematrix_hlines_bool
+\bool_new:N \l__nicematrix_nullify_dots_bool
+\bool_new:N \l__nicematrix_auto_columns_width_bool
+\str_new:N \l__nicematrix_name_str
+\bool_new:N \l__nicematrix_extra_nodes_bool
+\bool_new:N \g__nicematrix_extra_nodes_bool
+\dim_new:N \l__nicematrix_left_margin_dim
+\dim_new:N \l__nicematrix_right_margin_dim
+\dim_new:N \g__nicematrix_width_last_col_dim
+\dim_new:N \g__nicematrix_width_first_col_dim
+\dim_new:N \l__nicematrix_extra_left_margin_dim
+\dim_new:N \l__nicematrix_extra_right_margin_dim
 \keys_define:nn { NiceMatrix / Global }
   {
-    code-for-first-col .tl_set:N = \l__nm_code_for_first_col_tl ,
-    code-for-first-col .value_required:n = true ,
-    code-for-last-col .tl_set:N = \l__nm_code_for_last_col_tl ,
-    code-for-last-col .value_required:n = true ,
-    code-for-first-row .tl_set:N = \l__nm_code_for_first_row_tl ,
-    code-for-first-row .value_required:n = true ,
-    code-for-last-row .tl_set:N = \l__nm_code_for_last_row_tl ,
-    code-for-last-row .value_required:n = true ,
-    small .bool_set:N = \l__nm_small_bool ,
-    hlines .bool_set:N = \l__nm_hlines_bool ,
-    parallelize-diags .bool_set:N = \l__nm_parallelize_diags_bool ,
-    renew-dots .bool_set:N = \l__nm_renew_dots_bool ,
-    renew-dots .value_forbidden:n = true ,
-    nullify-dots .bool_set:N = \l__nm_nullify_dots_bool ,
-    create-extra-nodes .bool_set:N = \l__nm_extra_nodes_bool ,
-    left-margin .dim_set:N = \l__nm_left_margin_dim ,
+    code-for-first-col .tl_set:N = \l__nicematrix_code_for_first_col_tl ,
+    code-for-last-col .tl_set:N = \l__nicematrix_code_for_last_col_tl ,
+    code-for-first-row .tl_set:N = \l__nicematrix_code_for_first_row_tl ,
+    code-for-last-row .tl_set:N = \l__nicematrix_code_for_last_row_tl ,
+    small .bool_set:N = \l__nicematrix_small_bool ,
+    hlines .bool_set:N = \l__nicematrix_hlines_bool ,
+    parallelize-diags .bool_set:N = \l__nicematrix_parallelize_diags_bool ,
+    renew-dots .bool_set:N = \l__nicematrix_renew_dots_bool ,
+
+    nullify-dots .bool_set:N = \l__nicematrix_nullify_dots_bool ,
+    create-extra-nodes .bool_set:N = \l__nicematrix_extra_nodes_bool ,
+    left-margin .dim_set:N = \l__nicematrix_left_margin_dim ,
     left-margin .default:n = \arraycolsep ,
-    right-margin .dim_set:N = \l__nm_right_margin_dim ,
+    right-margin .dim_set:N = \l__nicematrix_right_margin_dim ,
     right-margin .default:n = \arraycolsep ,
     margin .meta:n = { left-margin = #1 , right-margin = #1 } ,
     margin .default:n = \arraycolsep ,
-    extra-left-margin .dim_set:N = \l__nm_extra_left_margin_dim ,
-    extra-right-margin .dim_set:N = \l__nm_extra_right_margin_dim ,
+    extra-left-margin .dim_set:N = \l__nicematrix_extra_left_margin_dim ,
+    extra-right-margin .dim_set:N = \l__nicematrix_extra_right_margin_dim ,
     extra-margin .meta:n =
      { extra-left-margin = #1 , extra-right-margin = #1 } ,
   }
@@ -198,23 +194,20 @@
   {
     columns-width .code:n =
       \str_if_eq:nnTF { #1 } { auto }
-        { \bool_set_true:N \l__nm_auto_columns_width_bool }
-        { \dim_set:Nn \l__nm_columns_width_dim { #1 } } ,
-    columns-width .value_required:n = true ,
+        { \bool_set_true:N \l__nicematrix_auto_columns_width_bool }
+        { \dim_set:Nn \l__nicematrix_columns_width_dim { #1 } } ,
     name .code:n =
       \unless \ifmeasuring@
          \str_set:Nn \l_tmpa_str { #1 }
-         \seq_if_in:NVTF \g__nm_names_seq \l_tmpa_str
-           { \__nm_error:nn { Duplicate~name } { #1 } }
-           { \seq_gput_left:NV \g__nm_names_seq \l_tmpa_str }
-         \str_set_eq:NN \l__nm_name_str \l_tmpa_str
+         \seq_if_in:NVTF \g__nicematrix_names_seq \l_tmpa_str
+           { \__nicematrix_error:nn { Duplicate~name } { #1 } }
+           { \seq_gput_left:NV \g__nicematrix_names_seq \l_tmpa_str }
+         \str_set_eq:NN \l__nicematrix_name_str \l_tmpa_str
       \fi ,
-    name .value_required:n = true ,
-    code-after .tl_gset:N = \g__nm_code_after_tl ,
-    code-after .value_required:n = true ,
-    first-col .code:n = \int_zero:N \l__nm_first_col_int ,
-    first-row .code:n = \int_zero:N \l__nm_first_row_int ,
-    last-row .int_set:N = \l__nm_last_row_int ,
+    code-after .tl_gset:N = \g__nicematrix_code_after_tl ,
+    first-col .code:n = \int_zero:N \l__nicematrix_first_col_int ,
+    first-row .code:n = \int_zero:N \l__nicematrix_first_row_int ,
+    last-row .int_set:N = \l__nicematrix_last_row_int ,
     last-row .default:n = -1 ,
   }
 \keys_define:nn { NiceMatrix }
@@ -241,117 +234,117 @@
   }
 \keys_define:nn { NiceMatrix / NiceMatrixOptions }
   {
-    renew-matrix .code:n = \__nm_renew_matrix: ,
+    renew-matrix .code:n = \__nicematrix_renew_matrix: ,
     renew-matrix .value_forbidden:n = true ,
-    RenewMatrix .code:n = \__nm_error:n { Option~RenewMatrix~suppressed }
-                          \__nm_renew_matrix: ,
+    RenewMatrix .code:n = \__nicematrix_error:n { Option~RenewMatrix~suppressed }
+                          \__nicematrix_renew_matrix: ,
     transparent .meta:n = { renew-dots , renew-matrix } ,
     transparent .value_forbidden:n = true,
-    Transparent .code:n = \__nm_error:n { Option~Transparent~suppressed }
-                          \__nm_renew_matrix:
-                          \bool_set_true:N \l__nm_renew_dots_bool ,
-    exterior-arraycolsep .bool_set:N = \l__nm_exterior_arraycolsep_bool ,
+    Transparent .code:n = \__nicematrix_error:n { Option~Transparent~suppressed }
+                          \__nicematrix_renew_matrix:
+                          \bool_set_true:N \l__nicematrix_renew_dots_bool ,
+    exterior-arraycolsep .bool_set:N = \l__nicematrix_exterior_arraycolsep_bool ,
     columns-width .code:n =
       \str_if_eq:nnTF { #1 } { auto }
-        { \__nm_error:n { Option~auto~for~columns-width } }
-        { \dim_set:Nn \l__nm_columns_width_dim { #1 } } ,
+        { \__nicematrix_error:n { Option~auto~for~columns-width } }
+        { \dim_set:Nn \l__nicematrix_columns_width_dim { #1 } } ,
     allow-duplicate-names .code:n =
-      \__nm_msg_redirect_name:nn { Duplicate~name } { none } ,
+      \__nicematrix_msg_redirect_name:nn { Duplicate~name } { none } ,
     allow-duplicate-names .value_forbidden:n = true ,
     letter-for-dotted-lines .code:n =
       {
         \int_compare:nTF { \tl_count:n { #1 } = \c_one_int }
-          { \str_set:Nx \l__nm_letter_for_dotted_lines_str { #1 } }
-          { \__nm_error:n { Bad~value~for~letter~for~dotted~lines } }
+          { \str_set:Nx \l__nicematrix_letter_for_dotted_lines_str { #1 } }
+          { \__nicematrix_error:n { Bad~value~for~letter~for~dotted~lines } }
       } ,
     letter-for-dotted-lines .value_required:n = true ,
-    unknown .code:n  = \__nm_error:n { Unknown~key~for~NiceMatrixOptions }
+    unknown .code:n  = \__nicematrix_error:n { Unknown~key~for~NiceMatrixOptions }
   }
-\str_new:N \l__nm_letter_for_dotted_lines_str
-\str_set_eq:NN \l__nm_letter_for_dotted_lines_str \c_colon_str
+\str_new:N \l__nicematrix_letter_for_dotted_lines_str
+\str_set_eq:NN \l__nicematrix_letter_for_dotted_lines_str \c_colon_str
 \NewDocumentCommand \NiceMatrixOptions { m }
   { \keys_set:nn { NiceMatrix / NiceMatrixOptions } { #1 } }
 \keys_define:nn { NiceMatrix / NiceMatrix }
   {
     last-col .code:n = \tl_if_empty:nTF {#1}
-                         { \__nm_error:n { last-col~empty~for~NiceMatrix } }
-                         { \int_set:Nn \l__nm_last_col_int { #1 } } ,
-    unknown .code:n = \__nm_error:n { Unknown~option~for~NiceMatrix }
+                         { \__nicematrix_error:n { last-col~empty~for~NiceMatrix } }
+                         { \int_set:Nn \l__nicematrix_last_col_int { #1 } } ,
+    unknown .code:n = \__nicematrix_error:n { Unknown~option~for~NiceMatrix }
   }
 \keys_define:nn { NiceMatrix / NiceArray }
   {
-    c .code:n = \str_set:Nn \l__nm_pos_env_str c ,
-    t .code:n = \str_set:Nn \l__nm_pos_env_str t ,
-    b .code:n = \str_set:Nn \l__nm_pos_env_str b ,
+    c .code:n = \str_set:Nn \l__nicematrix_pos_env_str c ,
+    t .code:n = \str_set:Nn \l__nicematrix_pos_env_str t ,
+    b .code:n = \str_set:Nn \l__nicematrix_pos_env_str b ,
     last-col .code:n = \tl_if_empty:nF {#1}
-                         { \__nm_error:n { last-col~non~empty~for~NiceArray } }
-                       \int_zero:N \l__nm_last_col_int ,
-    unknown .code:n = \__nm_error:n { Unknown~option~for~NiceArray }
+                         { \__nicematrix_error:n { last-col~non~empty~for~NiceArray } }
+                       \int_zero:N \l__nicematrix_last_col_int ,
+    unknown .code:n = \__nicematrix_error:n { Unknown~option~for~NiceArray }
   }
 \keys_define:nn { NiceMatrix / pNiceArray }
   {
-    first-col .code:n = \int_zero:N \l__nm_first_col_int ,
+    first-col .code:n = \int_zero:N \l__nicematrix_first_col_int ,
     last-col .code:n = \tl_if_empty:nF {#1}
-                         { \__nm_error:n { last-col~non~empty~for~NiceArray } }
-                       \int_zero:N \l__nm_last_col_int ,
-    first-row .code:n = \int_zero:N \l__nm_first_row_int ,
-    last-row .int_set:N = \l__nm_last_row_int ,
+                         { \__nicematrix_error:n { last-col~non~empty~for~NiceArray } }
+                       \int_zero:N \l__nicematrix_last_col_int ,
+    first-row .code:n = \int_zero:N \l__nicematrix_first_row_int ,
+    last-row .int_set:N = \l__nicematrix_last_row_int ,
     last-row .default:n = -1 ,
-    unknown .code:n = \__nm_error:n { Unknown~option~for~NiceMatrix }
+    unknown .code:n = \__nicematrix_error:n { Unknown~option~for~NiceMatrix }
   }
-\cs_new_protected:Nn \__nm_Cell:
+\cs_new_protected:Nn \__nicematrix_Cell:
   {
     \int_gincr:N \c@jCol
     \int_compare:nNnT \c@jCol = \c_one_int
       {
-        \int_compare:nNnT \l__nm_first_col_int = \c_one_int
-          \__nm_begin_of_row:
+        \int_compare:nNnT \l__nicematrix_first_col_int = \c_one_int
+          \__nicematrix_begin_of_row:
       }
-    \int_gset:Nn \g__nm_col_total_int
-      { \int_max:nn \g__nm_col_total_int \c@jCol }
+    \int_gset:Nn \g__nicematrix_col_total_int
+      { \int_max:nn \g__nicematrix_col_total_int \c@jCol }
     \hbox_set:Nw \l_tmpa_box
     \c_math_toggle_token
-    \bool_if:NT \l__nm_small_bool \scriptstyle
+    \bool_if:NT \l__nicematrix_small_bool \scriptstyle
     \int_compare:nNnTF \c@iRow = \c_zero_int
-      { \int_compare:nNnT \c@jCol > \c_zero_int \l__nm_code_for_first_row_tl }
+      { \int_compare:nNnT \c@jCol > \c_zero_int \l__nicematrix_code_for_first_row_tl }
       {
-        \int_compare:nNnT \c@iRow = \l__nm_last_row_int
-          \l__nm_code_for_last_row_tl
+        \int_compare:nNnT \c@iRow = \l__nicematrix_last_row_int
+          \l__nicematrix_code_for_last_row_tl
       }
   }
-\cs_new_protected:Nn \__nm_begin_of_row:
+\cs_new_protected:Nn \__nicematrix_begin_of_row:
   {
     \int_gincr:N \c@iRow
-    \dim_gset_eq:NN \g__nm_dp_ante_last_row_dim \g__nm_dp_last_row_dim
-    \dim_gzero:N \g__nm_dp_last_row_dim
-    \dim_gzero:N \g__nm_ht_last_row_dim
+    \dim_gset_eq:NN \g__nicematrix_dp_ante_last_row_dim \g__nicematrix_dp_last_row_dim
+    \dim_gzero:N \g__nicematrix_dp_last_row_dim
+    \dim_gzero:N \g__nicematrix_ht_last_row_dim
   }
-\cs_new_protected:Npn \__nm_actualization_for_first_and_last_row:
+\cs_new_protected:Npn \__nicematrix_actualization_for_first_and_last_row:
   {
     \int_compare:nNnT \c@iRow = \c_zero_int
       {
-        \dim_gset:Nn \g__nm_dp_row_zero_dim
-          { \dim_max:nn \g__nm_dp_row_zero_dim { \box_dp:N \l_tmpa_box } }
-        \dim_gset:Nn \g__nm_ht_row_zero_dim
-          { \dim_max:nn \g__nm_ht_row_zero_dim { \box_ht:N \l_tmpa_box } }
+        \dim_gset:Nn \g__nicematrix_dp_row_zero_dim
+          { \dim_max:nn \g__nicematrix_dp_row_zero_dim { \box_dp:N \l_tmpa_box } }
+        \dim_gset:Nn \g__nicematrix_ht_row_zero_dim
+          { \dim_max:nn \g__nicematrix_ht_row_zero_dim { \box_ht:N \l_tmpa_box } }
       }
     \int_compare:nNnT \c@iRow = \c_one_int
       {
-        \dim_gset:Nn \g__nm_ht_row_one_dim
-          { \dim_max:nn \g__nm_ht_row_one_dim { \box_ht:N \l_tmpa_box } }
+        \dim_gset:Nn \g__nicematrix_ht_row_one_dim
+          { \dim_max:nn \g__nicematrix_ht_row_one_dim { \box_ht:N \l_tmpa_box } }
       }
-    \dim_gset:Nn \g__nm_ht_last_row_dim
-      { \dim_max:nn \g__nm_ht_last_row_dim { \box_ht:N \l_tmpa_box } }
-    \dim_gset:Nn \g__nm_dp_last_row_dim
-      { \dim_max:nn \g__nm_dp_last_row_dim { \box_dp:N \l_tmpa_box } }
+    \dim_gset:Nn \g__nicematrix_ht_last_row_dim
+      { \dim_max:nn \g__nicematrix_ht_last_row_dim { \box_ht:N \l_tmpa_box } }
+    \dim_gset:Nn \g__nicematrix_dp_last_row_dim
+      { \dim_max:nn \g__nicematrix_dp_last_row_dim { \box_dp:N \l_tmpa_box } }
   }
-\cs_new_protected:Nn \__nm_end_Cell:
+\cs_new_protected:Nn \__nicematrix_end_Cell:
   {
     \c_math_toggle_token
     \hbox_set_end:
-    \dim_gset:Nn \g__nm_max_cell_width_dim
-      { \dim_max:nn \g__nm_max_cell_width_dim { \box_wd:N \l_tmpa_box } }
-    \__nm_actualization_for_first_and_last_row:
+    \dim_gset:Nn \g__nicematrix_max_cell_width_dim
+      { \dim_max:nn \g__nicematrix_max_cell_width_dim { \box_wd:N \l_tmpa_box } }
+    \__nicematrix_actualization_for_first_and_last_row:
     \tikz
       [
         remember~picture ,
@@ -362,13 +355,13 @@
     \node
       [
         anchor = base ,
-        name = nm - \int_use:N \g__nm_env_int -
+        name = nm - \int_use:N \g__nicematrix_env_int -
                     \int_use:N \c@iRow -
                     \int_use:N \c@jCol ,
         alias =
-          \str_if_empty:NF \l__nm_name_str
+          \str_if_empty:NF \l__nicematrix_name_str
             {
-              \l__nm_name_str -
+              \l__nicematrix_name_str -
               \int_use:N \c@iRow -
               \int_use:N \c@jCol
             }
@@ -378,17 +371,17 @@
     \egroup ;
   }
 \cs_generate_variant:Nn \dim_set:Nn { N x }
-\cs_new_protected:Nn \__nm_renewcolumntype:nn
+\cs_new_protected:Nn \__nicematrix_renewcolumntype:nn
   {
     \newcolumntype #1 [ 2 ]
       {
         > {
             \hbox_set:Nw \l_tmpa_box
-            \__nm_Cell:
+            \__nicematrix_Cell:
           }
         c
         < {
-            \__nm_end_Cell:
+            \__nicematrix_end_Cell:
             \hbox_set_end:
             #2
             \hbox_set:Nn \l_tmpb_box
@@ -402,12 +395,12 @@
                       {
                         \hfil
                         \tikz [ remember~picture , overlay ]
-                        \coordinate (__nm~north~east) ;
+                        \coordinate (__nicematrix~north~east) ;
                       }
                     \hbox:n
                       {
                         \tikz [ remember~picture , overlay ]
-                        \coordinate (__nm~south~west) ;
+                        \coordinate (__nicematrix~south~west) ;
                         \box_move_up:nn \l_tmpa_dim { \box_use:N \l_tmpb_box }
                       }
                   }
@@ -416,40 +409,40 @@
             \node
               [
                 node~contents = { } ,
-                name = nm - \int_use:N \g__nm_env_int -
+                name = nm - \int_use:N \g__nicematrix_env_int -
                             \int_use:N \c@iRow -
                             \int_use:N \c@jCol - w,
                 alias =
-                  \str_if_empty:NF \l__nm_name_str
+                  \str_if_empty:NF \l__nicematrix_name_str
                     {
-                      \l__nm_name_str -
+                      \l__nicematrix_name_str -
                       \int_use:N \c@iRow -
                       \int_use:N \c@jCol - w
                     } ,
                 inner~sep = \c_zero_dim ,
-                fit = (__nm~south~west) (__nm~north~east)
+                fit = (__nicematrix~south~west) (__nicematrix~north~east)
               ]
             ;
           }
       }
   }
-\bool_if:NTF \c__nm_draft_bool
-  { \cs_set_protected:Npn \__nm_instruction_of_type:n #1 { } }
+\bool_if:NTF \c__nicematrix_draft_bool
+  { \cs_set_protected:Npn \__nicematrix_instruction_of_type:n #1 { } }
   {
-    \cs_new_protected:Npn \__nm_instruction_of_type:n #1
+    \cs_new_protected:Npn \__nicematrix_instruction_of_type:n #1
       {
         \tl_gput_right:cx
-          { g__nm_ #1 _ lines _ tl }
+          { g__nicematrix_ #1 _ lines _ tl }
           {
-            \use:c { __nm _ draw _ #1 : nn }
+            \use:c { __nicematrix _ draw _ #1 : nn }
               { \int_use:N \c@iRow }
               { \int_use:N \c@jCol }
           }
       }
   }
-\cs_new_protected:Npn \__nm_array:
+\cs_new_protected:Npn \__nicematrix_array:
   {
-    \bool_if:NTF \c__nm_revtex_bool
+    \bool_if:NTF \c__nicematrix_revtex_bool
       {
         \cs_set_eq:NN \@acoll \@arrayacol
         \cs_set_eq:NN \@acolr \@arrayacol
@@ -458,18 +451,18 @@
         \@array@array
       }
       \array
-    [ \l__nm_pos_env_str ]
+    [ \l__nicematrix_pos_env_str ]
   }
-\cs_new:Npn \__nm_everycr:
-  { \noalign { \__nm_everycr_i: } }
-\cs_new_protected:Npn \__nm_everycr_i:
+\cs_new:Npn \__nicematrix_everycr:
+  { \noalign { \__nicematrix_everycr_i: } }
+\cs_new_protected:Npn \__nicematrix_everycr_i:
   {
     \int_gzero:N \c@jCol
-    \bool_if:NT \l__nm_hlines_bool
+    \bool_if:NT \l__nicematrix_hlines_bool
       {
         \int_compare:nNnT \c@iRow > { -1 }
           {
-            \int_compare:nNnF \c@iRow = \l__nm_last_row_int
+            \int_compare:nNnF \c@iRow = \l__nicematrix_last_row_int
               {
