stex-ltcmdhooks.sty

\ProvidesExplPackage{stex-ltcmdhooks}{}{}{}{}

\ifx\@kernel@after@enddocument\@undefined
  \let \@kernel@after@enddocument               \@empty
  \let \@kernel@after@enddocument@afterlastpage \@empty
  \let \@kernel@before@begindocument \@empty
  \let \@kernel@after@begindocument  \@empty
\fi

\bool_new:N \g__hook_debug_bool
\cs_new_eq:NN \__hook_debug:n \use_none:n
\cs_new_protected:Npn \hook_debug_on:
  {
    \bool_gset_true:N \g__hook_debug_bool
    \__hook_debug_gset:
  }
\cs_new_protected:Npn \hook_debug_off:
  {
    \bool_gset_false:N \g__hook_debug_bool
    \__hook_debug_gset:
  }
\cs_new_protected:Npn \__hook_debug_gset:
  {
    \cs_gset_protected:Npx \__hook_debug:n ##1
      { \bool_if:NT \g__hook_debug_bool {##1} }
  }
\cs_new_eq:NN \__hook_str_compare:nn \__str_if_eq:nn
\bool_new:N \l__hook_tmpa_bool
\tl_new:N \l__hook_return_tl
\tl_new:N \l__hook_tmpa_tl
\tl_new:N \l__hook_tmpb_tl
\seq_new:N \g__hook_all_seq
\tl_new:N \l__hook_cur_hook_tl
\prop_new:N \l__hook_work_prop
\prop_new:N \g__hook_used_prop
\tl_new:N \g__hook_hook_curr_name_tl
\seq_new:N \g__hook_name_stack_seq
\cs_new_eq:NN \__hook_tmp:w ?
\cs_generate_variant:Nn \tl_gremove_once:Nn { Nx }
\cs_generate_variant:Nn \tl_show:n { x }
\cs_generate_variant:Nn \tl_log:n { x }
\scan_new:N \s__hook_mark
\cs_new:Npn \__hook_clean_to_scan:w #1 \s__hook_mark { }
\cs_new_protected:Npn \__hook_tl_set:Nn #1#2
  { \cs_set_nopar:Npx #1 { \__kernel_exp_not:w {#2} } }
\cs_new_protected:Npn \__hook_tl_set:Nx #1#2
  { \cs_set_nopar:Npx #1 {#2} }
\cs_generate_variant:Nn \__hook_tl_set:Nn { c }
\cs_generate_variant:Nn \__hook_tl_set:Nx { c }
\cs_new_protected:Npn \__hook_tl_gset:Nn #1#2
  { \cs_gset_nopar:Npx #1 { \__kernel_exp_not:w {#2} } }
\cs_new_protected:Npn \__hook_tl_gset:No #1#2
  { \cs_gset_nopar:Npx #1 { \__kernel_exp_not:w \exp_after:wN {#2} } }
\cs_new_protected:Npn \__hook_tl_gset:Nx #1#2
  { \cs_gset_nopar:Npx #1 {#2} }
\cs_generate_variant:Nn \__hook_tl_gset:Nn { c }
\cs_generate_variant:Nn \__hook_tl_gset:No { c }
\cs_generate_variant:Nn \__hook_tl_gset:Nx { c }
\cs_new_protected:Npn \__hook_tl_gput_right:Nn #1#2
  { \__hook_tl_gset:Nx #1 { \__kernel_exp_not:w \exp_after:wN { #1 #2 } } }
\cs_generate_variant:Nn \__hook_tl_gput_right:Nn { No, cn }
\cs_new_protected:Npn \__hook_tl_gput_left:Nn #1#2
  {
    \__hook_tl_gset:Nx #1
      { \__kernel_exp_not:w {#2} \__kernel_exp_not:w \exp_after:wN {#1} }
  }
\cs_generate_variant:Nn \__hook_tl_gput_left:Nn { No }
\cs_new_eq:NN \__hook_tl_gset_eq:NN \tl_gset_eq:NN
\cs_new_protected:Npn \__hook_tl_gclear:N #1
  { \__hook_tl_gset_eq:NN #1 \c_empty_tl }
\cs_generate_variant:Nn \__hook_tl_gclear:N { c }


\cs_new_protected:Npn \hook_new:n #1
  { \__hook_normalize_hook_args:Nn \__hook_new:n {#1} }
\cs_new_protected:Npn \__hook_new:n #1
  {
    \__hook_if_declared:nTF {#1}
      { \msg_error:nnn { hooks } { exists } {#1} }
      {
        \tl_new:c { g__hook_#1_declared_tl }
        \__hook_make_usable:n {#1}
      }
  }
\cs_new_protected:Npn \__hook_make_usable:n #1
  {
    \tl_if_exist:cF { __hook~#1 }
      {
        \seq_gput_right:Nn \g__hook_all_seq {#1}
        \tl_new:c { __hook~#1 }
        \__hook_init_structure:n {#1}
        \clist_new:c { g__hook_#1_labels_clist }
        \tl_new:c { g__hook_#1_reversed_tl }
        \__hook_include_legacy_code_chunk:n {#1}
      }
  }
\cs_new_protected:Npn \__hook_init_structure:n #1
  {
    \__hook_if_structure_exist:nF {#1}
      {
        \prop_new:c { g__hook_#1_code_prop }
        \tl_new:c { __hook_toplevel~#1 }
        \tl_new:c { __hook_next~#1 }
      }
  }
\cs_new_protected:Npn \hook_new_reversed:n #1
  { \__hook_normalize_hook_args:Nn \__hook_new_reversed:n {#1} }
\cs_new_protected:Npn \__hook_new_reversed:n #1
  {
    \__hook_new:n {#1}
    \tl_gset:cn { g__hook_#1_reversed_tl } { - }
  }
\cs_new_protected:Npn \hook_new_pair:nn #1#2
  { \hook_new:n {#1} \hook_new_reversed:n {#2} }
\cs_new_protected:Npn \__hook_include_legacy_code_chunk:n #1
  {
    \tl_if_exist:cT { @#1hook }
      {
        \tl_if_empty:cF { @#1hook }
          {
            \exp_args:Nnnv \__hook_hook_gput_code_do:nnn {#1}
                                  { legacy } { @#1hook }
            \__hook_tl_gclear:c { @#1hook }
          }
      }
  }
\cs_new_protected:Npn \hook_disable_generic:n #1
  { \__hook_normalize_hook_args:Nn \__hook_disable:n {#1} }
\cs_new_protected:Npn \__hook_disable:n #1
  {
    \tl_gclear_new:c { g__hook_#1_declared_tl }
    \cs_undefine:c { __hook~#1 }
  }
\prg_new_conditional:Npnn \__hook_if_disabled:n #1 { p, T, F, TF }
  {
    \bool_lazy_and:nnTF
        { \tl_if_exist_p:c { g__hook_#1_declared_tl } }
        { ! \tl_if_exist_p:c { __hook~#1 } }
      { \prg_return_true: }
      { \prg_return_false: }
  }
\cs_new_protected:Npn \hook_activate_generic:n #1
  { \__hook_normalize_hook_args:Nn \__hook_activate_generic:nn {#1} {   } }
\cs_new_protected:Npn \__hook_activate_generic:nn #1 #2
  {
    \__hook_if_disabled:nTF {#1}
      { \msg_warning:nnn { hooks } { activate-disabled } {#1} }
      {
        \__hook_if_declared:nF {#1}
          {
            \tl_new:c { g__hook_#1_declared_tl }
            \__hook_make_usable:n {#1}
            \tl_gset:cx { g__hook_#1_reversed_tl }
              { \__hook_if_generic_reversed:nT {#1} { - } }
          }
      }
  }
\cs_new:Npn \__hook_parse_label_default:n #1
  {
    \tl_if_novalue:nTF {#1}
      { \__hook_currname_or_default: }
      { \tl_trim_spaces_apply:nN {#1} \__hook_parse_dot_label:n }
  }
\cs_new:Npn \__hook_parse_dot_label:n #1
  {
    \tl_if_empty:nTF {#1}
      {
        \msg_expandable_error:nn { hooks } { empty-label }
        \__hook_currname_or_default:
      }
      {
        \str_if_eq:nnTF {#1} { . }
          { \__hook_currname_or_default: }
