witharrows (25jul19)

git-svn-id: svn://tug.org/texlive/trunk@51728 c570f23f-e606-0410-a88d-b1316a301751

1 files changed, 1013 insertions, 801 deletions

diff --git a/Master/texmf-dist/tex/latex/witharrows/witharrows.sty b/Master/texmf-dist/tex/latex/witharrows/witharrows.sty
index 795d67b973b..563c6e8b260 100644
--- a/Master/texmf-dist/tex/latex/witharrows/witharrows.sty
+++ b/Master/texmf-dist/tex/latex/witharrows/witharrows.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{1.17}
-\def\myfiledate{2019/07/09}
+\def\myfileversion{1.18}
+\def\myfiledate{2019/07/24}
 \RequirePackage{tikz}
 \usetikzlibrary{arrows.meta,bending}
 \RequirePackage{expl3}[2019/02/15]
@@ -30,75 +30,79 @@
   {\myfileversion}
   {Draws arrows for explanations on the right}
 \RequirePackage { xparse } [ 2018-10-17 ]
-\bool_new:N \g__wa_footnotehyper_bool
-\bool_new:N \g__wa_footnote_bool
-\cs_new_protected:Npn \__wa_msg_new:nn { \msg_new:nnn { witharrows } }
-\cs_new_protected:Npn \__wa_msg_new:nnn { \msg_new:nnnn { witharrows } }
-\cs_new_protected:Npn \__wa_msg_redirect_name:nn
+\bool_new:N \g__wi_footnotehyper_bool
+\bool_new:N \g__wi_footnote_bool
+\cs_new_protected:Npn \__wi_msg_new:nn { \msg_new:nnn { witharrows } }
+\cs_new_protected:Npn \__wi_msg_new:nnn { \msg_new:nnnn { witharrows } }
+\cs_new_protected:Npn \__wi_msg_redirect_name:nn
   { \msg_redirect_name:nnn { witharrows } }
+\cs_new_protected:Npn \__wi_error:n { \msg_error:nn { witharrows } }
+\cs_new_protected:Npn \__wi_warning:n { \msg_error:nn { witharrows } }
+\cs_new_protected:Npn \__wi_fatal:n { \msg_fatal:nn { witharrows } }
+\cs_new_protected:Npn \__wi_error:nn  { \msg_error:nnn { witharrows } }
+\cs_generate_variant:Nn \__wi_error:nn { n x }
 \keys_define:nn { WithArrows / package }
   {
-    footnote .bool_gset:N = \g__wa_footnote_bool ,
-    footnotehyper .bool_gset:N = \g__wa_footnotehyper_bool ,
+    footnote .bool_gset:N = \g__wi_footnote_bool ,
+    footnotehyper .bool_gset:N = \g__wi_footnotehyper_bool ,
     unknown .code:n =
-      \msg_fatal:nn { witharrows } { Option~unknown~for~package }
+      \__wi_fatal:n { Option~unknown~for~package }
   }
-\__wa_msg_new:nn { Option~unknown~for~package }
+\__wi_msg_new:nn { Option~unknown~for~package }
   {
     You~can't~use~the~option~'\l_keys_key_tl'~when~loading~the~
     package~witharrows.~Try~to~use~the~command~
     \token_to_str:N\WithArrowsOptions.
   }
 \ProcessKeysOptions { WithArrows / package }
-\__wa_msg_new:nn { Option~incompatible~with~Beamer }
+\__wi_msg_new:nn { Option~incompatible~with~Beamer }
   {
     The~option~'\l_keys_key_tl'\ is~incompatible~
     with~Beamer~because~Beamer~has~its~own~system~to~extract~footnotes.
   }
-\__wa_msg_new:nn { footnote~with~footnotehyper~package }
+\__wi_msg_new:nn { footnote~with~footnotehyper~package }
   {
     You~can't~use~the~option~'footnote'~because~the~package~
     footnotehyper~has~already~been~loaded.~
     If~you~want,~you~can~use~the~option~'footnotehyper'~and~the~footnotes~
     within~the~environments~of~witharrows~will~be~extracted~with~the~tools~
-    of~the~package~footnotehyper.
+    of~the~package~footnotehyper.\\
+    If~you~go~on,~the~package~footnote~won't~be~loaded.
   }
-\__wa_msg_new:nn { footnotehyper~with~footnote~package }
+\__wi_msg_new:nn { footnotehyper~with~footnote~package }
   {
     You~can't~use~the~option~'footnotehyper'~because~the~package~
     footnote~has~already~been~loaded.~
     If~you~want,~you~can~use~the~option~'footnote'~and~the~footnotes~
     within~the~environments~of~witharrows~will~be~extracted~with~the~tools~
-    of~the~package~footnote.
+    of~the~package~footnote.\\
+    If~you~go~on,~the~package~footnotehyper~won't~be~loaded.
   }
-\bool_if:NT \g__wa_footnote_bool
+\bool_if:NT \g__wi_footnote_bool
   {
     \@ifclassloaded { beamer }
-      { \msg_fatal:nn { witharrows } { Option~incompatible~with~Beamer } }
-      { }
-    \@ifpackageloaded { footnotehyper }
-      { \msg_fatal:nn { witharrows } { footnote~with~footnotehyper~package } }
-      { }
-    \usepackage { footnote }
+      { \msg_info:nn { witharrows } { Option~incompatible~with~Beamer } }
+      {
+        \@ifpackageloaded { footnotehyper }
+          { \__wi_error:n { footnote~with~footnotehyper~package } }
+          { \usepackage { footnote } }
+      }
   }
-\bool_if:NT \g__wa_footnotehyper_bool
+\bool_if:NT \g__wi_footnotehyper_bool
   {
     \@ifclassloaded { beamer }
-      { \msg_fatal:nn { witharrows } { Option~incompatible~with~Beamer } }
-      { }
-    \@ifpackageloaded { footnote }
-      { \msg_fatal:nn { witharrows } { footnotehyper~with~footnote~package } }
-      { }
-    \usepackage { footnotehyper }
-    \bool_gset_true:N \g__wa_footnote_bool
-  }
-\bool_new:N \c__wa_leqno_bool
-\DeclareOption { leqno } { \bool_set_true:N \c__wa_leqno_bool }
+      { \__wi_info:n  { Option~incompatible~with~Beamer } }
+      {
+        \@ifpackageloaded { footnote }
+          { \__wi_error:n { footnotehyper~with~footnote~package } }
+          { \usepackage { footnotehyper } }
+      }
+    \bool_gset_true:N \g__wi_footnote_bool
+  }
+\bool_new:N \c__wi_leqno_bool
+\DeclareOption { leqno } { \bool_set_true:N \c__wi_leqno_bool }
 \DeclareOption* { }
 \ProcessOptions*
-\cs_new_protected:Npn \__wa_error:n { \msg_error:nn { witharrows } }
-\cs_new_protected:Npn \__wa_error:nn  { \msg_error:nnn { witharrows } }
-\cs_generate_variant:Nn \__wa_error:nn { n x }
 \cs_generate_variant:Nn \tl_put_right:Nn { N v }
 \cs_generate_variant:Nn \seq_set_split:Nnn { N x x }
 \AtBeginDocument
@@ -106,31 +110,31 @@
     \clist_map_inline:nn
       {
         amsmath, amsthm, autonum, cleveref, hyperref, mathtools, showlabels,
-        typedref, varwidth
+        typedref, unicode-math, varwidth
       }
       {
-        \bool_new:c { c__wa_#1_loaded_bool }
+        \bool_new:c { c__wi_#1_loaded_bool }
         \@ifpackageloaded { #1 }
-          { \bool_set_true:c { c__wa_#1_loaded_bool } }
+          { \bool_set_true:c { c__wi_#1_loaded_bool } }
           { }
       }
   }
 \sys_if_engine_luatex:TF
   {
-    \cs_new_protected:Npn \__wa_strcmp:nn  #1 #2
+    \cs_new_protected:Npn \__wi_strcmp:nn  #1 #2
       { \lua_now:e { l3kernel.strcmp('#1','#2') } }
   }
   {
-    \cs_new_protected:Npn \__wa_strcmp:nn #1 #2
+    \cs_new_protected:Npn \__wi_strcmp:nn #1 #2
       { \pdftex_strcmp:D { #1 } { #2 } }
   }
-\cs_new_protected:Npn \__wa_sort_seq:N #1
+\cs_new_protected:Npn \__wi_sort_seq:N #1
   {
     \seq_sort:Nn #1
       {
         \int_compare:nNnTF
           {
-            \__wa_strcmp:nn
+            \__wi_strcmp:nn
               { \str_lower_case:n { ##1 } }
               { \str_lower_case:n { ##2 } }
           }
@@ -139,7 +143,21 @@
           \sort_return_same:
       }
   }
-\cs_new_protected:Npn \__wa_save:N #1
+\cs_new_protected:Npn \__wi_convert_to_str_seq:N #1
+  {
+    \seq_clear:N \l_tmpa_seq
+    \seq_map_inline:Nn #1
+      {
+        \seq_put_left:Nx \l_tmpa_seq { \tl_to_str:n { ##1 } }
+      }
+    \seq_set_eq:NN #1 \l_tmpa_seq
+  }
+\cs_new_protected:Npn \__wi_set_seq_of_str_from_clist:Nn #1 #2
+  {
+    \seq_set_from_clist:Nn #1 { #2 }
+    \__wi_convert_to_str_seq:N #1
+  }
+\cs_new_protected:Npn \__wi_save:N #1
   {
     \seq_set_split:Nxx \l_tmpa_seq
        { \char_generate:nn { `_ } { 12 } }
@@ -155,7 +173,7 @@
     \use:c { \l_tmpa_str _gset_eq:cN }
       { g _\seq_use:Nnnn \l_tmpa_seq _ _ _ } #1
   }
-\cs_new_protected:Npn \__wa_restore:N #1
+\cs_new_protected:Npn \__wi_restore:N #1
   {
     \seq_set_split:Nxx \l_tmpa_seq
       { \char_generate:nn { `_ } { 12 } }
@@ -167,21 +185,21 @@
   }
 \tikzset
   {
-    __wa_node_style / .style =
+    __wi_node_style / .style =
       {
-        above = \l__wa_ystart_dim ,
+        above = \l__wi_ystart_dim ,
         inner~sep = \c_zero_dim ,
         minimum~width = \c_zero_dim ,
-        minimum~height = \l__wa_ygap_dim
+        minimum~height = \l__wi_ygap_dim
       }
   }
 \tikzset
   {
-    __wa_standard / .style =
+    __wi_standard / .style =
       {
         remember~picture ,
         overlay ,
-        name~prefix = wa - \l__wa_prefix_str -
+        name~prefix = wa - \l__wi_prefix_str -
       }
   }
 \tikzset
@@ -203,221 +221,249 @@
  }
 \AtBeginDocument
   {
-    \bool_if:NF \c__wa_amsmath_loaded_bool
+    \bool_if:NTF \c__wi_amsmath_loaded_bool
+      {
+        \seq_put_right:Nn \l__wi_options_WithArrowsOptions_seq { subequations }
+        \seq_put_right:Nn \l__wi_options_DispWithArrows_seq { subequations }
+      }
       {
-        \cs_set_protected:Npn \spread@equation
+        \cs_new_protected:Npn \spread@equation
           {
             \openup \jot
             \cs_set_eq:NN \spread@equation \prg_do_nothing:
           }
       }
   }
-\newtoks \__wa_parameter_token
-\__wa_parameter_token = { # }
-\bool_new:N \l__wa_in_WithArrows_bool
-\bool_new:N \l__wa_in_DispWithArrows_bool
-\bool_new:N \l__wa_in_code_after_bool
-\seq_new:N \g__wa_position_in_the_tree_seq
-\seq_gput_right:Nn \g__wa_position_in_the_tree_seq 1
-\int_new:N \g__wa_last_env_int
-\int_new:N \l__wa_pos_env_int
-\int_new:N \l__wa_pos_arrow_int
-\int_set:Nn \l__wa_pos_arrow_int 3
-\seq_new:N \g__wa_arrow_int_seq
-\int_new:N \g__wa_arrow_int
-\seq_new:N \g__wa_line_int_seq
-\int_new:N \g__wa_line_int
-\seq_new:N \g__wa_col_int_seq
-\int_new:N \g__wa_col_int
-\clist_new:N \l__wa_tags_clist
-\clist_set:Nn \l__wa_tags_clist { all }
-\cs_new_protected:Npn \__wa_test_if_to_tag:
-  {
-    \clist_if_in:NVT \l__wa_tags_clist \g__wa_line_int
-      { \clist_set:Nn \l__wa_tags_clist { all } }
-  }
-\str_new:N \l__wa_command_name_str
-\str_set:Nn \l__wa_command_name_str { Arrow }
-\str_new:N \l__wa_string_Arrow_for_msg_str
-\str_set:Nx \l__wa_string_Arrow_for_msg_str { \token_to_str:N \Arrow }
-\seq_new:N \g__wa_names_seq
-\bool_new:N \l__wa_sbwi_bool
-\bool_new:N \l__wa_in_first_columns_bool
-\bool_new:N \l__wa_tag_star_bool
-\bool_new:N \l__wa_tag_next_line_bool
-\bool_new:N \l__wa_qedhere_bool
-\bool_new:N \l__wa_new_group_bool
-\bool_new:N \l__wa_initial_r_bool
-\bool_new:N \l__wa_final_r_bool
-\tl_new:N \l__wa_initial_tl
-\tl_new:N \l__wa_final_tl
-\int_new:N \l__wa_nb_of_columns_int
-\bool_new:N \l__wa_last_col_bool
-\str_new:N \l__wa_format_str
-\cs_new_protected:Npn \__wa_eval_if_allowed:n #1
-  {
-    \str_if_empty:NTF \l__wa_previous_key_str
+\tl_new:N \l__wi_left_brace_tl
+\tl_set_eq:NN \l__wi_left_brace_tl \c_novalue_tl
+\bool_new:N \l__wi_in_WithArrows_bool
+\bool_new:N \l__wi_in_DispWithArrows_bool
+\bool_new:N \l__wi_in_code_after_bool
+\seq_new:N \g__wi_position_in_the_tree_seq
+\seq_gput_right:Nn \g__wi_position_in_the_tree_seq 1
+\int_new:N \g__wi_last_env_int
+\int_new:N \l__wi_pos_env_int
+\int_new:N \l__wi_pos_arrow_int
+\int_set:Nn \l__wi_pos_arrow_int 3
+\seq_new:N \g__wi_arrow_int_seq
+\int_new:N \g__wi_arrow_int
+\seq_new:N \g__wi_line_int_seq
+\int_new:N \g__wi_line_int
+\seq_new:N \g__wi_col_int_seq
+\int_new:N \g__wi_col_int
+\clist_new:N \l__wi_tags_clist
+\clist_set:Nn \l__wi_tags_clist { all }
+\cs_new_protected:Npn \__wi_test_if_to_tag:
+  {
+    \clist_if_in:NVT \l__wi_tags_clist \g__wi_line_int
+      { \clist_set:Nn \l__wi_tags_clist { all } }
+  }
+\str_new:N \l__wi_command_name_str
+\str_set:Nn \l__wi_command_name_str { Arrow }
+\str_new:N \l__wi_string_Arrow_for_msg_str
+\str_set:Nx \l__wi_string_Arrow_for_msg_str { \token_to_str:N \Arrow }
+\seq_new:N \g__wi_names_seq
+\bool_new:N \l__wi_sbwi_bool
+\bool_new:N \l__wi_in_first_columns_bool
+\bool_new:N \l__wi_tag_star_bool
+\bool_new:N \l__wi_tag_next_line_bool
+\bool_new:N \l__wi_qedhere_bool
+\bool_new:N \l__wi_new_group_bool
+\bool_new:N \l__wi_initial_r_bool
+\bool_new:N \l__wi_final_r_bool
+\tl_new:N \l__wi_initial_tl
+\tl_new:N \l__wi_final_tl
+\int_new:N \l__wi_nb_cols_int
+\str_new:N \l__wi_format_str
+\bool_new:N \l__wi_subequations_bool
+\cs_new_protected:Npn \__wi_eval_if_allowed:n #1
+  {
+    \str_if_empty:NTF \l__wi_previous_key_str
       {
-        \str_set_eq:NN \l__wa_previous_key_str \l_keys_key_tl
+        \str_set_eq:NN \l__wi_previous_key_str \l_keys_key_tl
         #1
       }
-      { \__wa_error:n { Incompatible~options } }
+      { \__wi_error:n { Incompatible~options } }
   }
-\cs_new_protected:Npn \__wa_fix_pos_option:n #1
-  { \__wa_eval_if_allowed:n { \int_set:Nn \l__wa_pos_arrow_int { #1 } } }
+\cs_new_protected:Npn \__wi_fix_pos_option:n #1
+  { \__wi_eval_if_allowed:n { \int_set:Nn \l__wi_pos_arrow_int { #1 } } }
 \keys_define:nn { WithArrows / Global }
   {
-    ygap .dim_set:N = \l__wa_ygap_dim ,
+    ygap .dim_set:N = \l__wi_ygap_dim ,
     ygap .value_required:n = true ,
     ygap .initial:n = 0.4 ex ,
-    ystart .dim_set:N = \l__wa_ystart_dim ,
+    ystart .dim_set:N = \l__wi_ystart_dim ,
     ystart .value_required:n = true ,
     ystart .initial:n = 0.4 ex ,
     more-columns .code:n =
-      \__wa_msg_redirect_name:nn { Too~much~columns~in~WithArrows } { none } ,
+      \__wi_msg_redirect_name:nn { Too~much~columns~in~WithArrows } { none } ,
     more-columns .value_forbidden:n = true,
     command-name .code:n =
-      \str_set:Nn \l__wa_command_name_str { #1 }
-      \str_set:Nx \l__wa_string_Arrow_for_msg_str
+      \str_set:Nn \l__wi_command_name_str { #1 }
+      \str_set:Nx \l__wi_string_Arrow_for_msg_str
         { \c_backslash_str Arrow~alias~\c_backslash_str #1 } ,
     command-name .value_required:n = true ,
-    tikz-code .tl_set:N = \l__wa_tikz_code_tl,
+    tikz-code .tl_set:N = \l__wi_tikz_code_tl,
     tikz-code .initial:n = \draw~(#1)~to~node{#3}~(#2)~; ,
     tikz-code .value_required:n = true ,
     TikzCode .meta:n = { tikz-code = #1 } ,