                 \hrule \@height \arrayrulewidth
                 \skip_vertical:n { - \arrayrulewidth }
@@ -477,45 +470,45 @@
           }
       }
   }
-\cs_new_protected:Npn \__nm_pre_array:
+\cs_new_protected:Npn \__nicematrix_pre_array:
   {
     \cs_if_exist:NT \theiRow
-      { \int_set_eq:NN \l__nm_save_iRow_int \c@iRow }
+      { \int_set_eq:NN \l__nicematrix_save_iRow_int \c@iRow }
     \int_gzero_new:N \c@iRow
     \cs_if_exist:NT \thejCol
-      { \int_set_eq:NN \l__nm_save_jCol_int \c@jCol }
+      { \int_set_eq:NN \l__nicematrix_save_jCol_int \c@jCol }
     \int_gzero_new:N \c@jCol
     \normalbaselines
-    \bool_if:NT \l__nm_small_bool
+    \bool_if:NT \l__nicematrix_small_bool
       {
         \cs_set:Npn \arraystretch { 0.47 }
         \dim_set:Nn \arraycolsep { 1.45 pt }
       }
-    \bool_gset_eq:NN \g__nm_extra_nodes_bool \l__nm_extra_nodes_bool
+    \bool_gset_eq:NN \g__nicematrix_extra_nodes_bool \l__nicematrix_extra_nodes_bool
     \cs_set:Npn \ialign
       {
-        \bool_if:NTF \c__nm_colortbl_loaded_bool
+        \bool_if:NTF \c__nicematrix_colortbl_loaded_bool
           {
             \CT@everycr
               {
                 \noalign { \cs_gset_eq:NN \CT@row@color \prg_do_nothing: }
-                \__nm_everycr:
+                \__nicematrix_everycr:
               }
           }
-          { \everycr { \__nm_everycr: } }
+          { \everycr { \__nicematrix_everycr: } }
         \tabskip = \c_zero_skip
-        \dim_gzero_new:N \g__nm_dp_row_zero_dim
-        \dim_gset:Nn \g__nm_dp_row_zero_dim { \box_dp:N \@arstrutbox }
-        \dim_gzero_new:N \g__nm_ht_row_zero_dim
-        \dim_gset:Nn \g__nm_ht_row_zero_dim { \box_ht:N \@arstrutbox }
-        \dim_gzero_new:N \g__nm_ht_row_one_dim
-        \dim_gset:Nn \g__nm_ht_row_one_dim { \box_ht:N \@arstrutbox }
-        \dim_gzero_new:N \g__nm_dp_ante_last_row_dim
-        \dim_gset:Nn \g__nm_dp_ante_last_row_dim { \box_dp:N \@arstrutbox }
-        \dim_gzero_new:N \g__nm_ht_last_row_dim
-        \dim_gset:Nn \g__nm_ht_last_row_dim { \box_ht:N \@arstrutbox }
-        \dim_gzero_new:N \g__nm_dp_last_row_dim
-        \dim_gset:Nn \g__nm_dp_last_row_dim { \box_dp:N \@arstrutbox }
+        \dim_gzero_new:N \g__nicematrix_dp_row_zero_dim
+        \dim_gset:Nn \g__nicematrix_dp_row_zero_dim { \box_dp:N \@arstrutbox }
+        \dim_gzero_new:N \g__nicematrix_ht_row_zero_dim
+        \dim_gset:Nn \g__nicematrix_ht_row_zero_dim { \box_ht:N \@arstrutbox }
+        \dim_gzero_new:N \g__nicematrix_ht_row_one_dim
+        \dim_gset:Nn \g__nicematrix_ht_row_one_dim { \box_ht:N \@arstrutbox }
+        \dim_gzero_new:N \g__nicematrix_dp_ante_last_row_dim
+        \dim_gset:Nn \g__nicematrix_dp_ante_last_row_dim { \box_dp:N \@arstrutbox }
+        \dim_gzero_new:N \g__nicematrix_ht_last_row_dim
+        \dim_gset:Nn \g__nicematrix_ht_last_row_dim { \box_ht:N \@arstrutbox }
+        \dim_gzero_new:N \g__nicematrix_dp_last_row_dim
+        \dim_gset:Nn \g__nicematrix_dp_last_row_dim { \box_dp:N \@arstrutbox }
         \cs_set:Npn \ialign
            {
              \everycr { }
@@ -524,122 +517,122 @@
            }
         \halign
       }
-    \newcolumntype L { > \__nm_Cell: l < \__nm_end_Cell: }
-    \newcolumntype C { > \__nm_Cell: c < \__nm_end_Cell: }
-    \newcolumntype R { > \__nm_Cell: r < \__nm_end_Cell: }
-    \cs_set_eq:NN \Ldots \__nm_Ldots
-    \cs_set_eq:NN \Cdots \__nm_Cdots
-    \cs_set_eq:NN \Vdots \__nm_Vdots
-    \cs_set_eq:NN \Ddots \__nm_Ddots
-    \cs_set_eq:NN \Iddots \__nm_Iddots
-    \cs_set_eq:NN \hdottedline \__nm_hdottedline:
-    \cs_set_eq:NN \Hspace \__nm_Hspace:
-    \cs_set_eq:NN \Hdotsfor \__nm_Hdotsfor:
-    \cs_set_eq:NN \multicolumn \__nm_multicolumn:nnn
-    \cs_set_eq:NN \Block \__nm_Block:
-    \bool_if:NT \l__nm_renew_dots_bool
-      {
-        \cs_set_eq:NN \ldots \__nm_Ldots
-        \cs_set_eq:NN \cdots \__nm_Cdots
-        \cs_set_eq:NN \vdots \__nm_Vdots
-        \cs_set_eq:NN \ddots \__nm_Ddots
-        \cs_set_eq:NN \iddots \__nm_Iddots
-        \cs_set_eq:NN \dots \__nm_Ldots
-        \cs_set_eq:NN \hdotsfor \__nm_Hdotsfor:
-      }
-    \seq_gclear_new:N \g__nm_multicolumn_cells_seq
-    \seq_gclear_new:N \g__nm_multicolumn_sizes_seq
-    \int_gset:Nn \c@iRow { \l__nm_first_row_int - 1 }
-    \int_gzero_new:N \g__nm_row_total_int
-    \int_gzero_new:N \g__nm_col_total_int
+    \newcolumntype L { > \__nicematrix_Cell: l < \__nicematrix_end_Cell: }
+    \newcolumntype C { > \__nicematrix_Cell: c < \__nicematrix_end_Cell: }
+    \newcolumntype R { > \__nicematrix_Cell: r < \__nicematrix_end_Cell: }
+    \cs_set_eq:NN \Ldots \__nicematrix_Ldots
+    \cs_set_eq:NN \Cdots \__nicematrix_Cdots
+    \cs_set_eq:NN \Vdots \__nicematrix_Vdots
+    \cs_set_eq:NN \Ddots \__nicematrix_Ddots
+    \cs_set_eq:NN \Iddots \__nicematrix_Iddots
+    \cs_set_eq:NN \hdottedline \__nicematrix_hdottedline:
+    \cs_set_eq:NN \Hspace \__nicematrix_Hspace:
+    \cs_set_eq:NN \Hdotsfor \__nicematrix_Hdotsfor:
+    \cs_set_eq:NN \multicolumn \__nicematrix_multicolumn:nnn
+    \cs_set_eq:NN \Block \__nicematrix_Block:
+    \bool_if:NT \l__nicematrix_renew_dots_bool
+      {
+        \cs_set_eq:NN \ldots \__nicematrix_Ldots
+        \cs_set_eq:NN \cdots \__nicematrix_Cdots
+        \cs_set_eq:NN \vdots \__nicematrix_Vdots
+        \cs_set_eq:NN \ddots \__nicematrix_Ddots
+        \cs_set_eq:NN \iddots \__nicematrix_Iddots
+        \cs_set_eq:NN \dots \__nicematrix_Ldots
+        \cs_set_eq:NN \hdotsfor \__nicematrix_Hdotsfor:
+      }
+    \seq_gclear_new:N \g__nicematrix_multicolumn_cells_seq
+    \seq_gclear_new:N \g__nicematrix_multicolumn_sizes_seq
+    \int_gset:Nn \c@iRow { \l__nicematrix_first_row_int - 1 }
+    \int_gzero_new:N \g__nicematrix_row_total_int
+    \int_gzero_new:N \g__nicematrix_col_total_int
     \cs_set_eq:NN \@ifnextchar \new@ifnextchar
     \cs_set_eq:NN \NC@find@w \relax
     \cs_set_eq:NN \NC@find@W \relax
-    \__nm_renewcolumntype:nn w { }
-    \__nm_renewcolumntype:nn W { \cs_set_eq:NN \hss \hfil }
+    \__nicematrix_renewcolumntype:nn w { }
+    \__nicematrix_renewcolumntype:nn W { \cs_set_eq:NN \hss \hfil }
     \tl_set_rescan:Nno
-      \l__nm_letter_for_dotted_lines_str { } \l__nm_letter_for_dotted_lines_str
-    \exp_args:NV \newcolumntype \l__nm_letter_for_dotted_lines_str
+      \l__nicematrix_letter_for_dotted_lines_str { } \l__nicematrix_letter_for_dotted_lines_str
+    \exp_args:NV \newcolumntype \l__nicematrix_letter_for_dotted_lines_str
       {
         !
           {
             \skip_horizontal:n { 0.53 pt }
             \bool_if:nF
               {
-                \l__nm_auto_columns_width_bool
-                || \dim_compare_p:nNn \l__nm_columns_width_dim > \c_zero_dim
+                \l__nicematrix_auto_columns_width_bool
+                || \dim_compare_p:nNn \l__nicematrix_columns_width_dim > \c_zero_dim
               }
-              { \bool_gset_true:N \g__nm_extra_nodes_bool }
-            \int_compare:nNnT \c@jCol > \g__nm_last_vdotted_col_int
+              { \bool_gset_true:N \g__nicematrix_extra_nodes_bool }
+            \int_compare:nNnT \c@jCol > \g__nicematrix_last_vdotted_col_int
               {
-                \int_gset_eq:NN \g__nm_last_vdotted_col_int \c@jCol
-                \tl_gput_right:Nx \g__nm_code_after_tl
-                  { \__nm_vdottedline:n { \int_use:N \c@jCol } }
+                \int_gset_eq:NN \g__nicematrix_last_vdotted_col_int \c@jCol
+                \tl_gput_right:Nx \g__nicematrix_code_after_tl
+                  { \__nicematrix_vdottedline:n { \int_use:N \c@jCol } }
               }
           }
       }
-    \int_gzero_new:N \g__nm_last_vdotted_col_int
-    \bool_if:NT \c__nm_siunitx_loaded_bool \__nm_renew_NC@rewrite@S:
-    \int_gset:Nn \g__nm_last_vdotted_col_int { -1 }
-    \bool_gset_false:N \g__nm_last_col_found_bool
-    \tl_gclear_new:N \g__nm_Cdots_lines_tl
-    \tl_gclear_new:N \g__nm_Ldots_lines_tl
-    \tl_gclear_new:N \g__nm_Vdots_lines_tl
-    \tl_gclear_new:N \g__nm_Ddots_lines_tl
-    \tl_gclear_new:N \g__nm_Iddots_lines_tl
-    \tl_gclear_new:N \g__nm_Hdotsfor_lines_tl
+    \int_gzero_new:N \g__nicematrix_last_vdotted_col_int
+    \bool_if:NT \c__nicematrix_siunitx_loaded_bool \__nicematrix_renew_NC@rewrite@S:
+    \int_gset:Nn \g__nicematrix_last_vdotted_col_int { -1 }
+    \bool_gset_false:N \g__nicematrix_last_col_found_bool
+    \tl_gclear_new:N \g__nicematrix_Cdots_lines_tl
+    \tl_gclear_new:N \g__nicematrix_Ldots_lines_tl
+    \tl_gclear_new:N \g__nicematrix_Vdots_lines_tl
+    \tl_gclear_new:N \g__nicematrix_Ddots_lines_tl
+    \tl_gclear_new:N \g__nicematrix_Iddots_lines_tl
+    \tl_gclear_new:N \g__nicematrix_Hdotsfor_lines_tl
  }
 \NewDocumentEnvironment { NiceArrayWithDelims } { m m O { } m ! O { } }
   {
-    \str_if_empty:NT \g__nm_type_env_str
+    \str_if_empty:NT \g__nicematrix_type_env_str
       {
-        \str_gset:Nn \g__nm_type_env_str
+        \str_gset:Nn \g__nicematrix_type_env_str
           { environment ~ { NiceArrayWithDelims } }
       }
-    \__nm_adapt_S_column:
-    \__nm_test_if_math_mode:
-    \bool_if:NT \l__nm_in_env_bool { \__nm_fatal:n { Yet~in~env } }
-    \bool_set_true:N \l__nm_in_env_bool
+    \__nicematrix_adapt_S_column:
+    \__nicematrix_test_if_math_mode:
+    \bool_if:NT \l__nicematrix_in_env_bool { \__nicematrix_fatal:n { Yet~in~env } }
+    \bool_set_true:N \l__nicematrix_in_env_bool
     \cs_if_exist:NT \tikz@library@external@loaded
       {
         \tikzset { external / export = false }
         \cs_if_exist:NT \ifstandalone
           { \tikzset { external / optimize = false } }
       }
-    \int_gincr:N \g__nm_env_int
-    \bool_if:NF \l__nm_block_auto_columns_width_bool
-      { \dim_gzero_new:N \g__nm_max_cell_width_dim }
-    \cs_set_protected:Npn \@arrayrule { \@addtopreamble \__nm_vline: }
-    \bool_if:NTF \l__nm_NiceArray_bool
+    \int_gincr:N \g__nicematrix_env_int
+    \bool_if:NF \l__nicematrix_block_auto_columns_width_bool
+      { \dim_gzero_new:N \g__nicematrix_max_cell_width_dim }
+    \cs_set_protected:Npn \@arrayrule { \@addtopreamble \__nicematrix_vline: }
+    \bool_if:NTF \l__nicematrix_NiceArray_bool
       { \keys_set:nn { NiceMatrix / NiceArray } }
       { \keys_set:nn { NiceMatrix / pNiceArray } }
     { #3 , #5 }
-    \int_compare:nNnT \l__nm_last_row_int = { -1 }
+    \int_compare:nNnT \l__nicematrix_last_row_int = { -1 }
       {
-        \bool_set_true:N \l__nm_last_row_without_value_bool
-        \str_if_empty:NTF \l__nm_name_str
+        \bool_set_true:N \l__nicematrix_last_row_without_value_bool
+        \str_if_empty:NTF \l__nicematrix_name_str
           {
-            \cs_if_exist:cT { __nm_last_row_ \int_use:N \g__nm_env_int }
+            \cs_if_exist:cT { __nicematrix_last_row_ \int_use:N \g__nicematrix_env_int }
               {
-                \int_set:Nn \l__nm_last_row_int
-                  { \use:c { __nm_last_row_ \int_use:N \g__nm_env_int } }
+                \int_set:Nn \l__nicematrix_last_row_int
+                  { \use:c { __nicematrix_last_row_ \int_use:N \g__nicematrix_env_int } }
               }
           }
           {
-            \cs_if_exist:cT { __nm_last_row_ \l__nm_name_str }
+            \cs_if_exist:cT { __nicematrix_last_row_ \l__nicematrix_name_str }
               {
-                \int_set:Nn \l__nm_last_row_int
-                  { \use:c { __nm_last_row_ \l__nm_name_str } }
+                \int_set:Nn \l__nicematrix_last_row_int
+                  { \use:c { __nicematrix_last_row_ \l__nicematrix_name_str } }
               }
           }
       }
-    \__nm_pre_array:
-    \dim_gzero_new:N \g__nm_left_delim_dim
-    \dim_gzero_new:N \g__nm_right_delim_dim
-    \bool_if:NTF \l__nm_NiceArray_bool
+    \__nicematrix_pre_array:
+    \dim_gzero_new:N \g__nicematrix_left_delim_dim
+    \dim_gzero_new:N \g__nicematrix_right_delim_dim
+    \bool_if:NTF \l__nicematrix_NiceArray_bool
       {
-        \dim_gset:Nn \g__nm_left_delim_dim { 2 \arraycolsep }
-        \dim_gset:Nn \g__nm_right_delim_dim { 2 \arraycolsep }
+        \dim_gset:Nn \g__nicematrix_left_delim_dim { 2 \arraycolsep }
+        \dim_gset:Nn \g__nicematrix_right_delim_dim { 2 \arraycolsep }
       }
       {
         \group_begin:
@@ -651,7 +644,7 @@
             \c_math_toggle_token
 
           }
-        \dim_gset:Nn \g__nm_left_delim_dim { \box_wd:N \l_tmpa_box }
+        \dim_gset:Nn \g__nicematrix_left_delim_dim { \box_wd:N \l_tmpa_box }
         \hbox_set:Nn \l_tmpa_box
           {
             \dim_set_eq:NN \nulldelimiterspace \c_zero_dim
@@ -659,69 +652,69 @@
             \left. \vcenter to 3 cm { } \right #2
             \c_math_toggle_token
           }
-        \dim_gset:Nn \g__nm_right_delim_dim { \box_wd:N \l_tmpa_box }
+        \dim_gset:Nn \g__nicematrix_right_delim_dim { \box_wd:N \l_tmpa_box }
         \group_end:
       }
-    \box_clear_new:N \l__nm_the_array_box
+    \box_clear_new:N \l__nicematrix_the_array_box
     \tl_set:Nn \l_tmpa_tl { #4 }
-    \int_compare:nNnTF \l__nm_first_col_int = \c_zero_int
-      { \tl_put_left:NV \l_tmpa_tl \c__nm_preamble_first_col_tl }
+    \int_compare:nNnTF \l__nicematrix_first_col_int = \c_zero_int
+      { \tl_put_left:NV \l_tmpa_tl \c__nicematrix_preamble_first_col_tl }
       {
-        \bool_if:NT \l__nm_NiceArray_bool
+        \bool_if:NT \l__nicematrix_NiceArray_bool
           {
-            \bool_if:NF \l__nm_exterior_arraycolsep_bool
+            \bool_if:NF \l__nicematrix_exterior_arraycolsep_bool
               { \tl_put_left:Nn \l_tmpa_tl { @ { } } }
           }
       }
-    \int_compare:nNnTF \l__nm_last_col_int > { -1 }
-      { \tl_put_right:NV \l_tmpa_tl \c__nm_preamble_last_col_tl }
+    \int_compare:nNnTF \l__nicematrix_last_col_int > { -1 }
+      { \tl_put_right:NV \l_tmpa_tl \c__nicematrix_preamble_last_col_tl }
       {
-        \bool_if:NT \l__nm_NiceArray_bool
+        \bool_if:NT \l__nicematrix_NiceArray_bool
           {
-            \bool_if:NF \l__nm_exterior_arraycolsep_bool
+            \bool_if:NF \l__nicematrix_exterior_arraycolsep_bool
               { \tl_put_right:Nn \l_tmpa_tl { @ { } } }
           }
       }
-    \hbox_set:Nw \l__nm_the_array_box
-    \skip_horizontal:n \l__nm_left_margin_dim
-    \skip_horizontal:n \l__nm_extra_left_margin_dim
+    \hbox_set:Nw \l__nicematrix_the_array_box
+    \skip_horizontal:n \l__nicematrix_left_margin_dim
+    \skip_horizontal:n \l__nicematrix_extra_left_margin_dim
     \c_math_toggle_token
-    \exp_args:NV \__nm_array: \l_tmpa_tl
+    \exp_args:NV \__nicematrix_array: \l_tmpa_tl
   }
   {
     \bool_if:nT
       {
-        \l__nm_auto_columns_width_bool
-        || \dim_compare_p:nNn \l__nm_columns_width_dim > \c_zero_dim
+        \l__nicematrix_auto_columns_width_bool
+        || \dim_compare_p:nNn \l__nicematrix_columns_width_dim > \c_zero_dim
       }
       {
         \crcr
-        \int_compare:nNnT \l__nm_first_col_int = 0 { \omit & }
+        \int_compare:nNnT \l__nicematrix_first_col_int = 0 { \omit & }
         \omit
         \skip_horizontal:N \arraycolsep
         \tikz [ remember~picture , overlay ]
-          \coordinate [ name = nm - \int_use:N \g__nm_env_int - col - 0 ] ;
+          \coordinate [ name = nm - \int_use:N \g__nicematrix_env_int - col - 0 ] ;
         \skip_horizontal:n { - \arraycolsep }
         \bool_if:nTF
           {
-            \l__nm_auto_columns_width_bool
-            && ! \l__nm_block_auto_columns_width_bool
+            \l__nicematrix_auto_columns_width_bool
+            && ! \l__nicematrix_block_auto_columns_width_bool
           }
           {
             \dim_gset:Nn \g_tmpa_dim
-              { \g__nm_max_cell_width_dim + 2 \arraycolsep }
+              { \g__nicematrix_max_cell_width_dim + 2 \arraycolsep }
           }
           {
             \dim_gset:Nn \g_tmpa_dim
-              { \l__nm_columns_width_dim + 2 \arraycolsep }
+              { \l__nicematrix_columns_width_dim + 2 \arraycolsep }
           }
         \skip_horizontal:N \g_tmpa_dim
         \tikz [ remember~picture , overlay ]
-          \coordinate [ name = nm - \int_use:N \g__nm_env_int - col - 1 ] ;
+          \coordinate [ name = nm - \int_use:N \g__nicematrix_env_int - col - 1 ] ;
         \int_gset:Nn \g_tmpa_int 1
-        \bool_if:nTF \g__nm_last_col_found_bool
-          { \prg_replicate:nn { \g__nm_col_total_int - 3 } }
-          { \prg_replicate:nn { \g__nm_col_total_int - 2 } }
+        \bool_if:nTF \g__nicematrix_last_col_found_bool
+          { \prg_replicate:nn { \g__nicematrix_col_total_int - 3 } }
+          { \prg_replicate:nn { \g__nicematrix_col_total_int - 2 } }
           {
              &
              \omit
@@ -730,7 +723,7 @@
              \tikz [ remember~picture , overlay ]
                \coordinate
                  [
-                   name = nm - \int_use:N \g__nm_env_int -
+                   name = nm - \int_use:N \g__nicematrix_env_int -
                           col - \int_use:N \g_tmpa_int
                  ] ;
           }
@@ -742,68 +735,68 @@
         \tikz [ remember~picture , overlay ]
           \coordinate
             [
-              name = nm - \int_use:N \g__nm_env_int -
+              name = nm - \int_use:N \g__nicematrix_env_int -
                      col - \int_use:N \g_tmpa_int
             ] ;
         \skip_horizontal:N \arraycolsep
       }
     \endarray
     \c_math_toggle_token
-    \skip_horizontal:n \l__nm_right_margin_dim
-    \skip_horizontal:n \l__nm_extra_right_margin_dim
+    \skip_horizontal:n \l__nicematrix_right_margin_dim
+    \skip_horizontal:n \l__nicematrix_extra_right_margin_dim