          { \__hook_parse_dot_label:w #1 ./ \s__hook_mark }
      }
  }
\cs_new:Npn \__hook_parse_dot_label:w #1 ./ #2 \s__hook_mark
  {
    \tl_if_empty:nTF {#1}
      { \__hook_parse_dot_label_aux:w #2 \s__hook_mark }
      {
        \tl_if_empty:nTF {#2}
          { \__hook_make_name:n {#1} }
          { \__hook_parse_dot_label_cleanup:w #1 ./ #2 \s__hook_mark }
      }
  }
\cs_new:Npn \__hook_parse_dot_label_cleanup:w #1 ./ \s__hook_mark {#1}
\cs_new:Npn \__hook_parse_dot_label_aux:w #1 ./ \s__hook_mark
  { \__hook_currname_or_default: / \__hook_make_name:n {#1} }
\cs_new:Npn \__hook_currname_or_default:
  {
    \tl_if_empty:NTF \g__hook_hook_curr_name_tl
      {
        \tl_if_empty:NTF \@currname
          {
            \msg_expandable_error:nnn { latex2e } { should-not-happen }
              { Empty~default~label. }
            \__hook_make_name:n { label-missing }
          }
          { \@currname }
      }
      { \g__hook_hook_curr_name_tl }
  }
\cs_new:Npn \__hook_make_name:n #1
  {
    \exp_after:wN \exp_after:wN \exp_after:wN \__hook_make_name:w
    \exp_after:wN \token_to_str:N \cs:w __hook~ #1 \cs_end:
  }
\exp_last_unbraced:NNNNo
\cs_new:Npn \__hook_make_name:w #1 \tl_to_str:n { __hook~ } { }
\cs_new_protected:Npn \__hook_normalize_hook_args_aux:Nn #1 #2
  {
    \group_begin:
    \use:e
      {
        \group_end:
        \exp_not:N #1 #2
      }
  }
\cs_new_protected:Npn \__hook_normalize_hook_args:Nn #1 #2
  {
    \__hook_normalize_hook_args_aux:Nn #1
      { { \__hook_parse_label_default:n {#2} } }
  }
\cs_new_protected:Npn \__hook_normalize_hook_args:Nnn #1 #2 #3
  {
    \__hook_normalize_hook_args_aux:Nn #1
      {
        { \__hook_parse_label_default:n {#2} }
        { \__hook_parse_label_default:n {#3} }
      }
  }
\cs_new_protected:Npn \__hook_normalize_hook_rule_args:Nnnnn #1 #2 #3 #4 #5
  {
    \__hook_normalize_hook_args_aux:Nn #1
      {
        { \__hook_parse_label_default:n {#2} }
        { \__hook_parse_label_default:n {#3} }
        { \tl_trim_spaces:n {#4} }
        { \__hook_parse_label_default:n {#5} }
      }
  }
\tl_gset:Nn \g__hook_hook_curr_name_tl { top-level }
\cs_new_protected:Npn \__hook_curr_name_push:n #1
  { \exp_args:Nx \__hook_curr_name_push_aux:n { \__hook_make_name:n {#1} } }
\cs_new_protected:Npn \__hook_curr_name_push_aux:n #1
  {
    \tl_if_blank:nTF {#1}
      { \msg_error:nn { hooks } { no-default-label } }
      {
        \str_if_eq:nnTF {#1} { top-level }
          {
            \msg_error:nnnnn { hooks } { set-top-level }
              { to } { PushDefaultHookLabel } {#1}
          }
          {
            \seq_gpush:NV \g__hook_name_stack_seq \g__hook_hook_curr_name_tl
            \tl_gset:Nn \g__hook_hook_curr_name_tl {#1}
          }
      }
  }
\cs_new_protected:Npn \__hook_curr_name_pop:
  {
    \seq_gpop:NNTF \g__hook_name_stack_seq \l__hook_return_tl
      { \tl_gset_eq:NN \g__hook_hook_curr_name_tl \l__hook_return_tl }
      { \msg_error:nn { hooks } { extra-pop-label } }
  }
\tl_gput_right:Nn \@kernel@after@enddocument@afterlastpage
  { \__hook_end_document_label_check: }
\cs_new_protected:Npn \__hook_end_document_label_check:
  {
    \seq_gpop:NNT \g__hook_name_stack_seq \l__hook_return_tl
      {
        \msg_error:nnx { hooks } { missing-pop-label }
          { \g__hook_hook_curr_name_tl }
        \tl_gset_eq:NN \g__hook_hook_curr_name_tl \l__hook_return_tl
        \__hook_end_document_label_check:
      }
  }
\cs_new_protected:Npn \__hook_set_default_hook_label:n #1
  {
    \seq_if_empty:NTF \g__hook_name_stack_seq
      {
        \msg_error:nnnnn { hooks } { set-top-level }
          { for } { SetDefaultHookLabel } {#1}
      }
      { \exp_args:Nx \__hook_set_default_label:n { \__hook_make_name:n {#1} } }
  }
\cs_new_protected:Npn \__hook_set_default_label:n #1
  {
    \str_if_eq:nnTF {#1} { top-level }
      {
        \msg_error:nnnnn { hooks } { set-top-level }
          { to } { SetDefaultHookLabel } {#1}
      }
      { \tl_gset:Nn \g__hook_hook_curr_name_tl {#1} }
  }
\cs_new_protected:Npn \hook_gput_code:nnn #1 #2
  { \__hook_normalize_hook_args:Nnn \__hook_gput_code:nnn {#1} {#2} }
\cs_new_protected:Npn \__hook_gput_code:nnn #1 #2 #3
  {
    \__hook_if_execute_immediately:nTF {#1}
      {#3}
      {
        \__hook_if_usable:nTF {#1}
          {
            \__hook_hook_gput_code_do:nnn {#1} {#2} {#3}
            \__hook_update_hook_code:n {#1}
          }
          {
            \__hook_if_disabled:nTF {#1}
              { \msg_error:nnn { hooks } { hook-disabled } {#1} }
              { \__hook_try_declaring_generic_hook:nnn {#1} {#2} {#3} }
          }
      }
  }
\cs_new_protected:Npn \__hook_hook_gput_code_do:nnn #1 #2 #3
  {
    \__hook_debug:n{\iow_term:x{****~ Add~ to~
                      \__hook_if_usable:nF {#1} { undeclared~ }
                      hook~ #1~ (#2)
                      \on@line\space <-~ \tl_to_str:n{#3}} }
    \str_if_eq:nnTF {#2} { top-level }
      {
        \str_if_eq:eeTF { top-level } { \__hook_currname_or_default: }
          {
            \__hook_init_structure:n {#1}
            \__hook_tl_gput_right:cn { __hook_toplevel~#1 } {#3}
          }
          { \msg_error:nnn { hooks } { misused-top-level } {#1} }
      }
      {
        \prop_get:cnNTF { g__hook_#1_code_prop } {#2} \l__hook_return_tl
          {
            \prop_gput:cno { g__hook_#1_code_prop } {#2}
              { \l__hook_return_tl #3 }
          }
          { \prop_gput:cnn { g__hook_#1_code_prop } {#2} {#3} }
      }
  }
\cs_new_protected:Npn \__hook_gput_undeclared_hook:nnn #1 #2 #3
  {
    \__hook_init_structure:n {#1}
    \__hook_hook_gput_code_do:nnn {#1} {#2} {#3}
  }
\cs_new_protected:Npn \__hook_try_declaring_generic_hook:nnn #1
  {
    \__hook_try_declaring_generic_hook:wnTF #1 / / / \scan_stop: {#1}