-    displaystyle .bool_set:N = \l__wa_displaystyle_bool ,
+    displaystyle .bool_set:N = \l__wi_displaystyle_bool ,
     displaystyle .default:n = true ,
     show-nodes .code:n =
-      \tikzset { __wa_node_style / .append~style = { draw , red } } ,
+      \tikzset { __wi_node_style / .append~style = { draw , red } } ,
     show-nodes .value_forbidden:n = true,
-    show-node-names .bool_set:N = \l__wa_show_node_names_bool ,
+    show-node-names .bool_set:N = \l__wi_show_node_names_bool ,
     show-node-names .default:n = true ,
     group .code:n =
-      \str_if_empty:NTF \l__wa_previous_key_str
+      \str_if_empty:NTF \l__wi_previous_key_str
         {
-          \str_set:Nn \l__wa_previous_key_str { group }
-          \seq_remove_all:Nn \l__wa_options_Arrow_seq { xoffset }
-          \int_set:Nn \l__wa_pos_arrow_int 7
+          \str_set:Nn \l__wi_previous_key_str { group }
+          \seq_remove_all:Nn \l__wi_options_Arrow_seq { xoffset }
+          \int_set:Nn \l__wi_pos_arrow_int 7
         }
-        { \__wa_error:n { Incompatible~options } } ,
+        { \__wi_error:n { Incompatible~options } } ,
     group .value_forbidden:n = true ,
     groups .code:n =
-      \str_if_empty:NTF \l__wa_previous_key_str
+      \str_if_empty:NTF \l__wi_previous_key_str
         {
-          \str_set:Nn \l__wa_previous_key_str { groups }
-          \seq_if_in:NnF \l__wa_options_Arrow_seq { new-group }
-            { \seq_put_right:Nn \l__wa_options_Arrow_seq { new-group } }
-          \seq_remove_all:Nn \l__wa_options_Arrow_seq { xoffset }
-          \int_set:Nn \l__wa_pos_arrow_int 6
+          \str_set:Nn \l__wi_previous_key_str { groups }
+          \seq_if_in:NnF \l__wi_options_Arrow_seq { new-group }
+            { \seq_put_right:Nn \l__wi_options_Arrow_seq { new-group } }
+          \seq_remove_all:Nn \l__wi_options_Arrow_seq { xoffset }
+          \int_set:Nn \l__wi_pos_arrow_int 6
         }
-        { \__wa_error:n { Incompatible~options } } ,
+        { \__wi_error:n { Incompatible~options } } ,
     groups .value_forbidden:n = true ,
     tikz   .code:n = \tikzset { WithArrows / arrow / .append~style = { #1 } } ,
     tikz   .initial:n         = \c_empty_tl ,
     tikz   .value_required:n  = true ,
     rr     .value_forbidden:n = true ,
-    rr     .code:n            = \__wa_fix_pos_option:n 3 ,
+    rr     .code:n            = \__wi_fix_pos_option:n 3 ,
     ll     .value_forbidden:n = true ,
-    ll     .code:n            = \__wa_fix_pos_option:n 1 ,
+    ll     .code:n            = \__wi_fix_pos_option:n 1 ,
     rl     .value_forbidden:n = true ,
-    rl     .code:n            = \__wa_fix_pos_option:n 2 ,
+    rl     .code:n            = \__wi_fix_pos_option:n 2 ,
     lr     .value_forbidden:n = true ,
-    lr     .code:n            = \__wa_fix_pos_option:n 0 ,
+    lr     .code:n            = \__wi_fix_pos_option:n 0 ,
     i      .value_forbidden:n = true ,
-    i      .code:n            = \__wa_fix_pos_option:n 5 ,
-    xoffset .dim_set:N  = \l__wa_xoffset_dim ,
+    i      .code:n            = \__wi_fix_pos_option:n 5 ,
+    xoffset .dim_set:N  = \l__wi_xoffset_dim ,
     xoffset .value_required:n  = true ,
     xoffset .initial:n = 3 mm ,
     jot .dim_set:N = \jot ,
     jot .value_required:n = true ,
-    interline .skip_set:N = \l__wa_interline_skip ,
+    interline .skip_set:N = \l__wi_interline_skip ,
     interline .value_required:n = true ,
-    start-adjust .dim_set:N = \l__wa_start_adjust_dim ,
+    start-adjust .dim_set:N = \l__wi_start_adjust_dim ,
     start-adjust .value_required:n = true ,
     start-adjust .initial:n = 0.4 ex ,
-    end-adjust .dim_set:N = \l__wa_end_adjust_dim ,
+    end-adjust .dim_set:N = \l__wi_end_adjust_dim ,
     end-adjust .value_required:n = true ,
     end-adjust .initial:n = 0.4 ex ,
-    adjust .code:n  =
-      \dim_zero_new:N \l__wa_start_adjust_dim
-      \dim_set:Nn \l__wa_start_adjust_dim { #1 }
-      \dim_zero_new:N \l__wa_end_adjust_dim
-      \dim_set:Nn \l__wa_end_adjust_dim { #1 } ,
+    adjust .meta:n  = { start-adjust = #1 , end-adjust = #1 } ,
     adjust .value_required:n = true ,
     no-arrows .code:n =
-      \cs_set_eq:NN \__wa_draw_arrows:nn \use_none:nn
-      \cs_set_eq:NN \__wa_draw_arrow:nnn \use_none:nnn  ,
+      \cs_set_eq:NN \__wi_draw_arrows:nn \use_none:nn
+      \cs_set_eq:NN \__wi_draw_arrow:nnn \use_none:nnn  ,
     no-arrows .value_forbidden:n = true ,
   }
 \keys_define:nn { WithArrows / WithArrowsSpecific }
   {
-    t   .code:n            = \int_set:Nn \l__wa_pos_env_int O ,
+    t   .code:n            = \int_set:Nn \l__wi_pos_env_int O ,
     t   .value_forbidden:n = true ,
-    c   .code:n            = \int_set:Nn \l__wa_pos_env_int 1 ,
+    c   .code:n            = \int_set:Nn \l__wi_pos_env_int 1 ,
     c   .value_forbidden:n = true ,
-    b   .code:n            = \int_set:Nn \l__wa_pos_env_int 2 ,
+    b   .code:n            = \int_set:Nn \l__wi_pos_env_int 2 ,
     b   .value_forbidden:n = true
   }
+\clist_new:N \c__wi_extensible_delimiters_clist
+\clist_set:Nn \c__wi_extensible_delimiters_clist
+  {
+    \{, (, [, \lbrace, \lbrack, \lgroup, \langle, \lmoustache, \lceil, \lfloor
+  }
+\AtBeginDocument
+  {
+    \bool_if:nT
+      { \c__wi_amsmath_loaded_bool || \use:c { c__wi_unicode-math_loaded_bool } }
+      {
+        \clist_put_right:Nn \c__wi_extensible_delimiters_clist { \lvert, \lVert }
+      }
+  }
 \keys_define:nn { WithArrows / DispWithArrowsSpecific }
   {
-    fleqn .bool_set:N = \l__wa_fleqn_bool ,
+    fleqn .bool_set:N = \l__wi_fleqn_bool ,
     fleqn .default:n = true ,
-    mathindent .dim_set:N = \l__wa_mathindent_dim ,
+    mathindent .dim_set:N = \l__wi_mathindent_dim ,
     mathindent .value_required:n = true ,
     mathindent .initial:n = 25 pt ,
     notag .code:n =
       \str_if_eq:nnTF { #1 } { true }
-        { \clist_clear:N \l__wa_tags_clist }
-        { \clist_set:Nn \l__wa_tags_clist { all } } ,
+        { \clist_clear:N \l__wi_tags_clist }
+        { \clist_set:Nn \l__wi_tags_clist { all } } ,
     notag .default:n = true ,
+    subequations .code:n =
+      \bool_if:NTF \c__wi_amsmath_loaded_bool
+        { \bool_set_true:N \l__wi_subequations_bool }
+        {
+          \__wi_error:n { amsmath~not~loaded }
+          \group_begin:
+          \globaldefs = 1
+          \__wi_msg_redirect_name:nn { amsmath~not~loaded } { info }
+          \group_end:
+        } ,
+    subequations .default:n = true ,
+    subequations .value_forbidden:n = true ,
     nonumber .meta:n = notag ,
     allow-multiple-labels .code:n =
-      \__wa_msg_redirect_name:nn { Multiple~labels } { none } ,
+      \__wi_msg_redirect_name:nn { Multiple~labels } { none } ,
     allow-multiple-labels .value_forbidden:n = true ,
-    wrap-lines .bool_set:N = \l__wa_wrap_lines_bool ,
+    wrap-lines .bool_set:N = \l__wi_wrap_lines_bool ,
     wrap-lines .default:n = true ,
     tagged-lines .code:n =
-      \clist_set:Nn \l__wa_tags_clist { #1 }
-      \clist_if_in:NnT \l__wa_tags_clist { first }
+      \clist_set:Nn \l__wi_tags_clist { #1 }
+      \clist_if_in:NnT \l__wi_tags_clist { first }
         {
-          \clist_remove_all:Nn \l__wa_tags_clist { first }
-          \clist_put_left:Nn \l__wa_tags_clist \c_one_int
+          \clist_remove_all:Nn \l__wi_tags_clist { first }
+          \clist_put_left:Nn \l__wi_tags_clist \c_one_int
         } ,
     tagged-lines .value_required:n = true ,
-    standard-behaviour-with-items .bool_set:N = \l__wa_sbwi_bool ,
+    replace-left-brace-by .code:n =
+      {
+        \clist_if_in:NnTF
+          \c__wi_extensible_delimiters_clist
+          { #1 }
+          { \tl_set:Nn \l__wi_replace_left_brace_by_tl { #1 } }
+          { \__wi_error:n { Bad~value~for~replace~brace~by } }
+      } ,
+    replace-left-brace-by .initial:n = \lbrace ,
+    standard-behaviour-with-items .bool_set:N = \l__wi_sbwi_bool ,
     standard-behaviour-with-items .default:n = true
   }
 \keys_define:nn { WithArrows / Env }
   {
     name .code:n =
-      \seq_if_in:NnTF \g__wa_names_seq { #1 }
-        { \__wa_error:n { Duplicate~name } }
-        { \seq_gput_left:Nn \g__wa_names_seq { #1 } }
-      \str_set:Nn \l__wa_name_str { #1 } ,
+      \str_set:Nn \l_tmpa_str { #1 }
+      \seq_if_in:NVTF \g__wi_names_seq \l_tmpa_str
+        { \__wi_error:n { Duplicate~name } }
+        { \seq_gput_left:NV \g__wi_names_seq \l_tmpa_str }
+      \str_set_eq:NN \l__wi_name_str \l_tmpa_str ,
     name .value_required:n = true ,
-    code-before .code:n = \tl_put_right:Nn \l__wa_code_before_tl { #1 } ,
+    code-before .code:n = \tl_put_right:Nn \l__wi_code_before_tl { #1 } ,
     code-before .value_required:n = true,
     CodeBefore .meta:n = { code-before = #1 } ,
-    code-after .code:n = \tl_put_right:Nn \l__wa_code_after_tl { #1 } ,
+    code-after .code:n = \tl_put_right:Nn \l__wi_code_after_tl { #1 } ,
     code-after .value_required:n = true ,
     CodeAfter  .meta:n = { code-after = #1 } ,
-    format .code:n = \__wa_set_option_format:n { #1 },
+    format .code:n =
+      \tl_if_empty:nTF { #1 }
+        { \__wi_error:n { Invalid~option~format } }
+        {
+          \regex_match:nnTF { \A[rcl]*\Z } { #1 }
+            { \tl_set:Nn \l__wi_format_str { #1 } }
+            { \__wi_error:n { Invalid~option~format } }
+        } ,
     format .value_required:n = true ,
   }
-\cs_new_protected:Npn \__wa_set_option_format:n #1
-  {
-    \bool_set_true:N \l_tmpa_bool
-    \str_map_inline:nn { #1 }
-      {
-        \str_if_in:nnF {rcl} { ##1 }
-          {
-            \bool_set_false:N \l_tmpa_bool
-            \__wa_error:n { Invalid~option~format }
-            \str_map_break:
-          }
-      }
-    \bool_if:NT \l_tmpa_bool { \tl_set:Nn \l__wa_format_str { #1 } }
-  }
 \keys_define:nn { WithArrows }
   {
     WithArrows .inherit:n =
@@ -439,46 +485,53 @@
         WithArrows / DispWithArrowsSpecific
       }
   }
-\seq_new:N \l__wa_options_WithArrows_seq
-\seq_set_from_clist:Nn \l__wa_options_WithArrows_seq
-  {
-    adjust, b, c, code-after, code-before, command-name, displaystyle, end-adjust,
-    format, group, groups, i, interline, jot, ll, lr, more-columns, name,
-    no-arrows, rl, rr, show-node-names, show-nodes, start-adjust, t, tikz,
-    tikz-code, xoffset, ygap, ystart
+\seq_new:N \l__wi_options_WithArrows_seq
+\__wi_set_seq_of_str_from_clist:Nn \l__wi_options_WithArrows_seq
+  {
+    adjust, b, c, code-after, code-before, command-name,
+    displaystyle, end-adjust,
+    format, group, groups, i,
+    interline, jot, ll,
+    lr, more-columns, name,
+    no-arrows, rl, rr,
+    show-node-names, show-nodes, start-adjust,
+    t, tikz, tikz-code,
+    xoffset, ygap, ystart
   }
+\__wi_convert_to_str_seq:N \l__wi_options_WithArrows_seq
 \keys_define:nn { WithArrows / WithArrows }
   {
     unknown .code:n  =
-      \__wa_sort_seq:N \l__wa_options_WithArrows_seq
-      \__wa_error:n { Unknown~option~WithArrows }
+      \__wi_sort_seq:N \l__wi_options_WithArrows_seq
+      \__wi_error:n { Unknown~option~WithArrows }
   }
 \keys_define:nn { WithArrows / DispWithArrows }
   {
+    left-brace .tl_set:N = \l__wi_left_brace_tl ,
     unknown .code:n  =
-      \__wa_sort_seq:N \l__wa_options_DispWithArrows_seq
-      \__wa_error:n { Unknown~option~DispWithArrows }
+      \__wi_sort_seq:N \l__wi_options_DispWithArrows_seq
+      \__wi_error:n { Unknown~option~DispWithArrows }
   }
-\seq_new:N \l__wa_options_DispWithArrows_seq
-\seq_set_from_clist:Nn \l__wa_options_DispWithArrows_seq
+\seq_new:N \l__wi_options_DispWithArrows_seq
+\__wi_set_seq_of_str_from_clist:Nn \l__wi_options_DispWithArrows_seq
   {
     allow-multiple-labels, code-after, code-before, command-name, tikz-code, adjust,
     displaystyle, end-adjust, fleqn, group, format, groups, i, interline, jot,
-    ll, lr, mathindent, name, no-arrows, nonumber, notag, rl, rr,
-    show-node-names, show-nodes, start-adjust, tagged-lines, tikz, wrap-lines,
-    xoffset, ygap, ystart
+    left-brace, ll, lr, mathindent, name, no-arrows, nonumber, notag,
+    replace-left-brace-by, rl, rr, show-node-names, show-nodes, start-adjust,
+    tagged-lines, tikz, wrap-lines, xoffset, ygap, ystart
   }
 \keys_define:nn { WithArrows / WithArrowsOptions }
   {
     allow-duplicate-names .code:n =
-      \__wa_msg_redirect_name:nn { Duplicate~name } { none } ,
+      \__wi_msg_redirect_name:nn { Duplicate~name } { none } ,
     allow-duplicate-names .value_forbidden:n = true ,
     unknown .code:n  =
-      \__wa_sort_seq:N \l__wa_options_WithArrowsOptions_seq
-      \__wa_error:n { Unknown~option~WithArrowsOptions }
+      \__wi_sort_seq:N \l__wi_options_WithArrowsOptions_seq
+      \__wi_error:n { Unknown~option~WithArrowsOptions }
   }
-\seq_new:N \l__wa_options_WithArrowsOptions_seq
-\seq_set_from_clist:Nn \l__wa_options_WithArrowsOptions_seq
+\seq_new:N \l__wi_options_WithArrowsOptions_seq
+\__wi_set_seq_of_str_from_clist:Nn \l__wi_options_WithArrowsOptions_seq
   {
     allow-duplicate-names, allow-multiple-labels, b, c, command-name,
     more-columns, tikz-code, adjust, displaystyle, end-adjust, fleqn, group,
@@ -486,29 +539,29 @@
     rl, rr, show-node-names, show-nodes, standard-behaviour-with-items,
     start-adjust, t, tagged-lines, tikz, wrap-lines, xoffset, ygap, ystart
   }
-\cs_new_protected:Npn \__wa_set_independent:
+\cs_new_protected:Npn \__wi_set_independent:
   {
-    \str_if_empty:NTF \l__wa_previous_key_str
+    \str_if_empty:NTF \l__wi_previous_key_str
       {
-        \str_set_eq:NN \l__wa_previous_key_str \l_keys_key_tl
-        \str_set:Nn \l__wa_status_arrow_str { independent }
+        \str_set_eq:NN \l__wi_previous_key_str \l_keys_key_tl