     \hbox_set_end:
-    \int_compare:nNnT \l__nm_last_row_int > { -2 }
+    \int_compare:nNnT \l__nicematrix_last_row_int > { -2 }
       {
-        \bool_if:NF \l__nm_last_row_without_value_bool
+        \bool_if:NF \l__nicematrix_last_row_without_value_bool
           {
-            \int_compare:nNnF \l__nm_last_row_int = \c@iRow
+            \int_compare:nNnF \l__nicematrix_last_row_int = \c@iRow
               {
-                \__nm_error:n { Wrong~last~row }
-                \int_gset_eq:NN \l__nm_last_row_int \c@iRow
+                \__nicematrix_error:n { Wrong~last~row }
+                \int_gset_eq:NN \l__nicematrix_last_row_int \c@iRow
               }
           }
       }
-    \int_compare:nNnTF \l__nm_first_row_int = \c_zero_int
+    \int_compare:nNnTF \l__nicematrix_first_row_int = \c_zero_int
       {
         \dim_set:Nn \l_tmpa_dim
-          { \g__nm_dp_row_zero_dim + \lineskip + \g__nm_ht_row_zero_dim }
+          { \g__nicematrix_dp_row_zero_dim + \lineskip + \g__nicematrix_ht_row_zero_dim }
       }
       { \dim_zero:N \l_tmpa_dim }
-    \int_compare:nNnTF \l__nm_last_row_int > { -2 }
+    \int_compare:nNnTF \l__nicematrix_last_row_int > { -2 }
       {
         \dim_set:Nn \l_tmpb_dim
-          { \g__nm_ht_last_row_dim + \lineskip + \g__nm_dp_last_row_dim }
+          { \g__nicematrix_ht_last_row_dim + \lineskip + \g__nicematrix_dp_last_row_dim }
       }
       { \dim_zero:N \l_tmpb_dim }
-    \int_compare:nNnT \l__nm_first_col_int = \c_zero_int
+    \int_compare:nNnT \l__nicematrix_first_col_int = \c_zero_int
       {
         \skip_horizontal:n \arraycolsep
-        \skip_horizontal:n \g__nm_width_first_col_dim
+        \skip_horizontal:n \g__nicematrix_width_first_col_dim
       }
-    \bool_if:NTF \l__nm_NiceArray_bool
+    \bool_if:NTF \l__nicematrix_NiceArray_bool
       {
-        \int_compare:nNnT \l__nm_first_row_int = \c_zero_int
+        \int_compare:nNnT \l__nicematrix_first_row_int = \c_zero_int
           {
-            \str_if_eq:VnTF \l__nm_pos_env_str { t }
+            \str_if_eq:VnTF \l__nicematrix_pos_env_str { t }
               {
                 \box_move_up:nn
-                  { \l_tmpa_dim - \g__nm_ht_row_zero_dim + \g__nm_ht_row_one_dim }
+                  { \l_tmpa_dim - \g__nicematrix_ht_row_zero_dim + \g__nicematrix_ht_row_one_dim }
               }
           }
           {
-            \int_compare:nNnT \l__nm_last_row_int > 0
+            \int_compare:nNnT \l__nicematrix_last_row_int > 0
               {
-                \str_if_eq:VnT \l__nm_pos_env_str { b }
+                \str_if_eq:VnT \l__nicematrix_pos_env_str { b }
                   {
                     \box_move_down:nn
                       {
                         \l_tmpb_dim
-                        - \g__nm_dp_last_row_dim + \g__nm_dp_ante_last_row_dim
+                        - \g__nicematrix_dp_last_row_dim + \g__nicematrix_dp_ante_last_row_dim
                       }
                   }
               }
           }
-        { \box_use_drop:N \l__nm_the_array_box }
+        { \box_use_drop:N \l__nicematrix_the_array_box }
       }
       {
         \hbox_set:Nn \l_tmpa_box
@@ -816,7 +809,7 @@
                 \hbox:n
                   {
                     \skip_horizontal:n { - \arraycolsep }
-                    \box_use_drop:N \l__nm_the_array_box
+                    \box_use_drop:N \l__nicematrix_the_array_box
                     \skip_horizontal:n { - \arraycolsep }
                   }
                 \skip_vertical:n { - \l_tmpb_dim }
@@ -828,43 +821,43 @@
         \box_set_dp:Nn \l_tmpa_box { \box_dp:N \l_tmpa_box + \l_tmpb_dim }
         \box_use_drop:N \l_tmpa_box
       }
-    \bool_if:NT \g__nm_last_col_found_bool
+    \bool_if:NT \g__nicematrix_last_col_found_bool
       {
-        \skip_horizontal:n \g__nm_width_last_col_dim
+        \skip_horizontal:n \g__nicematrix_width_last_col_dim
         \skip_horizontal:n \arraycolsep
       }
-    \__nm_after_array:
+    \__nicematrix_after_array:
   }
-\tl_const:Nn \c__nm_preamble_first_col_tl
+\tl_const:Nn \c__nicematrix_preamble_first_col_tl
   {
     >
       {
-        \__nm_begin_of_row:
+        \__nicematrix_begin_of_row:
         \hbox_set:Nw \l_tmpa_box
         \c_math_toggle_token
-        \bool_if:NT \l__nm_small_bool \scriptstyle
+        \bool_if:NT \l__nicematrix_small_bool \scriptstyle
         \bool_if:nT
           {
             \int_compare_p:nNn \c@iRow > \c_zero_int
             &&
             (
-              \int_compare_p:nNn \l__nm_last_row_int < 0
+              \int_compare_p:nNn \l__nicematrix_last_row_int < 0
               ||
-              \int_compare_p:nNn \c@iRow < \l__nm_last_row_int
+              \int_compare_p:nNn \c@iRow < \l__nicematrix_last_row_int
             )
           }
-          { \l__nm_code_for_first_col_tl }
+          { \l__nicematrix_code_for_first_col_tl }
       }
     l
     <
       {
         \c_math_toggle_token
         \hbox_set_end:
-        \__nm_actualization_for_first_and_last_row:
-        \dim_gset:Nn \g__nm_width_first_col_dim
+        \__nicematrix_actualization_for_first_and_last_row:
+        \dim_gset:Nn \g__nicematrix_width_first_col_dim
           {
             \dim_max:nn
-              \g__nm_width_first_col_dim
+              \g__nicematrix_width_first_col_dim
               { \box_wd:N \l_tmpa_box }
           }
         \hbox_overlap_left:n
@@ -881,13 +874,13 @@
                 anchor = base ,
                 name =
                   nm -
-                  \int_use:N \g__nm_env_int -
+                  \int_use:N \g__nicematrix_env_int -
                   \int_use:N \c@iRow -
                   0 ,
                 alias =
-                  \str_if_empty:NF \l__nm_name_str
+                  \str_if_empty:NF \l__nicematrix_name_str
                     {
-                      \l__nm_name_str -
+                      \l__nicematrix_name_str -
                       \int_use:N \c@iRow -
                       0
                     }
@@ -895,47 +888,47 @@
               { \box_use:N \l_tmpa_box } ;
             \skip_horizontal:n
               {
-                \g__nm_left_delim_dim +
-                \l__nm_left_margin_dim +
-                \l__nm_extra_left_margin_dim
+                \g__nicematrix_left_delim_dim +
+                \l__nicematrix_left_margin_dim +
+                \l__nicematrix_extra_left_margin_dim
               }
           }
         \skip_horizontal:n { - 2 \arraycolsep }
       }
   }
-\tl_const:Nn \c__nm_preamble_last_col_tl
+\tl_const:Nn \c__nicematrix_preamble_last_col_tl
   {
     >
       {
-        \bool_gset_true:N \g__nm_last_col_found_bool
+        \bool_gset_true:N \g__nicematrix_last_col_found_bool
         \int_gincr:N \c@jCol
-        \int_gset:Nn \g__nm_col_total_int
-          { \int_max:nn \g__nm_col_total_int \c@jCol }
+        \int_gset:Nn \g__nicematrix_col_total_int
+          { \int_max:nn \g__nicematrix_col_total_int \c@jCol }
         \hbox_set:Nw \l_tmpa_box
           \c_math_toggle_token
-          \bool_if:NT \l__nm_small_bool \scriptstyle
+          \bool_if:NT \l__nicematrix_small_bool \scriptstyle
         \bool_if:nT
           {
             \int_compare_p:nNn \c@iRow > \c_zero_int
             &&
             (
-              \int_compare_p:nNn \l__nm_last_row_int < 0
+              \int_compare_p:nNn \l__nicematrix_last_row_int < 0
               ||
-              \int_compare_p:nNn \c@iRow < \l__nm_last_row_int
+              \int_compare_p:nNn \c@iRow < \l__nicematrix_last_row_int
             )
           }
-          { \l__nm_code_for_last_col_tl }
+          { \l__nicematrix_code_for_last_col_tl }
       }
     l
     <
       {
         \c_math_toggle_token
         \hbox_set_end:
-        \__nm_actualization_for_first_and_last_row:
-        \dim_gset:Nn \g__nm_width_last_col_dim
+        \__nicematrix_actualization_for_first_and_last_row:
+        \dim_gset:Nn \g__nicematrix_width_last_col_dim
            {
              \dim_max:nn
-               \g__nm_width_last_col_dim
+               \g__nicematrix_width_last_col_dim
                { \box_wd:N \l_tmpa_box }
            }
         \skip_horizontal:n { - 2 \arraycolsep }
@@ -943,9 +936,9 @@
           {
             \skip_horizontal:n
               {
-                \g__nm_right_delim_dim +
-                \l__nm_right_margin_dim +
-                \l__nm_extra_right_margin_dim
+                \g__nicematrix_right_delim_dim +
+                \l__nicematrix_right_margin_dim +
+                \l__nicematrix_extra_right_margin_dim
               }
             \tikz
               [
@@ -959,13 +952,13 @@
                 anchor = base ,
                 name =
                   nm -
-                  \int_use:N \g__nm_env_int -
+                  \int_use:N \g__nicematrix_env_int -
                   \int_use:N \c@iRow -
                   \int_use:N \c@jCol ,
                 alias =
-                  \str_if_empty:NF \l__nm_name_str
+                  \str_if_empty:NF \l__nicematrix_name_str
                     {
-                      \l__nm_name_str -
+                      \l__nicematrix_name_str -
                       \int_use:N \c@iRow -
                       \int_use:N \c@jCol
                     }
@@ -976,88 +969,88 @@
   }
 \NewDocumentEnvironment { NiceArray } { }
   {
-    \bool_set_true:N \l__nm_NiceArray_bool
-    \str_if_empty:NT \g__nm_type_env_str
-      { \str_gset:Nn \g__nm_type_env_str { environment ~ { NiceArray } } }
+    \bool_set_true:N \l__nicematrix_NiceArray_bool
+    \str_if_empty:NT \g__nicematrix_type_env_str
+      { \str_gset:Nn \g__nicematrix_type_env_str { environment ~ { NiceArray } } }
     \NiceArrayWithDelims . .
   }
   { \endNiceArrayWithDelims }
 \NewDocumentEnvironment { pNiceArray } { }
   {
-    \str_if_empty:NT \g__nm_type_env_str
-      { \str_gset:Nn \g__nm_type_env_str { environment ~ { pNiceArray } } }
-    \__nm_test_if_math_mode:
+    \str_if_empty:NT \g__nicematrix_type_env_str
+      { \str_gset:Nn \g__nicematrix_type_env_str { environment ~ { pNiceArray } } }
+    \__nicematrix_test_if_math_mode:
     \NiceArrayWithDelims ( )
   }
   { \endNiceArrayWithDelims }
 \NewDocumentEnvironment { bNiceArray } { }
   {
-    \str_if_empty:NT \g__nm_type_env_str
-      { \str_gset:Nn \g__nm_type_env_str { environment ~ { bNiceArray } } }
-    \__nm_test_if_math_mode:
+    \str_if_empty:NT \g__nicematrix_type_env_str
+      { \str_gset:Nn \g__nicematrix_type_env_str { environment ~ { bNiceArray } } }
+    \__nicematrix_test_if_math_mode:
     \NiceArrayWithDelims [ ]
   }
   { \endNiceArrayWithDelims }
 \NewDocumentEnvironment { BNiceArray } { }
   {
-    \str_if_empty:NT \g__nm_type_env_str
-      { \str_gset:Nn \g__nm_type_env_str { environment ~ { BNiceArray } } }
-    \__nm_test_if_math_mode:
+    \str_if_empty:NT \g__nicematrix_type_env_str
+      { \str_gset:Nn \g__nicematrix_type_env_str { environment ~ { BNiceArray } } }
+    \__nicematrix_test_if_math_mode:
     \NiceArrayWithDelims \{ \}
   }
   { \endNiceArrayWithDelims }
 \NewDocumentEnvironment { vNiceArray } { }
   {
-    \str_if_empty:NT \g__nm_type_env_str
-      { \str_gset:Nn \g__nm_type_env_str { environment ~ { vNiceArray } } }
-    \__nm_test_if_math_mode:
+    \str_if_empty:NT \g__nicematrix_type_env_str
+      { \str_gset:Nn \g__nicematrix_type_env_str { environment ~ { vNiceArray } } }
+    \__nicematrix_test_if_math_mode:
     \NiceArrayWithDelims | |
   }
   { \endNiceArrayWithDelims }
 \NewDocumentEnvironment { VNiceArray } { }
   {
-    \str_if_empty:NT \g__nm_type_env_str
-      { \str_gset:Nn \g__nm_type_env_str { environment ~ { VNiceArray } } }
-    \__nm_test_if_math_mode:
+    \str_if_empty:NT \g__nicematrix_type_env_str
+      { \str_gset:Nn \g__nicematrix_type_env_str { environment ~ { VNiceArray } } }
+    \__nicematrix_test_if_math_mode:
     \NiceArrayWithDelims \| \|
   }
   { \endNiceArrayWithDelims }
-\cs_new_protected:Npn \__nm_define_env:n #1
+\cs_new_protected:Npn \__nicematrix_define_env:n #1
   {
     \NewDocumentEnvironment { #1 NiceMatrix } { ! O { } }
       {
-        \str_gset:Nn \g__nm_type_env_str { environment ~ { #1 NiceMatrix } }
+        \str_gset:Nn \g__nicematrix_type_env_str { environment ~ { #1 NiceMatrix } }
         \keys_set:nn { NiceMatrix / NiceMatrix } { ##1 }
         \begin { #1 NiceArray }
           {
             *
               {
-                \int_compare:nNnTF \l__nm_last_col_int = { -1 }
+                \int_compare:nNnTF \l__nicematrix_last_col_int = { -1 }
                   \c@MaxMatrixCols
-                  { \int_eval:n { \l__nm_last_col_int - 1 } }
+                  { \int_eval:n { \l__nicematrix_last_col_int - 1 } }
               }
               C
           }
       }
       { \end { #1 NiceArray } }
   }
-\__nm_define_env:n { }
-\__nm_define_env:n p
-\__nm_define_env:n b
-\__nm_define_env:n B
-\__nm_define_env:n v
-\__nm_define_env:n V
-\prg_set_conditional:Npnn \__nm_if_not_empty_cell:nn #1 #2 { T , TF }
+\__nicematrix_define_env:n { }
+\__nicematrix_define_env:n p
+\__nicematrix_define_env:n b
+\__nicematrix_define_env:n B
+\__nicematrix_define_env:n v
+\__nicematrix_define_env:n V
+\prg_set_conditional:Npnn \__nicematrix_if_not_empty_cell:nn #1 #2 { T , TF }
   {
     \bool_set_false:N \l_tmpa_bool
     \cs_if_exist:cTF
-      { __nm _ dotted _ \int_use:N #1 - \int_use:N #2 }
+      { __nicematrix _ dotted _ \int_use:N #1 - \int_use:N #2 }
       \prg_return_true:
       {
         \cs_if_free:cTF
           {
             pgf@sh@ns@nm -
-            \int_use:N \g__nm_env_int -
+            \int_use:N \g__nicematrix_env_int -
             \int_use:N #1 -
             \int_use:N #2
           }
@@ -1065,12 +1058,12 @@
           {
             \bool_set_false:N \l_tmpa_bool
             \cs_if_exist:cT
-              { __nm _ empty _ \int_use:N #1 - \int_use:N #2 }
+              { __nicematrix _ empty _ \int_use:N #1 - \int_use:N #2 }
               {
                 \int_compare:nNnT
-                  { \use:c { __nm _ empty _ \int_use:N #1 - \int_use:N #2 } }
+                  { \use:c { __nicematrix _ empty _ \int_use:N #1 - \int_use:N #2 } }
                   =
-                  \g__nm_env_int
+                  \g__nicematrix_env_int
                 { \bool_set_true:N \l_tmpa_bool }
               }
             \bool_if:NTF \l_tmpa_bool
@@ -1080,7 +1073,7 @@
                 \tl_set:Nx \l_tmpa_tl
                    {
                      nm -
-                     \int_use:N \g__nm_env_int -
+                     \int_use:N \g__nicematrix_env_int -
                      \int_use:N #1 -
                      \int_use:N #2
                    }
@@ -1097,138 +1090,138 @@
           }
       }
   }
-\cs_new_protected:Nn \__nm_after_array:
+\cs_new_protected:Nn \__nicematrix_after_array:
   {
     \int_compare:nNnTF \c@iRow > \c_zero_int
-      \__nm_after_array_i:
+      \__nicematrix_after_array_i:
       {
-        \__nm_error:n { Zero~row }
-        \__nm_restore_iRow_jCol:
+        \__nicematrix_error:n { Zero~row }
+        \__nicematrix_restore_iRow_jCol:
       }
   }
-\cs_new_protected:Nn \__nm_after_array_i:
+\cs_new_protected:Nn \__nicematrix_after_array_i:
   {
     \group_begin:
     \cs_if_exist:NT \tikz@library@external@loaded
       { \tikzset { external / export = false } }
-    \int_gset_eq:NN \c@jCol \g__nm_col_total_int
-    \bool_if:nT \g__nm_last_col_found_bool { \int_gdecr:N \c@jCol }
-    \int_gset_eq:NN \g__nm_row_total_int \c@iRow
-    \int_compare:nNnT \l__nm_last_row_int > { -1 }
+    \int_gset_eq:NN \c@jCol \g__nicematrix_col_total_int
+    \bool_if:nT \g__nicematrix_last_col_found_bool { \int_gdecr:N \c@jCol }
+    \int_gset_eq:NN \g__nicematrix_row_total_int \c@iRow
+    \int_compare:nNnT \l__nicematrix_last_row_int > { -1 }
       { \int_gsub:Nn \c@iRow \c_one_int }
-    \bool_if:NT \l__nm_last_row_without_value_bool
+    \bool_if:NT \l__nicematrix_last_row_without_value_bool
       {
         \iow_now:Nn \@mainaux \ExplSyntaxOn
         \iow_now:Nx \@mainaux
           {
-            \cs_gset:cpn { __nm_last_row_ \int_use:N \g__nm_env_int }
-              { \int_use:N \g__nm_row_total_int }
+            \cs_gset:cpn { __nicematrix_last_row_ \int_use:N \g__nicematrix_env_int }
+              { \int_use:N \g__nicematrix_row_total_int }
           }
-        \str_if_empty:NF \l__nm_name_str
+        \str_if_empty:NF \l__nicematrix_name_str
           {
             \iow_now:Nx \@mainaux
               {
-                \cs_gset:cpn { __nm_last_row_ \l__nm_name_str }
-                  { \int_use:N \g__nm_row_total_int }
+                \cs_gset:cpn { __nicematrix_last_row_ \l__nicematrix_name_str }
+                  { \int_use:N \g__nicematrix_row_total_int }
               }
           }
         \iow_now:Nn \@mainaux \ExplSyntaxOff
       }
-    \bool_if:NT \l__nm_parallelize_diags_bool
-      {
-        \int_zero_new:N \l__nm_ddots_int
-        \int_zero_new:N \l__nm_iddots_int
-        \dim_zero_new:N \l__nm_delta_x_one_dim
-        \dim_zero_new:N \l__nm_delta_y_one_dim
-        \dim_zero_new:N \l__nm_delta_x_two_dim
-        \dim_zero_new:N \l__nm_delta_y_two_dim
-      }
-    \bool_if:NT \g__nm_extra_nodes_bool \__nm_create_extra_nodes:
-    \int_zero_new:N \l__nm_initial_i_int
-    \int_zero_new:N \l__nm_initial_j_int
-    \int_zero_new:N \l__nm_final_i_int
-    \int_zero_new:N \l__nm_final_j_int
-    \bool_set_false:N \l__nm_initial_open_bool
-    \bool_set_false:N \l__nm_final_open_bool
-    \bool_if:NT \l__nm_small_bool