      \hook_gput_code:nnn
      \__hook_gput_undeclared_hook:nnn
        {#1}
  }
\cs_new_protected:Npn \__hook_try_declaring_generic_next_hook:nn #1
  {
    \__hook_try_declaring_generic_hook:wnTF #1 / / / \scan_stop: {#1}
      \hook_gput_next_code:nn
      \__hook_gput_next_do:nn
        {#1}
  }
\prg_new_protected_conditional:Npnn \__hook_try_declaring_generic_hook:wn
    #1 / #2 / #3 / #4 \scan_stop: #5 { TF }
  {
    \__hook_if_generic:nTF {#5}
      {
        \__hook_if_usable:nF {#5}
          {
            \str_if_eq:nnT {#1} { cmd }
              { \__hook_try_put_cmd_hook:n {#5} }
            \__hook_make_usable:n {#5}
          }
        \__hook_if_generic_reversed:nT {#5}
          { \tl_gset:cn { g__hook_#5_reversed_tl } { - } }
        \prg_return_true:
      }
      {
        \__hook_if_deprecated_generic:nTF {#5}
          {
            \__hook_deprecated_generic_warn:n {#5}
            \exp_after:wN \__hook_declare_deprecated_generic:NNn
            \exp:w % \exp_end:
          }
          { \prg_return_false: }
      }
  }
\cs_new_protected:Npn \__hook_deprecated_generic_warn:n #1
  { \__hook_deprecated_generic_warn:w #1 \s__hook_mark }
\cs_new_protected:Npn \__hook_deprecated_generic_warn:w
    #1 / #2 / #3 \s__hook_mark
  {
    \if_cs_exist:w __hook~#1/#2/#3 \cs_end: \else:
      \msg_warning:nnnnn { hooks } { generic-deprecated } {#1} {#2} {#3}
    \fi:
    \cs_gset_eq:cN { __hook~#1/#2/#3 } \scan_stop:
  }
\cs_new_protected:Npn \__hook_do_deprecated_generic:Nn #1 #2
  { \__hook_do_deprecated_generic:Nw #1 #2 \s__hook_mark }
\cs_new_protected:Npn \__hook_do_deprecated_generic:Nw #1
         #2 / #3 / #4 \s__hook_mark
  { #1 { #2 / #4 / #3 } }
\cs_new_protected:Npn \__hook_declare_deprecated_generic:NNn #1 #2 #3
  { \__hook_declare_deprecated_generic:NNw #1 #2 #3 \s__hook_mark }
\cs_new_protected:Npn \__hook_declare_deprecated_generic:NNw #1 #2
    #3 / #4 / #5 \s__hook_mark
  {
    \__hook_try_declaring_generic_hook:wnTF #3 / #5 / #4 / \scan_stop:
        { #3 / #5 / #4 }
      #1 #2 { #3 / #5 / #4 }
  }
\prg_new_conditional:Npnn \__hook_if_file_hook:w
    #1 / #2 \s__hook_mark #3 { TF }
  {
    \__hook_if_generic:nTF {#3}
      {
        \str_if_eq:nnTF {#1} { file }
          { \prg_return_true: }
          { \prg_return_false: }
      }
      { \prg_return_false: }
  }
\clist_map_inline:nn { cmd , env , file , package , class , include }
  {
    \tl_const:cn { c__hook_generic_#1/./before_tl } { + }
    \tl_const:cn { c__hook_generic_#1/./after_tl  } { - }
  }
\tl_const:cn { c__hook_generic_env/./begin_tl } { + }
\tl_const:cn { c__hook_generic_env/./end_tl   } { + }
\tl_const:cn { c__hook_generic_include/./end_tl } { - }
\clist_map_inline:nn { file , package , class , include }
  {
    \tl_const:cn { c__hook_deprecated_#1/./before_tl } { }
    \tl_const:cn { c__hook_deprecated_#1/./after_tl  } { }
  }
\tl_const:cn { c__hook_deprecated_include/./end_tl } { }
\cs_new_protected:Npn \hook_gremove_code:nn #1 #2
  { \__hook_normalize_hook_args:Nnn \__hook_gremove_code:nn {#1} {#2} }
\cs_new_protected:Npn \__hook_gremove_code:nn #1 #2
  {
    \__hook_if_structure_exist:nTF {#1}
      {
        \str_if_eq:nnTF {#2} {*}
          {
            \prop_gclear:c { g__hook_#1_code_prop }
            \__hook_tl_gclear:c { __hook_toplevel~#1 }
            \__hook_tl_gclear:c { __hook_next~#1 }
          }
          {
            \str_if_eq:nnTF {#2} { top-level }
              { \__hook_tl_gclear:c { __hook_toplevel~#1 } }
              {
                \prop_gpop:cnNF { g__hook_#1_code_prop } {#2} \l__hook_return_tl
                  { \msg_warning:nnnn { hooks } { cannot-remove } {#1} {#2} }
              }
          }
        \__hook_if_usable:nT {#1}
          { \__hook_update_hook_code:n {#1} }
      }
      {
        \__hook_if_deprecated_generic:nTF {#1}
          {
            \__hook_deprecated_generic_warn:n {#1}
            \__hook_do_deprecated_generic:Nn \__hook_gremove_code:nn {#1} {#2}
          }
          { \msg_warning:nnnn { hooks } { cannot-remove } {#1} {#2} }
      }
  }
\prop_new:c {g__hook_??_code_prop}
\prop_new:c {__hook~??}
\tl_new:c {g__hook_??_reversed_tl}
\cs_new_protected:Npn \hook_gset_rule:nnnn #1#2#3#4
  {
    \__hook_normalize_hook_rule_args:Nnnnn \__hook_gset_rule:nnnn
      {#1} {#2} {#3} {#4}
  }
\cs_new_protected:Npn \__hook_gset_rule:nnnn #1#2#3#4
  {
    \__hook_if_deprecated_generic:nT {#1}
      {
        \__hook_deprecated_generic_warn:n {#1}
        \__hook_do_deprecated_generic:Nn \__hook_gset_rule:nnnn {#1}
          {#2} {#3} {#4}
        \exp_after:wN \use_none:nnnnnnnnn \use_none:n
      }
    \__hook_init_structure:n {#1}
    \__hook_rule_gclear:nnn {#1} {#2} {#4}
    \cs_if_exist_use:cTF { __hook_rule_#3_gset:nnn }
      {
          {#1} {#2} {#4}
        \__hook_update_hook_code:n {#1}
      }
      { \msg_error:nnnnnn { hooks } { unknown-rule }
                          {#1} {#2} {#3} {#4}        }
  }
\cs_new_protected:Npn \__hook_rule_before_gset:nnn #1#2#3
  {
    \__hook_tl_gset:cx { g__hook_#1_rule_ \__hook_label_pair:nn {#2} {#3} _tl }
      { \__hook_label_ordered:nnTF {#2} {#3} { < } { > } }
  }
\cs_new_eq:cN { __hook_rule_<_gset:nnn } \__hook_rule_before_gset:nnn
\cs_new_protected:Npn \__hook_rule_after_gset:nnn #1#2#3
  {
    \__hook_tl_gset:cx { g__hook_#1_rule_ \__hook_label_pair:nn {#3} {#2} _tl }
      { \__hook_label_ordered:nnTF {#3} {#2} { < } { > } }
  }
\cs_new_eq:cN { __hook_rule_>_gset:nnn } \__hook_rule_after_gset:nnn
\cs_new_protected:Npn \__hook_rule_voids_gset:nnn #1#2#3
  {
    \__hook_tl_gset:cx { g__hook_#1_rule_ \__hook_label_pair:nn {#2} {#3} _tl }
      { \__hook_label_ordered:nnTF {#2} {#3} { -> } { <- } }
  }
\cs_new_protected:cpn { __hook_rule_incompatible-error_gset:nnn } #1#2#3