+        \str_set:Nn \l__wi_status_arrow_str { independent }
         \str_if_eq:VnF \l_keys_value_tl { NoValue }
-          { \__wa_error:n { Value~for~a~key } }
+          { \__wi_error:n { Value~for~a~key } }
       }
-      { \__wa_error:n { Incompatible~options~in~Arrow } }
+      { \__wi_error:n { Incompatible~options~in~Arrow } }
   }
 \keys_define:nn { WithArrows / Arrow / FirstPass }
   {
     jump .code:n =
       \int_compare:nTF { #1 > 0 }
-        { \int_set:Nn \l__wa_jump_int { #1 } }
-        { \__wa_error:n { Negative~jump } } ,
+        { \int_set:Nn \l__wi_jump_int { #1 } }
+        { \__wi_error:n { Negative~jump } } ,
     jump .value_required:n  = true,
-    rr .code:n = \__wa_set_independent: ,
-    ll .code:n = \__wa_set_independent: ,
-    rl .code:n = \__wa_set_independent: ,
-    lr .code:n = \__wa_set_independent: ,
-    i  .code:n = \__wa_set_independent: ,
+    rr .code:n = \__wi_set_independent: ,
+    ll .code:n = \__wi_set_independent: ,
+    rl .code:n = \__wi_set_independent: ,
+    lr .code:n = \__wi_set_independent: ,
+    i  .code:n = \__wi_set_independent: ,
     rr .default:n = NoValue ,
     ll .default:n = NoValue ,
     rl .default:n = NoValue ,
@@ -516,16 +569,16 @@
     i  .default:n = NoValue ,
     new-group .value_forbidden:n = true,
     new-group .code:n =
-      \int_compare:nTF { \l__wa_pos_arrow_int = 6 }
-        { \str_set:Nn \l__wa_status_arrow_str { new-group } }
-        { \__wa_error:n { new-group~without~groups } } ,
+      \int_compare:nTF { \l__wi_pos_arrow_int = 6 }
+        { \str_set:Nn \l__wi_status_arrow_str { new-group } }
+        { \__wi_error:n { new-group~without~groups } } ,
     tikz-code .code:n = \prg_do_nothing: ,
     tikz-code .value_required:n = true ,
     tikz .code:n = \prg_do_nothing: ,
     tikz .value_required:n = true ,
     xoffset .code:n =
-      \int_compare:nNnT \l__wa_pos_arrow_int > 5
-        { \__wa_error:n { Option~xoffset~forbidden } } ,
+      \int_compare:nNnT \l__wi_pos_arrow_int > 5
+        { \__wi_error:n { Option~xoffset~forbidden } } ,
     xoffset .value_required:n = true ,
     start-adjust .code:n = \prg_do_nothing: ,
     start-adjust .value_required:n = true ,
@@ -534,190 +587,202 @@
     adjust .code:n  = \prg_do_nothing: ,
     adjust .value_required:n = true ,
     unknown .code:n =
-      \__wa_sort_seq:N \l__wa_options_Arrow_seq
-      \__wa_error:n { Unknown~option~in~Arrow }
+      \__wi_sort_seq:N \l__wi_options_Arrow_seq
+      \seq_if_in:NVTF \l__wi_options_WithArrows_seq \l_keys_key_tl
+        {
+          \str_set:Nn \l_tmpa_str
+           { ~However,~this~key~can~be~used~in~the~options~of~\{WithArrows\}. }
+        }
+        { \str_clear:N \l_tmpa_str }
+      \__wi_error:n { Unknown~option~in~Arrow }
   }
-\seq_new:N \l__wa_options_Arrow_seq
-\seq_set_from_clist:Nn \l__wa_options_Arrow_seq
+\seq_new:N \l__wi_options_Arrow_seq
+\__wi_set_seq_of_str_from_clist:Nn \l__wi_options_Arrow_seq
   {
     adjust, end-adjust, i, jump, ll, lr, rl, rr, start-adjust, tikz, tikz-code,
     xoffset
   }
-\cs_new_protected:Npn \__wa_fix_pos_arrow:n #1
+\cs_new_protected:Npn \__wi_fix_pos_arrow:n #1
   {
-    \str_if_empty:NT \l__wa_previous_key_str
+    \str_if_empty:NT \l__wi_previous_key_str
       {
-        \str_set_eq:NN \l__wa_previous_key_str \l_keys_key_tl
-        \int_set:Nn \l__wa_pos_arrow_int { #1 }
+        \str_set_eq:NN \l__wi_previous_key_str \l_keys_key_tl
+        \int_set:Nn \l__wi_pos_arrow_int { #1 }
       }
   }
 \keys_define:nn {WithArrows / Arrow / SecondPass }
   {
-    tikz-code .tl_set:N = \l__wa_tikz_code_tl ,
+    tikz-code .tl_set:N = \l__wi_tikz_code_tl ,
     tikz-code .initial:n = \draw~(#1)~to~node{#3}~(#2)~; ,
     tikz .code:n = \tikzset { WithArrows / arrow / .append~style = { #1 } } ,
     tikz .initial:n = \c_empty_tl ,
-    rr .code:n = \__wa_fix_pos_arrow:n 3 ,
-    ll .code:n = \__wa_fix_pos_arrow:n 1 ,
-    rl .code:n = \__wa_fix_pos_arrow:n 2 ,
-    lr .code:n = \__wa_fix_pos_arrow:n 0 ,
-    i  .code:n = \__wa_fix_pos_arrow:n 5 ,
+    rr .code:n = \__wi_fix_pos_arrow:n 3 ,
+    ll .code:n = \__wi_fix_pos_arrow:n 1 ,
+    rl .code:n = \__wi_fix_pos_arrow:n 2 ,
+    lr .code:n = \__wi_fix_pos_arrow:n 0 ,
+    i  .code:n = \__wi_fix_pos_arrow:n 5 ,
     xoffset .code:n  =
-      \int_compare:nNnF \l__wa_pos_arrow_int > 5
-        { \dim_set:Nn \l__wa_xoffset_dim { #1 } } ,
-    start-adjust .dim_set:N = \l__wa_start_adjust_dim,
-    end-adjust .dim_set:N = \l__wa_end_adjust_dim,
+      \int_compare:nNnF \l__wi_pos_arrow_int > 5
+        { \dim_set:Nn \l__wi_xoffset_dim { #1 } } ,
+    start-adjust .dim_set:N = \l__wi_start_adjust_dim,
+    end-adjust .dim_set:N = \l__wi_end_adjust_dim,
     adjust .code:n  =
-      \dim_set:Nn \l__wa_start_adjust_dim { #1 }
-      \dim_set:Nn \l__wa_end_adjust_dim { #1 } ,
+      \dim_set:Nn \l__wi_start_adjust_dim { #1 }
+      \dim_set:Nn \l__wi_end_adjust_dim { #1 } ,
   }
 \NewDocumentCommand \WithArrowsOptions { m }
   {
-    \str_clear_new:N \l__wa_previous_key_str
+    \str_clear_new:N \l__wi_previous_key_str
     \keys_set:nn { WithArrows / WithArrowsOptions } { #1 }
   }
-\NewDocumentCommand \__wa_Arrow { O { } m ! O { } }
+\NewDocumentCommand \__wi_Arrow { O { } m ! O { } }
   {
-    \int_gincr:N \g__wa_arrow_int
-    \str_clear_new:N \l__wa_previous_key_str
+    \int_gincr:N \g__wi_arrow_int
+    \str_clear_new:N \l__wi_previous_key_str
     \keys_set:nn { WithArrows / Arrow / FirstPass } { #1 , #3 }
-    \prop_put:NnV \l_tmpa_prop { initial } \g__wa_line_int
-    \int_set:Nn \l_tmpa_int { \g__wa_line_int + \l__wa_jump_int }
+    \prop_put:NnV \l_tmpa_prop { initial } \g__wi_line_int
+    \int_set:Nn \l_tmpa_int { \g__wi_line_int + \l__wi_jump_int }
     \prop_put:NnV \l_tmpa_prop { final } \l_tmpa_int
-    \prop_put:NnV \l_tmpa_prop { status } \l__wa_status_arrow_str
+    \prop_put:NnV \l_tmpa_prop { status } \l__wi_status_arrow_str
     \prop_put:Nnn \l_tmpa_prop { options } { #1 , #3 }
     \prop_put:Nnn \l_tmpa_prop { label } { #2 }
     \prop_put:Nnx \l_tmpa_prop { input-line } \msg_line_number:
     \prop_gclear_new:c
-      { g__wa_arrow _ \l__wa_prefix_str _ \int_use:N \g__wa_arrow_int _ prop }
+      { g__wi_arrow _ \l__wi_prefix_str _ \int_use:N \g__wi_arrow_int _ prop }
     \prop_gset_eq:cN
-      { g__wa_arrow _ \l__wa_prefix_str _ \int_use:N \g__wa_arrow_int _ prop }
+      { g__wi_arrow _ \l__wi_prefix_str _ \int_use:N \g__wi_arrow_int _ prop }
       \l_tmpa_prop
   }
-\cs_new_protected:Npn \__wa_Arrow_first_columns:
-  { \__wa_error:n { Arrow~not~in~last~column } \__wa_Arrow }
-\cs_new_protected:Npn \__wa_pre_halign:n #1
+\cs_new_protected:Npn \__wi_Arrow_first_columns:
+  { \__wi_error:n { Arrow~not~in~last~column } \__wi_Arrow }
+\cs_new_protected:Npn \__wi_pre_halign:n #1
   {
-    \str_clear_new:N \l__wa_type_env_str
-    \str_set:NV \l__wa_type_env_str \@currenvir
+    \str_clear_new:N \l__wi_type_env_str
+    \str_set:NV \l__wi_type_env_str \@currenvir
     \cs_if_exist:NT \tikz@library@external@loaded
       { \tikzset { external / export = false } }
-    \str_clear_new:N \l__wa_name_str
-    \str_clear_new:N \l__wa_status_arrow_str
-    \dim_zero_new:N \l__wa_x_dim
-    \str_clear_new:N \l__wa_input_line_str
-    \seq_gput_right:NV \g__wa_arrow_int_seq \g__wa_arrow_int
-    \int_gzero:N \g__wa_arrow_int
-    \seq_gput_right:NV \g__wa_line_int_seq \g__wa_line_int
-    \int_gzero:N \g__wa_line_int
-    \seq_gput_right:NV \g__wa_col_int_seq \g__wa_col_int
-    \int_gzero:N \g__wa_col_int
-    \seq_gput_right:Nn \g__wa_position_in_the_tree_seq 1
-    \seq_set_eq:NN \l_tmpa_seq \g__wa_position_in_the_tree_seq
+    \str_clear_new:N \l__wi_name_str
+    \str_clear_new:N \l__wi_status_arrow_str
+    \dim_zero_new:N \l__wi_x_dim
+    \str_clear_new:N \l__wi_input_line_str
+    \seq_gput_right:NV \g__wi_arrow_int_seq \g__wi_arrow_int
+    \int_gzero:N \g__wi_arrow_int
+    \seq_gput_right:NV \g__wi_line_int_seq \g__wi_line_int
+    \int_gzero:N \g__wi_line_int
+    \seq_gput_right:NV \g__wi_col_int_seq \g__wi_col_int
+    \int_gzero:N \g__wi_col_int
+    \int_gzero_new:N \g__wi_static_col_int
+    \seq_gput_right:Nn \g__wi_position_in_the_tree_seq 1
+    \seq_set_eq:NN \l_tmpa_seq \g__wi_position_in_the_tree_seq
     \seq_pop_right:NN \l_tmpa_seq \l_tmpa_tl
-    \str_clear_new:N \l__wa_prefix_str
-    \str_set:Nx \l__wa_prefix_str { \seq_use:Nnnn \l_tmpa_seq - - - }
-    \cs_set_eq:NN \\ \__wa_cr:
+    \str_clear_new:N \l__wi_prefix_str
+    \str_set:Nx \l__wi_prefix_str { \seq_use:Nnnn \l_tmpa_seq - - - }
+    \cs_set_eq:NN \\ \__wi_cr:
     \dim_zero:N \mathsurround
-    \int_zero_new:N \l__wa_initial_int
-    \int_zero_new:N \l__wa_final_int
-    \int_zero_new:N \l__wa_arrow_int
-    \int_zero_new:N \l__wa_pos_of_arrow_int
-    \int_zero_new:N \l__wa_jump_int
-    \int_set:Nn \l__wa_jump_int \c_one_int
-    \str_set:Nn \l__wa_format_str { rl }
-    \bool_set_true:N \l__wa_last_col_bool
-    \seq_clear_new:N \l__wa_labels_seq
-    \bool_set_false:N \l__wa_tag_next_line_bool
-    \skip_zero:N \l__wa_interline_skip
-    \tl_clear_new:N \l__wa_code_before_tl
-    \tl_clear_new:N \l__wa_code_after_tl
-    \str_clear_new:N \l__wa_previous_key_str
-    \bool_if:NT \l__wa_in_WithArrows_bool
+    \int_zero_new:N \l__wi_initial_int
+    \int_zero_new:N \l__wi_final_int
+    \int_zero_new:N \l__wi_arrow_int
+    \int_zero_new:N \l__wi_pos_of_arrow_int
+    \int_zero_new:N \l__wi_jump_int
+    \int_set:Nn \l__wi_jump_int \c_one_int
+    \str_set:Nn \l__wi_format_str { rl }
+    \seq_clear_new:N \l__wi_labels_seq
+    \bool_set_false:N \l__wi_tag_next_line_bool
+    \skip_zero:N \l__wi_interline_skip
+    \tl_clear_new:N \l__wi_code_before_tl
+    \tl_clear_new:N \l__wi_code_after_tl
+    \str_clear_new:N \l__wi_previous_key_str
+    \bool_if:NT \l__wi_in_WithArrows_bool
       { \keys_set:nn { WithArrows / WithArrows } { #1 } }
-    \bool_if:NT \l__wa_in_DispWithArrows_bool
+    \bool_if:NT \l__wi_in_DispWithArrows_bool
       { \keys_set:nn { WithArrows / DispWithArrows } { #1 } }
-    \cs_set_eq:cN \l__wa_command_name_str \__wa_Arrow_first_columns:
-    \int_set:Nn \l__wa_nb_of_columns_int { \str_count:N \l__wa_format_str }
-    \seq_clear_new:N \l__wa_format_seq
-    \seq_set_split:NnV \l__wa_format_seq { } \l__wa_format_str
-    \bool_if:NT \g__wa_footnote_bool { \begin { savenotes } }
-    \l__wa_code_before_tl
+    \cs_set_eq:cN \l__wi_command_name_str \__wi_Arrow_first_columns:
+    \int_set:Nn \l__wi_nb_cols_int { \str_count:N \l__wi_format_str }
+    \int_gset_eq:NN \g__wi_col_int \l__wi_nb_cols_int
+    \seq_clear_new:N \l__wi_format_seq
+    \seq_set_split:NnV \l__wi_format_seq { } \l__wi_format_str
+    \bool_if:NT \g__wi_footnote_bool { \begin { savenotes } }
+    \l__wi_code_before_tl
     \spread@equation
-    \cs_set_eq:NN \notag \__wa_notag:
-    \cs_set_eq:NN \nonumber \__wa_notag:
-    \cs_set_eq:NN \tag \__wa_tag
-    \cs_set_eq:NN \__wa_old_label \label
-    \cs_set_eq:NN \label \__wa_label:n
-    \cs_set_eq:NN \tagnextline \__wa_tagnextline:
+    \cs_set_eq:NN \notag \__wi_notag:
+    \cs_set_eq:NN \nonumber \__wi_nonumber:
+    \cs_set_eq:NN \tag \__wi_tag
+    \cs_set_eq:NN \__wi_old_label \label
+    \cs_set_eq:NN \label \__wi_label:n
+    \cs_set_eq:NN \tagnextline \__wi_tagnextline:
   }
-\cs_new_protected:Npn \__wa_construct_halign:
+\cs_new_protected:Npn \__wi_construct_halign:
   {
-    \seq_pop_right:NNTF \l__wa_format_seq \l__wa_type_col_str
+    \seq_pop_right:NNTF \l__wi_format_seq \l__wi_type_col_str
       {
         \use:x
           {
-            \bool_set_false:N \l__wa_last_col_bool
-            \__wa_construct_halign:
-            \bool_if:NT \l__wa_last_col_bool
+            \int_gdecr:N \g__wi_col_int
+            \__wi_construct_halign:
+            \int_compare:nNnT \g__wi_col_int = \l__wi_nb_cols_int
               {
-                \cs_set_eq:cN { \l__wa_command_name_str } \__wa_Arrow
-                \bool_if:NT \l__wa_in_DispWithArrows_bool
+                \cs_set_eq:cN { \l__wi_command_name_str } \__wi_Arrow
+                \bool_if:NT \l__wi_in_DispWithArrows_bool
                   {
-                    \__wa_test_if_to_tag:
-                    \bool_if:NT \c__wa_amsthm_loaded_bool \__wa_set_qedhere:
+                    \__wi_test_if_to_tag:
+                    \bool_if:NT \c__wi_amsthm_loaded_bool \__wi_set_qedhere:
                   }
               }
-            \str_if_eq:VnT \l__wa_type_col_str { c } \hfil
-            \str_if_eq:VnT \l__wa_type_col_str { r } \hfill
-            \int_gincr:N \g__wa_col_int
-            $ % $
+            \str_if_eq:VnT \l__wi_type_col_str { c } \hfil
+            \str_if_eq:VnT \l__wi_type_col_str { r } \hfill
+            \int_gincr:N \g__wi_col_int
+            \int_gset:Nn \g__wi_static_col_int { \int_use:N \g__wi_col_int }
+            \c_math_toggle_token
               {
                 { }
-                \bool_if:NT \l__wa_displaystyle_bool \displaystyle
+                \bool_if:NT \l__wi_displaystyle_bool \displaystyle
                 ####
               }
-            $ % $
-            \bool_if:NTF \l__wa_last_col_bool
-              { \__wa_construct_nodes: }
+            \c_math_toggle_token
+            \int_compare:nNnTF \g__wi_col_int = \l__wi_nb_cols_int
+              { \__wi_construct_nodes: }
               {
-                \str_if_eq:VnT \l__wa_type_col_str { l } \hfil
-                \str_if_eq:VnT \l__wa_type_col_str { c } \hfil
-                \bool_if:NT \l__wa_in_DispWithArrows_bool { \tabskip = \c_zero_skip }
+                \str_if_eq:VnT \l__wi_type_col_str { l } \hfil
+                \str_if_eq:VnT \l__wi_type_col_str { c } \hfil