-      {
-        \dim_set:Nn \l__nm_radius_dim { 0.37 pt }
-        \dim_set:Nn \l__nm_inter_dots_dim { 0.25 em }
-      }
-    \g__nm_Hdotsfor_lines_tl
-    \g__nm_Vdots_lines_tl
-    \g__nm_Ddots_lines_tl
-    \g__nm_Iddots_lines_tl
-    \g__nm_Cdots_lines_tl
-    \g__nm_Ldots_lines_tl
+    \bool_if:NT \l__nicematrix_parallelize_diags_bool
+      {
+        \int_zero_new:N \l__nicematrix_ddots_int
+        \int_zero_new:N \l__nicematrix_iddots_int
+        \dim_zero_new:N \l__nicematrix_delta_x_one_dim
+        \dim_zero_new:N \l__nicematrix_delta_y_one_dim
+        \dim_zero_new:N \l__nicematrix_delta_x_two_dim
+        \dim_zero_new:N \l__nicematrix_delta_y_two_dim
+      }
+    \bool_if:NT \g__nicematrix_extra_nodes_bool \__nicematrix_create_extra_nodes:
+    \int_zero_new:N \l__nicematrix_initial_i_int
+    \int_zero_new:N \l__nicematrix_initial_j_int
+    \int_zero_new:N \l__nicematrix_final_i_int
+    \int_zero_new:N \l__nicematrix_final_j_int
+    \bool_set_false:N \l__nicematrix_initial_open_bool
+    \bool_set_false:N \l__nicematrix_final_open_bool
+    \bool_if:NT \l__nicematrix_small_bool
+      {
+        \dim_set:Nn \l__nicematrix_radius_dim { 0.37 pt }
+        \dim_set:Nn \l__nicematrix_inter_dots_dim { 0.25 em }
+      }
+    \g__nicematrix_Hdotsfor_lines_tl
+    \g__nicematrix_Vdots_lines_tl
+    \g__nicematrix_Ddots_lines_tl
+    \g__nicematrix_Iddots_lines_tl
+    \g__nicematrix_Cdots_lines_tl
+    \g__nicematrix_Ldots_lines_tl
     \tikzset
       {
         every~picture / .style =
           {
             overlay ,
             remember~picture ,
-            name~prefix = nm - \int_use:N \g__nm_env_int -
+            name~prefix = nm - \int_use:N \g__nicematrix_env_int -
           }
       }
-    \cs_set_eq:NN \line \__nm_line:nn
-    \g__nm_code_after_tl
-    \tl_gclear:N \g__nm_code_after_tl
+    \cs_set_eq:NN \line \__nicematrix_line:nn
+    \g__nicematrix_code_after_tl
+    \tl_gclear:N \g__nicematrix_code_after_tl
     \group_end:
-    \str_gclear:N \g__nm_type_env_str
-    \__nm_restore_iRow_jCol:
+    \str_gclear:N \g__nicematrix_type_env_str
+    \__nicematrix_restore_iRow_jCol:
   }
-\cs_new_protected:Nn \__nm_restore_iRow_jCol:
+\cs_new_protected:Nn \__nicematrix_restore_iRow_jCol:
   {
-    \cs_if_exist:NT \theiRow { \int_gset_eq:NN \c@iRow \l__nm_save_iRow_int }
-    \cs_if_exist:NT \thejCol { \int_gset_eq:NN \c@jCol \l__nm_save_jCol_int }
+    \cs_if_exist:NT \theiRow { \int_gset_eq:NN \c@iRow \l__nicematrix_save_iRow_int }
+    \cs_if_exist:NT \thejCol { \int_gset_eq:NN \c@jCol \l__nicematrix_save_jCol_int }
   }
-\cs_new_protected:Nn \__nm_find_extremities_of_line:nnnn
+\cs_new_protected:Nn \__nicematrix_find_extremities_of_line:nnnn
   {
-    \cs_set:cpn { __nm _ dotted _ #1 - #2 } { }
-    \int_set:Nn \l__nm_initial_i_int { #1 }
-    \int_set:Nn \l__nm_initial_j_int { #2 }
-    \int_set:Nn \l__nm_final_i_int { #1 }
-    \int_set:Nn \l__nm_final_j_int { #2 }
-    \bool_set_false:N \l__nm_stop_loop_bool
-    \bool_do_until:Nn \l__nm_stop_loop_bool
+    \cs_set:cpn { __nicematrix _ dotted _ #1 - #2 } { }
+    \int_set:Nn \l__nicematrix_initial_i_int { #1 }
+    \int_set:Nn \l__nicematrix_initial_j_int { #2 }
+    \int_set:Nn \l__nicematrix_final_i_int { #1 }
+    \int_set:Nn \l__nicematrix_final_j_int { #2 }
+    \bool_set_false:N \l__nicematrix_stop_loop_bool
+    \bool_do_until:Nn \l__nicematrix_stop_loop_bool
       {
-        \int_add:Nn \l__nm_final_i_int { #3 }
-        \int_add:Nn \l__nm_final_j_int { #4 }
-        \bool_set_false:N \l__nm_final_open_bool
-        \int_compare:nNnTF \l__nm_final_i_int > \c@iRow
+        \int_add:Nn \l__nicematrix_final_i_int { #3 }
+        \int_add:Nn \l__nicematrix_final_j_int { #4 }
+        \bool_set_false:N \l__nicematrix_final_open_bool
+        \int_compare:nNnTF \l__nicematrix_final_i_int > \c@iRow
           {
             \int_compare:nNnT { #3 } = 1
-              { \bool_set_true:N \l__nm_final_open_bool }
+              { \bool_set_true:N \l__nicematrix_final_open_bool }
           }
           {
-            \int_compare:nNnTF \l__nm_final_j_int < 1
+            \int_compare:nNnTF \l__nicematrix_final_j_int < 1
               {
                 \int_compare:nNnT { #4 } = { -1 }
-                  { \bool_set_true:N \l__nm_final_open_bool }
+                  { \bool_set_true:N \l__nicematrix_final_open_bool }
               }
               {
-                \int_compare:nNnT \l__nm_final_j_int > \c@jCol
+                \int_compare:nNnT \l__nicematrix_final_j_int > \c@jCol
                   {
                     \int_compare:nNnT { #4 } = 1
-                      { \bool_set_true:N \l__nm_final_open_bool }
+                      { \bool_set_true:N \l__nicematrix_final_open_bool }
                   }
               }
           }
-        \bool_if:NTF \l__nm_final_open_bool
+        \bool_if:NTF \l__nicematrix_final_open_bool
           {
-            \int_sub:Nn \l__nm_final_i_int { #3 }
-            \int_sub:Nn \l__nm_final_j_int { #4 }
-            \bool_set_true:N \l__nm_stop_loop_bool
+            \int_sub:Nn \l__nicematrix_final_i_int { #3 }
+            \int_sub:Nn \l__nicematrix_final_j_int { #4 }
+            \bool_set_true:N \l__nicematrix_stop_loop_bool
           }
           {
-            \__nm_if_not_empty_cell:nnTF \l__nm_final_i_int \l__nm_final_j_int
-              { \bool_set_true:N \l__nm_stop_loop_bool }
+            \__nicematrix_if_not_empty_cell:nnTF \l__nicematrix_final_i_int \l__nicematrix_final_j_int
+              { \bool_set_true:N \l__nicematrix_stop_loop_bool }
               {
                 \cs_set:cpn
                   {
-                    __nm _ dotted _
-                    \int_use:N \l__nm_final_i_int -
-                    \int_use:N \l__nm_final_j_int
+                    __nicematrix _ dotted _
+                    \int_use:N \l__nicematrix_final_i_int -
+                    \int_use:N \l__nicematrix_final_j_int
                   }
                   { }
               }
@@ -1237,59 +1230,59 @@
     \cs_if_free:cT
       {
         pgf@sh@ns@nm -
-        \int_use:N \g__nm_env_int -
-        \int_use:N \l__nm_final_i_int -
-        \int_use:N \l__nm_final_j_int
+        \int_use:N \g__nicematrix_env_int -
+        \int_use:N \l__nicematrix_final_i_int -
+        \int_use:N \l__nicematrix_final_j_int
       }
       {
-        \bool_if:NF \l__nm_final_open_bool
+        \bool_if:NF \l__nicematrix_final_open_bool
           {
             \msg_error:nnx { nicematrix } { Impossible~line }
-              { \int_use:N \l__nm_final_i_int }
-            \bool_set_true:N \l__nm_impossible_line_bool
+              { \int_use:N \l__nicematrix_final_i_int }
+            \bool_set_true:N \l__nicematrix_impossible_line_bool
           }
       }
-    \bool_set_false:N \l__nm_stop_loop_bool
-    \bool_do_until:Nn \l__nm_stop_loop_bool
+    \bool_set_false:N \l__nicematrix_stop_loop_bool
+    \bool_do_until:Nn \l__nicematrix_stop_loop_bool
       {
-        \int_sub:Nn \l__nm_initial_i_int { #3 }
-        \int_sub:Nn \l__nm_initial_j_int { #4 }
-        \bool_set_false:N \l__nm_initial_open_bool
-        \int_compare:nNnTF \l__nm_initial_i_int < 1
+        \int_sub:Nn \l__nicematrix_initial_i_int { #3 }
+        \int_sub:Nn \l__nicematrix_initial_j_int { #4 }
+        \bool_set_false:N \l__nicematrix_initial_open_bool
+        \int_compare:nNnTF \l__nicematrix_initial_i_int < 1
           {
             \int_compare:nNnT { #3 } = 1
-              { \bool_set_true:N \l__nm_initial_open_bool }
+              { \bool_set_true:N \l__nicematrix_initial_open_bool }
           }
           {
-            \int_compare:nNnTF \l__nm_initial_j_int < 1
+            \int_compare:nNnTF \l__nicematrix_initial_j_int < 1
               {
                 \int_compare:nNnT { #4 } = 1
-                  { \bool_set_true:N \l__nm_initial_open_bool }
+                  { \bool_set_true:N \l__nicematrix_initial_open_bool }
               }
               {
-                \int_compare:nNnT \l__nm_initial_j_int > \c@jCol
+                \int_compare:nNnT \l__nicematrix_initial_j_int > \c@jCol
                   {
                     \int_compare:nNnT { #4 } = { -1 }
-                      { \bool_set_true:N \l__nm_initial_open_bool }
+                      { \bool_set_true:N \l__nicematrix_initial_open_bool }
                   }
               }
           }
-        \bool_if:NTF \l__nm_initial_open_bool
+        \bool_if:NTF \l__nicematrix_initial_open_bool
           {
-            \int_add:Nn \l__nm_initial_i_int { #3 }
-            \int_add:Nn \l__nm_initial_j_int { #4 }
-            \bool_set_true:N \l__nm_stop_loop_bool
+            \int_add:Nn \l__nicematrix_initial_i_int { #3 }
+            \int_add:Nn \l__nicematrix_initial_j_int { #4 }
+            \bool_set_true:N \l__nicematrix_stop_loop_bool
           }
           {
-            \__nm_if_not_empty_cell:nnTF
-              \l__nm_initial_i_int \l__nm_initial_j_int
-              { \bool_set_true:N \l__nm_stop_loop_bool }
+            \__nicematrix_if_not_empty_cell:nnTF
+              \l__nicematrix_initial_i_int \l__nicematrix_initial_j_int
+              { \bool_set_true:N \l__nicematrix_stop_loop_bool }
               {
                 \cs_set:cpn
                   {
-                    __nm _ dotted _
-                    \int_use:N \l__nm_initial_i_int -
-                    \int_use:N \l__nm_initial_j_int
+                    __nicematrix _ dotted _
+                    \int_use:N \l__nicematrix_initial_i_int -
+                    \int_use:N \l__nicematrix_initial_j_int
                   }
                   { }
               }
@@ -1298,97 +1291,94 @@
     \cs_if_free:cT
       {
         pgf@sh@ns@nm -
-        \int_use:N \g__nm_env_int -
-        \int_use:N \l__nm_initial_i_int -
-        \int_use:N \l__nm_initial_j_int
+        \int_use:N \g__nicematrix_env_int -
+        \int_use:N \l__nicematrix_initial_i_int -
+        \int_use:N \l__nicematrix_initial_j_int
       }
       {
-        \bool_if:NF \l__nm_initial_open_bool
+        \bool_if:NF \l__nicematrix_initial_open_bool
           {
             \msg_error:nnx { nicematrix } { Impossible~line }
-              { \int_use:N \l__nm_initial_i_int }
-            \bool_set_true:N \l__nm_impossible_line_bool
+              { \int_use:N \l__nicematrix_initial_i_int }
+            \bool_set_true:N \l__nicematrix_impossible_line_bool
           }
       }
-    \bool_if:nT \l__nm_initial_open_bool \__nm_create_extra_nodes:
-    \bool_if:NT \l__nm_final_open_bool \__nm_create_extra_nodes:
+    \bool_if:nT \l__nicematrix_initial_open_bool \__nicematrix_create_extra_nodes:
+    \bool_if:NT \l__nicematrix_final_open_bool \__nicematrix_create_extra_nodes:
   }
-\cs_new_protected:Nn \__nm_retrieve_coords:nn
+\cs_new_protected:Nn \__nicematrix_retrieve_coords:nn
   {
-    \dim_gzero_new:N \g__nm_x_initial_dim
-    \dim_gzero_new:N \g__nm_y_initial_dim
-    \dim_gzero_new:N \g__nm_x_final_dim
-    \dim_gzero_new:N \g__nm_y_final_dim
+    \dim_gzero_new:N \g__nicematrix_x_initial_dim
+    \dim_gzero_new:N \g__nicematrix_y_initial_dim
+    \dim_gzero_new:N \g__nicematrix_x_final_dim
+    \dim_gzero_new:N \g__nicematrix_y_final_dim
     \begin { tikzpicture } [ remember~picture ]
       \tikz@parse@node \pgfutil@firstofone
-        ( nm - \int_use:N \g__nm_env_int -
-               \int_use:N \l__nm_initial_i_int -
-               \int_use:N \l__nm_initial_j_int #1 )
-      \dim_gset:Nn \g__nm_x_initial_dim \pgf@x
-      \dim_gset:Nn \g__nm_y_initial_dim \pgf@y
+        ( nm - \int_use:N \g__nicematrix_env_int -
+               \int_use:N \l__nicematrix_initial_i_int -
+               \int_use:N \l__nicematrix_initial_j_int #1 )
+      \dim_gset:Nn \g__nicematrix_x_initial_dim \pgf@x
+      \dim_gset:Nn \g__nicematrix_y_initial_dim \pgf@y
       \tikz@parse@node \pgfutil@firstofone
-        ( nm - \int_use:N \g__nm_env_int -
-               \int_use:N \l__nm_final_i_int -
-               \int_use:N \l__nm_final_j_int #2 )
-      \dim_gset:Nn \g__nm_x_final_dim \pgf@x
-      \dim_gset:Nn \g__nm_y_final_dim \pgf@y
+        ( nm - \int_use:N \g__nicematrix_env_int -
+               \int_use:N \l__nicematrix_final_i_int -
+               \int_use:N \l__nicematrix_final_j_int #2 )
+      \dim_gset:Nn \g__nicematrix_x_final_dim \pgf@x
+      \dim_gset:Nn \g__nicematrix_y_final_dim \pgf@y
     \end { tikzpicture }
   }
-\cs_generate_variant:Nn \__nm_retrieve_coords:nn { x x }
-\cs_new_protected:Nn \__nm_adjust_with_col_nodes:
+\cs_generate_variant:Nn \__nicematrix_retrieve_coords:nn { x x }
+\cs_new_protected:Nn \__nicematrix_adjust_with_col_nodes:
   {
-    \bool_if:NT \l__nm_initial_open_bool
+    \bool_if:NT \l__nicematrix_initial_open_bool
       {
         \cs_if_exist:cT
-          { pgf@sh@ns@nm - \int_use:N \g__nm_env_int - col - 0 }
+          { pgf@sh@ns@nm - \int_use:N \g__nicematrix_env_int - col - 0 }
           {
             \begin { tikzpicture } [ remember~picture ]
             \tikz@parse@node \pgfutil@firstofone
-              ( nm - \int_use:N \g__nm_env_int - col - 0 )
-            \dim_gset:Nn \g__nm_x_initial_dim \pgf@x
+              ( nm - \int_use:N \g__nicematrix_env_int - col - 0 )
+            \dim_gset:Nn \g__nicematrix_x_initial_dim \pgf@x
             \end { tikzpicture }
           }
       }
-    \bool_if:NT \l__nm_final_open_bool
+    \bool_if:NT \l__nicematrix_final_open_bool
       {
         \cs_if_exist:cT
           {
-            pgf@sh@ns@nm - \int_use:N \g__nm_env_int - col -
+            pgf@sh@ns@nm - \int_use:N \g__nicematrix_env_int - col -
             \int_use:N \c@jCol
           }
           {
             \begin { tikzpicture } [ remember~picture ]
             \tikz@parse@node \pgfutil@firstofone
-              (
-                nm - \int_use:N \g__nm_env_int - col -
-                \int_use:N \c@jCol
-              )
-            \dim_gset:Nn \g__nm_x_final_dim \pgf@x
+              ( nm - \int_use:N \g__nicematrix_env_int - col - \int_use:N \c@jCol )
+            \dim_gset:Nn \g__nicematrix_x_final_dim \pgf@x
             \end { tikzpicture }
           }
       }
   }
-\cs_new_protected:Nn \__nm_draw_Ldots:nn
+\cs_new_protected:Nn \__nicematrix_draw_Ldots:nn
   {
-    \cs_if_free:cT { __nm _ dotted _ #1 - #2 }
+    \cs_if_free:cT { __nicematrix _ dotted _ #1 - #2 }
       {
-        \bool_set_false:N \l__nm_impossible_line_bool
-        \__nm_find_extremities_of_line:nnnn { #1 } { #2 } \c_zero_int \c_one_int
-        \bool_if:NF \l__nm_impossible_line_bool \__nm_actually_draw_Ldots:
+        \bool_set_false:N \l__nicematrix_impossible_line_bool
+        \__nicematrix_find_extremities_of_line:nnnn { #1 } { #2 } \c_zero_int \c_one_int
+        \bool_if:NF \l__nicematrix_impossible_line_bool \__nicematrix_actually_draw_Ldots:
       }
   }
-\cs_new_protected:Nn \__nm_actually_draw_Ldots:
+\cs_new_protected:Nn \__nicematrix_actually_draw_Ldots:
   {
-    \__nm_retrieve_coords:xx
+    \__nicematrix_retrieve_coords:xx
       {
-        \bool_if:NTF \l__nm_initial_open_bool
+        \bool_if:NTF \l__nicematrix_initial_open_bool
           {
            \cs_if_exist:cTF
              {
                pgf@sh@ns@nm
-               - \int_use:N \g__nm_env_int
-               - \int_use:N \l__nm_initial_i_int
-               - \int_use:N \l__nm_initial_j_int - w
+               - \int_use:N \g__nicematrix_env_int
+               - \int_use:N \l__nicematrix_initial_i_int
+               - \int_use:N \l__nicematrix_initial_j_int - w
              }
              { - w.base~west }
              { - medium.base~west }
@@ -1396,47 +1386,47 @@
          { .base~east }
       }
       {
-        \bool_if:NTF \l__nm_final_open_bool
+        \bool_if:NTF \l__nicematrix_final_open_bool
           {
             \cs_if_exist:cTF
               {
                 pgf@sh@ns@nm
-                - \int_use:N \g__nm_env_int
-                - \int_use:N \l__nm_final_i_int
-                - \int_use:N \l__nm_final_j_int - w
+                - \int_use:N \g__nicematrix_env_int
+                - \int_use:N \l__nicematrix_final_i_int
+                - \int_use:N \l__nicematrix_final_j_int - w
               }
               { - w.base~east }
               { - medium.base~east }
           }
           { .base~west }
       }
-    \__nm_adjust_with_col_nodes:
-    \bool_if:NT \l__nm_initial_open_bool
-      { \dim_gset_eq:NN \g__nm_y_initial_dim \g__nm_y_final_dim }
-    \bool_if:NT \l__nm_final_open_bool
-      { \dim_gset_eq:NN \g__nm_y_final_dim \g__nm_y_initial_dim }
-    \dim_gadd:Nn \g__nm_y_initial_dim { 0.53 pt }
-    \dim_gadd:Nn \g__nm_y_final_dim { 0.53 pt }
-    \__nm_draw_tikz_line:
+    \__nicematrix_adjust_with_col_nodes:
+    \bool_if:NT \l__nicematrix_initial_open_bool
+      { \dim_gset_eq:NN \g__nicematrix_y_initial_dim \g__nicematrix_y_final_dim }
+    \bool_if:NT \l__nicematrix_final_open_bool
+      { \dim_gset_eq:NN \g__nicematrix_y_final_dim \g__nicematrix_y_initial_dim }
+    \dim_gadd:Nn \g__nicematrix_y_initial_dim { 0.53 pt }
+    \dim_gadd:Nn \g__nicematrix_y_final_dim { 0.53 pt }
+    \__nicematrix_draw_tikz_line:
   }
-\cs_new_protected:Nn \__nm_draw_Cdots:nn
+\cs_new_protected:Nn \__nicematrix_draw_Cdots:nn
   {
-    \cs_if_free:cT { __nm _ dotted _ #1 - #2 }
+    \cs_if_free:cT { __nicematrix _ dotted _ #1 - #2 }
       {
-        \bool_set_false:N \l__nm_impossible_line_bool
-        \__nm_find_extremities_of_line:nnnn { #1 } { #2 } \c_zero_int \c_one_int
-        \bool_if:NF \l__nm_impossible_line_bool