  { \__hook_tl_gset:cn { g__hook_#1_rule_ \__hook_label_pair:nn {#2} {#3} _tl }
                   { xE } }
\cs_new_protected:cpn { __hook_rule_incompatible-warning_gset:nnn } #1#2#3
  { \__hook_tl_gset:cn { g__hook_#1_rule_ \__hook_label_pair:nn {#2} {#3} _tl }
                   { xW } }
\cs_new_protected:Npn \__hook_rule_unrelated_gset:nnn #1#2#3 { }
\cs_new_protected:Npn \__hook_rule_gclear:nnn #1#2#3
  { \cs_undefine:c { g__hook_#1_rule_ \__hook_label_pair:nn {#2} {#3} _tl } }
\cs_new:Npn \__hook_label_pair:nn #1#2
  {
    \if_case:w \__hook_str_compare:nn {#1} {#2} \exp_stop_f:
           #1 | #1 %  0
    \or:   #1 | #2 % +1
    \else: #2 | #1 % -1
    \fi:
  }
\prg_new_conditional:Npnn \__hook_label_ordered:nn #1#2 { TF }
  {
    \if_int_compare:w \__hook_str_compare:nn {#1} {#2} > 0 \exp_stop_f:
      \prg_return_true:
    \else:
      \prg_return_false:
    \fi:
  }
\cs_new:Npn \__hook_if_label_case:nnnnn #1#2
  {
    \cs:w use_
      \if_case:w \__hook_str_compare:nn {#1} {#2}
         i \or: ii \else: iii \fi: :nnn
    \cs_end:
  }
\cs_new_eq:NN \__hook_update_hook_code:n \use_none:n
\cs_new_protected:Npn \__hook_initialize_all: {
  \cs_gset_eq:NN \__hook_update_hook_code:n \__hook_initialize_hook_code:n
  \__hook_debug:n { \prop_gclear:N \g__hook_used_prop }
  \seq_map_inline:Nn \g__hook_all_seq
      {
        \__hook_update_hook_code:n {##1}
      }
  \__hook_debug:n
     { \iow_term:x{^^JAll~ initialized~ (non-empty)~ hooks:}
       \prop_map_inline:Nn \g__hook_used_prop
           { \iow_term:x{^^J~ ##1~ ->~
               \exp_not:v {__hook~##1}~ }
           }
     }
  \cs_gset_eq:NN \hook_use:n \__hook_use_initialized:n
  \cs_gset_eq:NN \__hook_preamble_hook:n \use_none:n
}
\cs_new_protected:Npn \__hook_initialize_hook_code:n #1
  {
    \__hook_debug:n{ \iow_term:x{^^JUpdate~ code~ for~ hook~
                                    '#1' \on@line :^^J} }
    \__hook_include_legacy_code_chunk:n {#1}
    \__hook_if_usable:nT {#1}
      {
        \prop_if_empty:cTF { g__hook_#1_code_prop }
          {
            \__hook_tl_gset:co { __hook~#1 }
              {
                \cs:w __hook_toplevel~#1 \exp_after:wN \cs_end:
                \cs:w __hook_next~#1 \cs_end:
              }
          }
          {
            \__hook_if_reversed:nTF {#1}
              { \cs_set_eq:NN \__hook_tl_gput:Nn    \__hook_tl_gput_left:Nn
                \cs_set_eq:NN \__hook_clist_gput:NV \clist_gput_left:NV  }
              { \cs_set_eq:NN \__hook_tl_gput:Nn    \__hook_tl_gput_right:Nn
                \cs_set_eq:NN \__hook_clist_gput:NV \clist_gput_right:NV }
            \prop_set_eq:Nc \l__hook_work_prop { g__hook_#1_code_prop }
            \__hook_initialize_single:ccn
              { __hook~#1 } { g__hook_#1_labels_clist } {#1}
            \__hook_debug:n{ \exp_args:NNx \prop_gput:Nnn
                                       \g__hook_used_prop {#1}{} }
          }
      }
  }
\cs_new:Npn \__hook_tl_csname:n #1 { l__hook_label_#1_tl }
\cs_new:Npn \__hook_seq_csname:n #1 { l__hook_label_#1_seq }
\seq_new:N \l__hook_labels_seq
\int_new:N \l__hook_labels_int
\tl_new:N \l__hook_front_tl
\tl_new:N \l__hook_rear_tl
\tl_new:c { \__hook_tl_csname:n { 0 } }
\cs_new_protected:Npn \__hook_initialize_single:NNn #1#2#3
  {
    \seq_clear:N \l__hook_labels_seq
    \int_zero:N  \l__hook_labels_int
    \tl_set:Nn \l__hook_cur_hook_tl {#3}
    \prop_map_inline:Nn \l__hook_work_prop
       {
         \int_incr:N \l__hook_labels_int
         \seq_put_right:Nn \l__hook_labels_seq {##1}
         \__hook_tl_set:cn { \__hook_tl_csname:n {##1} } { 0 }
         \seq_clear_new:c { \__hook_seq_csname:n {##1} }
       }
    \prop_map_inline:Nn \l__hook_work_prop
      {
        \prop_map_inline:Nn \l__hook_work_prop
          {
            \__hook_if_label_case:nnnnn {##1} {####1}
              { \prop_map_break: }
              { \__hook_apply_label_pair:nnn {##1} {####1} }
              { \__hook_apply_label_pair:nnn {####1} {##1} }
                  {#3}
          }
      }
    \__hook_debug:n { \__hook_debug_label_data:N \l__hook_work_prop }
    \tl_set:Nn \l__hook_rear_tl { 0 }
    \tl_set:cn { \__hook_tl_csname:n { 0 } } { 0 }
    \seq_map_inline:Nn \l__hook_labels_seq
      {
        \int_compare:nNnT { \cs:w \__hook_tl_csname:n {##1} \cs_end: } = 0
            {
              \tl_set:cn { \__hook_tl_csname:n { \l__hook_rear_tl } }{##1}
              \tl_set:Nn \l__hook_rear_tl {##1}
            }
      }
    \tl_set_eq:Nc \l__hook_front_tl { \__hook_tl_csname:n { 0 } }
    \__hook_tl_gclear:N #1
    \clist_gclear:N #2
    \bool_while_do:nn { ! \str_if_eq_p:Vn \l__hook_front_tl { 0 } }
      {
        \int_decr:N \l__hook_labels_int
        \prop_get:NVN \l__hook_work_prop \l__hook_front_tl \l__hook_return_tl
        \exp_args:NNV \__hook_tl_gput:Nn #1 \l__hook_return_tl
        \__hook_clist_gput:NV #2 \l__hook_front_tl
        \__hook_debug:n{ \iow_term:x{Handled~ code~ for~ \l__hook_front_tl} }
        \seq_map_inline:cn { \__hook_seq_csname:n { \l__hook_front_tl } }
          {
            \tl_set:cx { \__hook_tl_csname:n {##1} }
                       { \int_eval:n
                           { \cs:w \__hook_tl_csname:n {##1} \cs_end: - 1 }
                       }
            \int_compare:nNnT
                { \cs:w \__hook_tl_csname:n {##1} \cs_end: } = 0
                {
                  \tl_set:cn { \__hook_tl_csname:n { \l__hook_rear_tl } } {##1}
                  \tl_set:Nn \l__hook_rear_tl            {##1}
                }
          }
        \tl_set_eq:Nc \l__hook_front_tl
                      { \__hook_tl_csname:n { \l__hook_front_tl } }
      }
    \int_compare:nNnF \l__hook_labels_int = 0
      {
        \iow_term:x{====================}