+                \bool_if:NT \l__wi_in_DispWithArrows_bool { \tabskip = \c_zero_skip }
                 &
               }
           }
       }
       {
-        \bool_if:NTF \l__wa_in_WithArrows_bool
+        \bool_if:NTF \l__wi_in_WithArrows_bool
           {
             \ialign
             \bgroup
           }
           {
-            \halign to
-            \bool_if:NTF \l__wa_inlabel_bool \linewidth \displaywidth
+            \halign to \l__wi_linewidth_dim
             \bgroup
-            \bool_if:NT \l__wa_fleqn_bool
-              { \skip_horizontal:N \l__wa_mathindent_dim }
+            \bool_if:NT \l__wi_fleqn_bool
+              { \skip_horizontal:N \l__wi_mathindent_dim }
+          }
+        \int_gincr:N \g__wi_line_int
+        \int_gzero:N \g__wi_col_int
+        \tl_if_eq:NNF \l__wi_left_brace_tl \c_novalue_tl
+          {
+            \skip_horizontal:n
+              { \box_wd:N \l__wi_left_brace_box + \l__wi_delim_wd_dim }
           }
-        \int_gincr:N \g__wa_line_int
-        \int_gzero:N \g__wa_col_int
         \strut
       }
   }
-\cs_new_protected:Npn \__wa_construct_nodes:
+\cs_new_protected:Npn \__wi_construct_nodes:
   {
     \tikz [ remember~picture , overlay ]
       \node
         [
           node~contents = { } ,
-          __wa_node_style ,
-          name = wa - \l__wa_prefix_str - \int_use:N \g__wa_line_int - l ,
+          __wi_node_style ,
+          name = wa - \l__wi_prefix_str - \int_use:N \g__wi_line_int - l ,
           alias =
             {
-              \str_if_empty:NF \l__wa_name_str
-                { \l__wa_name_str - \int_use:N \g__wa_line_int - l }
+              \str_if_empty:NF \l__wi_name_str
+                { \l__wi_name_str - \int_use:N \g__wi_line_int - l }
             }
         ]
         ;
@@ -726,100 +791,111 @@
       \node
         [
           node~contents = { } ,
-          __wa_node_style ,
-          name = wa - \l__wa_prefix_str - \int_use:N \g__wa_line_int - r ,
+          __wi_node_style ,
+          name = wa - \l__wi_prefix_str - \int_use:N \g__wi_line_int - r ,
           alias =
             {
-              \str_if_empty:NF \l__wa_name_str
-                { \l__wa_name_str - \int_use:N \g__wa_line_int - r }
+              \str_if_empty:NF \l__wi_name_str
+                { \l__wi_name_str - \int_use:N \g__wi_line_int - r }
             }
         ]
         ;
-    \bool_if:NT \l__wa_show_node_names_bool
+    \bool_if:NT \l__wi_show_node_names_bool
       {
         \hbox_overlap_right:n
-          { \small wa - \l__wa_prefix_str - \int_use:N \g__wa_line_int - r }
+          { \small wa - \l__wi_prefix_str - \int_use:N \g__wi_line_int - r }
       }
   }
 \NewDocumentEnvironment { WithArrows } { ! O { } }
   {
-    \bool_set_true:N \l__wa_in_WithArrows_bool
-    \bool_set_false:N \l__wa_in_DispWithArrows_bool
-    \__wa_pre_halign:n { #1 }
+    \bool_set_true:N \l__wi_in_WithArrows_bool
+    \bool_set_false:N \l__wi_in_DispWithArrows_bool
+    \__wi_pre_halign:n { #1 }
     \if_mode_math: \else:
-      \__wa_error:n { WithArrows~outside~math~mode }
+      \__wi_error:n { WithArrows~outside~math~mode }
     \fi:
-    \int_case:nn \l__wa_pos_env_int { 0 \vtop 1 \vcenter 2 \vbox }
+    \int_case:nn \l__wi_pos_env_int { 0 \vtop 1 \vcenter 2 \vbox }
     \bgroup
-    \__wa_construct_halign:
+    \__wi_construct_halign:
     &&
-    \__wa_error:n { Too~much~columns~in~WithArrows }
-    $
-    \bool_if:NT \l__wa_displaystyle_bool \displaystyle
+    \__wi_error:n { Too~much~columns~in~WithArrows }
+    \c_math_toggle_token
+    \bool_if:NT \l__wi_displaystyle_bool \displaystyle
     { ## }
-    $
+    \c_math_toggle_token
     \cr
   }
   {
     \\
     \egroup
     \egroup
-    \__wa_post_halign:
-    \bool_if:NT \g__wa_footnote_bool { \end { savenotes } }
+    \__wi_post_halign:
+    \bool_if:NT \g__wi_footnote_bool { \end { savenotes } }
   }
-\cs_new_protected:Npn \__wa_post_halign:
+\cs_new_protected:Npn \__wi_post_halign:
   {
-    \cs_set:Npn \WithArrowsRightX { \g__wa_right_x_dim }
-    \int_compare:nNnT \g__wa_arrow_int > 0 \__wa_scan_arrows:
+    \cs_set:Npn \WithArrowsRightX { \g__wi_right_x_dim }
+    \int_compare:nNnT \g__wi_arrow_int > 0 \__wi_scan_arrows:
     \group_begin:
-      \tikzset { every~picture / .style = __wa_standard }
-      \cs_set:Npn \WithArrowsNbLines { \int_use:N \g__wa_line_int }
-      \cs_set_eq:NN \MultiArrow \__wa_MultiArrow:nn
-      \cs_set_eq:cN \l__wa_command_name_str \__wa_Arrow_code_after
-      \bool_set_true:N \l__wa_in_code_after_bool
-      \l__wa_code_after_tl
+      \tikzset { every~picture / .style = __wi_standard }
+      \cs_set:Npn \WithArrowsNbLines { \int_use:N \g__wi_line_int }
+      \cs_set_eq:NN \MultiArrow \__wi_MultiArrow:nn
+      \cs_set_eq:cN \l__wi_command_name_str \__wi_Arrow_code_after
+      \bool_set_true:N \l__wi_in_code_after_bool
+      \l__wi_code_after_tl
     \group_end:
-    \seq_gpop_right:NN \g__wa_position_in_the_tree_seq \l_tmpa_tl
-    \seq_gpop_right:NN \g__wa_position_in_the_tree_seq \l_tmpa_tl
-    \seq_gput_right:Nx \g__wa_position_in_the_tree_seq
+    \seq_gpop_right:NN \g__wi_position_in_the_tree_seq \l_tmpa_tl
+    \seq_gpop_right:NN \g__wi_position_in_the_tree_seq \l_tmpa_tl
+    \seq_gput_right:Nx \g__wi_position_in_the_tree_seq
       { \int_eval:n { \l_tmpa_tl + 1 } }
-    \int_compare:nNnT { \seq_count:N \g__wa_position_in_the_tree_seq } = 1
-      { \int_gincr:N \g__wa_last_env_int }
-    \seq_gpop_right:NN \g__wa_arrow_int_seq \l_tmpa_tl
-    \int_gset:Nn \g__wa_arrow_int \l_tmpa_tl
-    \seq_gpop_right:NN \g__wa_line_int_seq \l_tmpa_tl
-    \int_gset:Nn \g__wa_line_int \l_tmpa_tl
-    \seq_gpop_right:NN \g__wa_col_int_seq \l_tmpa_tl
-    \int_gset:Nn \g__wa_col_int \l_tmpa_tl
+    \int_compare:nNnT { \seq_count:N \g__wi_position_in_the_tree_seq } = 1
+      { \int_gincr:N \g__wi_last_env_int }
+    \seq_gpop_right:NN \g__wi_arrow_int_seq \l_tmpa_tl
+    \int_gset:Nn \g__wi_arrow_int \l_tmpa_tl
+    \seq_gpop_right:NN \g__wi_line_int_seq \l_tmpa_tl
+    \int_gset:Nn \g__wi_line_int \l_tmpa_tl
+    \seq_gpop_right:NN \g__wi_col_int_seq \l_tmpa_tl
+    \int_gset:Nn \g__wi_col_int \l_tmpa_tl
   }
-\cs_new_protected:Npn \__wa_cr:
+\cs_new_protected:Npn \__wi_cr:
   {
     \scan_stop:
-    \prg_replicate:nn { \l__wa_nb_of_columns_int - \g__wa_col_int } { & { } }
+    \int_compare:nNnF \g__wi_col_int = \g__wi_static_col_int
+      { \__wi_error:n { omit~probably~used } }
+    \prg_replicate:nn { \l__wi_nb_cols_int - \g__wi_static_col_int } { & { } }
     \group_align_safe_begin:
-    \peek_meaning_remove:NTF * \__wa_cr_i: \__wa_cr_i:
+    \peek_meaning_remove:NTF * \__wi_cr_i: \__wi_cr_i:
+  }
+\cs_new_protected:Npn \__wi_cr_i:
+  { \peek_meaning:NTF [ \__wi_cr_ii: { \__wi_cr_ii: [ \c_zero_dim ] } }
+\cs_new_protected:Npn \__wi_cr_ii: [ #1 ]
+  {
+    \peek_meaning_ignore_spaces:NTF \end
+      {
+        \__wi_cr_iii:n { #1 }
+        \__wi_analyze_end:Nn
+      }
+      { \__wi_cr_iii:n { #1 } }
   }
-\cs_new_protected:Npn \__wa_cr_i:
-  { \peek_meaning:NTF [ \__wa_cr_ii: { \__wa_cr_ii: [ \c_zero_dim ] } }
-\cs_new_protected:Npn \__wa_cr_ii: [ #1 ]
+\cs_new_protected:Npn \__wi_cr_iii:n #1
   {
     \group_align_safe_end:
-    \bool_if:NT \l__wa_in_DispWithArrows_bool
+    \bool_if:NT \l__wi_in_DispWithArrows_bool
       {
-        \clist_if_in:NnTF \l__wa_tags_clist { all }
+        \clist_if_in:NnTF \l__wi_tags_clist { all }
           {
-            \tl_if_empty:NT \l__wa_tag_tl { \int_gincr:N \c@equation }
+            \tl_if_empty:NT \l__wi_tag_tl { \int_gincr:N \c@equation }
             \cs_gset:Npx \g_tmpa_tl
-              { \tl_if_empty:NTF \l__wa_tag_tl \theequation \l__wa_tag_tl }
-            \seq_if_empty:NF \l__wa_labels_seq
+              { \tl_if_empty:NTF \l__wi_tag_tl \theequation \l__wi_tag_tl }
+            \seq_if_empty:NF \l__wi_labels_seq
               {
                 \cs_set:Npx \@currentlabel { \p@equation \g_tmpa_tl }
-                \bool_if:NT \c__wa_hyperref_loaded_bool
+                \bool_if:NT \c__wi_hyperref_loaded_bool
                   {
                     \str_set:Nn \This@name { equation }
                     \hyper@refstepcounter { equation }
                   }
-                \bool_if:NT \c__wa_cleveref_loaded_bool
+                \bool_if:NT \c__wi_cleveref_loaded_bool
                   {
                     \cref@constructprefix { equation } \cref@result
                     \protected@edef \cref@currentlabel
@@ -833,56 +909,71 @@
                         \p@equation \g_tmpa_tl
                       }
                   }
-                \seq_map_function:NN \l__wa_labels_seq \__wa_old_label
+                \seq_map_function:NN \l__wi_labels_seq \__wi_old_label
               }
-            \__wa_save:N \l__wa_tag_star_bool
-            \__wa_save:N \l__wa_qedhere_bool
-            \bool_if:NT \l__wa_tag_next_line_bool
+            \__wi_save:N \l__wi_tag_star_bool
+            \__wi_save:N \l__wi_qedhere_bool
+            \bool_if:NT \l__wi_tag_next_line_bool
               {
                 \openup -\jot
-                \bool_set_false:N \l__wa_tag_next_line_bool
+                \bool_set_false:N \l__wi_tag_next_line_bool
                 \notag \\ &
               }
             &
-            \__wa_restore:N \l__wa_tag_star_bool
-            \__wa_restore:N \l__wa_qedhere_bool
-            \bool_if:NT \l__wa_qedhere_bool
-               { \hbox_overlap_left:n \__wa_qedhere_i: }
+            \__wi_restore:N \l__wi_tag_star_bool
+            \__wi_restore:N \l__wi_qedhere_bool
+            \bool_if:NT \l__wi_qedhere_bool
+               { \hbox_overlap_left:n \__wi_qedhere_i: }
             \cs_set_eq:NN \theequation \g_tmpa_tl
-            \bool_if:NT \l__wa_tag_star_bool
+            \bool_if:NT \l__wi_tag_star_bool
               { \cs_set_eq:NN \tagform@ \prg_do_nothing: }
             \hbox_overlap_left:n
               {
-                \bool_if:NF \c__wa_leqno_bool
+                \bool_if:NF \c__wi_leqno_bool
                   {
-                    \tikz [ __wa_standard ]
-                      \coordinate ( \int_use:N \g__wa_line_int - v ) ;
+                    \tikz [ __wi_standard ]
+                      \coordinate ( \int_use:N \g__wi_line_int - v ) ;
                   }
                 \quad
                 \@eqnnum
               }
-            \bool_if:NT \c__wa_leqno_bool
+            \bool_if:NT \c__wi_leqno_bool
               {
-                \tikz [ __wa_standard ]
-                  \coordinate ( \int_use:N \g__wa_line_int - v ) ;
+                \tikz [ __wi_standard ]
+                  \coordinate ( \int_use:N \g__wi_line_int - v ) ;
               }
           }
           {
-            \__wa_save:N \l__wa_qedhere_bool
+            \__wi_save:N \l__wi_qedhere_bool
             &
-            \__wa_restore:N \l__wa_qedhere_bool
-            \bool_if:NT \l__wa_qedhere_bool
-               { \hbox_overlap_left:n \__wa_qedhere_i: }
-            \tikz [ __wa_standard ]
-               \coordinate ( \int_use:N \g__wa_line_int - v ) ;
+            \__wi_restore:N \l__wi_qedhere_bool
+            \bool_if:NT \l__wi_qedhere_bool
+               { \hbox_overlap_left:n \__wi_qedhere_i: }
+            \tikz [ __wi_standard ]
+               \coordinate ( \int_use:N \g__wi_line_int - v ) ;
           }
       }
-    \cr \noalign { \skip_vertical:n { #1 + \l__wa_interline_skip } \scan_stop: }
+    \dim_compare:nNnT { #1 } < \c_zero_dim
+       { \__wi_error:n { option~of~cr~negative } }
+    \dim_set:Nn \l_tmpa_dim { \dim_max:nn { #1 } \c_zero_dim }
+    \cr
+    \noalign
+      {
+        \skip_vertical:n { \l_tmpa_dim + \l__wi_interline_skip }
+        \scan_stop:
+      }
   }
-\bool_new:N \l__wa_inlabel_bool
-\NewDocumentEnvironment { DispWithArrows } { ! O { } }
+\cs_new_protected:Npn \__wi_analyze_end:Nn #1 #2
   {
-    \bool_if:nT \c__wa_mathtools_loaded_bool
+    \exp_args:NV \str_if_eq:nnT \l__wi_type_env_str { #2 }
+      { \__wi_warning:n { newline~at~the~end~of~env } }
+    \end { #2 }
+  }
+\bool_new:N \l__wi_in_label_or_minipage_bool
+\NewDocumentEnvironment { DispWithArrows } { ! d < > ! O { } }
+  {
+    \bool_set_true:N \l__wi_in_DispWithArrows_bool
+    \bool_if:nT \c__wi_mathtools_loaded_bool
       {
         \MH_if_boolean:nT { show_only_refs }
           {
@@ -890,77 +981,150 @@
             \MH_set_boolean_T:n { show_only_refs }
           }
       }
-    \bool_if:NT \c__wa_typedref_loaded_bool { \str_set:Nn \sr@name { equation } }
-    \bool_if:NT \c__wa_amsmath_loaded_bool \intertext@
-    \bool_set_true:N \l__wa_in_DispWithArrows_bool
-    \__wa_pre_halign:n { #1 }
-    \bool_if:NF \l__wa_sbwi_bool
+    \bool_if:NT \c__wi_typedref_loaded_bool { \str_set:Nn \sr@name { equation } }
+    \bool_if:NT \c__wi_amsmath_loaded_bool \intertext@
+    \IfValueT { #1 } { \tl_set:Nn \l__wi_left_brace_tl { #1 } }
+    \__wi_pre_halign:n { #2 }
+    \bool_if:NT \l__wi_subequations_bool { \begin { subequations } }
+    \bool_if:NF \l__wi_sbwi_bool
       {
         \if@inlabel
-        \bool_set_true:N \l__wa_inlabel_bool
+        \bool_set_true:N \l__wi_in_label_or_minipage_bool
+        \fi
+        \if@minipage
+        \bool_set_true:N \l__wi_in_label_or_minipage_bool
         \fi
       }
-    \tl_clear_new:N \l__wa_tag_tl
-    \bool_set_false:N \l__wa_qedhere_bool
-    \bool_set_false:N \l__wa_tag_star_bool
+    \tl_if_eq:NNF \l__wi_left_brace_tl \c_novalue_tl
+      {
+        \hbox_set:Nn \l_tmpa_box
+          {
+            \c_math_toggle_token
+            \left \l__wi_replace_left_brace_by_tl \vcenter to 1 cm { } \right.