+        \bool_set_false:N \l__nicematrix_impossible_line_bool
+        \__nicematrix_find_extremities_of_line:nnnn { #1 } { #2 } \c_zero_int \c_one_int
+        \bool_if:NF \l__nicematrix_impossible_line_bool
           {
-            \__nm_retrieve_coords:xx
+            \__nicematrix_retrieve_coords:xx
               {
-                \bool_if:NTF \l__nm_initial_open_bool
+                \bool_if:NTF \l__nicematrix_initial_open_bool
                   {
                     \cs_if_exist:cTF
                       {
                         pgf@sh@ns@nm
-                        - \int_use:N \g__nm_env_int
-                        - \int_use:N \l__nm_initial_i_int
-                        - \int_use:N \l__nm_initial_j_int - w
+                        - \int_use:N \g__nicematrix_env_int
+                        - \int_use:N \l__nicematrix_initial_i_int
+                        - \int_use:N \l__nicematrix_initial_j_int - w
                       }
                       { - w.mid~west }
                       { - medium.mid~west }
@@ -1444,323 +1434,323 @@
                   { .mid~east }
               }
               {
-                \bool_if:NTF \l__nm_final_open_bool
+                \bool_if:NTF \l__nicematrix_final_open_bool
                   {
                     \cs_if_exist:cTF
                       {
                         pgf@sh@ns@nm
-                        - \int_use:N \g__nm_env_int
-                        - \int_use:N \l__nm_final_i_int
-                        - \int_use:N \l__nm_final_j_int - w
+                        - \int_use:N \g__nicematrix_env_int
+                        - \int_use:N \l__nicematrix_final_i_int
+                        - \int_use:N \l__nicematrix_final_j_int - w
                       }
                       { - w.mid~east }
                       { - medium.mid~east }
                   }
                   { .mid~west }
               }
-            \__nm_adjust_with_col_nodes:
-            \bool_if:NT \l__nm_initial_open_bool
-              { \dim_gset_eq:NN \g__nm_y_initial_dim \g__nm_y_final_dim }
-            \bool_if:NT \l__nm_final_open_bool
-              { \dim_gset_eq:NN \g__nm_y_final_dim \g__nm_y_initial_dim }
-            \__nm_draw_tikz_line:
+            \__nicematrix_adjust_with_col_nodes:
+            \bool_if:NT \l__nicematrix_initial_open_bool
+              { \dim_gset_eq:NN \g__nicematrix_y_initial_dim \g__nicematrix_y_final_dim }
+            \bool_if:NT \l__nicematrix_final_open_bool
+              { \dim_gset_eq:NN \g__nicematrix_y_final_dim \g__nicematrix_y_initial_dim }
+            \__nicematrix_draw_tikz_line:
           }
       }
   }
-\cs_new_protected:Nn \__nm_draw_Vdots:nn
+\cs_new_protected:Nn \__nicematrix_draw_Vdots:nn
   {
-    \cs_if_free:cT { __nm _ dotted _ #1 - #2 }
+    \cs_if_free:cT { __nicematrix _ dotted _ #1 - #2 }
       {
-        \bool_set_false:N \l__nm_impossible_line_bool
-        \__nm_find_extremities_of_line:nnnn { #1 } { #2 } \c_one_int \c_zero_int
-        \bool_if:NF \l__nm_impossible_line_bool
+        \bool_set_false:N \l__nicematrix_impossible_line_bool
+        \__nicematrix_find_extremities_of_line:nnnn { #1 } { #2 } \c_one_int \c_zero_int
+        \bool_if:NF \l__nicematrix_impossible_line_bool
           {
-            \__nm_retrieve_coords:xx
+            \__nicematrix_retrieve_coords:xx
               {
-                \bool_if:NTF \l__nm_initial_open_bool
+                \bool_if:NTF \l__nicematrix_initial_open_bool
                   { - medium.north~west }
                   { .south~west }
               }
               {
-                \bool_if:NTF \l__nm_final_open_bool
+                \bool_if:NTF \l__nicematrix_final_open_bool
                   { - medium.south~west }
                   { .north~west }
               }
             \bool_set:Nn \l_tmpa_bool
-              { \dim_compare_p:nNn \g__nm_x_initial_dim = \g__nm_x_final_dim }
-            \__nm_retrieve_coords:xx
+              { \dim_compare_p:nNn \g__nicematrix_x_initial_dim = \g__nicematrix_x_final_dim }
+            \__nicematrix_retrieve_coords:xx
               {
-                \bool_if:NTF \l__nm_initial_open_bool
+                \bool_if:NTF \l__nicematrix_initial_open_bool
                   { - medium.north }
                   { .south }
               }
               {
-                \bool_if:NTF \l__nm_final_open_bool
+                \bool_if:NTF \l__nicematrix_final_open_bool
                   { - medium.south }
                   { .north }
               }
             \bool_set:Nn \l_tmpb_bool
-              { \dim_compare_p:nNn \g__nm_x_initial_dim = \g__nm_x_final_dim }
+              { \dim_compare_p:nNn \g__nicematrix_x_initial_dim = \g__nicematrix_x_final_dim }
             \bool_if:NF \l_tmpb_bool
               {
-                \dim_gset:Nn \g__nm_x_initial_dim
+                \dim_gset:Nn \g__nicematrix_x_initial_dim
                   {
                     \bool_if:NTF \l_tmpa_bool \dim_min:nn \dim_max:nn
-                      \g__nm_x_initial_dim \g__nm_x_final_dim
+                      \g__nicematrix_x_initial_dim \g__nicematrix_x_final_dim
                   }
-                \dim_gset_eq:NN \g__nm_x_final_dim \g__nm_x_initial_dim
+                \dim_gset_eq:NN \g__nicematrix_x_final_dim \g__nicematrix_x_initial_dim
               }
-            \__nm_draw_tikz_line:
+            \__nicematrix_draw_tikz_line:
           }
       }
   }
-\cs_new_protected:Nn \__nm_draw_Ddots:nn
+\cs_new_protected:Nn \__nicematrix_draw_Ddots:nn
   {
-    \cs_if_free:cT { __nm _ dotted _ #1 - #2 }
+    \cs_if_free:cT { __nicematrix _ dotted _ #1 - #2 }
       {
-        \bool_set_false:N \l__nm_impossible_line_bool
-        \__nm_find_extremities_of_line:nnnn { #1 } { #2 } \c_one_int \c_one_int
-        \bool_if:NF \l__nm_impossible_line_bool
+        \bool_set_false:N \l__nicematrix_impossible_line_bool
+        \__nicematrix_find_extremities_of_line:nnnn { #1 } { #2 } \c_one_int \c_one_int
+        \bool_if:NF \l__nicematrix_impossible_line_bool
           {
-            \__nm_retrieve_coords:xx
+            \__nicematrix_retrieve_coords:xx
               {
-                \bool_if:NTF \l__nm_initial_open_bool
+                \bool_if:NTF \l__nicematrix_initial_open_bool
                   { - medium.north~west }
                   { .south~east }
               }
               {
-                \bool_if:NTF \l__nm_final_open_bool
+                \bool_if:NTF \l__nicematrix_final_open_bool
                   { - medium.south~east }
                   { .north~west }
               }
-            \bool_if:NT \l__nm_parallelize_diags_bool
+            \bool_if:NT \l__nicematrix_parallelize_diags_bool
               {
-                \int_incr:N \l__nm_ddots_int
-                \int_compare:nNnTF \l__nm_ddots_int = \c_one_int
+                \int_incr:N \l__nicematrix_ddots_int
+                \int_compare:nNnTF \l__nicematrix_ddots_int = \c_one_int
                   {
-                    \dim_set:Nn \l__nm_delta_x_one_dim
-                      { \g__nm_x_final_dim - \g__nm_x_initial_dim }
-                    \dim_set:Nn \l__nm_delta_y_one_dim
-                      { \g__nm_y_final_dim - \g__nm_y_initial_dim }
+                    \dim_set:Nn \l__nicematrix_delta_x_one_dim
+                      { \g__nicematrix_x_final_dim - \g__nicematrix_x_initial_dim }
+                    \dim_set:Nn \l__nicematrix_delta_y_one_dim
+                      { \g__nicematrix_y_final_dim - \g__nicematrix_y_initial_dim }
                   }
                   {
-                    \dim_gset:Nn \g__nm_y_final_dim
+                    \dim_gset:Nn \g__nicematrix_y_final_dim
                       {
-                        \g__nm_y_initial_dim +
-                        ( \g__nm_x_final_dim - \g__nm_x_initial_dim ) *
-                        \dim_ratio:nn \l__nm_delta_y_one_dim \l__nm_delta_x_one_dim
+                        \g__nicematrix_y_initial_dim +
+                        ( \g__nicematrix_x_final_dim - \g__nicematrix_x_initial_dim ) *
+                        \dim_ratio:nn \l__nicematrix_delta_y_one_dim \l__nicematrix_delta_x_one_dim
                       }
                   }
               }
-            \__nm_draw_tikz_line:
+            \__nicematrix_draw_tikz_line:
           }
       }
   }
-\cs_new_protected:Nn \__nm_draw_Iddots:nn
+\cs_new_protected:Nn \__nicematrix_draw_Iddots:nn
   {
-    \cs_if_free:cT { __nm _ dotted _ #1 - #2 }
+    \cs_if_free:cT { __nicematrix _ dotted _ #1 - #2 }
       {
-        \bool_set_false:N \l__nm_impossible_line_bool
-        \__nm_find_extremities_of_line:nnnn { #1 } { #2 } 1 { -1 }
-        \bool_if:NF \l__nm_impossible_line_bool
+        \bool_set_false:N \l__nicematrix_impossible_line_bool
+        \__nicematrix_find_extremities_of_line:nnnn { #1 } { #2 } 1 { -1 }
+        \bool_if:NF \l__nicematrix_impossible_line_bool
           {
-            \__nm_retrieve_coords:xx
+            \__nicematrix_retrieve_coords:xx
               {
-                \bool_if:NTF \l__nm_initial_open_bool
+                \bool_if:NTF \l__nicematrix_initial_open_bool
                   { - medium.north~east }
                   { .south~west }
               }
               {
-                \bool_if:NTF \l__nm_final_open_bool
+                \bool_if:NTF \l__nicematrix_final_open_bool
                   { - medium.south~west }
                   { .north~east }
               }
-            \bool_if:NT \l__nm_parallelize_diags_bool
+            \bool_if:NT \l__nicematrix_parallelize_diags_bool
               {
-                \int_incr:N \l__nm_iddots_int
-                \int_compare:nNnTF \l__nm_iddots_int = \c_one_int
+                \int_incr:N \l__nicematrix_iddots_int
+                \int_compare:nNnTF \l__nicematrix_iddots_int = \c_one_int
                   {
-                    \dim_set:Nn \l__nm_delta_x_two_dim
-                      { \g__nm_x_final_dim - \g__nm_x_initial_dim }
-                    \dim_set:Nn \l__nm_delta_y_two_dim
-                      { \g__nm_y_final_dim - \g__nm_y_initial_dim }
+                    \dim_set:Nn \l__nicematrix_delta_x_two_dim
+                      { \g__nicematrix_x_final_dim - \g__nicematrix_x_initial_dim }
+                    \dim_set:Nn \l__nicematrix_delta_y_two_dim
+                      { \g__nicematrix_y_final_dim - \g__nicematrix_y_initial_dim }
                   }
                   {
-                    \dim_gset:Nn \g__nm_y_final_dim
+                    \dim_gset:Nn \g__nicematrix_y_final_dim
                        {
-                         \g__nm_y_initial_dim +
-                         ( \g__nm_x_final_dim - \g__nm_x_initial_dim ) *
-                         \dim_ratio:nn \l__nm_delta_y_two_dim \l__nm_delta_x_two_dim
+                         \g__nicematrix_y_initial_dim +
+                         ( \g__nicematrix_x_final_dim - \g__nicematrix_x_initial_dim ) *
+                         \dim_ratio:nn \l__nicematrix_delta_y_two_dim \l__nicematrix_delta_x_two_dim
                        }
                   }
               }
-            \__nm_draw_tikz_line:
+            \__nicematrix_draw_tikz_line:
           }
       }
   }
-\cs_new_protected:Nn \__nm_draw_tikz_line:
+\cs_new_protected:Nn \__nicematrix_draw_tikz_line:
   {
-    \dim_zero_new:N \l__nm_l_dim
-    \dim_set:Nn \l__nm_l_dim
+    \dim_zero_new:N \l__nicematrix_l_dim
+    \dim_set:Nn \l__nicematrix_l_dim
       {
         \fp_to_dim:n
           {
             sqrt
              (
-               (   \dim_use:N \g__nm_x_final_dim
-                 - \dim_use:N \g__nm_x_initial_dim
+               (   \dim_use:N \g__nicematrix_x_final_dim
+                 - \dim_use:N \g__nicematrix_x_initial_dim
                ) ^ 2
                   +
-               (   \dim_use:N \g__nm_y_final_dim
-                 - \dim_use:N \g__nm_y_initial_dim
+               (   \dim_use:N \g__nicematrix_y_final_dim
+                 - \dim_use:N \g__nicematrix_y_initial_dim
                ) ^ 2
              )
           }
       }
-    \dim_compare:nNnF \l__nm_l_dim = \c_zero_dim
+    \dim_compare:nNnF \l__nicematrix_l_dim = \c_zero_dim
       {
-        \bool_if:NTF \l__nm_initial_open_bool
+        \bool_if:NTF \l__nicematrix_initial_open_bool
           {
-            \bool_if:NTF \l__nm_final_open_bool
+            \bool_if:NTF \l__nicematrix_final_open_bool
               {
                 \int_set:Nn \l_tmpa_int
-                  { \dim_ratio:nn \l__nm_l_dim \l__nm_inter_dots_dim }
+                  { \dim_ratio:nn \l__nicematrix_l_dim \l__nicematrix_inter_dots_dim }
               }
               {
                 \int_set:Nn \l_tmpa_int
-                  { \dim_ratio:nn { \l__nm_l_dim - 0.3 em } \l__nm_inter_dots_dim }
+                  { \dim_ratio:nn { \l__nicematrix_l_dim - 0.3 em } \l__nicematrix_inter_dots_dim }
               }
           }
           {
-            \bool_if:NTF \l__nm_final_open_bool
+            \bool_if:NTF \l__nicematrix_final_open_bool
               {
                 \int_set:Nn \l_tmpa_int
-                  { \dim_ratio:nn { \l__nm_l_dim - 0.3 em } \l__nm_inter_dots_dim }
+                  { \dim_ratio:nn { \l__nicematrix_l_dim - 0.3 em } \l__nicematrix_inter_dots_dim }
               }
               {
                 \int_set:Nn \l_tmpa_int
-                  { \dim_ratio:nn { \l__nm_l_dim - 0.6 em } \l__nm_inter_dots_dim}
+                  { \dim_ratio:nn { \l__nicematrix_l_dim - 0.6 em } \l__nicematrix_inter_dots_dim}
               }
           }
         \dim_set:Nn \l_tmpa_dim
           {
-            ( \g__nm_x_final_dim - \g__nm_x_initial_dim ) *
-            \dim_ratio:nn \l__nm_inter_dots_dim \l__nm_l_dim
+            ( \g__nicematrix_x_final_dim - \g__nicematrix_x_initial_dim ) *
+            \dim_ratio:nn \l__nicematrix_inter_dots_dim \l__nicematrix_l_dim
           }
         \dim_set:Nn \l_tmpb_dim
           {
-            ( \g__nm_y_final_dim - \g__nm_y_initial_dim ) *
-            \dim_ratio:nn \l__nm_inter_dots_dim \l__nm_l_dim
+            ( \g__nicematrix_y_final_dim - \g__nicematrix_y_initial_dim ) *
+            \dim_ratio:nn \l__nicematrix_inter_dots_dim \l__nicematrix_l_dim
           }
         \int_set:Nn \l_tmpb_int
           {
-            \bool_if:NTF \l__nm_initial_open_bool
-              { \bool_if:NTF \l__nm_final_open_bool 1 0 }
-              { \bool_if:NTF \l__nm_final_open_bool 2 1 }
+            \bool_if:NTF \l__nicematrix_initial_open_bool
+              { \bool_if:NTF \l__nicematrix_final_open_bool 1 0 }
+              { \bool_if:NTF \l__nicematrix_final_open_bool 2 1 }
           }
-        \dim_gadd:Nn \g__nm_x_initial_dim
+        \dim_gadd:Nn \g__nicematrix_x_initial_dim
           {
-            ( \g__nm_x_final_dim - \g__nm_x_initial_dim ) *
+            ( \g__nicematrix_x_final_dim - \g__nicematrix_x_initial_dim ) *
             \dim_ratio:nn
-            { \l__nm_l_dim - \l__nm_inter_dots_dim * \l_tmpa_int }
-            { \l__nm_l_dim * 2 }
+            { \l__nicematrix_l_dim - \l__nicematrix_inter_dots_dim * \l_tmpa_int }
+            { \l__nicematrix_l_dim * 2 }
             * \l_tmpb_int
           }
-        \dim_gadd:Nn \g__nm_y_initial_dim
+        \dim_gadd:Nn \g__nicematrix_y_initial_dim
           {
-            ( \g__nm_y_final_dim - \g__nm_y_initial_dim ) *
+            ( \g__nicematrix_y_final_dim - \g__nicematrix_y_initial_dim ) *
             \dim_ratio:nn
-              { \l__nm_l_dim - \l__nm_inter_dots_dim * \l_tmpa_int }
-              { \l__nm_l_dim * 2 } *
+              { \l__nicematrix_l_dim - \l__nicematrix_inter_dots_dim * \l_tmpa_int }
+              { \l__nicematrix_l_dim * 2 } *
             \l_tmpb_int
           }
         \begin { tikzpicture } [ overlay ]
           \int_step_inline:nnn 0 \l_tmpa_int
             {
               \pgfpathcircle
-                { \pgfpoint { \g__nm_x_initial_dim } { \g__nm_y_initial_dim } }
-                { \l__nm_radius_dim }
+                { \pgfpoint { \g__nicematrix_x_initial_dim } { \g__nicematrix_y_initial_dim } }
+                { \l__nicematrix_radius_dim }
               \pgfusepath { fill }
-              \dim_gadd:Nn \g__nm_x_initial_dim \l_tmpa_dim
-              \dim_gadd:Nn \g__nm_y_initial_dim \l_tmpb_dim
+              \dim_gadd:Nn \g__nicematrix_x_initial_dim \l_tmpa_dim
+              \dim_gadd:Nn \g__nicematrix_y_initial_dim \l_tmpb_dim
             }
         \end { tikzpicture }
       }
   }
-\cs_set_eq:NN \__nm_ldots \ldots
-\cs_set_eq:NN \__nm_cdots \cdots
-\cs_set_eq:NN \__nm_vdots \vdots
-\cs_set_eq:NN \__nm_ddots \ddots
-\cs_set_eq:NN \__nm_iddots \iddots
-\cs_new_protected:Nn \__nm_add_to_empty_cells:
+\cs_set_eq:NN \__nicematrix_ldots \ldots
+\cs_set_eq:NN \__nicematrix_cdots \cdots
+\cs_set_eq:NN \__nicematrix_vdots \vdots
+\cs_set_eq:NN \__nicematrix_ddots \ddots
+\cs_set_eq:NN \__nicematrix_iddots \iddots
+\cs_new_protected:Nn \__nicematrix_add_to_empty_cells:
   {
     \cs_gset:cpx
-      { __nm _ empty _ \int_use:N \c@iRow - \int_use:N \c@jCol }
-      { \int_use:N \g__nm_env_int }
+      { __nicematrix _ empty _ \int_use:N \c@iRow - \int_use:N \c@jCol }
+      { \int_use:N \g__nicematrix_env_int }
   }
-\NewDocumentCommand \__nm_Ldots { s }
+\NewDocumentCommand \__nicematrix_Ldots { s }
   {
-    \bool_if:nF { #1 } { \__nm_instruction_of_type:n { Ldots } }
-    \bool_if:NF \l__nm_nullify_dots_bool { \phantom \__nm_ldots }
-    \__nm_add_to_empty_cells:
+    \bool_if:nF { #1 } { \__nicematrix_instruction_of_type:n { Ldots } }