        \iow_term:x{Error:~ label~ rules~ are~ incompatible:}
        \__hook_debug_label_data:N \l__hook_work_prop
        \iow_term:x{====================}
      }
    \exp_args:NNo \__hook_tl_gput:Nn #1 { \cs:w __hook_toplevel~#3 \cs_end: }
    \__hook_tl_gput_right:No #1 { \cs:w __hook_next~#3 \cs_end: }
  }
\cs_generate_variant:Nn \__hook_initialize_single:NNn { cc }
\cs_new:Npn \__hook_tl_gput:Nn    { \ERROR }
\cs_new:Npn \__hook_clist_gput:NV { \ERROR }
\cs_new_protected:Npn \__hook_apply_label_pair:nnn #1#2#3
  {
    \__hook_label_if_exist_apply:nnnF {#1} {#2} {#3}
      {
        \__hook_label_if_exist_apply:nnnF {#1} {#2} { ?? } { }
      }
  }
\cs_new_protected:Npn \__hook_label_if_exist_apply:nnnF #1#2#3
  {
    \if_cs_exist:w g__hook_ #3 _rule_ #1 | #2 _tl \cs_end:
      \__hook_apply_rule:nnn {#1} {#2} {#3}
      \exp_after:wN \use_none:n
    \else:
      \use:nn
    \fi:
  }
\cs_new_protected:Npn \__hook_apply_rule:nnn #1#2#3
  {
    \cs:w __hook_apply_
      \cs:w g__hook_#3_reversed_tl \cs_end: rule_
        \cs:w g__hook_ #3 _rule_ #1 | #2 _tl \cs_end: :nnn \cs_end:
      {#1} {#2} {#3}
  }
\cs_new_protected:cpn { __hook_apply_rule_<:nnn } #1#2#3
  {
    \__hook_debug:n { \__hook_msg_pair_found:nnn {#1} {#2} {#3} }
    \tl_set:cx { \__hook_tl_csname:n {#2} }
       { \int_eval:n{ \cs:w \__hook_tl_csname:n {#2} \cs_end: + 1 } }
    \seq_put_right:cn{ \__hook_seq_csname:n {#1} }{#2}
  }
\cs_new_protected:cpn { __hook_apply_rule_>:nnn } #1#2#3
  {
    \__hook_debug:n { \__hook_msg_pair_found:nnn {#1} {#2} {#3} }
    \tl_set:cx { \__hook_tl_csname:n {#1} }
       { \int_eval:n{ \cs:w \__hook_tl_csname:n {#1} \cs_end: + 1 } }
    \seq_put_right:cn{ \__hook_seq_csname:n {#2} }{#1}
  }
\cs_new_protected:cpn { __hook_apply_rule_xE:nnn } #1#2#3
  {
    \__hook_debug:n { \__hook_msg_pair_found:nnn {#1} {#2} {#3} }
    \msg_error:nnnnnn { hooks } { labels-incompatible }
      {#1} {#2} {#3} { 1 }
    \use:c { __hook_apply_rule_->:nnn } {#1} {#2} {#3}
    \use:c { __hook_apply_rule_<-:nnn } {#1} {#2} {#3}
  }
\cs_new_protected:cpn { __hook_apply_rule_xW:nnn } #1#2#3
  {
    \__hook_debug:n { \__hook_msg_pair_found:nnn {#1} {#2} {#3} }
    \msg_warning:nnnnnn { hooks } { labels-incompatible }
      {#1} {#2} {#3} { 0 }
  }
\cs_new_protected:cpn { __hook_apply_rule_->:nnn } #1#2#3
  {
    \__hook_debug:n
       {
         \__hook_msg_pair_found:nnn {#1} {#2} {#3}
         \iow_term:x{--->~ Drop~ '#2'~ code~ from~
           \iow_char:N \\ g__hook_ \l__hook_cur_hook_tl _code_prop ~
           because~ of~ '#1' }
       }
    \prop_put:Nnn \l__hook_work_prop {#2} { }
  }
\cs_new_protected:cpn { __hook_apply_rule_<-:nnn } #1#2#3
  {
    \__hook_debug:n
       {
         \__hook_msg_pair_found:nnn {#1} {#2} {#3}
         \iow_term:x{--->~ Drop~ '#1'~ code~ from~
           \iow_char:N \\ g__hook_ \l__hook_cur_hook_tl _code_prop ~
           because~ of~ '#2' }
       }
    \prop_put:Nnn \l__hook_work_prop {#1} { }
  }
\cs_new_eq:cc { __hook_apply_-rule_<:nnn  } { __hook_apply_rule_>:nnn }
\cs_new_eq:cc { __hook_apply_-rule_>:nnn  } { __hook_apply_rule_<:nnn }
\cs_new_eq:cc { __hook_apply_-rule_<-:nnn } { __hook_apply_rule_<-:nnn }
\cs_new_eq:cc { __hook_apply_-rule_->:nnn } { __hook_apply_rule_->:nnn }
\cs_new_eq:cc { __hook_apply_-rule_xE:nnn  } { __hook_apply_rule_xE:nnn }
\cs_new_eq:cc { __hook_apply_-rule_xW:nnn  } { __hook_apply_rule_xW:nnn }
\cs_new_protected:Npn \__hook_msg_pair_found:nnn #1#2#3
  {
    \iow_term:x{~ \str_if_eq:nnTF {#3} {??} {default} {~normal} ~
        rule~ \__hook_label_pair:nn {#1} {#2}:~
        \use:c { g__hook_#3_rule_ \__hook_label_pair:nn {#1} {#2} _tl } ~
        found}
  }
\cs_new_protected:Npn \__hook_debug_label_data:N #1 {
  \iow_term:x{Code~ labels~ for~ sorting:}
  \iow_term:x{~ \seq_use:Nnnn\l__hook_labels_seq {~and~}{,~}{~and~} }
  \iow_term:x{^^J Data~ structure~ for~ label~ rules:}
  \prop_map_inline:Nn #1
       {
         \iow_term:x{~ ##1~ =~ \tl_use:c{ \__hook_tl_csname:n {##1} }~ ->~
           \seq_use:cnnn{ \__hook_seq_csname:n {##1} }{~->~}{~->~}{~->~}
         }
       }
  \iow_term:x{}
}
\cs_new_protected:Npn \hook_log:n #1
  {
    \cs_set_eq:NN \__hook_log_cmd:x \iow_log:x
    \__hook_normalize_hook_args:Nn \__hook_log:nN {#1} \tl_log:x
  }
\cs_new_protected:Npn \hook_show:n #1
  {
    \cs_set_eq:NN \__hook_log_cmd:x \iow_term:x
    \__hook_normalize_hook_args:Nn \__hook_log:nN {#1} \tl_show:x
  }
\cs_new_protected:Npn \__hook_log_line:x #1
  { \__hook_log_cmd:x { >~#1 } }
\cs_new_protected:Npn \__hook_log_line_indent:x #1
  { \__hook_log_cmd:x { >~\@spaces #1 } }
\cs_new_protected:Npn \__hook_log:nN #1 #2
  {
    \__hook_if_deprecated_generic:nT {#1}
      {
        \__hook_deprecated_generic_warn:n {#1}
        \__hook_do_deprecated_generic:Nn \__hook_log:nN {#1} #2
        \exp_after:wN \use_none:nnnnnnnnn \use_none:nnnnn
      }
    \__hook_preamble_hook:n {#1}
    \__hook_log_cmd:x
      { ^^J ->~The~ \__hook_if_generic:nT {#1} { generic~ } hook~'#1': }
    \__hook_if_usable:nF {#1}
      { \__hook_log_line:x { The~hook~is~not~declared. } }
    \__hook_if_disabled:nT {#1}
      { \__hook_log_line:x { The~hook~is~disabled. } }
    \hook_if_empty:nTF {#1}
      { #2 { The~hook~is~empty } }
      {
        \__hook_log_line:x { Code~chunks: }
        \prop_if_empty:cTF { g__hook_#1_code_prop }
          { \__hook_log_line_indent:x { --- } }
          {
            \prop_map_inline:cn { g__hook_#1_code_prop }
              { \__hook_log_line_indent:x { ##1~->~\tl_to_str:n {##2} } }
          }
        \__hook_log_line:x
          {
            Document-level~(top-level)~code
            \__hook_if_usable:nT {#1}
              { ~(executed~\__hook_if_reversed:nTF {#1} {first} {last} ) } :
          }
        \__hook_log_line_indent:x
          {