+            \c_math_toggle_token
+          }
+        \dim_zero_new:N \l__wi_delim_wd_dim
+        \dim_set:Nn \l__wi_delim_wd_dim { \box_wd:N \l_tmpa_box }
+        \box_clear_new:N \l__wi_left_brace_box
+        \hbox_set:Nn \l__wi_left_brace_box
+          {
+            \group_begin:
+              \cs_set_eq:NN \label \__wi_old_label
+              \c_math_toggle_token
+              \bool_if:NT \l__wi_displaystyle_bool \displaystyle
+              \l__wi_left_brace_tl
+              { }
+              \c_math_toggle_token
+            \group_end:
+          }
+      }
+    \tl_clear_new:N \l__wi_tag_tl
+    \bool_set_false:N \l__wi_qedhere_bool
+    \bool_set_false:N \l__wi_tag_star_bool
     \if_mode_math:
-      \__wa_error:n { DispWithArrows~in~math~mode }
+      \__wi_fatal:n { DispWithArrows~in~math~mode }
     \fi:
-    \bool_if:NTF \l__wa_inlabel_bool
-      { $ } % $
+    \bool_if:NTF \l__wi_in_label_or_minipage_bool
+      { \c_math_toggle_token }
       {
         \if_mode_vertical:
         \nointerlineskip
         \hbox_to_wd:nn { .6 \linewidth } { }
         \fi:
-        $$
+        \c_math_toggle_token \c_math_toggle_token
       }
-    \vtop \bgroup
-    \bool_if:NTF \l__wa_fleqn_bool
-      { \tabskip = \c_zero_skip }
-      { \tabskip = 0 pt plus 1000 pt minus 1000 pt }
-    \__wa_construct_halign:
+    \dim_zero_new:N \l__wi_linewidth_dim
+    \bool_if:NTF \l__wi_in_label_or_minipage_bool
+       { \dim_set_eq:NN \l__wi_linewidth_dim \linewidth }
+       { \dim_set_eq:NN \l__wi_linewidth_dim \displaywidth }
+    \box_clear_new:N \l__wi_halign_box
+    \setbox \l__wi_halign_box \vtop \bgroup
+    \tabskip =
+      \bool_if:NTF \l__wi_fleqn_bool
+        \c_zero_skip
+        { 0 pt plus 1000 pt minus 1000 pt }
+    \__wi_construct_halign:
     \tabskip = 0 pt plus 1000 pt minus 1000 pt
     &
     $ ## $
     \tabskip = \c_zero_skip
     &&
-    \__wa_error:n { Too~much~columns~in~DispWithArrows }
+    \__wi_fatal:n { Too~much~columns~in~DispWithArrows }
     \bool_if:nT \c_false_bool { ## }
     \cr
   }
   {
-    \clist_if_in:NnT \l__wa_tags_clist { last }
-      { \clist_set:Nn \l__wa_tags_clist { all } }
+    \clist_if_in:NnT \l__wi_tags_clist { last }
+      { \clist_set:Nn \l__wi_tags_clist { all } }
     \\
     \egroup
+    \unskip \unpenalty \unskip \unpenalty
+    \box_set_to_last:N \l_tmpa_box
+    \nointerlineskip
+    \box_use:N \l_tmpa_box
+    \dim_gzero_new:N \g__wi_alignment_dim
+    \dim_gset:Nn \g__wi_alignment_dim { \box_wd:N \l_tmpa_box }
+    \box_clear_new:N \l__wi_new_box
+    \hbox_set:Nn \l__wi_new_box { \hbox_unpack_clear:N \l_tmpa_box }
+    \dim_compare:nNnT
+      { \box_wd:N \l__wi_new_box } < \g__wi_alignment_dim
+      { \dim_gset:Nn \g__wi_alignment_dim { \box_wd:N \l__wi_new_box } }
     \egroup
-    \dim_gzero_new:N \g__wa_right_x_dim
-    \dim_gset_eq:NN \g__wa_right_x_dim \c_max_dim
-    \begin { tikzpicture } [ __wa_standard ]
-      \int_step_variable:nNn \g__wa_line_int \l_tmpa_int
+     \tl_if_eq:NNTF \l__wi_left_brace_tl \c_novalue_tl
+       { \box_use_drop:N \l__wi_halign_box }
+       {
+         \hbox_to_wd:nn \l__wi_linewidth_dim
+           {
+            \bool_if:NTF \l__wi_fleqn_bool
+              { \skip_horizontal:n \l__wi_mathindent_dim }
+              \hfil
+            \hbox_to_wd:nn \g__wi_alignment_dim
+              {
+                \box_use_drop:N \l__wi_left_brace_box
+                \dim_set:Nn \l_tmpa_dim
+                  {
+                    \box_ht:N \l__wi_halign_box
+                    + \box_dp:N \l__wi_halign_box
+                  }
+                \c_math_toggle_token
+                  \left \l__wi_replace_left_brace_by_tl
+                    \vcenter to \l_tmpa_dim { \vfil }
+                  \right.
+                \c_math_toggle_token
+                \hfil
+              }
+            \hfil
+           }
+         \skip_horizontal:n { - \l__wi_linewidth_dim }
+         \vcenter { \box_use_drop:N \l__wi_halign_box }
+       }
+    \dim_gzero_new:N \g__wi_right_x_dim
+    \dim_gset_eq:NN \g__wi_right_x_dim \c_max_dim
+    \begin { tikzpicture } [ __wi_standard ]
+      \int_step_variable:nNn \g__wi_line_int \l_tmpa_int
         {
           \cs_if_free:cTF
-            { pgf@sh@ns@wa - \l__wa_prefix_str - \l_tmpa_int - v }
-            { \__wa_error:n { Inexistent~v-node } }
+            { pgf@sh@ns@wa - \l__wi_prefix_str - \l_tmpa_int - v }
+            { \__wi_fatal:n { Inexistent~v-node } }
             {
               \tikz@parse@node\pgfutil@firstofone ( \l_tmpa_int - v )
               \dim_set:Nn \l_tmpa_dim \pgf@x
-              \dim_compare:nNnT \l_tmpa_dim < \g__wa_right_x_dim
-                { \dim_gset:Nn \g__wa_right_x_dim \l_tmpa_dim }
+              \dim_compare:nNnT \l_tmpa_dim < \g__wi_right_x_dim
+                { \dim_gset:Nn \g__wi_right_x_dim \l_tmpa_dim }
             }
         }
     \end { tikzpicture }
-    \__wa_post_halign:
-    \bool_if:nT \c__wa_mathtools_loaded_bool
+    \__wi_post_halign:
+    \bool_if:nT \c__wi_mathtools_loaded_bool
       { \MH_if_boolean:nT { show_only_refs } \MT_showonlyrefs_true: }
-    \bool_if:NTF \l__wa_inlabel_bool
+    \bool_if:NTF \l__wi_in_label_or_minipage_bool
       {
-        $ % $
+        \c_math_toggle_token
         \skip_vertical:N \belowdisplayskip
       }
-      { $$ }
-    \bool_if:NT \g__wa_footnote_bool { \end {savenotes } }
+      { \c_math_toggle_token \c_math_toggle_token }
+    \bool_if:NT \l__wi_subequations_bool { \end { subequations } }
+    \bool_if:NT \g__wi_footnote_bool { \end { savenotes } }
     \ignorespacesafterend
   }
 \NewDocumentEnvironment { DispWithArrows* } { }
@@ -969,75 +1133,77 @@
     \DispWithArrows
   }
   \endDispWithArrows
-\cs_new_protected:Npn \__wa_if_in_last_col_of_disp:Nn #1 #2
+\cs_new_protected:Npn \__wi_if_in_last_col_of_disp:Nn #1 #2
   {
-    \bool_if:NTF \l__wa_in_WithArrows_bool
-      { \__wa_error:nn { Not~allowed~in~WithArrows } { #1 } }
+    \bool_if:NTF \l__wi_in_WithArrows_bool
+      { \__wi_error:nn { Not~allowed~in~WithArrows } { #1 } }
       {
-        \int_compare:nNnTF \g__wa_col_int < \l__wa_nb_of_columns_int
-          { \__wa_error:nn { Not~allowed~in~DispWithArrows } { #1 } }
+        \int_compare:nNnTF \g__wi_col_int < \l__wi_nb_cols_int
+          { \__wi_error:nn { Not~allowed~in~DispWithArrows } { #1 } }
           { #2 }
       }
   }
-\cs_new_protected:Npn \__wa_notag:
-  { \__wa_if_in_last_col_of_disp:Nn \notag { \clist_clear:N \l__wa_tags_clist } }
-\NewDocumentCommand \__wa_tag { s m }
+\cs_new_protected:Npn \__wi_notag:
+  { \__wi_if_in_last_col_of_disp:Nn \notag { \clist_clear:N \l__wi_tags_clist } }
+\cs_new_protected:Npn \__wi_nonumber:
+  { \__wi_if_in_last_col_of_disp:Nn \nonumber { \clist_clear:N \l__wi_tags_clist } }
+\NewDocumentCommand \__wi_tag { s m }
   {
-    \__wa_if_in_last_col_of_disp:Nn \tag
+    \__wi_if_in_last_col_of_disp:Nn \tag
       {
-        \tl_if_empty:NF \l__wa_tag_tl
-          { \__wa_error:nn  { Multiple~tags } { #2 } }
-        \clist_set:Nn \l__wa_tags_clist { all }
-        \bool_if:nT \c__wa_mathtools_loaded_bool
+        \tl_if_empty:NF \l__wi_tag_tl
+          { \__wi_error:nn  { Multiple~tags } { #2 } }
+        \clist_set:Nn \l__wi_tags_clist { all }
+        \bool_if:nT \c__wi_mathtools_loaded_bool
           {
             \MH_if_boolean:nT { show_only_refs }
               {
                 \MH_if_boolean:nF { show_manual_tags }
-                  { \clist_clear:N \l__wa_tags_clist }
+                  { \clist_clear:N \l__wi_tags_clist }
               }
           }
-        \tl_set:Nn \l__wa_tag_tl { #2 }
-        \bool_set:Nn \l__wa_tag_star_bool { #1 }
-        \bool_if:nT { #1 && ! \bool_if_p:N \c__wa_amsmath_loaded_bool }
-          { \__wa_error:n { tag*~without~amsmath } }
+        \tl_set:Nn \l__wi_tag_tl { #2 }
+        \bool_set:Nn \l__wi_tag_star_bool { #1 }
+        \bool_if:nT { #1 && ! \bool_if_p:N \c__wi_amsmath_loaded_bool }
+          { \__wi_error:n { tag*~without~amsmath } }
       }
   }
-\cs_new_protected:Npn \__wa_label:n #1
+\cs_new_protected:Npn \__wi_label:n #1
   {
-    \__wa_if_in_last_col_of_disp:Nn \label
+    \__wi_if_in_last_col_of_disp:Nn \label
       {
-        \seq_if_empty:NF \l__wa_labels_seq
+        \seq_if_empty:NF \l__wi_labels_seq
           {
-            \bool_if:NTF \c__wa_cleveref_loaded_bool
-              { \__wa_error:n { Multiple~labels~with~cleveref } }
-              { \__wa_error:n { Multiple~labels } }
+            \bool_if:NTF \c__wi_cleveref_loaded_bool
+              { \__wi_error:n { Multiple~labels~with~cleveref } }
+              { \__wi_error:n { Multiple~labels } }
           }
-        \seq_put_right:Nn \l__wa_labels_seq { #1 }
-        \bool_if:nT \c__wa_mathtools_loaded_bool
+        \seq_put_right:Nn \l__wi_labels_seq { #1 }
+        \bool_if:nT \c__wi_mathtools_loaded_bool
           {
             \MH_if_boolean:nT { show_only_refs }
               {
                 \cs_if_exist:cTF { MT_r_#1 }
-                  { \clist_set:Nn \l__wa_tags_clist { all } }
-                  { \clist_clear:N \l__wa_tags_clist }
+                  { \clist_set:Nn \l__wi_tags_clist { all } }
+                  { \clist_clear:N \l__wi_tags_clist }
               }
           }
-        \bool_if:nT \c__wa_autonum_loaded_bool
+        \bool_if:nT \c__wi_autonum_loaded_bool
           {
             \cs_if_exist:cTF { autonum@#1Referenced }
-              { \clist_set:Nn \l__wa_tags_clist { all } }
-              { \clist_clear:N \l__wa_tags_clist }
+              { \clist_set:Nn \l__wi_tags_clist { all } }
+              { \clist_clear:N \l__wi_tags_clist }
           }
       }
   }
-\cs_new_protected:Npn \__wa_tagnextline:
+\cs_new_protected:Npn \__wi_tagnextline:
   {
-    \__wa_if_in_last_col_of_disp:Nn \tagnextline
-      { \bool_set_true:N \l__wa_tag_next_line_bool }
+    \__wi_if_in_last_col_of_disp:Nn \tagnextline
+      { \bool_set_true:N \l__wi_tag_next_line_bool }
   }
-\cs_new_protected:Npn \__wa_qedhere: { \bool_set_true:N \l__wa_qedhere_bool }
-\cs_new_protected:Npn \__wa_set_qedhere: { \cs_set_eq:NN \qedhere \__wa_qedhere: }
-\cs_new_protected:Npn \__wa_qedhere_i:
+\cs_new_protected:Npn \__wi_qedhere: { \bool_set_true:N \l__wi_qedhere_bool }
+\cs_new_protected:Npn \__wi_set_qedhere: { \cs_set_eq:NN \qedhere \__wi_qedhere: }
+\cs_new_protected:Npn \__wi_qedhere_i:
   {
     \group_begin:
       \cs_set_eq:NN \qed \qedsymbol
@@ -1045,245 +1211,246 @@
       \QED@stack \relax \relax
     \group_end:
   }
-\cs_new_protected:Npn \__wa_scan_arrows:
+\cs_new_protected:Npn \__wi_scan_arrows:
   {
     \group_begin:
-    \int_compare:nNnT \l__wa_pos_arrow_int = 7
+    \int_compare:nNnT \l__wi_pos_arrow_int = 7
       {
-        \__wa_scan_arrows_i:
-        \int_set:Nn \l__wa_pos_arrow_int 8
+        \__wi_scan_arrows_i:
+        \int_set:Nn \l__wi_pos_arrow_int 8
       }
-    \__wa_scan_arrows_i:
+    \__wi_scan_arrows_i:
     \group_end:
   }
-\cs_new_protected:Npn \__wa_scan_arrows_i:
+\cs_new_protected:Npn \__wi_scan_arrows_i:
   {
-    \int_zero_new:N \l__wa_first_arrow_of_group_int
-    \int_zero_new:N \l__wa_first_line_of_group_int
-    \int_zero_new:N \l__wa_last_line_of_group_int
-    \seq_clear_new:N \l__wa_first_arrows_seq
-    \seq_clear_new:N \l__wa_last_arrows_seq
-    \bool_set_true:N \l__wa_new_group_bool
-    \int_set:Nn \l__wa_arrow_int \c_one_int
-    \int_until_do:nNnn \l__wa_arrow_int > \g__wa_arrow_int
+    \int_zero_new:N \l__wi_first_arrow_of_group_int
+    \int_zero_new:N \l__wi_first_line_of_group_int
+    \int_zero_new:N \l__wi_last_line_of_group_int
+    \seq_clear_new:N \l__wi_first_arrows_seq
+    \seq_clear_new:N \l__wi_last_arrows_seq
+    \bool_set_true:N \l__wi_new_group_bool
+    \int_set:Nn \l__wi_arrow_int \c_one_int
+    \int_until_do:nNnn \l__wi_arrow_int > \g__wi_arrow_int
       {
         \prop_get:cnN
-          { g__wa_arrow _ \l__wa_prefix_str _ \int_use:N \l__wa_arrow_int _ prop }
+          { g__wi_arrow _ \l__wi_prefix_str _ \int_use:N \l__wi_arrow_int _ prop }
           { initial } \l_tmpa_tl
-        \int_set:Nn \l__wa_initial_int \l_tmpa_tl
+        \int_set:Nn \l__wi_initial_int \l_tmpa_tl
         \prop_get:cnN
-          { g__wa_arrow _ \l__wa_prefix_str _ \int_use:N \l__wa_arrow_int _ prop }
+          { g__wi_arrow _ \l__wi_prefix_str _ \int_use:N \l__wi_arrow_int _ prop }
           { final } \l_tmpa_tl
-        \int_set:Nn \l__wa_final_int \l_tmpa_tl
+        \int_set:Nn \l__wi_final_int \l_tmpa_tl
         \prop_get:cnN
-          { g__wa_arrow _ \l__wa_prefix_str _ \int_use:N \l__wa_arrow_int _ prop }
-          { status } \l__wa_status_arrow_str
+          { g__wi_arrow _ \l__wi_prefix_str _ \int_use:N \l__wi_arrow_int _ prop }
+          { status } \l__wi_status_arrow_str
         \prop_get:cnN
-          { g__wa_arrow _ \l__wa_prefix_str _ \int_use:N \l__wa_arrow_int _ prop }
-          { input-line } \l__wa_input_line_str
-        \int_compare:nNnTF \l__wa_final_int > \g__wa_line_int
+          { g__wi_arrow _ \l__wi_prefix_str _ \int_use:N \l__wi_arrow_int _ prop }
+          { input-line } \l__wi_input_line_str
+        \int_compare:nNnTF \l__wi_final_int > \g__wi_line_int
           {
-            \int_compare:nNnF \l__wa_pos_arrow_int = 8
-              { \__wa_error:n { Too~few~lines~for~an~arrow } }
+            \int_compare:nNnF \l__wi_pos_arrow_int = 8
+              { \__wi_error:n { Too~few~lines~for~an~arrow } }
           }
-          \__wa_code_for_possible_arrow:
-        \int_incr:N \l__wa_arrow_int
+          \__wi_code_for_possible_arrow:
+        \int_incr:N \l__wi_arrow_int
       }
     \bool_if:nT
       {
-        \int_compare_p:n { \l__wa_pos_arrow_int != 7 }
+        \int_compare_p:n { \l__wi_pos_arrow_int != 7 }
           &&
-        \int_compare_p:nNn \l__wa_first_arrow_of_group_int > 0
+        \int_compare_p:nNn \l__wi_first_arrow_of_group_int > 0
       }
-      { \__wa_draw_arrows:nn \l__wa_first_arrow_of_group_int \g__wa_arrow_int }
+      { \__wi_draw_arrows:nn \l__wi_first_arrow_of_group_int \g__wi_arrow_int }
   }
-\cs_new_protected:Npn \__wa_code_for_possible_arrow:
+\cs_new_protected:Npn \__wi_code_for_possible_arrow:
   {
     \bool_if:nT
       {
-        \int_compare_p:nNn \l__wa_arrow_int > \c_one_int
+        \int_compare_p:nNn \l__wi_arrow_int > \c_one_int
         &&
-       ( \int_compare_p:n { \l__wa_initial_int > \l__wa_last_line_of_group_int }
+       ( \int_compare_p:n { \l__wi_initial_int > \l__wi_last_line_of_group_int }