+    \bool_if:NF \l__nicematrix_nullify_dots_bool { \phantom \__nicematrix_ldots }
+    \__nicematrix_add_to_empty_cells:
   }
-\NewDocumentCommand \__nm_Cdots { s }
+\NewDocumentCommand \__nicematrix_Cdots { s }
   {
-    \bool_if:nF { #1 } { \__nm_instruction_of_type:n { Cdots } }
-    \bool_if:NF \l__nm_nullify_dots_bool { \phantom \__nm_cdots }
-    \__nm_add_to_empty_cells:
+    \bool_if:nF { #1 } { \__nicematrix_instruction_of_type:n { Cdots } }
+    \bool_if:NF \l__nicematrix_nullify_dots_bool { \phantom \__nicematrix_cdots }
+    \__nicematrix_add_to_empty_cells:
   }
-\NewDocumentCommand \__nm_Vdots { s }
+\NewDocumentCommand \__nicematrix_Vdots { s }
   {
-    \bool_if:nF { #1 } { \__nm_instruction_of_type:n { Vdots } }
-    \bool_if:NF \l__nm_nullify_dots_bool { \phantom \__nm_vdots }
-    \__nm_add_to_empty_cells:
+    \bool_if:nF { #1 } { \__nicematrix_instruction_of_type:n { Vdots } }
+    \bool_if:NF \l__nicematrix_nullify_dots_bool { \phantom \__nicematrix_vdots }
+    \__nicematrix_add_to_empty_cells:
   }
-\NewDocumentCommand \__nm_Ddots { s }
+\NewDocumentCommand \__nicematrix_Ddots { s }
   {
-    \bool_if:nF { #1 } { \__nm_instruction_of_type:n { Ddots } }
-    \bool_if:NF \l__nm_nullify_dots_bool { \phantom \__nm_ddots }
-    \__nm_add_to_empty_cells:
+    \bool_if:nF { #1 } { \__nicematrix_instruction_of_type:n { Ddots } }
+    \bool_if:NF \l__nicematrix_nullify_dots_bool { \phantom \__nicematrix_ddots }
+    \__nicematrix_add_to_empty_cells:
   }
-\NewDocumentCommand \__nm_Iddots { s }
+\NewDocumentCommand \__nicematrix_Iddots { s }
   {
-    \bool_if:nF { #1 } { \__nm_instruction_of_type:n { Iddots } }
-    \bool_if:NF \l__nm_nullify_dots_bool { \phantom \__nm_iddots }
-    \__nm_add_to_empty_cells:
+    \bool_if:nF { #1 } { \__nicematrix_instruction_of_type:n { Iddots } }
+    \bool_if:NF \l__nicematrix_nullify_dots_bool { \phantom \__nicematrix_iddots }
+    \__nicematrix_add_to_empty_cells:
   }
-\cs_new_protected:Nn \__nm_Hspace:
+\cs_new_protected:Nn \__nicematrix_Hspace:
   {
-   \__nm_add_to_empty_cells:
+   \__nicematrix_add_to_empty_cells:
    \hspace
   }
-\cs_set_eq:NN \__nm_old_multicolumn \multicolumn
-\cs_new:Npn \__nm_multicolumn:nnn #1 #2 #3
+\cs_set_eq:NN \__nicematrix_old_multicolumn \multicolumn
+\cs_new:Npn \__nicematrix_multicolumn:nnn #1 #2 #3
   {
-    \__nm_old_multicolumn { #1 } { #2 } { #3 }
+    \__nicematrix_old_multicolumn { #1 } { #2 } { #3 }
     \int_compare:nNnT #1 > 1
       {
-        \seq_gput_left:Nx \g__nm_multicolumn_cells_seq
+        \seq_gput_left:Nx \g__nicematrix_multicolumn_cells_seq
           { \int_eval:n \c@iRow - \int_use:N \c@jCol }
-        \seq_gput_left:Nn \g__nm_multicolumn_sizes_seq { #1 }
+        \seq_gput_left:Nn \g__nicematrix_multicolumn_sizes_seq { #1 }
       }
     \int_gadd:Nn \c@jCol { #1 - 1 }
   }
-\cs_new:Npn \__nm_Hdotsfor:
+\cs_new:Npn \__nicematrix_Hdotsfor:
   {
     \multicolumn { 1 } { C } { }
-    \__nm_Hdotsfor_i
+    \__nicematrix_Hdotsfor_i
   }
-\bool_if:NTF \c__nm_draft_bool
+\bool_if:NTF \c__nicematrix_draft_bool
   {
-    \NewDocumentCommand \__nm_Hdotsfor_i { O { }  m }
+    \NewDocumentCommand \__nicematrix_Hdotsfor_i { O { }  m }
       { \prg_replicate:nn { #2 - 1 } { & \multicolumn { 1 } { C } { } } }
   }
   {
-    \NewDocumentCommand \__nm_Hdotsfor_i { O { }  m }
+    \NewDocumentCommand \__nicematrix_Hdotsfor_i { O { }  m }
       {
-        \tl_gput_right:Nx \g__nm_Hdotsfor_lines_tl
+        \tl_gput_right:Nx \g__nicematrix_Hdotsfor_lines_tl
           {
-            \__nm_draw_Hdotsfor:nnn
+            \__nicematrix_draw_Hdotsfor:nnn
               { \int_use:N \c@iRow }
               { \int_use:N \c@jCol }
               { #2 }
@@ -1768,169 +1758,169 @@
         \prg_replicate:nn { #2 - 1 } { & \multicolumn { 1 } { C } { } }
       }
   }
-\cs_new_protected:Nn \__nm_draw_Hdotsfor:nnn
+\cs_new_protected:Nn \__nicematrix_draw_Hdotsfor:nnn
   {
-    \bool_set_false:N \l__nm_initial_open_bool
-    \bool_set_false:N \l__nm_final_open_bool
-    \int_set:Nn \l__nm_initial_i_int { #1 }
-    \int_set:Nn \l__nm_final_i_int { #1 }
+    \bool_set_false:N \l__nicematrix_initial_open_bool
+    \bool_set_false:N \l__nicematrix_final_open_bool
+    \int_set:Nn \l__nicematrix_initial_i_int { #1 }
+    \int_set:Nn \l__nicematrix_final_i_int { #1 }
     \int_compare:nNnTF #2 = 1
       {
-        \int_set:Nn \l__nm_initial_j_int 1
-        \bool_set_true:N \l__nm_initial_open_bool
+        \int_set:Nn \l__nicematrix_initial_j_int 1
+        \bool_set_true:N \l__nicematrix_initial_open_bool
       }
       {
         \int_set:Nn \l_tmpa_int { #2 - 1 }
-        \__nm_if_not_empty_cell:nnTF \l__nm_initial_i_int \l_tmpa_int
-          { \int_set:Nn \l__nm_initial_j_int { #2 - 1 } }
+        \__nicematrix_if_not_empty_cell:nnTF \l__nicematrix_initial_i_int \l_tmpa_int
+          { \int_set:Nn \l__nicematrix_initial_j_int { #2 - 1 } }
           {
-            \int_set:Nn \l__nm_initial_j_int {#2}
-            \bool_set_true:N \l__nm_initial_open_bool
+            \int_set:Nn \l__nicematrix_initial_j_int {#2}
+            \bool_set_true:N \l__nicematrix_initial_open_bool
           }
       }
     \int_compare:nNnTF { #2 + #3 -1 } = \c@jCol
       {
-        \int_set:Nn \l__nm_final_j_int { #2 + #3 - 1 }
-        \bool_set_true:N \l__nm_final_open_bool
+        \int_set:Nn \l__nicematrix_final_j_int { #2 + #3 - 1 }
+        \bool_set_true:N \l__nicematrix_final_open_bool
       }
       {
         \int_set:Nn \l_tmpa_int { #2 + #3 }
-        \__nm_if_not_empty_cell:nnTF \l__nm_final_i_int \l_tmpa_int
-          { \int_set:Nn \l__nm_final_j_int { #2 + #3 } }
+        \__nicematrix_if_not_empty_cell:nnTF \l__nicematrix_final_i_int \l_tmpa_int
+          { \int_set:Nn \l__nicematrix_final_j_int { #2 + #3 } }
           {
-            \int_set:Nn \l__nm_final_j_int { #2 + #3 - 1 }
-            \bool_set_true:N \l__nm_final_open_bool
+            \int_set:Nn \l__nicematrix_final_j_int { #2 + #3 - 1 }
+            \bool_set_true:N \l__nicematrix_final_open_bool
           }
       }
-    \bool_if:nT { \l__nm_initial_open_bool || \l__nm_final_open_bool }
-      \__nm_create_extra_nodes:
-    \__nm_actually_draw_Ldots:
+    \bool_if:nT { \l__nicematrix_initial_open_bool || \l__nicematrix_final_open_bool }
+      \__nicematrix_create_extra_nodes:
+    \__nicematrix_actually_draw_Ldots:
     \int_step_inline:nnn { #2 } { #2 + #3 - 1 }
-      { \cs_set:cpn { __nm _ dotted _ #1 - ##1 } { } }
+      { \cs_set:cpn { __nicematrix _ dotted _ #1 - ##1 } { } }
   }
-\cs_new:Npn \__nm_double_int_eval:n #1-#2 \q_stop
+\cs_new:Npn \__nicematrix_double_int_eval:n #1-#2 \q_stop
   { \int_eval:n { #1 } - \int_eval:n { #2 } }
-\cs_new_protected:Npn \__nm_line:nn #1 #2
+\cs_new_protected:Npn \__nicematrix_line:nn #1 #2
   {
     \use:x
       {
-        \__nm_line_i:nn
-          { \__nm_double_int_eval:n #1 \q_stop }
-          { \__nm_double_int_eval:n #2 \q_stop }
+        \__nicematrix_line_i:nn
+          { \__nicematrix_double_int_eval:n #1 \q_stop }
+          { \__nicematrix_double_int_eval:n #2 \q_stop }
       }
   }
-\cs_new_protected:Nn \__nm_line_i:nn
+\cs_new_protected:Nn \__nicematrix_line_i:nn
   {
-    \bool_if:NF \c__nm_draft_bool
+    \bool_if:NF \c__nicematrix_draft_bool
       {
-        \dim_zero_new:N \g__nm_x_initial_dim
-        \dim_zero_new:N \g__nm_y_initial_dim
-        \dim_zero_new:N \g__nm_x_final_dim
-        \dim_zero_new:N \g__nm_y_final_dim
-        \bool_set_false:N \l__nm_initial_open_bool
-        \bool_set_false:N \l__nm_final_open_bool
+        \dim_zero_new:N \g__nicematrix_x_initial_dim
+        \dim_zero_new:N \g__nicematrix_y_initial_dim
+        \dim_zero_new:N \g__nicematrix_x_final_dim
+        \dim_zero_new:N \g__nicematrix_y_final_dim
+        \bool_set_false:N \l__nicematrix_initial_open_bool
+        \bool_set_false:N \l__nicematrix_final_open_bool
         \bool_if:nTF
           {
-            \cs_if_exist_p:c { pgf@sh@ns@nm - \int_use:N \g__nm_env_int - #1 }
+            \cs_if_exist_p:c { pgf@sh@ns@nm - \int_use:N \g__nicematrix_env_int - #1 }
             &&
-            \cs_if_exist_p:c { pgf@sh@ns@nm - \int_use:N \g__nm_env_int - #2 }
+            \cs_if_exist_p:c { pgf@sh@ns@nm - \int_use:N \g__nicematrix_env_int - #2 }
           }
           {
             \begin { tikzpicture }
               \path~(#1)~--~(#2)~node[at~start]~(i)~{}~node[at~end]~(f)~{} ;
               \tikz@parse@node \pgfutil@firstofone ( i )
-              \dim_gset:Nn \g__nm_x_initial_dim \pgf@x
-              \dim_gset:Nn \g__nm_y_initial_dim \pgf@y
+              \dim_gset:Nn \g__nicematrix_x_initial_dim \pgf@x
+              \dim_gset:Nn \g__nicematrix_y_initial_dim \pgf@y
               \tikz@parse@node \pgfutil@firstofone ( f )
-              \dim_gset:Nn \g__nm_x_final_dim \pgf@x
-              \dim_gset:Nn \g__nm_y_final_dim \pgf@y
+              \dim_gset:Nn \g__nicematrix_x_final_dim \pgf@x
+              \dim_gset:Nn \g__nicematrix_y_final_dim \pgf@y
             \end { tikzpicture }
-            \__nm_draw_tikz_line:
+            \__nicematrix_draw_tikz_line:
           }
           {
-            \__nm_error:nnn { unknown~cell~for~line~in~code-after }
+            \__nicematrix_error:nnn { unknown~cell~for~line~in~code-after }
               { #1 } { #2 }
           }
       }
   }
-\bool_if:NTF \c__nm_draft_bool
-  { \cs_set_eq:NN \__nm_dotfill: \prg_do_nothing: }
+\bool_if:NTF \c__nicematrix_draft_bool
+  { \cs_set_eq:NN \__nicematrix_dotfill: \prg_do_nothing: }
   {
-    \cs_set:Npn \__nm_dotfill:
+    \cs_set:Npn \__nicematrix_dotfill:
       {
-        \bool_if:NT \l__nm_small_bool
-          { \dim_set:Nn \l__nm_inter_dots_dim { 0.25 em } }
+        \bool_if:NT \l__nicematrix_small_bool
+          { \dim_set:Nn \l__nicematrix_inter_dots_dim { 0.25 em } }
         \cleaders
         \hbox_to_wd:nn
-          { \l__nm_inter_dots_dim }
+          { \l__nicematrix_inter_dots_dim }
           {
             \c_math_toggle_token
-            \bool_if:NT \l__nm_small_bool \scriptstyle
+            \bool_if:NT \l__nicematrix_small_bool \scriptstyle
             \hss . \hss
             \c_math_toggle_token
           }
         \hfill
       }
   }
-\cs_new:Npn \__nm_hdottedline:
+\cs_new:Npn \__nicematrix_hdottedline:
   {
     \noalign
       {
-        \bool_gset_true:N \g__nm_extra_nodes_bool
-        \cs_if_exist:cTF { __nm_width_ \int_use:N \g__nm_env_int }
-          { \dim_set_eq:Nc \l_tmpa_dim { __nm_width_ \int_use:N \g__nm_env_int } }
+        \bool_gset_true:N \g__nicematrix_extra_nodes_bool
+        \cs_if_exist:cTF { __nicematrix_width_ \int_use:N \g__nicematrix_env_int }
+          { \dim_set_eq:Nc \l_tmpa_dim { __nicematrix_width_ \int_use:N \g__nicematrix_env_int } }
           { \dim_set:Nn \l_tmpa_dim { 5 mm } }
         \hbox_overlap_right:n
           {
             \bool_if:nT
               {
-                \l__nm_NiceArray_bool
+                \l__nicematrix_NiceArray_bool
                     &&
-                ! \l__nm_exterior_arraycolsep_bool
+                ! \l__nicematrix_exterior_arraycolsep_bool
                     &&
-                \int_compare_p:nNn \l__nm_first_col_int > \c_zero_int
+                \int_compare_p:nNn \l__nicematrix_first_col_int > \c_zero_int
               }
               { \skip_horizontal:n { - \arraycolsep } }
             \hbox_to_wd:nn
               {
                 \l_tmpa_dim + 2 \arraycolsep
-                - \l__nm_left_margin_dim - \l__nm_right_margin_dim
+                - \l__nicematrix_left_margin_dim - \l__nicematrix_right_margin_dim
               }
-            \__nm_dotfill:
+            \__nicematrix_dotfill:
           }
       }
   }
-\cs_new_protected:Nn \__nm_vdottedline:n
+\cs_new_protected:Nn \__nicematrix_vdottedline:n
   {
     \int_compare:nNnTF #1 = \c_zero_int
-      { \__nm_error:n { Use~of~:~in~first~position } }
+      { \__nicematrix_error:n { Use~of~:~in~first~position } }
       {
-        \bool_if:NF \c__nm_draft_bool
+        \bool_if:NF \c__nicematrix_draft_bool
           {
-            \dim_zero_new:N \g__nm_x_initial_dim
-            \dim_zero_new:N \g__nm_y_initial_dim
-            \dim_zero_new:N \g__nm_x_final_dim
-            \dim_zero_new:N \g__nm_y_final_dim
-            \bool_set_true:N \l__nm_initial_open_bool
-            \bool_set_true:N \l__nm_final_open_bool
+            \dim_zero_new:N \g__nicematrix_x_initial_dim
+            \dim_zero_new:N \g__nicematrix_y_initial_dim
+            \dim_zero_new:N \g__nicematrix_x_final_dim
+            \dim_zero_new:N \g__nicematrix_y_final_dim
+            \bool_set_true:N \l__nicematrix_initial_open_bool
+            \bool_set_true:N \l__nicematrix_final_open_bool
             \cs_if_exist:cTF
-              { pgf@sh@ns@nm -\int_use:N \g__nm_env_int - col - #1 }
+              { pgf@sh@ns@nm -\int_use:N \g__nicematrix_env_int - col - #1 }
               {
                 \begin { tikzpicture } [ remember~picture ]
                   \tikz@parse@node\pgfutil@firstofone
                     ( col - #1 )
-                  \dim_gset:Nn \g__nm_x_initial_dim \pgf@x
-                  \dim_gset:Nn \g__nm_x_final_dim \pgf@x
-                  \dim_gset:Nn \g__nm_y_final_dim \pgf@y
+                  \dim_gset:Nn \g__nicematrix_x_initial_dim \pgf@x
+                  \dim_gset:Nn \g__nicematrix_x_final_dim \pgf@x
+                  \dim_gset:Nn \g__nicematrix_y_final_dim \pgf@y
                 \end { tikzpicture }
-                \dim_gset:Nn \g__nm_y_initial_dim { - \c_max_dim }
+                \dim_gset:Nn \g__nicematrix_y_initial_dim { - \c_max_dim }
                 \int_step_inline:nn \c@jCol
                   {
                     \begin { tikzpicture } [ remember~picture ]
                       \tikz@parse@node\pgfutil@firstofone
                         ( 1 - ##1 . north~east )
-                      \dim_gset:Nn \g__nm_y_initial_dim
-                        { \dim_max:nn \g__nm_y_initial_dim \pgf@y }
+                      \dim_gset:Nn \g__nicematrix_y_initial_dim
+                        { \dim_max:nn \g__nicematrix_y_initial_dim \pgf@y }
                     \end { tikzpicture }
                   }
               }
@@ -1938,59 +1928,59 @@
                 \begin { tikzpicture } [ remember~picture ]
                   \tikz@parse@node\pgfutil@firstofone
                     ( 1 - #1 - large .north~east )
-                  \dim_gset:Nn \g__nm_x_initial_dim \pgf@x
-                  \dim_gset:Nn \g__nm_y_initial_dim \pgf@y
+                  \dim_gset:Nn \g__nicematrix_x_initial_dim \pgf@x
+                  \dim_gset:Nn \g__nicematrix_y_initial_dim \pgf@y
                   \tikz@parse@node\pgfutil@firstofone
                     ( \int_use:N \c@iRow - #1 - large .south~east )
-                  \dim_gset:Nn \g__nm_x_final_dim \pgf@x
-                  \dim_gset:Nn \g__nm_y_final_dim \pgf@y
+                  \dim_gset:Nn \g__nicematrix_x_final_dim \pgf@x
+                  \dim_gset:Nn \g__nicematrix_y_final_dim \pgf@y
                 \end { tikzpicture }
                 \cs_if_exist:cT
-                  { pgf@sh@ns@nm -\int_use:N \g__nm_env_int - 1 - #1 - w }
+                  { pgf@sh@ns@nm -\int_use:N \g__nicematrix_env_int - 1 - #1 - w }
                   {
                     \begin { tikzpicture } [ remember~picture ]
                       \tikz@parse@node\pgfutil@firstofone
                         ( 1 - #1 - w .north~east )
-                      \dim_gset:Nn \g__nm_x_initial_dim \pgf@x
+                      \dim_gset:Nn \g__nicematrix_x_initial_dim \pgf@x
                       \tikz@parse@node\pgfutil@firstofone
                         ( \int_use:N \c@iRow - #1 - w .south~east )
-                      \dim_gset:Nn \g__nm_x_final_dim \pgf@x
+                      \dim_gset:Nn \g__nicematrix_x_final_dim \pgf@x
                     \end { tikzpicture }
-                    \dim_gadd:Nn \g__nm_x_initial_dim \arraycolsep
-                    \dim_gadd:Nn \g__nm_x_final_dim \arraycolsep
+                    \dim_gadd:Nn \g__nicematrix_x_initial_dim \arraycolsep
+                    \dim_gadd:Nn \g__nicematrix_x_final_dim \arraycolsep
                   }
               }
-            \__nm_draw_tikz_line:
+            \__nicematrix_draw_tikz_line:
           }
       }
   }
-\cs_new_protected:Npn \__nm_vline:
+\cs_new_protected:Npn \__nicematrix_vline:
   {
-    \int_compare:nNnTF \l__nm_first_col_int = \c_zero_int
+    \int_compare:nNnTF \l__nicematrix_first_col_int = \c_zero_int
       {
         \int_compare:nNnTF \c@jCol = \c_zero_int
           {
-            \int_compare:nNnTF \l__nm_first_row_int = \c_zero_int
+            \int_compare:nNnTF \l__nicematrix_first_row_int = \c_zero_int
               {
                 \int_compare:nNnF \c@iRow = \c_zero_int
                   {
-                    \int_compare:nNnF \c@iRow = \l__nm_last_row_int
-                    \__nm_vline_i:
+                    \int_compare:nNnF \c@iRow = \l__nicematrix_last_row_int
+                    \__nicematrix_vline_i:
                   }
               }
               {
                 \int_compare:nNnF \c@iRow = \c_zero_int
                   {
-                    \int_compare:nNnF \c@iRow = \l__nm_last_row_int
-                    \__nm_vline_i:
+                    \int_compare:nNnF \c@iRow = \l__nicematrix_last_row_int
+                    \__nicematrix_vline_i:
                   }
               }
            }
            {
              \int_compare:nNnF \c@iRow = \c_zero_int