            \tl_if_empty:cTF { __hook_toplevel~#1 }
              { --- }
              { -> ~ \exp_args:Nv \tl_to_str:n { __hook_toplevel~#1 } }
          }
        \__hook_log_line:x { Extra~code~for~next~invocation: }
        \__hook_log_line_indent:x
          {
            \tl_if_empty:cTF { __hook_next~#1 }
              { --- }
              { ->~ \exp_args:Nv \__hook_log_next_code:n { __hook_next~#1 } }
          }
        \__hook_log_line:x { Rules: }
        \bool_set_true:N \l__hook_tmpa_bool
        \__hook_list_rules:nn {#1}
          {
            \bool_set_false:N \l__hook_tmpa_bool
            \__hook_log_line_indent:x
              {
                ##2~ with~
                \str_if_eq:nnT {##3} {??} { default~ }
                relation~ ##1
              }
          }
        \bool_if:NT \l__hook_tmpa_bool
          { \__hook_log_line_indent:x { --- } }
        \bool_lazy_and:nnTF
            { \__hook_if_usable_p:n {#1} }
            { ! \hook_if_empty_p:n {#1} }
          {
            \__hook_log_line:x
              {
                Execution~order
                \bool_if:NTF \l__hook_tmpa_bool
                  { \__hook_if_reversed:nT {#1} { ~(after~reversal) } }
                  { ~(after~
                    \__hook_if_reversed:nT {#1} { reversal~and~ }
                    applying~rules)
                  } :
              }
            #2 % \tl_show:n
              {
                \@spaces
                \clist_if_empty:cTF { g__hook_#1_labels_clist }
                  { --- }
                  { \clist_use:cn {g__hook_#1_labels_clist} { ,~ } }
              }
          }
          {
            \__hook_log_line:x { Execution~order: }
            #2
              {
                \@spaces Not~set~because~the~hook~ \__hook_if_usable:nTF {#1}
                  { code~pool~is~empty }
                  { is~\__hook_if_disabled:nTF {#1} {disabled} {undeclared} }
              }
          }
      }
  }
\cs_new:Npn \__hook_log_next_code:n #1
  { \exp_args:No \tl_to_str:n { \use_none:nn #1 } }
\cs_new_protected:Npn \__hook_list_rules:nn #1 #2
  {
    \cs_set_protected:Npn \__hook_tmp:w ##1 ##2 ##3 {#2}
    \prop_map_inline:cn { g__hook_#1_code_prop }
      {
        \prop_map_inline:cn { g__hook_#1_code_prop }
          {
            \__hook_if_label_case:nnnnn {##1} {####1}
              { \prop_map_break: }
              { \__hook_list_one_rule:nnn {##1} {####1} }
              { \__hook_list_one_rule:nnn {####1} {##1} }
                  {#1}
          }
      }
  }
\cs_new_protected:Npn \__hook_list_one_rule:nnn #1#2#3
  {
    \__hook_list_if_rule_exists:nnnF {#1} {#2} {#3}
      { \__hook_list_if_rule_exists:nnnF {#1} {#2} { ?? } { } }
  }
\cs_new_protected:Npn \__hook_list_if_rule_exists:nnnF #1#2#3
  {
    \if_cs_exist:w g__hook_ #3 _rule_ #1 | #2 _tl \cs_end:
      \exp_args:Nv \__hook_tmp:w
        { g__hook_ #3 _rule_ #1 | #2 _tl } { #1 | #2 } {#3}
      \exp_after:wN \use_none:nn
    \fi:
    \use:n
  }
\cs_new_protected:Npn \__hook_debug_print_rules:n #1
  {
    \iow_term:n { The~hook~#1~contains~the~rules: }
    \cs_set_protected:Npn \__hook_tmp:w ##1
      {
        \__hook_list_rules:nn {#1}
          {
            \iow_term:x
              {
                > ##1 {####2} ##1 => ##1 {####1}
                \str_if_eq:nnT {####3} {??} { ~(default) }
              }
          }
      }
    \exp_args:No \__hook_tmp:w { \use:nn { ~ } { ~ } }
  }
\cs_new_protected:Npn \hook_gput_next_code:nn #1
  { \__hook_normalize_hook_args:Nn \__hook_gput_next_code:nn {#1} }
\cs_new_protected:Npn \__hook_gput_next_code:nn #1 #2
  {
    \__hook_if_disabled:nTF {#1}
      { \msg_error:nnn { hooks } { hook-disabled } {#1} }
      {
        \__hook_if_structure_exist:nTF {#1}
          { \__hook_gput_next_do:nn {#1} {#2} }
          { \__hook_try_declaring_generic_next_hook:nn {#1} {#2} }
      }
  }
\cs_new_protected:Npn \__hook_gput_next_do:nn #1
  {
    \exp_args:Nc \__hook_gput_next_do:Nnn
      { __hook_next~#1 } {#1}
  }
\cs_new_protected:Npn \__hook_gput_next_do:Nnn #1 #2
  {
    \tl_if_empty:cT { __hook~#2 }
      { \__hook_update_hook_code:n {#2} }
    \tl_if_empty:NT #1
      { \__hook_tl_gset:Nn #1 { \__hook_clear_next:n {#2} } }
    \__hook_tl_gput_right:Nn #1
  }
\cs_new_protected:Npn \hook_gclear_next_code:n #1
  { \__hook_normalize_hook_args:Nn \__hook_clear_next:n {#1} }
\cs_new_protected:Npn \__hook_clear_next:n #1
  { \cs_gset_eq:cN { __hook_next~#1 } \c_empty_tl }
\cs_new_protected:Npn \hook_use:n #1
  {
    \tl_if_exist:cT { __hook~#1 }
      {
        \__hook_preamble_hook:n {#1}
        \cs:w __hook~#1 \cs_end:
      }
  }
\cs_new:Npn \__hook_use_initialized:n #1
  {
    \if_cs_exist:w __hook~#1 \cs_end:
      \cs:w __hook~#1 \exp_after:wN \cs_end:
    \fi:
  }
\cs_new_protected:Npn \__hook_preamble_hook:n #1
  { \__hook_initialize_hook_code:n {#1} }
\cs_new_protected:Npn \hook_use_once:n #1
  {
    \__hook_if_execute_immediately:nF {#1}
      { \__hook_normalize_hook_args:Nn \__hook_use_once:n { \use:n {#1} } }
  }
\cs_new_protected:Npn \__hook_use_once:n #1
  {
    \__hook_preamble_hook:n {#1}
    \__hook_use_once_set:n {#1}
    \__hook_use_initialized:n {#1}
    \__hook_use_once_clear:n {#1}
  }
\cs_new_protected:Npn \__hook_use_once_set:n #1
  { \__hook_tl_gset:cn { g__hook_#1_reversed_tl } { I } }
\cs_new_protected:Npn \__hook_use_once_clear:n #1
  {
    \__hook_tl_gclear:c { __hook~#1 }
    \__hook_tl_gclear:c { __hook_next~#1 }
    \__hook_tl_gclear:c { __hook_toplevel~#1 }
    \prop_gclear:c { g__hook_#1_code_prop }
  }
\prg_new_conditional:Npnn \__hook_if_execute_immediately:n #1 { F, TF }
  {
    \__hook_if_usable:nTF {#1}
      {
        \exp_after:wN \__hook_clean_to_scan:w
        \if:w I \cs:w g__hook_#1_reversed_tl \cs_end:
          \s__hook_mark \prg_return_true:
        \else:
          \s__hook_mark \prg_return_false:
        \fi:
      }
      { \prg_return_false: }
  }

\prg_new_conditional:Npnn \hook_if_empty:n #1 { p , T , F , TF }
  {
    \__hook_if_structure_exist:nTF {#1}
      {
        \bool_lazy_and:nnTF
            { \prop_if_empty_p:c { g__hook_#1_code_prop } }
            {
              \bool_lazy_and_p:nn
                { \tl_if_empty_p:c { __hook_toplevel~#1 } }
                { \tl_if_empty_p:c { __hook_next~#1 } }
            }
          { \prg_return_true: }
          { \prg_return_false: }
      }
      { \prg_return_true: }
  }
\prg_new_conditional:Npnn \__hook_if_usable:n #1 { p , T , F , TF }
  {
    \tl_if_exist:cTF { __hook~#1 }
      { \prg_return_true: }
      { \prg_return_false: }
  }
\prg_new_conditional:Npnn \__hook_if_structure_exist:n #1 { p , T , F , TF }
  {
    \prop_if_exist:cTF { g__hook_#1_code_prop }
      { \prg_return_true: }
      { \prg_return_false: }
  }
\prg_new_conditional:Npnn \__hook_if_declared:n #1 { p, T, F, TF }
  {
    \tl_if_exist:cTF { g__hook_#1_declared_tl }
      { \prg_return_true: }
      { \prg_return_false: }
  }
\prg_new_conditional:Npnn \__hook_if_reversed:n #1 { p , T , F , TF }
  {
    \exp_after:wN \__hook_clean_to_scan:w
    \if:w - \cs:w g__hook_#1_reversed_tl \cs_end:
      \s__hook_mark \prg_return_true:
    \else:
      \s__hook_mark \prg_return_false:
    \fi:
  }
\prg_new_conditional:Npnn \__hook_if_generic:n #1 { T, TF }
  { \__hook_if_generic:w #1 / / / \s__hook_mark }
\cs_new:Npn \__hook_if_generic:w #1 / #2 / #3 / #4 \s__hook_mark
  {
    \cs_if_exist:cTF { c__hook_generic_#1/./#3_tl }
      { \prg_return_true: }
      { \prg_return_false: }
  }
\prg_new_conditional:Npnn \__hook_if_deprecated_generic:n #1 { T, TF }
  { \__hook_if_deprecated_generic:w #1 / / / \s__hook_mark }
\cs_new:Npn \__hook_if_deprecated_generic:w #1 / #2 / #3 / #4 \s__hook_mark
  {
    \cs_if_exist:cTF { c__hook_deprecated_#1/./#2_tl }
      {
        \tl_if_empty:nTF {#3}
          { \prg_return_false: }
          { \prg_return_true: }
      }
      { \prg_return_false: }
  }
\prg_new_conditional:Npnn \__hook_if_generic_reversed:n #1 { T }
  { \__hook_if_generic_reversed:w #1 / / / \scan_stop: }
\cs_new:Npn \__hook_if_generic_reversed:w #1 / #2 / #3 / #4 \scan_stop:
  {
    \if_charcode:w - \cs:w c__hook_generic_#1/./#3_tl \cs_end:
      \prg_return_true:
    \else:
      \prg_return_false:
    \fi:
  }
\prop_gput:Nnn \g_msg_module_type_prop { hooks } { LaTeX }
\prop_gput:Nnn \g_msg_module_type_prop { latex2e } { LaTeX }
\prop_gput:Nnn \g_msg_module_name_prop { latex2e } { kernel }
\msg_new:nnnn { hooks } { labels-incompatible }
  {
    Labels~'#1'~and~'#2'~are~incompatible
    \str_if_eq:nnF {#3} {??} { ~in~hook~'#3' } .~
    \int_compare:nNnTF {#4} = { 1 }
      { The~ code~ for~ both~ labels~ will~ be~ dropped. }
      { You~ may~ see~ errors~ later. }
  }
  { LaTeX~found~two~incompatible~labels~in~the~same~hook.~
    This~indicates~an~incompatibility~between~packages.  }
\msg_new:nnnn { hooks } { exists }
    { Hook~'#1'~ has~ already~ been~ declared. }
    { There~ already~ exists~ a~ hook~ declaration~ with~ this~
      name.\\
      Please~ use~ a~ different~ name~ for~ your~ hook.}
\msg_new:nnnn { hooks } { hook-disabled }
  { Cannot~add~code~to~disabled~hook~'#1'. }
  {
    The~hook~'#1'~you~tried~to~add~code~to~was~previously~disabled~
    with~\iow_char:N\\hook_disable_generic:n~or~\iow_char:N\\DisableGenericHook,~so~
    it~cannot~have~code~added~to~it.
  }
\msg_new:nnn { hooks } { empty-label }
  {
    Empty~code~label~\msg_line_context:.~
    Using~'\__hook_currname_or_default:'~instead.
  }
\msg_new:nnn { hooks } { no-default-label }
  {
    Missing~(empty)~default~label~\msg_line_context:. \\
    This~command~was~ignored.
  }
\msg_new:nnnn { hooks } { unknown-rule }
  { Unknown~ relationship~ '#3'~
    between~ labels~ '#2'~ and~ '#4'~
    \str_if_eq:nnF {#1} {??} { ~in~hook~'#1' }. ~
    Perhaps~ a~ misspelling?
  }
  {
    The~ relation~ used~ not~ known~ to~ the~ system.~ Allowed~ values~ are~
    'before'~ or~ '<',~
    'after'~ or~ '>',~
    'incompatible-warning',~
    'incompatible-error',~
    'voids'~ or~
    'unrelated'.
  }
\msg_new:nnnn { hooks } { misused-top-level }
  {
    Illegal~use~of~\iow_char:N \\AddToHook{#1}[top-level]{...}.\\
    'top-level'~is~reserved~for~the~user's~document.
  }
  {
    The~'top-level'~label~is~meant~for~user~code~only,~and~should~only~
    be~used~(sparingly)~in~the~main~document.~Use~the~default~label~
    '\__hook_currname_or_default:'~for~this~\@cls@pkg,~or~another~
    suitable~label.
  }
\msg_new:nnn { hooks } { set-top-level }
  {
    You~cannot~change~the~default~label~#1~'top-level'.~Illegal \\
    \use:nn { ~ } { ~ } \iow_char:N \\#2{#3} \\
    \msg_line_context:.
  }
\msg_new:nnn { hooks } { extra-pop-label }
  {
    Extra~\iow_char:N \\PopDefaultHookLabel. \\
    This~command~will~be~ignored.
  }
\msg_new:nnn { hooks } { missing-pop-label }
  {
    Missing~\iow_char:N \\PopDefaultHookLabel. \\
    The~label~'#1'~was~pushed~but~never~popped.~Something~is~wrong.
  }
\msg_new:nnn { latex2e } { should-not-happen }
  {
    This~should~not~happen.~#1 \\
    Please~report~at~https://github.com/latex3/latex2e.
  }
\msg_new:nnn { hooks } { activate-disabled }
  {
    Cannot~ activate~ hook~ '#1'~ because~ it~ is~ disabled!
  }
\msg_new:nnn { hooks } { cannot-remove }
  {
    Cannot~remove~chunk~'#2'~from~hook~'#1'~because~
    \__hook_if_structure_exist:nTF {#1}
      { it~does~not~exist~in~that~hook. }
      { the~hook~does~not~exist. }
  }
\msg_new:nnn { hooks } { generic-deprecated }
  {
    Generic~hook~'#1/#2/#3'~is~deprecated. \\
    Use~hook~'#1/#3/#2'~instead.