            &&
-         \int_compare_p:n { \l__wa_pos_arrow_int != 7 }
+         \int_compare_p:n { \l__wi_pos_arrow_int != 7 }
            ||
-         \str_if_eq_p:Vn \l__wa_status_arrow_str { new-group }
+         \str_if_eq_p:Vn \l__wi_status_arrow_str { new-group }
        )
       }
       {
-        \int_compare:nNnF \l__wa_first_arrow_of_group_int = \c_zero_int
+        \int_compare:nNnF \l__wi_first_arrow_of_group_int = \c_zero_int
           {
-            \__wa_draw_arrows:nn
-              \l__wa_first_arrow_of_group_int
-              { \l__wa_arrow_int - 1 }
+            \__wi_draw_arrows:nn
+              \l__wi_first_arrow_of_group_int
+              { \l__wi_arrow_int - 1 }
           }
-        \bool_set_true:N \l__wa_new_group_bool
+        \bool_set_true:N \l__wi_new_group_bool
       }
-    \bool_if:nTF \l__wa_new_group_bool
+    \bool_if:nTF \l__wi_new_group_bool
       {
-        \bool_set_false:N \l__wa_new_group_bool
-        \int_set_eq:NN \l__wa_first_arrow_of_group_int \l__wa_arrow_int
-        \int_set_eq:NN \l__wa_first_line_of_group_int \l__wa_initial_int
-        \int_set_eq:NN \l__wa_last_line_of_group_int \l__wa_final_int
-        \seq_clear:N \l__wa_first_arrows_seq
-        \seq_put_left:NV \l__wa_first_arrows_seq \l__wa_arrow_int
-        \seq_clear:N \l__wa_last_arrows_seq
-        \seq_put_left:NV \l__wa_last_arrows_seq \l__wa_arrow_int
-        \int_compare:nT { \l__wa_pos_arrow_int != 8 }
-          { \dim_set:Nn \l__wa_x_dim { - \c_max_dim } }
+        \bool_set_false:N \l__wi_new_group_bool
+        \int_set_eq:NN \l__wi_first_arrow_of_group_int \l__wi_arrow_int
+        \int_set_eq:NN \l__wi_first_line_of_group_int \l__wi_initial_int
+        \int_set_eq:NN \l__wi_last_line_of_group_int \l__wi_final_int
+        \seq_clear:N \l__wi_first_arrows_seq
+        \seq_put_left:NV \l__wi_first_arrows_seq \l__wi_arrow_int
+        \seq_clear:N \l__wi_last_arrows_seq
+        \seq_put_left:NV \l__wi_last_arrows_seq \l__wi_arrow_int
+        \int_compare:nT { \l__wi_pos_arrow_int != 8 }
+          { \dim_set:Nn \l__wi_x_dim { - \c_max_dim } }
       }
       {
         \bool_if:nF
-          { \str_if_eq_p:Vn \l__wa_status_arrow_str { independent } }
+          { \str_if_eq_p:Vn \l__wi_status_arrow_str { independent } }
           {
             \int_compare:nT
-              { \l__wa_initial_int = \l__wa_first_line_of_group_int }
-              { \seq_put_left:NV \l__wa_first_arrows_seq \l__wa_arrow_int }
-            \int_compare:nNnTF \l__wa_final_int > \l__wa_last_line_of_group_int
+              { \l__wi_initial_int = \l__wi_first_line_of_group_int }
+              { \seq_put_left:NV \l__wi_first_arrows_seq \l__wi_arrow_int }
+            \int_compare:nNnTF \l__wi_final_int > \l__wi_last_line_of_group_int
               {
-                \int_set_eq:NN \l__wa_last_line_of_group_int \l__wa_final_int
-                \seq_clear:N \l__wa_last_arrows_seq
-                \seq_put_left:NV \l__wa_last_arrows_seq \l__wa_arrow_int
+                \int_set_eq:NN \l__wi_last_line_of_group_int \l__wi_final_int
+                \seq_clear:N \l__wi_last_arrows_seq
+                \seq_put_left:NV \l__wi_last_arrows_seq \l__wi_arrow_int
               }
               {
-                \int_compare:nNnT \l__wa_final_int = \l__wa_last_line_of_group_int
-                  { \seq_put_left:NV \l__wa_last_arrows_seq \l__wa_arrow_int }
+                \int_compare:nNnT \l__wi_final_int = \l__wi_last_line_of_group_int
+                  { \seq_put_left:NV \l__wi_last_arrows_seq \l__wi_arrow_int }
               }
           }
       }
-    \bool_if:nF { \str_if_eq_p:Vn \l__wa_status_arrow_str { independent } }
+    \bool_if:nF { \str_if_eq_p:Vn \l__wi_status_arrow_str { independent } }
       {
-        \int_compare:nT { \l__wa_pos_arrow_int != 8 }
-          { \__wa_update_x:nn \l__wa_initial_int \l__wa_final_int }
+        \int_compare:nT { \l__wi_pos_arrow_int != 8 }
+          { \__wi_update_x:nn \l__wi_initial_int \l__wi_final_int }
       }
   }
 \cs_generate_variant:Nn \keys_set:nn { n o }
-\cs_new_protected:Npn \__wa_keys_set:
+\cs_new_protected:Npn \__wi_keys_set:
   { \keys_set_known:no { WithArrows / Arrow / SecondPass } }
-\cs_new_protected:Npn \__wa_draw_arrows:nn #1 #2
+\cs_new_protected:Npn \__wi_draw_arrows:nn #1 #2
   {
     \group_begin:
-    \int_zero_new:N \l__wa_first_arrow_int
-    \int_set:Nn \l__wa_first_arrow_int { #1 }
-    \int_zero_new:N \l__wa_last_arrow_int
-    \int_set:Nn \l__wa_last_arrow_int { #2 }
-    \int_set:Nn \l__wa_arrow_int \l__wa_first_arrow_int
-    \int_until_do:nNnn \l__wa_arrow_int > \l__wa_last_arrow_int
+    \int_zero_new:N \l__wi_first_arrow_int
+    \int_set:Nn \l__wi_first_arrow_int { #1 }
+    \int_zero_new:N \l__wi_last_arrow_int
+    \int_set:Nn \l__wi_last_arrow_int { #2 }
+    \int_set:Nn \l__wi_arrow_int \l__wi_first_arrow_int
+    \int_until_do:nNnn \l__wi_arrow_int > \l__wi_last_arrow_int
       {
         \prop_get:cnN
-          { g__wa_arrow _ \l__wa_prefix_str _ \int_use:N \l__wa_arrow_int _ prop }
+          { g__wi_arrow _ \l__wi_prefix_str _ \int_use:N \l__wi_arrow_int _ prop }
           { initial } \l_tmpa_tl
-        \int_set:Nn \l__wa_initial_int \l_tmpa_tl
+        \int_set:Nn \l__wi_initial_int \l_tmpa_tl
         \prop_get:cnN
-          { g__wa_arrow _ \l__wa_prefix_str _ \int_use:N \l__wa_arrow_int _ prop }
+          { g__wi_arrow _ \l__wi_prefix_str _ \int_use:N \l__wi_arrow_int _ prop }
           { final } \l_tmpa_tl
-        \int_set:Nn \l__wa_final_int \l_tmpa_tl
-        \int_compare:nT { \l__wa_final_int <= \g__wa_line_int } \__wa_draw_arrows_i:
-        \int_incr:N \l__wa_arrow_int
+        \int_set:Nn \l__wi_final_int \l_tmpa_tl
+        \int_compare:nT { \l__wi_final_int <= \g__wi_line_int } \__wi_draw_arrows_i:
+        \int_incr:N \l__wi_arrow_int
       }
     \group_end:
   }
-\cs_new_protected:Npn \__wa_draw_arrows_i:
+\cs_new_protected:Npn \__wi_draw_arrows_i:
   {
     \group_begin:
     \prop_get:cnN
-      { g__wa_arrow _\l__wa_prefix_str _ \int_use:N \l__wa_arrow_int _ prop }
+      { g__wi_arrow _\l__wi_prefix_str _ \int_use:N \l__wi_arrow_int _ prop }
       { options } \l_tmpa_tl
-    \str_clear_new:N \l__wa_previous_key_str
+    \str_clear_new:N \l__wi_previous_key_str
     \exp_args:NNo \exp_args:No
-    \__wa_keys_set: { \l_tmpa_tl , tikz = { xshift = \l__wa_xoffset_dim } }
-    \bool_set_false:N \l__wa_initial_r_bool
-    \bool_set_false:N \l__wa_final_r_bool
-    \int_case:nn \l__wa_pos_arrow_int
+    \__wi_keys_set: { \l_tmpa_tl , tikz = { xshift = \l__wi_xoffset_dim } }
+    \bool_set_false:N \l__wi_initial_r_bool
+    \bool_set_false:N \l__wi_final_r_bool
+    \int_case:nn \l__wi_pos_arrow_int
       {
-        0 { \bool_set_true:N \l__wa_final_r_bool }
-        2 { \bool_set_true:N \l__wa_initial_r_bool }
+        0 { \bool_set_true:N \l__wi_final_r_bool }
+        2 { \bool_set_true:N \l__wi_initial_r_bool }
         3
           {
-            \bool_set_true:N \l__wa_initial_r_bool
-            \bool_set_true:N \l__wa_final_r_bool
+            \bool_set_true:N \l__wi_initial_r_bool
+            \bool_set_true:N \l__wi_final_r_bool
           }
       }
-    \int_compare:nNnT \l__wa_pos_arrow_int = 5
+    \int_compare:nNnT \l__wi_pos_arrow_int = 5
       {
-        \dim_set:Nn \l__wa_x_dim { - \c_max_dim }
-        \__wa_update_x:nn \l__wa_initial_int \l__wa_final_int
+        \dim_set:Nn \l__wi_x_dim { - \c_max_dim }
+        \__wi_update_x:nn \l__wi_initial_int \l__wi_final_int
       }
-    \tl_set:Nx \l__wa_initial_tl
+    \tl_set:Nx \l__wi_initial_tl
       {
-        \int_use:N \l__wa_initial_int - \bool_if:NTF \l__wa_initial_r_bool rl
+        \int_use:N \l__wi_initial_int - \bool_if:NTF \l__wi_initial_r_bool rl
         .south
       }
-    \tl_set:Nx \l__wa_final_tl
-      { \int_use:N \l__wa_final_int - \bool_if:NTF \l__wa_final_r_bool rl .north }
+    \tl_set:Nx \l__wi_final_tl
+      { \int_use:N \l__wi_final_int - \bool_if:NTF \l__wi_final_r_bool rl .north }
     \prop_get:cnN
-      { g__wa_arrow _ \l__wa_prefix_str _ \int_use:N \l__wa_arrow_int _ prop }
+      { g__wi_arrow _ \l__wi_prefix_str _ \int_use:N \l__wi_arrow_int _ prop }
       { label }
       \l_tmpa_tl
-    \seq_if_in:NxTF \l__wa_first_arrows_seq
-      { \int_use:N \l__wa_arrow_int }
+    \seq_if_in:NxTF \l__wi_first_arrows_seq
+      { \int_use:N \l__wi_arrow_int }
       { \bool_set_true:N \l_tmpa_bool }
       { \bool_set_false:N \l_tmpa_bool }
-    \seq_if_in:NxTF \l__wa_last_arrows_seq
-      { \int_use:N \l__wa_arrow_int }
+    \seq_if_in:NxTF \l__wi_last_arrows_seq
+      { \int_use:N \l__wi_arrow_int }
       { \bool_set_true:N \l_tmpb_bool }
       { \bool_set_false:N \l_tmpb_bool }
-    \int_compare:nNnT \l__wa_pos_arrow_int = 5
+    \int_compare:nNnT \l__wi_pos_arrow_int = 5
       {
         \bool_set_true:N \l_tmpa_bool
         \bool_set_true:N \l_tmpb_bool
       }
-    \begin { tikzpicture } [ __wa_standard ]
-      \tikz@scan@one@point \pgfutil@firstofone ( \l__wa_initial_tl )
+    \begin { tikzpicture } [ __wi_standard ]
+      \tikz@scan@one@point \pgfutil@firstofone ( \l__wi_initial_tl )
       \tl_gset:Nx \g_tmpa_tl
         {
-          \int_compare:nNnTF \l__wa_pos_arrow_int < 5
+          \int_compare:nNnTF \l__wi_pos_arrow_int < 5
             { \dim_use:N \pgf@x }
-            { \dim_use:N \l__wa_x_dim } ,
+            { \dim_use:N \l__wi_x_dim } ,
           \bool_if:NTF \l_tmpa_bool
-            { \dim_eval:n { \pgf@y + \l__wa_start_adjust_dim } }
+            { \dim_eval:n { \pgf@y + \l__wi_start_adjust_dim } }
             { \dim_use:N \pgf@y }
         }
-      \tikz@scan@one@point \pgfutil@firstofone ( \l__wa_final_tl )
+      \tikz@scan@one@point \pgfutil@firstofone ( \l__wi_final_tl )
       \tl_gset:Nx \g_tmpb_tl
         {
-          \int_compare:nNnTF \l__wa_pos_arrow_int < 5
+          \int_compare:nNnTF \l__wi_pos_arrow_int < 5
             { \dim_use:N \pgf@x }
-            { \dim_use:N \l__wa_x_dim } ,
+            { \dim_use:N \l__wi_x_dim } ,
           \bool_if:NTF \l_tmpb_bool
-            { \dim_eval:n { \pgf@y - \l__wa_end_adjust_dim } }
+            { \dim_eval:n { \pgf@y - \l__wi_end_adjust_dim } }
             { \dim_use:N \pgf@y }
         }
     \end { tikzpicture }
-    \__wa_draw_arrow:nno \g_tmpa_tl \g_tmpb_tl \l_tmpa_tl
+    \__wi_draw_arrow:nno \g_tmpa_tl \g_tmpb_tl \l_tmpa_tl
     \group_end:
   }
-\cs_new_protected:Npn \__wa_def_function_tmpa:n #1
+\cs_new_protected:Npn \__wi_def_function_tmpa:n #1
   {
-    \cs_set:Npn \__wa_tmpa:nnn ##1 ##2 ##3
+    \cs_set:Npn \__wi_tmpa:nnn ##1 ##2 ##3
       {
         \begin{tikzpicture}
           [
-            __wa_standard ,
+            __wi_standard ,
             every~path / .style = WithArrows / arrow
           ]
           #1
         \end{tikzpicture}
       }
   }
-\cs_new_protected:Npn \__wa_draw_arrow:nnn #1 #2 #3
+\cs_new_protected:Npn \__wi_draw_arrow:nnn #1 #2 #3
   {
-    \bool_if:nT { \l__wa_wrap_lines_bool && \l__wa_in_DispWithArrows_bool }
-       { \tl_set_eq:NN \l__wa_tikz_code_tl \c__wa_tikz_code_wrap_lines_tl }
-    \exp_args:NV \__wa_def_function_tmpa:n \l__wa_tikz_code_tl
-    \__wa_tmpa:nnn { #1 } { #2 } { #3 }
+    \bool_if:nT { \l__wi_wrap_lines_bool && \l__wi_in_DispWithArrows_bool }
+       { \tl_set_eq:NN \l__wi_tikz_code_tl \c__wi_tikz_code_wrap_lines_tl }
+    \exp_args:NV \__wi_def_function_tmpa:n \l__wi_tikz_code_tl
+    \__wi_tmpa:nnn { #1 } { #2 } { #3 }
   }
-\cs_generate_variant:Nn \__wa_draw_arrow:nnn { n n o }
-\tl_const:Nn \c__wa_tikz_code_wrap_lines_tl
+\cs_generate_variant:Nn \__wi_draw_arrow:nnn { n n o }
+\tl_const:Nn \c__wi_tikz_code_wrap_lines_tl
   {
-    \draw ( #1 ) to node ( __wa_label ) { } ( #2 ) ;
-    \tikz@parse@node \pgfutil@firstofone ( __wa_label.west )
-    \dim_set:Nn \l_tmpa_dim { \g__wa_right_x_dim - \pgf@x - 0.3333 em }
+    \draw ( #1 ) to node ( __wi_label ) { } ( #2 ) ;
+    \tikz@parse@node \pgfutil@firstofone ( __wi_label.west )
+    \dim_set:Nn \l_tmpa_dim
+      { \g__wi_right_x_dim - \pgf@x - \pgfkeysvalueof { / pgf / inner~xsep } }
     \path \pgfextra { \tl_gset:Nx \g_tmpa_tl \tikz@text@width } ;
     \tl_if_empty:NF \g_tmpa_tl
       {
@@ -1293,79 +1460,80 @@
       }
     \dim_compare:nNnT \l_tmpa_dim > \c_zero_dim
       {
-        \path ( __wa_label.west )
+        \path ( __wi_label.west )
            node [ anchor = west , text~width = \dim_use:N \l_tmpa_dim ]
                 { #3 } ;
       }
   }
-\cs_new_protected:Npn \__wa_update_x:nn #1 #2
+\cs_new_protected:Npn \__wi_update_x:nn #1 #2
   {
     \int_step_inline:nnn { #1 } { #2 }
       {
-        \begin { tikzpicture } [ __wa_standard ]
+        \begin { tikzpicture } [ __wi_standard ]
           \tikz@scan@one@point \pgfutil@firstofone ( ##1 - l )
-          \dim_gset:Nn \g_tmpa_dim { \dim_max:nn \l__wa_x_dim \pgf@x }
+          \dim_gset:Nn \g_tmpa_dim { \dim_max:nn \l__wi_x_dim \pgf@x }
         \end { tikzpicture }
-        \dim_set_eq:NN \l__wa_x_dim \g_tmpa_dim
+        \dim_set_eq:NN \l__wi_x_dim \g_tmpa_dim
       }
   }
-\cs_new:Npn \WithArrowsLastEnv { \int_use:N \g__wa_last_env_int }
+\cs_new:Npn \WithArrowsLastEnv { \int_use:N \g__wi_last_env_int }
 \keys_define:nn { WithArrows / Arrow / code-after }
   {
     tikz     .code:n =
       \tikzset { WithArrows / arrow / .append~style = { #1 } } ,
     tikz     .value_required:n  = true ,
     rr       .value_forbidden:n = true ,
-    rr       .code:n            = \__wa_fix_pos_option:n 0 ,
+    rr       .code:n            = \__wi_fix_pos_option:n 0 ,
     ll       .value_forbidden:n = true,
-    ll       .code:n            = \__wa_fix_pos_option:n 1 ,
+    ll       .code:n            = \__wi_fix_pos_option:n 1 ,
     rl       .value_forbidden:n = true ,
-    rl       .code:n            = \__wa_fix_pos_option:n 2 ,
+    rl       .code:n            = \__wi_fix_pos_option:n 2 ,
     lr       .value_forbidden:n = true ,
-    lr       .code:n            = \__wa_fix_pos_option:n 3 ,
+    lr       .code:n            = \__wi_fix_pos_option:n 3 ,
     v        .value_forbidden:n = true ,
-    v        .code:n            = \__wa_fix_pos_option:n 4 ,
-    tikz-code .tl_set:N          = \l__wa_tikz_code_tl ,
+    v        .code:n            = \__wi_fix_pos_option:n 4 ,
+    tikz-code .tl_set:N          = \l__wi_tikz_code_tl ,
     tikz-code .value_required:n  = true ,
-    xoffset  .dim_set:N         = \l__wa_xoffset_dim ,