                {
-                 \int_compare:nNnF \c@iRow = \l__nm_last_row_int
-                 \__nm_vline_i:
+                 \int_compare:nNnF \c@iRow = \l__nicematrix_last_row_int
+                 \__nicematrix_vline_i:
                }
            }
       }
@@ -1999,242 +1989,243 @@
           {
             \int_compare:nNnF \c@iRow = { -1 }
               {
-                \int_compare:nNnF \c@iRow = { \l__nm_last_row_int - 1 }
-                  \__nm_vline_i:
+                \int_compare:nNnF \c@iRow = { \l__nicematrix_last_row_int - 1 }
+                  \__nicematrix_vline_i:
               }
           }
           {
             \int_compare:nNnF \c@iRow = \c_zero_int
               {
-                \int_compare:nNnF \c@iRow = \l__nm_last_row_int
-                \__nm_vline_i:
+                \int_compare:nNnF \c@iRow = \l__nicematrix_last_row_int
+                \__nicematrix_vline_i:
               }
           }
       }
   }
-\cs_set_eq:NN \__nm_vline_i: \vline
-\bool_new:N \l__nm_block_auto_columns_width_bool
+\cs_set_eq:NN \__nicematrix_vline_i: \vline
+\bool_new:N \l__nicematrix_block_auto_columns_width_bool
 \keys_define:nn { NiceMatrix / NiceMatrixBlock }
   {
     auto-columns-width .code:n =
       {
-        \bool_set_true:N \l__nm_block_auto_columns_width_bool
-        \dim_gzero_new:N \g__nm_max_cell_width_dim
-        \bool_set_true:N \l__nm_auto_columns_width_bool
+        \bool_set_true:N \l__nicematrix_block_auto_columns_width_bool
+        \dim_gzero_new:N \g__nicematrix_max_cell_width_dim
+        \bool_set_true:N \l__nicematrix_auto_columns_width_bool
       }
   }
 \NewDocumentEnvironment { NiceMatrixBlock } { ! O { } }
   {
-    \int_gincr:N \g__nm_NiceMatrixBlock_int
-    \dim_zero:N \l__nm_columns_width_dim
+    \int_gincr:N \g__nicematrix_NiceMatrixBlock_int
+    \dim_zero:N \l__nicematrix_columns_width_dim
     \keys_set:nn { NiceMatrix / NiceMatrixBlock } { #1 }
-    \bool_if:NT \l__nm_block_auto_columns_width_bool
+    \bool_if:NT \l__nicematrix_block_auto_columns_width_bool
       {
-        \cs_if_exist:cT { __nm_max_cell_width_ \int_use:N \g__nm_NiceMatrixBlock_int }
+        \cs_if_exist:cT { __nicematrix_max_cell_width_ \int_use:N \g__nicematrix_NiceMatrixBlock_int }
           {
-            \dim_set:Nx \l__nm_columns_width_dim
-              { \use:c { __nm_max_cell_width _ \int_use:N \g__nm_NiceMatrixBlock_int } }
+            \dim_set:Nx \l__nicematrix_columns_width_dim
+              { \use:c { __nicematrix_max_cell_width _ \int_use:N \g__nicematrix_NiceMatrixBlock_int } }
           }
       }
   }
   {
-    \bool_if:NT \l__nm_block_auto_columns_width_bool
+    \bool_if:NT \l__nicematrix_block_auto_columns_width_bool
       {
         \iow_now:Nn \@mainaux \ExplSyntaxOn
         \iow_now:Nx \@mainaux
           {
             \cs_gset:cpn
-              { __nm _ max _ cell _ width _ \int_use:N \g__nm_NiceMatrixBlock_int }
-              { \dim_use:N \g__nm_max_cell_width_dim }
+              { __nicematrix _ max _ cell _ width _ \int_use:N \g__nicematrix_NiceMatrixBlock_int }
+              { \dim_use:N \g__nicematrix_max_cell_width_dim }
           }
         \iow_now:Nn \@mainaux \ExplSyntaxOff
       }
   }
 \cs_generate_variant:Nn \dim_min:nn { v n }
 \cs_generate_variant:Nn \dim_max:nn { v n }
-\cs_new_protected:Nn \__nm_create_extra_nodes:
+\cs_new_protected:Nn \__nicematrix_create_extra_nodes:
   {
     \begin { tikzpicture } [ remember~picture , overlay ]
-      \int_step_variable:nnNn \l__nm_first_row_int \g__nm_row_total_int \__nm_i:
+      \int_step_variable:nnNn \l__nicematrix_first_row_int \g__nicematrix_row_total_int \__nicematrix_i:
         {
-          \dim_zero_new:c { l__nm_row_\__nm_i: _min_dim }
-          \dim_set_eq:cN { l__nm_row_\__nm_i: _min_dim } \c_max_dim
-          \dim_zero_new:c { l__nm_row_\__nm_i: _max_dim }
-          \dim_set:cn { l__nm_row_\__nm_i: _max_dim } { - \c_max_dim }
+          \dim_zero_new:c { l__nicematrix_row_\__nicematrix_i: _min_dim }
+          \dim_set_eq:cN { l__nicematrix_row_\__nicematrix_i: _min_dim } \c_max_dim
+          \dim_zero_new:c { l__nicematrix_row_\__nicematrix_i: _max_dim }
+          \dim_set:cn { l__nicematrix_row_\__nicematrix_i: _max_dim } { - \c_max_dim }
         }
-      \int_step_variable:nnNn \l__nm_first_col_int \g__nm_col_total_int \__nm_j:
+      \int_step_variable:nnNn \l__nicematrix_first_col_int \g__nicematrix_col_total_int \__nicematrix_j:
         {
-          \dim_zero_new:c { l__nm_column_\__nm_j: _min_dim }
-          \dim_set_eq:cN { l__nm_column_\__nm_j: _min_dim } \c_max_dim
-          \dim_zero_new:c { l__nm_column_\__nm_j: _max_dim }
-          \dim_set:cn { l__nm_column_\__nm_j: _max_dim } { - \c_max_dim }
+          \dim_zero_new:c { l__nicematrix_column_\__nicematrix_j: _min_dim }
+          \dim_set_eq:cN { l__nicematrix_column_\__nicematrix_j: _min_dim } \c_max_dim
+          \dim_zero_new:c { l__nicematrix_column_\__nicematrix_j: _max_dim }
+          \dim_set:cn { l__nicematrix_column_\__nicematrix_j: _max_dim } { - \c_max_dim }
         }
-      \int_step_variable:nnNn \l__nm_first_row_int \g__nm_row_total_int \__nm_i:
+      \int_step_variable:nnNn \l__nicematrix_first_row_int \g__nicematrix_row_total_int \__nicematrix_i:
         {
           \int_step_variable:nnNn
-            \l__nm_first_col_int \g__nm_col_total_int \__nm_j:
+            \l__nicematrix_first_col_int \g__nicematrix_col_total_int \__nicematrix_j:
             { \cs_if_exist:cT
-                { pgf@sh@ns@nm - \int_use:N \g__nm_env_int - \__nm_i: - \__nm_j: }
+                { pgf@sh@ns@nm - \int_use:N \g__nicematrix_env_int - \__nicematrix_i: - \__nicematrix_j: }
                 {
                   \tikz@parse@node \pgfutil@firstofone
-                    ( nm - \int_use:N \g__nm_env_int
-                         - \__nm_i: - \__nm_j: .south~west )
-                  \dim_set:cn { l__nm_row_\__nm_i: _min_dim}
-                    { \dim_min:vn { l__nm_row _ \__nm_i: _min_dim } \pgf@y }
-                  \seq_if_in:NxF \g__nm_multicolumn_cells_seq { \__nm_i: - \__nm_j: }
+                    ( nm - \int_use:N \g__nicematrix_env_int
+                         - \__nicematrix_i: - \__nicematrix_j: .south~west )
+                  \dim_set:cn { l__nicematrix_row_\__nicematrix_i: _min_dim}
+                    { \dim_min:vn { l__nicematrix_row _ \__nicematrix_i: _min_dim } \pgf@y }
+                  \seq_if_in:NxF \g__nicematrix_multicolumn_cells_seq { \__nicematrix_i: - \__nicematrix_j: }
                     {
-                      \dim_set:cn { l__nm_column _ \__nm_j: _min_dim}
-                        { \dim_min:vn { l__nm_column _ \__nm_j: _min_dim } \pgf@x }
+                      \dim_set:cn { l__nicematrix_column _ \__nicematrix_j: _min_dim}
+                        { \dim_min:vn { l__nicematrix_column _ \__nicematrix_j: _min_dim } \pgf@x }
                     }
                   \tikz@parse@node \pgfutil@firstofone
-                    ( nm - \int_use:N \g__nm_env_int - \__nm_i: - \__nm_j: .north~east )
-                  \dim_set:cn { l__nm_row _ \__nm_i: _ max_dim }
-                    { \dim_max:vn { l__nm_row _ \__nm_i: _ max_dim } \pgf@y }
-                  \seq_if_in:NxF \g__nm_multicolumn_cells_seq { \__nm_i: - \__nm_j: }
+                    ( nm - \int_use:N \g__nicematrix_env_int - \__nicematrix_i: - \__nicematrix_j: .north~east )
+                  \dim_set:cn { l__nicematrix_row _ \__nicematrix_i: _ max_dim }
+                    { \dim_max:vn { l__nicematrix_row _ \__nicematrix_i: _ max_dim } \pgf@y }
+                  \seq_if_in:NxF \g__nicematrix_multicolumn_cells_seq { \__nicematrix_i: - \__nicematrix_j: }
                     {
-                      \dim_set:cn { l__nm_column _ \__nm_j: _ max_dim }
-                        { \dim_max:vn { l__nm_column _ \__nm_j: _max_dim } \pgf@x }
+                      \dim_set:cn { l__nicematrix_column _ \__nicematrix_j: _ max_dim }
+                        { \dim_max:vn { l__nicematrix_column _ \__nicematrix_j: _max_dim } \pgf@x }
                     }
                 }
             }
         }
       \tikzset { name~suffix = -medium }
-      \__nm_create_nodes:
-      \int_set:Nn \l__nm_first_row_int 1
-      \int_set:Nn \l__nm_first_col_int 1
-      \int_step_variable:nNn { \c@iRow - 1 } \__nm_i:
+      \__nicematrix_create_nodes:
+      \int_set:Nn \l__nicematrix_first_row_int 1
+      \int_set:Nn \l__nicematrix_first_col_int 1
+      \int_step_variable:nNn { \c@iRow - 1 } \__nicematrix_i:
         {
-          \dim_set:cn { l__nm_row _ \__nm_i: _ min _ dim }
+          \dim_set:cn { l__nicematrix_row _ \__nicematrix_i: _ min _ dim }
             {
               (
-                \dim_use:c { l__nm_row _ \__nm_i: _ min _ dim } +
-                \dim_use:c { l__nm_row _ \int_eval:n { \__nm_i: + 1 } _ max _ dim }
+                \dim_use:c { l__nicematrix_row _ \__nicematrix_i: _ min _ dim } +
+                \dim_use:c { l__nicematrix_row _ \int_eval:n { \__nicematrix_i: + 1 } _ max _ dim }
               )
               / 2
             }
-          \dim_set_eq:cc { l__nm_row _ \int_eval:n { \__nm_i: + 1 } _ max _ dim }
-            { l__nm_row_\__nm_i: _min_dim }
+          \dim_set_eq:cc { l__nicematrix_row _ \int_eval:n { \__nicematrix_i: + 1 } _ max _ dim }
+            { l__nicematrix_row_\__nicematrix_i: _min_dim }
         }
-      \int_step_variable:nNn { \c@jCol - 1 } \__nm_j:
+      \int_step_variable:nNn { \c@jCol - 1 } \__nicematrix_j:
         {
-          \dim_set:cn { l__nm_column _ \__nm_j: _ max _ dim }
+          \dim_set:cn { l__nicematrix_column _ \__nicematrix_j: _ max _ dim }
             {
               (
                 \dim_use:c
-                  { l__nm_column _ \__nm_j: _ max _ dim } +
+                  { l__nicematrix_column _ \__nicematrix_j: _ max _ dim } +
                 \dim_use:c
-                  { l__nm_column _ \int_eval:n { \__nm_j: + 1 } _ min _ dim }
+                  { l__nicematrix_column _ \int_eval:n { \__nicematrix_j: + 1 } _ min _ dim }
               )
               / 2
             }
-          \dim_set_eq:cc { l__nm_column _ \int_eval:n { \__nm_j: + 1 } _ min _ dim }
-            { l__nm_column _ \__nm_j: _ max _ dim }
+          \dim_set_eq:cc { l__nicematrix_column _ \int_eval:n { \__nicematrix_j: + 1 } _ min _ dim }
+            { l__nicematrix_column _ \__nicematrix_j: _ max _ dim }
         }
       \dim_sub:cn
-        { l__nm_column _ 1 _ min _ dim }
-        \l__nm_left_margin_dim
+        { l__nicematrix_column _ 1 _ min _ dim }
+        \l__nicematrix_left_margin_dim
       \dim_add:cn
-        { l__nm_column _ \int_use:N \c@jCol _ max _ dim }
-        \l__nm_right_margin_dim
+        { l__nicematrix_column _ \int_use:N \c@jCol _ max _ dim }
+        \l__nicematrix_right_margin_dim
       \tikzset { name~suffix = -large }
-      \__nm_create_nodes:
+      \__nicematrix_create_nodes:
       \end{tikzpicture}
-      \cs_set:Npn \__nm_create_extra_nodes: { }
+      \cs_set:Npn \__nicematrix_create_extra_nodes: { }
       \begin { tikzpicture } [ remember~picture , overlay ]
         \tikz@parse@node \pgfutil@firstofone
-          ( nm - \int_use:N \g__nm_env_int - 1 - 1 - large .north~west )
+          ( nm - \int_use:N \g__nicematrix_env_int - 1 - 1 - large .north~west )
         \dim_gset:Nn \g_tmpa_dim \pgf@x
         \tikz@parse@node \pgfutil@firstofone
-          ( nm - \int_use:N \g__nm_env_int - 1 -
+          ( nm - \int_use:N \g__nicematrix_env_int - 1 -
                  \int_use:N \c@jCol - large .north~east )
         \dim_gset:Nn \g_tmpb_dim \pgf@x
       \end { tikzpicture }
       \iow_now:Nn \@mainaux \ExplSyntaxOn
       \iow_now:Nx \@mainaux
         {
-          \cs_gset:cpn { __nm_width_ \int_use:N \g__nm_env_int }
+          \cs_gset:cpn { __nicematrix_width_ \int_use:N \g__nicematrix_env_int }
             { \dim_eval:n { \g_tmpb_dim - \g_tmpa_dim } }
         }
       \iow_now:Nn \@mainaux \ExplSyntaxOff
   }
-\cs_new_protected:Nn \__nm_create_nodes:
+\cs_new_protected:Nn \__nicematrix_create_nodes:
   {
-    \int_step_variable:nnNn \l__nm_first_row_int \g__nm_row_total_int \__nm_i:
+    \int_step_variable:nnNn \l__nicematrix_first_row_int \g__nicematrix_row_total_int \__nicematrix_i:
       {
-        \int_step_variable:nnNn \l__nm_first_col_int \g__nm_col_total_int \__nm_j:
+        \int_step_variable:nnNn \l__nicematrix_first_col_int \g__nicematrix_col_total_int \__nicematrix_j:
           {
-            \coordinate ( __nm~south~west )
-               at ( \dim_use:c { l__nm_column_ \__nm_j: _min_dim } ,
-                    \dim_use:c { l__nm_row_ \__nm_i: _min_dim } ) ;
-            \coordinate ( __nm~north~east )
-               at ( \dim_use:c { l__nm_column_ \__nm_j: _max_dim } ,
-                    \dim_use:c { l__nm_row_ \__nm_i: _max_dim } ) ;
+            \coordinate ( __nicematrix~south~west )
+               at ( \dim_use:c { l__nicematrix_column_ \__nicematrix_j: _min_dim } ,
+                    \dim_use:c { l__nicematrix_row_ \__nicematrix_i: _min_dim } ) ;
+            \coordinate ( __nicematrix~north~east )
+               at ( \dim_use:c { l__nicematrix_column_ \__nicematrix_j: _max_dim } ,
+                    \dim_use:c { l__nicematrix_row_ \__nicematrix_i: _max_dim } ) ;
             \node
               [
                 node~contents = { } ,
-                fit = ( __nm~south~west ) ( __nm~north~east )  ,
+                fit = ( __nicematrix~south~west ) ( __nicematrix~north~east )  ,
                 inner~sep = \c_zero_dim ,
-                name = nm - \int_use:N \g__nm_env_int - \__nm_i: - \__nm_j: ,
+                name = nm - \int_use:N \g__nicematrix_env_int - \__nicematrix_i: - \__nicematrix_j: ,
                 alias =
-                  \str_if_empty:NF \l__nm_name_str
-                    { \l__nm_name_str - \__nm_i: - \__nm_j: }
+                  \str_if_empty:NF \l__nicematrix_name_str
+                    { \l__nicematrix_name_str - \__nicematrix_i: - \__nicematrix_j: }
               ]
               ;
           }
       }
     \seq_mapthread_function:NNN
-      \g__nm_multicolumn_cells_seq
-      \g__nm_multicolumn_sizes_seq
-      \__nm_node_for_multicolumn:nn
+      \g__nicematrix_multicolumn_cells_seq
+      \g__nicematrix_multicolumn_sizes_seq
+      \__nicematrix_node_for_multicolumn:nn
   }
-\cs_new_protected:Npn \__nm_extract_coords: #1 - #2 \q_stop
+\cs_new_protected:Npn \__nicematrix_extract_coords: #1 - #2 \q_stop
   {
-    \cs_set:Npn \__nm_i: { #1 }
-    \cs_set:Npn \__nm_j: { #2 }
+    \cs_set:Npn \__nicematrix_i: { #1 }
+    \cs_set:Npn \__nicematrix_j: { #2 }
   }
-\cs_new_protected:Nn \__nm_node_for_multicolumn:nn
+\cs_new_protected:Nn \__nicematrix_node_for_multicolumn:nn
   {
-    \__nm_extract_coords: #1 \q_stop
-    \coordinate ( __nm~south~west ) at
+    \__nicematrix_extract_coords: #1 \q_stop
+    \coordinate ( __nicematrix~south~west ) at
       (
-        \dim_use:c { l__nm_column _ \__nm_j: _ min _ dim } ,
-        \dim_use:c { l__nm_row _ \__nm_i: _ min _ dim }
+        \dim_use:c { l__nicematrix_column _ \__nicematrix_j: _ min _ dim } ,
+        \dim_use:c { l__nicematrix_row _ \__nicematrix_i: _ min _ dim }
       ) ;
-    \coordinate ( __nm~north~east ) at
+    \coordinate ( __nicematrix~north~east ) at
       (
-        \dim_use:c { l__nm_column _ \int_eval:n { \__nm_j: + #2 - 1 } _ max _ dim} ,
-        \dim_use:c { l__nm_row _ \__nm_i: _ max _ dim }
+        \dim_use:c { l__nicematrix_column _ \int_eval:n { \__nicematrix_j: + #2 - 1 } _ max _ dim} ,
+        \dim_use:c { l__nicematrix_row _ \__nicematrix_i: _ max _ dim }
       ) ;
     \node
       [
         node~contents = { } ,
-        fit = ( __nm~south~west ) ( __nm~north~east ) ,
+        fit = ( __nicematrix~south~west ) ( __nicematrix~north~east ) ,
         inner~sep = \c_zero_dim ,
-        name = nm - \int_use:N \g__nm_env_int - \__nm_i: - \__nm_j: ,
+        name = nm - \int_use:N \g__nicematrix_env_int - \__nicematrix_i: - \__nicematrix_j: ,
         alias =
-          \str_if_empty:NF \l__nm_name_str
-            { \l__nm_name_str - \__nm_i: - \__nm_j: }
+          \str_if_empty:NF \l__nicematrix_name_str
+            { \l__nicematrix_name_str - \__nicematrix_i: - \__nicematrix_j: }
       ]
       ;
   }
-\NewExpandableDocumentCommand \__nm_Block: { m D < > { } m }
-  { \__nm_Block_i #1 \q_stop { #2 } { #3 } }
-\cs_new:Npn \__nm_Block_i #1-#2 \q_stop { \__nm_Block_ii:nnnn { #1 } { #2 } }
-\cs_new:Npn \__nm_Block_ii:nnnn #1 #2 #3 #4
+\NewDocumentCommand \__nicematrix_Block: { m D < > { } m }
+  { \__nicematrix_Block_i #1 \q_stop { #2 } { #3 } }
+\cs_new:Npn \__nicematrix_Block_i #1-#2 \q_stop { \__nicematrix_Block_ii:nnnn { #1 } { #2 } }
+\cs_new:Npn \__nicematrix_Block_ii:nnnn #1 #2 #3 #4
   {
-    \int_compare:nNnTF { #1 } = 1
+    \int_compare:nNnT { #1 } = 1
       {
-        \multicolumn { #2 } { C } { \hbox:n { #3 $#4$ } }
-        \__nm_gobble_ampersands:n { #2 - 1 }
+        \begin { tikzpicture } [ remember~picture , baseline ]
+          \coordinate
+            ( nm - \int_use:N \g__nicematrix_env_int
+                 - Block
+                 - \int_use:N \c@iRow
+                 - \int_use:N \c@jCol ) ;
+        \end { tikzpicture }
       }
-      { \__nm_Block_iii:nnnn { #1 } { #2 } { #3 } { #4 } }
-  }
-\cs_new_protected:Npn \__nm_Block_iii:nnnn #1 #2 #3 #4
-  {
-    \bool_gset_true:N \g__nm_extra_nodes_bool
-    \tl_gput_left:Nx \g__nm_code_after_tl
+    \bool_gset_true:N \g__nicematrix_extra_nodes_bool
+    \tl_gput_left:Nx \g__nicematrix_code_after_tl
       {
-        \__nm_Block_iv:nnnnn
+        \__nicematrix_Block_iii:nnnnn
           { \int_use:N \c@iRow }
           { \int_use:N \c@jCol }
           { \int_eval:n { \c@iRow + #1 - 1 } }
@@ -2242,18 +2233,7 @@
           \exp_not:n { { #3 $ #4 $ } }
       }
   }
-\group_begin:
-  \char_set_catcode_letter:N \&
-  \cs_new:Npn \__nm_gobble_ampersands:n #1
-    {
-      \int_compare:nNnT { #1 } > 0
-        {
-          \peek_charcode_remove_ignore_spaces:NT &
-            { \__nm_gobble_ampersands:n { #1 - 1 } }
-        }
-    }
-\group_end:
-\cs_new_protected:Npn \__nm_Block_iv:nnnnn #1 #2 #3 #4 #5
+\cs_new_protected:Npn \__nicematrix_Block_iii:nnnnn #1 #2 #3 #4 #5
   {
     \bool_if:nTF
       {
@@ -2262,19 +2242,37 @@
       }
       { \msg_error:nnnn { nicematrix } { Block~too~large } { #1 } { #2 } }
       {
-        \begin{tikzpicture}
-        \node
-          [
-            fit = ( #1 - #2 - medium . north~west )
-                  ( #3 - #4 - medium . south~east ) ,
-            inner~sep = 0 pt ,
-          ]
-          (#1-#2) { } ;
-         \node at (#1-#2.center) { #5 } ;
-    \end{tikzpicture}
+        \int_compare:nNnTF { #1 } = { #3 }
+          {
+            \begin { tikzpicture }
+              \tikz@parse@node \pgfutil@firstofone (Block-#1-#2)
+              \dim_set:Nn \l_tmpa_dim \pgf@y
+              \node
+                [
+                  fit = ( #1 - #2 - medium . north~west )
+                        ( #3 - #4 - medium . south~east ) ,
+                  inner~sep = 0 pt ,
+                ]
+              (#1-#2) { } ;
+              \tikz@parse@node \pgfutil@firstofone (#1-#2)
+              \path (\pgf@x,\l_tmpa_dim) node [ anchor = base ] { #5 } ;
+            \end { tikzpicture }
+          }
+          {
+            \begin { tikzpicture }
+            \node
+              [
+                fit = ( #1 - #2 - medium . north~west )
+                      ( #3 - #4 - medium . south~east ) ,
+                inner~sep = 0 pt ,
+              ]
+              (#1-#2) { } ;
+             \node at (#1-#2.center) { #5 } ;
+             \end { tikzpicture }
+          }
       }
   }
-\cs_set_protected:Npn \__nm_renew_matrix:
+\cs_set_protected:Npn \__nicematrix_renew_matrix:
   {
     \RenewDocumentEnvironment { pmatrix } { }
       { \pNiceMatrix }
@@ -2292,128 +2290,130 @@
       { \BNiceMatrix }
       { \endBNiceMatrix }
   }
-\cs_new_protected:Npn \__nm_set_size:n #1-#2 \q_stop
+\cs_new_protected:Npn \__nicematrix_set_size:n #1-#2 \q_stop
   {
-    \int_set:Nn \l__nm_nb_rows_int { #1 }
-    \int_set:Nn \l__nm_nb_cols_int { #2 }
+    \int_set:Nn \l__nicematrix_nb_rows_int { #1 }
+    \int_set:Nn \l__nicematrix_nb_cols_int { #2 }
   }
 \NewDocumentCommand \AutoNiceMatrixWithDelims { m m O { } m O { } m ! O { } }
   {
-    \int_zero_new:N \l__nm_nb_rows_int
-    \int_zero_new:N \l__nm_nb_cols_int
-    \__nm_set_size:n #4 \q_stop
+    \int_zero_new:N \l__nicematrix_nb_rows_int
+    \int_zero_new:N \l__nicematrix_nb_cols_int
+    \__nicematrix_set_size:n #4 \q_stop
     \begin { NiceArrayWithDelims } { #1 } { #2 }
-      { * { \l__nm_nb_cols_int } { C } } [ #3 , #5 , #7 ]
-    \int_compare:nNnT \l__nm_first_row_int = \c_zero_int
+      { * { \l__nicematrix_nb_cols_int } { C } } [ #3 , #5 , #7 ]
+    \int_compare:nNnT \l__nicematrix_first_row_int = \c_zero_int
       {
-        \int_compare:nNnT \l__nm_first_col_int = \c_zero_int { & }
-        \prg_replicate:nn { \l__nm_nb_cols_int - 1 } { & }
-        \int_compare:nNnT \l__nm_last_col_int > { -1 } { & } \\
+        \int_compare:nNnT \l__nicematrix_first_col_int = \c_zero_int { & }
+        \prg_replicate:nn { \l__nicematrix_nb_cols_int - 1 } { & }
+        \int_compare:nNnT \l__nicematrix_last_col_int > { -1 } { & } \\
       }
-    \prg_replicate:nn \l__nm_nb_rows_int
+    \prg_replicate:nn \l__nicematrix_nb_rows_int
       {
-        \int_compare:nNnT \l__nm_first_col_int = \c_zero_int { & }
-        \prg_replicate:nn { \l__nm_nb_cols_int - 1 } { { } #6 & } #6
-        \int_compare:nNnT \l__nm_last_col_int > { -1 } { & } \\
+        \int_compare:nNnT \l__nicematrix_first_col_int = \c_zero_int { & }
+        \prg_replicate:nn { \l__nicematrix_nb_cols_int - 1 } { { } #6 & } #6
+        \int_compare:nNnT \l__nicematrix_last_col_int > { -1 } { & } \\
       }
-    \int_compare:nNnT \l__nm_last_row_int > { -2 }
+    \int_compare:nNnT \l__nicematrix_last_row_int > { -2 }
       {
-        \int_compare:nNnT \l__nm_first_col_int = \c_zero_int { & }
-        \prg_replicate:nn { \l__nm_nb_cols_int - 1 } { & }
-        \int_compare:nNnT \l__nm_last_col_int > { -1 } { & } \\
+        \int_compare:nNnT \l__nicematrix_first_col_int = \c_zero_int { & }
+        \prg_replicate:nn { \l__nicematrix_nb_cols_int - 1 } { & }
+        \int_compare:nNnT \l__nicematrix_last_col_int > { -1 } { & } \\
       }
     \end { NiceArrayWithDelims }
   }
-\cs_set_protected:Npn \__nm_define_com:nnn #1 #2 #3
+\cs_set_protected:Npn \__nicematrix_define_com:nnn #1 #2 #3
   {
     \cs_set_protected:cpn { #1 AutoNiceMatrix }
       {
-        \str_gset:Nx \g__nm_type_env_str
+        \str_gset:Nx \g__nicematrix_type_env_str
           { command ~ \c_backslash_str #1 AutoNiceMatrix }
         \AutoNiceMatrixWithDelims { #2 } { #3 }
       }
   }
-\__nm_define_com:nnn p ( )
-\__nm_define_com:nnn b [ ]
-\__nm_define_com:nnn v | |
-\__nm_define_com:nnn V \| \|
-\__nm_define_com:nnn B \{ \}
+\__nicematrix_define_com:nnn p ( )
+\__nicematrix_define_com:nnn b [ ]
+\__nicematrix_define_com:nnn v | |
+\__nicematrix_define_com:nnn V \| \|
+\__nicematrix_define_com:nnn B \{ \}
 \keys_define:nn { NiceMatrix / Package }
   {
-    renew-dots .bool_set:N = \l__nm_renew_dots_bool ,
+    renew-dots .bool_set:N = \l__nicematrix_renew_dots_bool ,
     renew-dots .value_forbidden:n = true ,
-    renew-matrix .code:n = \__nm_renew_matrix: ,
+    renew-matrix .code:n = \__nicematrix_renew_matrix: ,
     renew-matrix .value_forbidden:n = true ,
     transparent .meta:n = { renew-dots , renew-matrix } ,
     transparent .value_forbidden:n = true,
+    obsolete-environments .code:n =
+      \__nicematrix_msg_redirect_name:nn { Obsolete~environment } { none }
   }
 \ProcessKeysOptions { NiceMatrix / Package }
-\__nm_msg_new:nn { unknown~cell~for~line~in~code-after }
+\__nicematrix_msg_new:nn { unknown~cell~for~line~in~code-after }
   {
     Your~command~\token_to_str:N\line\{#1\}\{#2\}~in~the~'code-after'~
     can't~be~executed~because~a~Tikz~node~doesn't~exist.\\
     If~you~go~on~this~command~will~be~ignored.
   }
-\__nm_msg_new:nn { last-col~non~empty~for~NiceArray }
+\__nicematrix_msg_new:nn { last-col~non~empty~for~NiceArray }
   {
-    In~the~\g__nm_type_env_str,~you~must~use~the~option~
+    In~the~\g__nicematrix_type_env_str,~you~must~use~the~option~
     'last-col'~without~value.\\
     However,~you~can~go~on~for~this~time~
     (the~value~'\l_keys_value_tl'~will~be~ignored).
   }
-\__nm_msg_new:nn { last-col~empty~for~NiceMatrix }
+\__nicematrix_msg_new:nn { last-col~empty~for~NiceMatrix }
   {
-    In~the~\g__nm_type_env_str, you~can't~use~the~option~
+    In~the~\g__nicematrix_type_env_str, you~can't~use~the~option~
     'last-col'~without~value.~You~must~give~the~number~of~that~last~column.\\
     If~you~go~on~this~option~will~be~ignored.
   }
-\__nm_msg_new:nn { Block~too~large }
+\__nicematrix_msg_new:nn { Block~too~large }
   {
     You~try~to~draw~a~block~in~the~cell~#1-#2~of~your~matrix~but~the~matrix~is~
     too~small~for~that~block.\\
     If~you~go~on,~this~command~will~be~ignored.
   }
-\__nm_msg_new:nn { Impossible~line }
+\__nicematrix_msg_new:nn { Impossible~line }
   {
     A~dotted~line~can't~be~drawn~because~you~have~not~put~
     all~the~ampersands~required~on~the~row~#1.\\
     If~you~go~on,~this~dotted~line~will~be~ignored.
   }
-\__nm_msg_new:nn { Wrong~last~row }
+\__nicematrix_msg_new:nn { Wrong~last~row }
   {
-    You~have~used~'last-row=\int_use:N \l__nm_last_row_int'~but~your~
-    \g__nm_type_env_str\ seems~to~have~\int_use:N \c@iRow \ rows.~
+    You~have~used~'last-row=\int_use:N \l__nicematrix_last_row_int'~but~your~
+    \g__nicematrix_type_env_str\ seems~to~have~\int_use:N \c@iRow \ rows.~
     If~you~go~on,~the~value~of~\int_use:N \c@iRow \ will~be~used~for~
     last~row.~You~can~avoid~this~problem~by~using~'last-row'~
     without~value~(more~compilations~might~be~necessary).
   }
-\__nm_msg_new:nn { Yet~in~env }
+\__nicematrix_msg_new:nn { Yet~in~env }
   {
     Environments~\{NiceArray\}~(or~\{NiceMatrix\},~etc.)~can't~be~nested.\\
     This~error~is~fatal.
   }
-\__nm_msg_new:nn { Outside~math~mode }
+\__nicematrix_msg_new:nn { Outside~math~mode }
   {
-    The~\g__nm_type_env_str\ can~be~used~only~in~math~mode~
+    The~\g__nicematrix_type_env_str\ can~be~used~only~in~math~mode~
     (and~not~in~\token_to_str:N \vcenter).\\
     This~error~is~fatal.
   }
-\__nm_msg_new:nn { Option~Transparent~suppressed }
+\__nicematrix_msg_new:nn { Option~Transparent~suppressed }
   {
     The~option~'Transparent'~has~been~renamed~'transparent'.\\
     However,~you~can~go~on~for~this~time.
   }
-\__nm_msg_new:nn { Option~RenewMatrix~suppressed }
+\__nicematrix_msg_new:nn { Option~RenewMatrix~suppressed }
   {
     The~option~'RenewMatrix'~has~been~renamed~'renew-matrix'.\\
     However,~you~can~go~on~for~this~time.
   }
-\__nm_msg_new:nn { Bad~value~for~letter~for~dotted~lines }
+\__nicematrix_msg_new:nn { Bad~value~for~letter~for~dotted~lines }
   {
     The~value~of~key~'\tl_use:N\l_keys_key_tl'~must~be~of~length~1.\\
     If~you~go~on,~it~will~be~ignored.
   }
-\__nm_msg_new:nnn { Unknown~key~for~NiceMatrixOptions }
+\__nicematrix_msg_new:nnn { Unknown~key~for~NiceMatrixOptions }
   {
     The~key~'\tl_use:N\l_keys_key_tl'~is~unknown~for~the~command~
     \token_to_str:N \NiceMatrixOptions. \\
@@ -2439,7 +2439,7 @@
     small~
     and~transparent
   }
-\__nm_msg_new:nnn { Unknown~option~for~NiceArray }
+\__nicematrix_msg_new:nnn { Unknown~option~for~NiceArray }
   {
     The~option~'\tl_use:N\l_keys_key_tl'~is~unknown~for~the~environment~
     \{NiceArray\}. \\
@@ -2473,10 +2473,10 @@
     small~
     and~t.
   }
-\__nm_msg_new:nnn { Unknown~option~for~NiceMatrix }
+\__nicematrix_msg_new:nnn { Unknown~option~for~NiceMatrix }
   {
     The~option~'\tl_use:N\l_keys_key_tl'~is~unknown~for~the~
-    \g__nm_type_env_str. \\
+    \g__nicematrix_type_env_str. \\
     If~you~go~on,~it~will~be~ignored. \\
     For~a~list~of~the~available~options,~type~H~<return>.
   }
@@ -2504,7 +2504,7 @@
     right-margin~
     and~small.
   }
-\__nm_msg_new:nnn { Duplicate~name }
+\__nicematrix_msg_new:nnn { Duplicate~name }
   {
     The~name~'\l_keys_value_tl'~is~already~used~and~you~shouldn't~use~
     the~same~environment~name~twice.~You~can~go~on,~but,~
@@ -2516,130 +2516,132 @@
   }
   {
     The~names~already~defined~in~this~document~are:~
-    \seq_use:Nnnn \g__nm_names_seq { ,~ } { ,~ } { ~and~ }.
+    \seq_use:Nnnn \g__nicematrix_names_seq { ,~ } { ,~ } { ~and~ }.
   }
-\__nm_msg_new:nn { Option~auto~for~columns-width }
+\__nicematrix_msg_new:nn { Option~auto~for~columns-width }
   {
     You~can't~give~the~value~'auto'~to~the~option~'columns-width'~here.~
     If~you~go~on,~the~option~will~be~ignored.
   }
-\__nm_msg_new:nn { Zero~row }
+\__nicematrix_msg_new:nn { Zero~row }
   {
-    There~is~a~problem.~Maybe~your~\g__nm_type_env_str\ is~empty.~
+    There~is~a~problem.~Maybe~your~\g__nicematrix_type_env_str\ is~empty.~
     Maybe~you~have~used~l,~c~and~r~instead~of~L,~C~and~R~in~the~preamble~
     of~your~environment. \\
     If~you~go~on,~the~result~may~be~incorrect.
   }
-\__nm_msg_new:nn { Use~of~:~in~first~position }
+\__nicematrix_msg_new:nn { Use~of~:~in~first~position }
   {
-    You~can't~use~the~column~specifier~'\l__nm_letter_for_dotted_lines_str'~in~the~
-    first~position~of~the~preamble~of~the~\g__nm_type_env_str. \\
+    You~can't~use~the~column~specifier~'\l__nicematrix_letter_for_dotted_lines_str'~in~the~
+    first~position~of~the~preamble~of~the~\g__nicematrix_type_env_str. \\
     If~you~go~on,~this~dotted~line~will~be~ignored.
   }
-\__nm_msg_new:nn { Obsolete~environment }
+\__nicematrix_msg_new:nn { Obsolete~environment }
   {
-    The~environment~\{\@currenvir\}~is~obsolete~and~will~be~deleted~in~future~version.~
-    We~should~use~#1~instead.
+    The~environment~\{\@currenvir\}~is~obsolete.~We~should~use~#1~instead.~
+    However,~you~can~go~on~for~this~time.~
+    If~you~don't~want~to~see~this~error~again,~you~should~load~'nicematrix'~
+    with~the~option~'obsolete-environments'.
   }
 \NewDocumentEnvironment { pNiceArrayC } { }
   {
-    \msg_info:nnn { nicematrix } { Obsolete~environment }
+    \__nicematrix_error:nn { Obsolete~environment }
       { the~option~'last-col' }
-    \int_set:Nn \l__nm_last_col_int \c_zero_dim
+    \int_set:Nn \l__nicematrix_last_col_int \c_zero_dim
     \pNiceArray
   }
   { \endpNiceArray }
 \NewDocumentEnvironment { bNiceArrayC } { }
   {
-    \msg_info:nnn { nicematrix } { Obsolete~environment }
+    \__nicematrix_error:nn { Obsolete~environment }
       { the~option~'last-col' }
-    \int_set:Nn \l__nm_last_col_int \c_zero_dim
+    \int_set:Nn \l__nicematrix_last_col_int \c_zero_dim
     \bNiceArray
   }
   { \endbNiceArray }
 \NewDocumentEnvironment { BNiceArrayC } { }
   {
-    \msg_info:nnn { nicematrix } { Obsolete~environment }
+    \__nicematrix_error:nn { Obsolete~environment }
       { the~option~'last-col' }
-    \int_set:Nn \l__nm_last_col_int \c_zero_dim
+    \int_set:Nn \l__nicematrix_last_col_int \c_zero_dim
     \BNiceArray
   }
   { \endBNiceArray }
 \NewDocumentEnvironment { vNiceArrayC } { }
   {
-    \msg_info:nnn { nicematrix } { Obsolete~environment }
+    \__nicematrix_error:nn { Obsolete~environment }
       { the~option~'last-col' }
-    \int_set:Nn \l__nm_last_col_int \c_zero_dim
+    \int_set:Nn \l__nicematrix_last_col_int \c_zero_dim
     \vNiceArray
   }
   { \endvNiceArray }
 \NewDocumentEnvironment { VNiceArrayC } { }
   {
-    \msg_info:nnn { nicematrix } { Obsolete~environment }
+    \__nicematrix_error:nn { Obsolete~environment }
       { the~option~'last-col' }
-    \int_set:Nn \l__nm_last_col_int \c_zero_dim
+    \int_set:Nn \l__nicematrix_last_col_int \c_zero_dim
     \VNiceArray
   }
   { \endVNiceArray }
 \NewDocumentEnvironment { pNiceArrayRC } { }
   {
-    \msg_info:nnn { nicematrix } { Obsolete~environment }
+    \__nicematrix_error:nn { Obsolete~environment }
       { the~options~'last-col'~and~'first-row' }
-    \int_set:Nn \l__nm_last_col_int \c_zero_dim
-    \int_set:Nn \l__nm_first_row_int \c_zero_int
+    \int_set:Nn \l__nicematrix_last_col_int \c_zero_dim
+    \int_set:Nn \l__nicematrix_first_row_int \c_zero_int
     \pNiceArray
   }
   { \endpNiceArray }
 \NewDocumentEnvironment { bNiceArrayRC } { }
   {
-    \msg_info:nnn { nicematrix } { Obsolete~environment }
+    \__nicematrix_error:nn { Obsolete~environment }
       { the~options~'last-col'~and~'first-row' }
-    \int_set:Nn \l__nm_last_col_int \c_zero_dim
-    \int_set:Nn \l__nm_first_row_int \c_zero_int
+    \int_set:Nn \l__nicematrix_last_col_int \c_zero_dim
+    \int_set:Nn \l__nicematrix_first_row_int \c_zero_int
     \bNiceArray
   }
   { \endbNiceArray }
 \NewDocumentEnvironment { BNiceArrayRC } { }
   {
-    \msg_info:nnn { nicematrix } { Obsolete~environment }
+    \__nicematrix_error:nn { Obsolete~environment }
       { the~options~'last-col'~and~'first-row' }
-    \int_set:Nn \l__nm_last_col_int \c_zero_dim
-    \int_set:Nn \l__nm_first_row_int \c_zero_int
+    \int_set:Nn \l__nicematrix_last_col_int \c_zero_dim
+    \int_set:Nn \l__nicematrix_first_row_int \c_zero_int
     \BNiceArray
   }
   { \endBNiceArray }
 \NewDocumentEnvironment { vNiceArrayRC } { }
   {
-    \msg_info:nnn { nicematrix } { Obsolete~environment }
+    \__nicematrix_error:nn { Obsolete~environment }
       { the~options~'last-col'~and~'first-row' }
-    \bool_set_true:N \l__nm_last_col_bool
-    \int_set:Nn \l__nm_first_row_int \c_zero_int
+    \bool_set_true:N \l__nicematrix_last_col_bool
+    \int_set:Nn \l__nicematrix_first_row_int \c_zero_int
     \vNiceArray
   }
   { \endvNiceArray }
 \NewDocumentEnvironment { VNiceArrayRC } { }
   {
-    \msg_info:nnn { nicematrix } { Obsolete~environment }
+    \__nicematrix_error:nn { Obsolete~environment }
       { the~options~'last-col'~and~'first-row' }
-    \int_set:Nn \l__nm_last_col_int \c_zero_dim
-    \int_set:Nn \l__nm_first_row_int \c_zero_int
+    \int_set:Nn \l__nicematrix_last_col_int \c_zero_dim
+    \int_set:Nn \l__nicematrix_first_row_int \c_zero_int
     \VNiceArray
   }
   { \endVNiceArray }
 \NewDocumentEnvironment { NiceArrayCwithDelims } { }
   {
-    \msg_info:nnn { nicematrix } { Obsolete~environment }
+    \__nicematrix_error:nn { Obsolete~environment }
       { the~option~'last-col' }
-    \int_set:Nn \l__nm_last_col_int \c_zero_dim
+    \int_set:Nn \l__nicematrix_last_col_int \c_zero_dim
     \NiceArrayWithDelims
   }
   { \endNiceArrayWithDelims }
 \NewDocumentEnvironment { NiceArrayRCwithDelims } { }
   {
-    \msg_info:nnn { nicematrix } { Obsolete~environment }
+    \__nicematrix_error:nn { Obsolete~environment }
       { the~options~'last-col'~and~'first-row' }
-    \int_set:Nn \l__nm_last_col_int \c_zero_dim
-    \int_set:Nn \l__nm_first_row_int \c_zero_int
+    \int_set:Nn \l__nicematrix_last_col_int \c_zero_dim
+    \int_set:Nn \l__nicematrix_first_row_int \c_zero_int
     \NiceArrayWithDelims
   }
   { \endNiceArrayWithDelims }