+    xoffset  .dim_set:N         = \l__wi_xoffset_dim ,
     xoffset  .value_required:n  = true ,
     unknown .code:n  =
-      \__wa_sort_seq:N \l__wa_options_Arrow_code_after_seq
-      \__wa_error:n { Unknown~option~Arrow~in~code-after }
+      \__wi_sort_seq:N \l__wi_options_Arrow_code_after_seq
+      \__wi_error:n { Unknown~option~Arrow~in~code-after }
   }
-\seq_new:N \l__wa_options_Arrow_code_after_seq
-\seq_set_from_clist:Nn \l__wa_options_Arrow_code_after_seq
+\seq_new:N \l__wi_options_Arrow_code_after_seq
+\__wi_set_seq_of_str_from_clist:Nn \l__wi_options_Arrow_code_after_seq
   { ll, lr, rl, rr, tikz, tikz-code, v, x, offset }
-\NewDocumentCommand \__wa_Arrow_code_after { O { } m m m ! O { } }
+\NewDocumentCommand \__wi_Arrow_code_after { O { } m m m ! O { } }
   {
-    \int_set:Nn \l__wa_pos_arrow_int 1
-    \str_clear_new:N \l__wa_previous_key_str
+    \int_set:Nn \l__wi_pos_arrow_int 1
+    \str_clear_new:N \l__wi_previous_key_str
     \group_begin:
       \keys_set:nn { WithArrows / Arrow / code-after }
-        { #1, #5, tikz = { xshift = \l__wa_xoffset_dim } }
-      \bool_set_false:N \l__wa_initial_r_bool
-      \bool_set_false:N \l__wa_final_r_bool
-      \int_case:nn \l__wa_pos_arrow_int
-        { 0
+        { #1, #5, tikz = { xshift = \l__wi_xoffset_dim } }
+      \bool_set_false:N \l__wi_initial_r_bool
+      \bool_set_false:N \l__wi_final_r_bool
+      \int_case:nn \l__wi_pos_arrow_int
+        {
+          0
             {
-              \bool_set_true:N \l__wa_initial_r_bool
-              \bool_set_true:N \l__wa_final_r_bool
+              \bool_set_true:N \l__wi_initial_r_bool
+              \bool_set_true:N \l__wi_final_r_bool
             }
-          2 { \bool_set_true:N \l__wa_initial_r_bool }
-          3 { \bool_set_true:N \l__wa_final_r_bool }
+          2 { \bool_set_true:N \l__wi_initial_r_bool }
+          3 { \bool_set_true:N \l__wi_final_r_bool }
         }
       \tl_if_eq:nnTF { #2 } { #3 }
-        { \__wa_error:nn { Both~lines~are~equal } { #2 } }
+        { \__wi_error:nn { Both~lines~are~equal } { #2 } }
         {
-          \cs_if_free:cTF { pgf@sh@ns@wa - \l__wa_prefix_str - #2 - l }
-            { \__wa_error:nx { Wrong~line~in~Arrow } { #2 } }
+          \cs_if_free:cTF { pgf@sh@ns@wa - \l__wi_prefix_str - #2 - l }
+            { \__wi_error:nx { Wrong~line~in~Arrow } { #2 } }
             {
-              \cs_if_free:cTF { pgf@sh@ns@wa - \l__wa_prefix_str - #3 - l }
-                { \__wa_error:nx { Wrong~line~in~Arrow } { #3 }  }
+              \cs_if_free:cTF { pgf@sh@ns@wa - \l__wi_prefix_str - #3 - l }
+                { \__wi_error:nx { Wrong~line~in~Arrow } { #3 }  }
                 {
-                  \int_compare:nNnTF \l__wa_pos_arrow_int = 4
+                  \int_compare:nNnTF \l__wi_pos_arrow_int = 4
                     {
-                      \begin { tikzpicture } [ __wa_standard ]
+                      \begin { tikzpicture } [ __wi_standard ]
                         \tikz@scan@one@point \pgfutil@firstofone (#2-l.south)
                         \dim_set_eq:NN \l_tmpa_dim \pgf@x
                         \dim_set_eq:NN \l_tmpb_dim \pgf@y
@@ -1379,33 +1547,33 @@
                       \end { tikzpicture }
                     }
                     {
-                      \begin { tikzpicture } [ __wa_standard ]
+                      \begin { tikzpicture } [ __wi_standard ]
                         \tikz@scan@one@point \pgfutil@firstofone
-                           ( #2-\bool_if:NTF\l__wa_initial_r_bool rl .south )
+                           ( #2-\bool_if:NTF\l__wi_initial_r_bool rl .south )
                         \tl_gset:Nx \g_tmpa_tl
                            { \dim_use:N \pgf@x , \dim_use:N \pgf@y }
                         \tikz@scan@one@point \pgfutil@firstofone
-                           ( #3-\bool_if:NTF\l__wa_final_r_bool rl .north )
+                           ( #3-\bool_if:NTF\l__wi_final_r_bool rl .north )
                         \tl_gset:Nx \g_tmpb_tl
                            { \dim_use:N \pgf@x , \dim_use:N \pgf@y }
                       \end { tikzpicture }
                     }
-                  \__wa_draw_arrow:nnn \g_tmpa_tl \g_tmpb_tl { #4 }
+                  \__wi_draw_arrow:nnn \g_tmpa_tl \g_tmpb_tl { #4 }
                 }
             }
         }
     \group_end:
   }
-\cs_new_protected:Npn \__wa_MultiArrow:nn #1 #2
+\cs_new_protected:Npn \__wi_MultiArrow:nn #1 #2
   {
     \foreach \x in { #1 }
       {
-        \cs_if_free:cTF { pgf@sh@ns@wa - \l__wa_prefix_str - \x - l }
-           { \__wa_error:nx { Wrong~line~specification~in~MultiArrow } \x }
+        \cs_if_free:cTF { pgf@sh@ns@wa - \l__wi_prefix_str - \x - l }
+           { \__wi_error:nx { Wrong~line~specification~in~MultiArrow } \x }
            { \clist_gput_right:Nx \g_tmpa_clist \x }
       }
     \int_compare:nTF { \clist_count:N \g_tmpa_clist < 2 }
-      { \__wa_error:n { Too~small~specification~for~MultiArrow } }
+      { \__wi_error:n { Too~small~specification~for~MultiArrow } }
       {
         \clist_sort:Nn \g_tmpa_clist
           {
@@ -1416,296 +1584,353 @@
         \clist_pop:NN \g_tmpa_clist \l_tmpa_tl
         \clist_reverse:N \g_tmpa_clist
         \clist_pop:NN \g_tmpa_clist \l_tmpb_tl
-        \exp_args:NV \__wa_MultiArrow_i:n \g_tmpa_clist
+        \exp_args:NV \__wi_MultiArrow_i:n \g_tmpa_clist
         \begin { tikzpicture }
           [
-            __wa_standard ,
+            __wi_standard ,
             every~path / .style = { WithArrows / arrow }
           ]
-          \draw [<->] ([xshift = \l__wa_xoffset_dim]\l_tmpa_tl-r.south)
+          \draw [<->] ([xshift = \l__wi_xoffset_dim]\l_tmpa_tl-r.south)
                       -- ++(5mm,0)
-                      -- node (__wa_label) {}
-                         ([xshift = \l__wa_xoffset_dim+5mm]\l_tmpb_tl-r.south)
-                      -- ([xshift = \l__wa_xoffset_dim]\l_tmpb_tl-r.south)  ;
-          \tikz@parse@node \pgfutil@firstofone (__wa_label.west)
+                      -- node (__wi_label) {}
+                         ([xshift = \l__wi_xoffset_dim+5mm]\l_tmpb_tl-r.south)
+                      -- ([xshift = \l__wi_xoffset_dim]\l_tmpb_tl-r.south)  ;
+          \tikz@parse@node \pgfutil@firstofone (__wi_label.west)
           \dim_set:Nn \l_tmpa_dim { 20 cm }
           \path \pgfextra { \tl_gset:Nx \g_tmpa_tl \tikz@text@width } ;
           \tl_if_empty:NF \g_tmpa_tl { \dim_set:Nn \l_tmpa_dim \g_tmpa_tl }
-          \bool_if:nT { \l__wa_wrap_lines_bool && \l__wa_in_DispWithArrows_bool }
+          \bool_if:nT { \l__wi_wrap_lines_bool && \l__wi_in_DispWithArrows_bool }
             {
               \dim_set:Nn \l_tmpb_dim
-                { \g__wa_right_x_dim - \pgf@x - 0.3333 em }
+                { \g__wi_right_x_dim - \pgf@x - 0.3333 em }
               \dim_compare:nNnT \l_tmpb_dim < \l_tmpa_dim
                 { \dim_set_eq:NN \l_tmpa_dim \l_tmpb_dim }
             }
-          \path (__wa_label.west)
+          \path (__wi_label.west)
            node [ anchor = west, text~width = \dim_use:N \l_tmpa_dim ] { #2 } ;
         \end{tikzpicture}
       }
   }
-\cs_new_protected:Npn \__wa_MultiArrow_i:n #1
+\cs_new_protected:Npn \__wi_MultiArrow_i:n #1
   {
     \begin {tikzpicture }
       [
-        __wa_standard ,
+        __wi_standard ,
         every~path / .style = { WithArrows / arrow }
       ]
       \foreach \k in { #1 }
         {
           \draw [ <- ]
-            ( [xshift = \l__wa_xoffset_dim]\k-r.south ) -- ++(5mm,0) ;
+            ( [xshift = \l__wi_xoffset_dim]\k-r.south ) -- ++(5mm,0) ;
         } ;
     \end { tikzpicture }
   }
-\str_const:Nn \c__wa_option_ignored_str
+\str_const:Nn \c__wi_option_ignored_str
   { If~you~go~on,~this~option~will~be~ignored. }
-\str_const:Nn \c__wa_command_ignored_str
+\str_const:Nn \c__wi_command_ignored_str
   { If~you~go~on,~this~command~will~be~ignored. }
-\__wa_msg_new:nn { Invalid~option~format }
+\__wi_msg_new:nn { amsmath~not~loaded }
+  {
+    You~can't~use~the~option~'\l_keys_key_tl'~because~the~
+    package~'amsmath'~has~not~been~loaded.\\
+    If~you~go~on,~this~option~will~be~ignored~in~the~rest~
+    of~the~document.
+  }
+\__wi_msg_new:nn { Bad~value~for~replace~brace~by }
+  {
+    Bad~value~for~the~option~'\l_keys_key_tl'.~The~value~must~be~
+    an~extensible~left~delimiter.~The~possible~values~are:~
+    \token_to_str:N \{,~(,~[,~\token_to_str:N \lbrace,~
+    \token_to_str:N \lbrack,~\token_to_str:N \lgroup,~
+    \token_to_str:N \langle,~\token_to_str:N \lmoustache,~
+    \token_to_str:N \lfloor\ and~\token_to_str:N \lceil\
+    (and~\token_to_str:N \lvert\ and~\token_to_str:N \lVert\
+    if~amsmath~or~unicode-math~is~loaded).\\
+    \c__wi_option_ignored_str
+  }
+\__wi_msg_new:nn { option~of~cr~negative }
+  {
+    The~argument~of~the~command~\token_to_str:N\\~
+    should~be~positive~in~the~row~\int_use:N \g__wi_line_int\
+    of~your~environment~\{\l__wi_type_env_str\}.\\
+    \c__wi_option_ignored_str
+  }
+\__wi_msg_new:nn { omit~probably~used }
+  {
+    There~is~a~problem.~Maybe~you~have~used~a~command~
+    \token_to_str:N\omit\ in~the~line~\int_use:N \g__wi_line_int\
+    (or~another~line)~of~your~environment~\{\l__wi_type_env_str\}.\\
+    You~can~go~on~but~you~may~have~others~errors.
+  }
+\__wi_msg_new:nn { newline~at~the~end~of~env }
+  {
+    Your~environment~\{\l__wi_type_env_str\}~should~not~end~with~
+    a~\token_to_str:N \\.\\
+    This~warning~might~become~an~error~in~a~future~version.
+  }
+\__wi_msg_new:nn { Invalid~option~format }
   {
-    The~option~'format'~should~contain~only~letters~r,~c~and~l.\\
-    \c__wa_option_ignored_str
+    The~key~'format'~should~contain~only~letters~r,~c~and~l~and~
+    must~not~be~empty.\\
+    \c__wi_option_ignored_str
   }
-\__wa_msg_new:nn { Value~for~a~key }
+\__wi_msg_new:nn { Value~for~a~key }
   {
     The~key~'\l_keys_key_tl'~should~be~used~without~value. \\
     However,~you~can~go~on~for~this~time.
   }
-\__wa_msg_new:nnn { Unknown~option~in~Arrow }
+\__wi_msg_new:nnn { Unknown~option~in~Arrow }
   {
-    The~option~'\l_keys_key_tl'~
-    is~unknown~for~the~command~\l__wa_string_Arrow_for_msg_str\
-    in~the~row~\int_use:N \g__wa_line_int\
-    of~your~environment~\{\l__wa_type_env_str\}. \\
-    \c__wa_option_ignored_str \\
+    The~key~'\l_keys_key_tl'~is~unknown~for~the~command~
+    \l__wi_string_Arrow_for_msg_str\ in~the~row~
+    \int_use:N \g__wi_line_int\ of~your~environment~
+    \{\l__wi_type_env_str\}. \l_tmpa_str \\
+    \c__wi_option_ignored_str \\
     For~a~list~of~the~available~keys,~type~H~<return>.
   }
   {
     The~available~keys~are~(in~alphabetic~order):~
-    \seq_use:Nnnn \l__wa_options_Arrow_seq {~and~} {,~} {~and~}.
+    \seq_use:Nnnn \l__wi_options_Arrow_seq {~and~} {,~} {~and~}.
   }
-\__wa_msg_new:nnn { Unknown~option~WithArrows }
+\__wi_msg_new:nnn { Unknown~option~WithArrows }
   {
-    The~option~'\l_keys_key_tl'~is~unknown~in~\{\l__wa_type_env_str\}. \\
-    \c__wa_option_ignored_str \\
+    The~key~'\l_keys_key_tl'~is~unknown~in~\{\l__wi_type_env_str\}. \\
+    \c__wi_option_ignored_str \\
     For~a~list~of~the~available~keys,~type~H~<return>.
   }
   {
     The~available~keys~are~(in~alphabetic~order):~
-    \seq_use:Nnnn \l__wa_options_WithArrows_seq {~and~} {,~} {~and~}.
+    \seq_use:Nnnn \l__wi_options_WithArrows_seq {~and~} {,~} {~and~}.
   }
-\__wa_msg_new:nnn { Unknown~option~DispWithArrows }
+\__wi_msg_new:nnn { Unknown~option~DispWithArrows }
   {
-    The~option~'\l_keys_key_tl'~is~unknown~in~\{\l__wa_type_env_str\}. \\
-    \c__wa_option_ignored_str \\
+    The~key~'\l_keys_key_tl'~is~unknown~in~\{\l__wi_type_env_str\}. \\
+    \c__wi_option_ignored_str \\
     For~a~list~of~the~available~keys,~type~H~<return>.
   }
   {
     The~available~keys~are~(in~alphabetic~order):~
-    \seq_use:Nnnn \l__wa_options_DispWithArrows_seq {~and~} {,~} {~and~}.
+    \seq_use:Nnnn \l__wi_options_DispWithArrows_seq {~and~} {,~} {~and~}.
   }
-\__wa_msg_new:nnn { Unknown~option~WithArrowsOptions }
+\__wi_msg_new:nnn { Unknown~option~WithArrowsOptions }
   {
-    The~option~'\l_keys_key_tl'~is~unknown~in~
+    The~key~'\l_keys_key_tl'~is~unknown~in~
     \token_to_str:N \WithArrowsOptions. \\
-    \c__wa_option_ignored_str \\
+    \c__wi_option_ignored_str \\
     For~a~list~of~the~available~keys,~type~H~<return>.
   }
   {
     The~available~keys~are~(in~alphabetic~order):~
-    \seq_use:Nnnn \l__wa_options_WithArrowsOptions_seq {~and~} {,~} {~and~}.
+    \seq_use:Nnnn \l__wi_options_WithArrowsOptions_seq {~and~} {,~} {~and~}.
   }
-\__wa_msg_new:nnn { Unknown~option~Arrow~in~code-after }
+\__wi_msg_new:nnn { Unknown~option~Arrow~in~code-after }
   {
-    The~option~'\l_keys_key_tl'~is~unknown~in~
-    \token_to_str:N \Arrow\
-    in~\token_to_str:N \code-after. \\
-    \c__wa_option_ignored_str \\
+    The~key~'\l_keys_key_tl'~is~unknown~in~
+    \token_to_str:N \Arrow\ in~code-after. \\
+    \c__wi_option_ignored_str \\
     For~a~list~of~the~available~keys,~type~H~<return>.
   }
   {
     The~available~keys~are~(in~alphabetic~order):~
-    \seq_use:Nnnn \l__wa_options_Arrow_code_after_seq {~and~} {,~} {~and~}.
+    \seq_use:Nnnn \l__wi_options_Arrow_code_after_seq {~and~} {,~} {~and~}.
   }
-\__wa_msg_new:nn { Too~much~columns~in~WithArrows }
+\__wi_msg_new:nn { Too~much~columns~in~WithArrows }
   {
-    Your~environment~\{\l__wa_type_env_str\}~has~\int_use:N
-    \l__wa_nb_of_columns_int\ columns~and~you~try~to~use~one~more.~
+    Your~environment~\{\l__wi_type_env_str\}~has~\int_use:N
+    \l__wi_nb_cols_int\ columns~and~you~try~to~use~one~more.~
     Maybe~you~have~forgotten~a~\c_backslash_str\c_backslash_str.~
     If~you~really~want~to~use~more~columns~(after~the~arrows)~you~should~use~
     the~option~'more-columns'~at~a~global~level~or~for~an~environment. \\
     However,~you~can~go~one~for~this~time.
   }
-\__wa_msg_new:nn { Too~much~columns~in~DispWithArrows }
+\__wi_msg_new:nn { Too~much~columns~in~DispWithArrows }
   {
-    Your~environment~\{\l__wa_type_env_str\}~has~\int_use:N
-    \l__wa_nb_of_columns_int\ columns~and~you~try~to~use~one~more.~
+    Your~environment~\{\l__wi_type_env_str\}~has~\int_use:N
+    \l__wi_nb_cols_int\ columns~and~you~try~to~use~one~more.~
     Maybe~you~have~forgotten~a~\c_backslash_str\c_backslash_str\
-    at~the~end~of~row~\int_use:N \g__wa_line_int. \\
-    If~you~go~on,~you~may~have~other~errors.
+    at~the~end~of~row~\int_use:N \g__wi_line_int. \\
+    This~error~is~fatal.
   }
-\__wa_msg_new:nn { Negative~jump }
+\__wi_msg_new:nn { Negative~jump }
   {
     You~can't~use~a~negative~value~for~the~option~'jump'~of~command~
-    \l__wa_string_Arrow_for_msg_str\
-    in~the~row~\int_use:N \g__wa_line_int\
-    of~your~environment~\{\l__wa_type_env_str\}.~
+    \l__wi_string_Arrow_for_msg_str\
+    in~the~row~\int_use:N \g__wi_line_int\
+    of~your~environment~\{\l__wi_type_env_str\}.~
     You~can~create~an~arrow~going~backwards~with~the~option~'<-'~of~Tikz. \\
-    \c__wa_option_ignored_str
+    \c__wi_option_ignored_str
   }
-\__wa_msg_new:nn { new-group~without~groups }
+\__wi_msg_new:nn { new-group~without~groups }
   {
     You~can't~use~the~option~'new-group'~for~the~command~
-    \l__wa_string_Arrow_for_msg_str\
+    \l__wi_string_Arrow_for_msg_str\
     because~you~are~not~in~'groups'~mode.~Try~to~use~the~option~
-    'groups'~in~your~environment~\{\l__wa_type_env_str\}. \\
-    \c__wa_option_ignored_str
+    'groups'~in~your~environment~\{\l__wi_type_env_str\}. \\
+    \c__wi_option_ignored_str
   }
-\__wa_msg_new:nn
+\__wi_msg_new:nn
   { Too~few~lines~for~an~arrow }
-  { Line~\l__wa_input_line_str\
-    :~an~arrow~specified~in~the~row~\int_use:N \l__wa_initial_int\
-    of~your~environment~\{\l__wa_type_env_str\}~can't~be~drawn~
+  {
+    Line~\l__wi_input_line_str\
+    :~an~arrow~specified~in~the~row~\int_use:N \l__wi_initial_int\
+    of~your~environment~\{\l__wi_type_env_str\}~can't~be~drawn~
     because~it~arrives~after~the~last~row~of~the~environment. \\
     If~you~go~on,~this~arrow~will~be~ignored.
   }
-\__wa_msg_new:nn { WithArrows~outside~math~mode }
+\__wi_msg_new:nn { WithArrows~outside~math~mode }
   {
-    The~environment~\{\l__wa_type_env_str\}~should~be~used~only~in~math~mode~
+    The~environment~\{\l__wi_type_env_str\}~should~be~used~only~in~math~mode~
     like~the~environment~\{aligned\}~of~amsmath. \\
     Nevertheless,~you~can~go~on.
   }
-\__wa_msg_new:nn { DispWithArrows~in~math~mode }
+\__wi_msg_new:nn { DispWithArrows~in~math~mode }
   {
-    The~environment~\{\l__wa_type_env_str\}~should~be~used~only~outside~math~
+    The~environment~\{\l__wi_type_env_str\}~should~be~used~only~outside~math~
     mode~like~the~environment~\{align\}~of~amsmath. \\
-    If~you~go~on,~you~will~have~other~errors.
+    This~error~is~fatal.
   }
-\__wa_msg_new:nn { Incompatible~options~in~Arrow }
+\__wi_msg_new:nn { Incompatible~options~in~Arrow }
   {
     You~try~to~use~the~option~'\l_keys_key_tl'~but~
     this~option~is~incompatible~or~redundant~with~the~option~
-    '\l__wa_previous_key_str'~set~in~the~same~command~
-    \l__wa_string_Arrow_for_msg_str. \\
-    \c__wa_option_ignored_str
+    '\l__wi_previous_key_str'~set~in~the~same~command~
+    \l__wi_string_Arrow_for_msg_str. \\
+    \c__wi_option_ignored_str
   }
-\__wa_msg_new:nn { Incompatible~options }
+\__wi_msg_new:nn { Incompatible~options }
   { You~try~to~use~the~option~'\l_keys_key_tl'~but~
     this~option~is~incompatible~or~redundant~with~the~option~
-    '\l__wa_previous_key_str'~set~in~the~same~command~
-    \bool_if:NT \l__wa_in_code_after_bool
+    '\l__wi_previous_key_str'~set~in~the~same~command~
+    \bool_if:NT \l__wi_in_code_after_bool
       {
-        \l__wa_string_Arrow_for_msg_str\
-        in~the~code-after~of~your~environment~\{\l__wa_type_env_str\}
+        \l__wi_string_Arrow_for_msg_str\
+        in~the~code-after~of~your~environment~\{\l__wi_type_env_str\}
       }. \\
-    \c__wa_option_ignored_str
+    \c__wi_option_ignored_str
   }
-\__wa_msg_new:nn { Arrow~not~in~last~column }
+\__wi_msg_new:nn { Arrow~not~in~last~column }
   {
-    You~should~use~the~command~\l__wa_string_Arrow_for_msg_str\
-    only~in~the~last~column~of~your~environment~\{\l__wa_type_env_str\}.\\
+    You~should~use~the~command~\l__wi_string_Arrow_for_msg_str\
+    only~in~the~last~column~(column~\int_use:N\l__wi_nb_cols_int)~
+    of~your~environment~\{\l__wi_type_env_str\}.\\
     However~you~can~go~on~for~this~time.
   }
-\__wa_msg_new:nn { Wrong~line~in~Arrow }
+\__wi_msg_new:nn { Wrong~line~in~Arrow }
   {
     The~specification~of~line~'#1'~you~use~in~the~command~
-    \l__wa_string_Arrow_for_msg_str\
-    in~the~'code-after'~of~\{\l__wa_type_env_str\}~doesn't~exist. \\
-    \c__wa_option_ignored_str
+    \l__wi_string_Arrow_for_msg_str\
+    in~the~'code-after'~of~\{\l__wi_type_env_str\}~doesn't~exist. \\
+    \c__wi_option_ignored_str
   }
-\__wa_msg_new:nn { Both~lines~are~equal }
+\__wi_msg_new:nn { Both~lines~are~equal }
   {
-    In~the~'code-after'~of~\{\l__wa_type_env_str\}~you~try~to~
+    In~the~'code-after'~of~\{\l__wi_type_env_str\}~you~try~to~
     draw~an~arrow~going~to~it~self~from~the~line~'#1'.~This~is~not~possible. \\
-    \c__wa_option_ignored_str
+    \c__wi_option_ignored_str
   }
-\__wa_msg_new:nn { Wrong~line~specification~in~MultiArrow }
+\__wi_msg_new:nn { Wrong~line~specification~in~MultiArrow }
   {
     The~specification~of~line~'#1'~doesn't~exist. \\
     If~you~go~on,~it~will~be~ignored~for~\token_to_str:N \MultiArrow.
   }
-\__wa_msg_new:nn { Too~small~specification~for~MultiArrow }
+\__wi_msg_new:nn { Too~small~specification~for~MultiArrow }
   {
     The~specification~of~lines~you~gave~to~\token_to_str:N \MultiArrow\
     is~too~small:~you~need~at~least~two~lines. \\
-    \c__wa_option_ignored_str
+    \c__wi_option_ignored_str
   }
-\__wa_msg_new:nn { tag*~without~amsmath }
+\__wi_msg_new:nn { tag*~without~amsmath }
   {
     We~can't~use~\token_to_str:N\tag*~because~you~haven't~loaded~amsmath~
     (or~mathtools). \\
     If~you~go~on,~the~command~\token_to_str:N\tag\
     will~be~used~instead.
   }
-\__wa_msg_new:nn { Not~allowed~in~DispWithArrows }
+\__wi_msg_new:nn { Not~allowed~in~DispWithArrows }
   {
     The~command~\token_to_str:N #1
-    is~allowed~only~in~the~last~columnm~of~\{\l__wa_type_env_str\}. \\
-    \c__wa_option_ignored_str
+    is~allowed~only~in~the~last~column~
+    (column~\int_use:N\l__wi_nb_cols_int)~of~\{\l__wi_type_env_str\}. \\
+    \c__wi_option_ignored_str
   }
-\__wa_msg_new:nn { Not~allowed~in~WithArrows }
+\__wi_msg_new:nn { Not~allowed~in~WithArrows }
   {
-    The~command~\token_to_str:N #1 is~not~allowed~in~\{\l__wa_type_env_str\}~
+    The~command~\token_to_str:N #1 is~not~allowed~in~\{\l__wi_type_env_str\}~
     (it's~allowed~in~the~last~column~of~\{DispWithArrows\}). \\
-    \c__wa_option_ignored_str
+    \c__wi_option_ignored_str
   }
-\__wa_msg_new:nn { Multiple~tags }
+\__wi_msg_new:nn { Multiple~tags }
   {
     You~can't~use~twice~the~command~\token_to_str:N\tag\
-    in~a~line~of~the~environment~\{\l__wa_type_env_str\}. \\
+    in~a~line~of~the~environment~\{\l__wi_type_env_str\}. \\
     If~you~go~on,~the~tag~'#1'~will~be~used.
   }
-\__wa_msg_new:nn { Multiple~labels }
+\__wi_msg_new:nn { Multiple~labels }
   {
     Normally,~we~can't~use~the~command~\token_to_str:N\label\
-    twice~in~a~line~of~the~environment~\{\l__wa_type_env_str\}. \\
+    twice~in~a~line~of~the~environment~\{\l__wi_type_env_str\}. \\
     However,~you~can~go~on.~
-    \bool_if:NT \c__wa_showlabels_loaded_bool
+    \bool_if:NT \c__wi_showlabels_loaded_bool
       { However,~only~the~last~label~will~be~shown~by~showlabels.~ }
     If~you~don't~want~to~see~this~message~again,~you~can~use~the~option~
     'allow-multiple-labels'~at~the~global~or~environment~level.
   }
-\__wa_msg_new:nn { Multiple~labels~with~cleveref }
+\__wi_msg_new:nn { Multiple~labels~with~cleveref }
   {
     Since~you~use~cleveref,~you~can't~use~the~command~\token_to_str:N\label\
-    twice~in~a~line~of~the~environment~\{\l__wa_type_env_str\}. \\
+    twice~in~a~line~of~the~environment~\{\l__wi_type_env_str\}. \\
     If~you~go~on,~you~may~have~undefined~references.
   }
-\__wa_msg_new:nn { Inexistent~v-node }
+\__wi_msg_new:nn { Inexistent~v-node }
   {
     There~is~a~problem.~Maybe~you~have~put~a~command~\token_to_str:N\cr\
     instead~of~a~command~\token_to_str:N\\~at~the~end~of~
-    the~row~\int_use:N \l_tmpa_int\
-    of~your~environment~\{\l__wa_type_env_str\}. \\
-    If~you~go~on,~you~may~have~an~incorrect~output.
+    the~row~\l_tmpa_int\
+    of~your~environment~\{\l__wi_type_env_str\}. \\
+    This~error~is~fatal.
   }
-\__wa_msg_new:nn { Option~xoffset~forbidden }
+\__wi_msg_new:nn { Option~xoffset~forbidden }
   {
     You~can't~use~the~option~'xoffset'~in~the~command~
-    \l__wa_string_Arrow_for_msg_str\
+    \l__wi_string_Arrow_for_msg_str\
     while~you~are~using~the~option~
-    ' \int_compare:nNnTF \l__wa_pos_arrow_int = 7
+    ' \int_compare:nNnTF \l__wi_pos_arrow_int = 7
         { group }
         { groups } '. \\
-    \c__wa_option_ignored_str
+    \c__wi_option_ignored_str
+  }
+\__wi_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,~
+    maybe,~you~will~have~incorrect~results. \\
+    For~a~list~of~the~names~already~used,~type~H~<return>. \\
+    If~you~don't~want~to~see~this~message~again,~use~the~option~
+    'allow-duplicate-names'.
+  }
+  {
+    The~names~already~defined~in~this~document~are:~
+    \seq_use:Nnnn \g__wi_names_seq { ,~ } { ,~ } { ~and~ }.
   }
 \NewDocumentCommand \WithArrowsNewStyle { m m }
   {
     \keys_if_exist:nnTF { WithArrows / Global } { #1 }
-      { \__wa_error:nn { Key~already~defined } { #1 } }
+      { \__wi_error:nn { Key~already~defined } { #1 } }
       {
         \keys_define:nn { WithArrows / Global }
           {
             #1 .code:n =
              { \keys_set_known:nn { WithArrows / WithArrowsOptions } { #2 } }
           }
-        \seq_put_right:Nn \l__wa_options_WithArrows_seq {#1}
-        \seq_put_right:Nn \l__wa_options_DispWithArrows_seq { #1 }
-        \seq_put_right:Nn \l__wa_options_WithArrowsOptions_seq { #1 }
+        \seq_put_right:Nx \l__wi_options_WithArrows_seq { \tl_to_str:n { #1 } }
+        \seq_put_right:Nx \l__wi_options_DispWithArrows_seq
+          { \tl_to_str:n { #1 } }
+        \seq_put_right:Nx \l__wi_options_WithArrowsOptions_seq
+          { \tl_to_str:N { #1 } }
         \group_begin:
           \msg_set:nnn { witharrows } { Unknown~option~WithArrowsOptions }
             {
-              The~option~'\l_keys_key_tl'~can't~be~set~in~the~
+              The~key~'\l_keys_key_tl'~can't~be~set~in~the~
               definition~of~a~style.~You~can~go~on~for~this~time~
               but~you~should~suppress~this~key.
             }
@@ -1713,13 +1938,13 @@
         \group_end:
       }
   }
-\__wa_msg_new:nn { Key~already~defined }
+\__wi_msg_new:nn { Key~already~defined }
   {
     The~key~'#1'~is~already~defined. \\
     If~you~go~on,~your~instruction~\token_to_str:N\WithArrowsNewStyle\
     will~be~ignored.
   }
-\tl_const:Nn \c__wa_tikz_code_up_tl
+\tl_const:Nn \c__wi_tikz_code_up_tl
   {
     \draw [ rounded~corners ]
        let \p1 = (#1) ,
@@ -1733,7 +1958,7 @@
                         }
           (\x2,\y1) -- (\p2) ;
   }
-\tl_const:Nn \c__wa_tikz_code_down_tl
+\tl_const:Nn \c__wi_tikz_code_down_tl
   {
     \draw [ rounded~corners ]
       let \p1 = (#1) ,
@@ -1750,75 +1975,62 @@
   }
 \keys_define:nn { WithArrows / Arrow / FirstPass }
   {
-    up   .code:n = \__wa_set_independent: ,
-    down .code:n = \__wa_set_independent: ,
+    up   .code:n = \__wi_set_independent: ,
+    down .code:n = \__wi_set_independent: ,
     up   .default:n = NoValue ,
     down .default:n = NoValue
   }
 \keys_define:nn { WithArrows / Arrow / SecondPass }
   {
     up .code:n =
-      \str_if_empty:NT \l__wa_previous_key_str
+      \str_if_empty:NT \l__wi_previous_key_str
         {
-          \str_set:Nn \l__wa_previous_key_str { up }
-          \bool_if:NTF \c__wa_varwidth_loaded_bool
+          \str_set:Nn \l__wi_previous_key_str { up }
+          \bool_if:NTF \c__wi_varwidth_loaded_bool
             {
               \cs_if_exist:cTF { tikz@library@calc@loaded }
                 {
-                  \int_set:Nn \l__wa_pos_arrow_int \c_one_int
-                  \bool_set_false:N \l__wa_wrap_lines_bool
-                  \tl_set_eq:NN \l__wa_tikz_code_tl
-                    \c__wa_tikz_code_up_tl
+                  \int_set:Nn \l__wi_pos_arrow_int \c_one_int
+                  \bool_set_false:N \l__wi_wrap_lines_bool
+                  \tl_set_eq:NN \l__wi_tikz_code_tl
+                    \c__wi_tikz_code_up_tl
                 }
-                { \__wa_error:n { calc~not~loaded } }
+                { \__wi_error:n { calc~not~loaded } }
             }
-            { \__wa_error:n { varwidth~not~loaded } }
+            { \__wi_error:n { varwidth~not~loaded } }
         } ,
     down .code:n =
-      \str_if_empty:NT \l__wa_previous_key_str
+      \str_if_empty:NT \l__wi_previous_key_str
         {
-          \str_set:Nn \l__wa_previous_key_str { down }
-          \bool_if:NTF \c__wa_varwidth_loaded_bool
+          \str_set:Nn \l__wi_previous_key_str { down }
+          \bool_if:NTF \c__wi_varwidth_loaded_bool
             {
               \cs_if_exist:cTF { tikz@library@calc@loaded }
                 {
-                  \int_set:Nn \l__wa_pos_arrow_int \c_one_int
-                  \bool_set_false:N \l__wa_wrap_lines_bool
-                  \tl_set_eq:NN \l__wa_tikz_code_tl
-                    \c__wa_tikz_code_down_tl
+                  \int_set:Nn \l__wi_pos_arrow_int \c_one_int
+                  \bool_set_false:N \l__wi_wrap_lines_bool
+                  \tl_set_eq:NN \l__wi_tikz_code_tl
+                    \c__wi_tikz_code_down_tl
                 }
-                { \__wa_error:n { calc~not~loaded } }
+                { \__wi_error:n { calc~not~loaded } }
             }
-            { \__wa_error:n { varwidth~not~loaded } }
+            { \__wi_error:n { varwidth~not~loaded } }
         }
   }
-\seq_put_right:Nn \l__wa_options_Arrow_seq { down }
-\seq_put_right:Nn \l__wa_options_Arrow_seq { up }
-\__wa_msg_new:nn { varwidth~not~loaded }
+\seq_put_right:Nn \l__wi_options_Arrow_seq { down }
+\seq_put_right:Nn \l__wi_options_Arrow_seq { up }
+\__wi_msg_new:nn { varwidth~not~loaded }
   {
     You~can't~use~the~option~'\l_keys_key_tl'~because~
     you~don't~have~loaded~the~package~'varwidth'. \\
-    \c__wa_option_ignored_str
+    \c__wi_option_ignored_str
   }
-\__wa_msg_new:nn { calc~not~loaded }
+\__wi_msg_new:nn { calc~not~loaded }
   {
     You~can't~use~the~option~'\l_keys_key_tl'~because~you~don't~have~loaded~the~
     Tikz~library~'calc'.You~should~add~'\token_to_str:N\usetikzlibrary{calc}'
     ~in~the~preamble~of~your~document. \\
-    \c__wa_option_ignored_str
-  }
-\__wa_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,~
-    maybe,~you~will~have~incorrect~results. \\
-    For~a~list~of~the~names~already~used,~type~H~<return>. \\
-    If~you~don't~want~to~see~this~message~again,~use~the~option~
-    'allow-duplicate-names'.
-  }
-  {
-    The~names~already~defined~in~this~document~are:~
-    \seq_use:Nnnn \g__wa_names_seq { ,~ } { ,~ } { ~and~ }.
+    \c__wi_option_ignored_str
   }
 \endinput
 %%