  }
\NewDocumentCommand \NewHook             { m }{ \hook_new:n {#1} }
\NewDocumentCommand \NewReversedHook     { m }{ \hook_new_reversed:n {#1} }
\NewDocumentCommand \NewMirroredHookPair { mm }{ \hook_new_pair:nn {#1}{#2} }
\NewDocumentCommand \ActivateGenericHook { m }{ \hook_activate_generic:n {#1} }
\NewDocumentCommand \DisableGenericHook { m }{ \hook_disable_generic:n {#1} }
\NewDocumentCommand \AddToHook { m o +m }
  { \hook_gput_code:nnn {#1} {#2} {#3} }
\NewDocumentCommand \AddToHookNext { m +m }
  { \hook_gput_next_code:nn {#1} {#2} }
\NewDocumentCommand \ClearHookNext { m }
  { \hook_gclear_next_code:n {#1} }
\NewDocumentCommand \RemoveFromHook { m o }
  { \hook_gremove_code:nn {#1} {#2} }
\NewDocumentCommand \SetDefaultHookLabel { m }
  { \__hook_set_default_hook_label:n {#1} }
\NewDocumentCommand \PushDefaultHookLabel { m }
  { \__hook_curr_name_push:n {#1} }
\NewDocumentCommand \PopDefaultHookLabel { }
  { \__hook_curr_name_pop: }
\cs_gset_protected:Npn \@expl@push@filename@aux@@ #1#2#3
  {
    \__hook_curr_name_push:n {#3}
    \str_gset:Nx \g_file_curr_name_str {#3}
    #1 #2 {#3}
  }
\cs_new:Npn \UseHook        { \hook_use:n }
\cs_new:Npn \UseOneTimeHook { \hook_use_once:n }
\cs_new_protected:Npn \ShowHook { \hook_show:n }
\cs_new_protected:Npn \LogHook { \hook_log:n }
\cs_new_protected:Npn \DebugHooksOn  { \hook_debug_on:  }
\cs_new_protected:Npn \DebugHooksOff { \hook_debug_off: }
\NewDocumentCommand \DeclareHookRule { m m m m }
                    { \hook_gset_rule:nnnn {#1}{#2}{#3}{#4} }
\NewDocumentCommand \DeclareDefaultHookRule { m m m }
                    { \hook_gset_rule:nnnn {??}{#1}{#2}{#3} }
\@onlypreamble\DeclareDefaultHookRule
\NewDocumentCommand \ClearHookRule { m m m }
{ \hook_gset_rule:nnnn {#1}{#2}{unrelated}{#3} }
\cs_new_eq:NN \IfHookEmptyTF \hook_if_empty:nTF
\cs_new_eq:NN \IfHookExistsTF \__hook_if_usable:nTF
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\cs_new_protected:Npn \hook_disable:n
  {
    \__hook_deprecated_warn:nn
      { hook_disable:n }
      { hook_disable_generic:n }
    \hook_disable_generic:n
  }
\cs_new_protected:Npn \hook_provide:n
  {
    \__hook_deprecated_warn:nn
      { hook_provide:n }
      { hook_activate_generic:n }
    \hook_activate_generic:n
  }
\cs_new_protected:Npn \hook_provide_reversed:n
  {
    \__hook_deprecated_warn:nn
      { hook_provide_reversed:n }
      { hook_activate_generic:n }
    \__hook_activate_generic_reversed:n
  }
\cs_new_protected:Npn \hook_provide_pair:nn
  {
    \__hook_deprecated_warn:nn
      { hook_provide_pair:nn }
      { hook_activate_generic:n }
    \__hook_activate_generic_pair:nn
  }
\cs_new_protected:Npn \__hook_activate_generic_reversed:n #1
  { \__hook_normalize_hook_args:Nn \__hook_activate_generic:nn {#1} { - } }
\cs_new_protected:Npn \__hook_activate_generic_pair:nn #1#2
  { \hook_activate_generic:n {#1} \__hook_activate_generic_reversed:n {#2} }
\cs_new_protected:Npn \DisableHook
  {
    \__hook_deprecated_warn:nn
      { DisableHook }
      { DisableGenericHook }
    \hook_disable_generic:n
  }
\cs_new_protected:Npn \ProvideHook
  {
    \__hook_deprecated_warn:nn
      { ProvideHook }
      { ActivateGenericHook }
    \hook_activate_generic:n
  }
\cs_new_protected:Npn \ProvideReversedHook
  {
    \__hook_deprecated_warn:nn
      { ProvideReversedHook }
      { ActivateGenericHook }
    \__hook_activate_generic_reversed:n
  }
\cs_new_protected:Npn \ProvideMirroredHookPair
  {
    \__hook_deprecated_warn:nn
      { ProvideMirroredHookPair }
      { ActivateGenericHook }
    \__hook_activate_generic_pair:nn
  }
\cs_new_protected:Npn \__hook_deprecated_warn:nn #1 #2
  { \msg_warning:nnnn { hooks } { deprecated } {#1} {#2} }
\msg_new:nnn { hooks } { deprecated }
  {
    Command~\iow_char:N\\#1~is~deprecated~and~will~be~removed~in~a~
    future~release. \\ \\
    Use~\iow_char:N\\#2~instead.
  }
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\cs_new_eq:NN \@expl@@@initialize@all@@
              \__hook_initialize_all:
\cs_new_eq:NN \@expl@@@hook@curr@name@pop@@
              \__hook_curr_name_pop:
\ExplSyntaxOff
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% File: ltcmdhooks.dtx (C) Copyright 2020-2021
%%       Frank Mittelbach, Phelype Oleinik, LaTeX Team
%%% From File: ltcmdhooks.dtx
\def\ltcmdhooksversion{v1.0f}
\def\ltcmdhooksdate{2021/10/20}
\ExplSyntaxOn
\tl_new:N \g_hook_patch_action_list_tl
\int_new:N \l__hook_patch_num_args_int
\tl_new:N \l__hook_patch_prefixes_tl
\tl_new:N \l__hook_param_text_tl
\tl_new:N \l__hook_replace_text_tl
\tl_const:Nn \c__hook_hash_tl { # # }
\cs_new_eq:NN \__hook_exp_not:NN ?
\cs_new_eq:NN \__hook_def_cmd:w ?
\quark_new:N \q__hook_recursion_tail
\quark_new:N \q__hook_recursion_stop
\prop_new:N \g__hook_delayed_patches_prop
\cs_new_protected:Npn \__hook_patch_debug:x #1
  { \__hook_debug:n { \iow_term:x { [lthooks]~#1 } } }
\cs_generate_variant:Nn \tl_rescan:nn { nV }
\cs_new_protected:Npn \__hook_try_put_cmd_hook:n #1
  { \__hook_try_put_cmd_hook:w #1 / / / \s__hook_mark {#1} }
\cs_new_protected:Npn \__hook_try_put_cmd_hook:w
    #1 / #2 / #3 / #4 \s__hook_mark #5
  {
    \__hook_debug:n { \iow_term:n { ->~Adding~cmd~hook~to~'#2'~(#3): } }
    \exp_args:Nc \__hook_patch_cmd_or_delay:Nnn {#2} {#2} {#3}
  }
\cs_new_protected:Npn \__hook_patch_cmd_or_delay:Nnn #1 #2 #3
  {
    \__hook_debug:n { \iow_term:n { ->~Add~generic~cmd~hook~for~#2~(#3). } }
    \__hook_debug:n
      { \iow_term:n { !~In~the~preamble:~delaying. } }
    \prop_gput:Nnn \g__hook_delayed_patches_prop { #2 / #3 }
      { \__hook_cmd_try_patch:nn {#2} {#3} }
  }
\cs_new_protected:Npn \__hook_cmd_begindocument_code:
  {
    \cs_gset_eq:NN \__hook_patch_cmd_or_delay:Nnn \__hook_patch_command:Nnn
    \prop_map_function:NN \g__hook_delayed_patches_prop { \use_ii:nn }
    \prop_gclear:N \g__hook_delayed_patches_prop
    \cs_undefine:N \__hook_cmd_begindocument_code:
  }
\g@addto@macro \@kernel@after@begindocument
  { \__hook_cmd_begindocument_code: }
\cs_new_protected:Npn \__hook_cmd_try_patch:nn #1 #2
  {
    \__hook_debug:n
      { \iow_term:x { ->~\string\begin{document}~try~cmd / #1 / #2. } }
    \__hook_if_declared:nTF { cmd / #1 / #2 }
      {
        \__hook_debug:n
          { \iow_term:n { .->~Giving~up:~hook~already~created. } }
      }
      {
        \cs_if_exist:cT {#1}
          { \exp_args:Nc \__hook_patch_command:Nnn {#1} {#1} {#2} }
      }
  }
\cs_new_protected:Npn \__hook_patch_command:Nnn #1 #2 #3
  {
    \__hook_patch_debug:x { analyzing~'\token_to_str:N #1' }
    \__hook_patch_debug:x { \token_to_str:N #1 = \token_to_meaning:N #1 }
    \__hook_patch_check:NNnn \cs_if_exist:NTF #1 { undef }
      {
        \__hook_patch_debug:x { ++~control~sequence~is~defined }
        \__hook_patch_check:NNnn \token_if_macro:NTF #1 { macro }
          {
            \__hook_patch_debug:x { ++~control~sequence~is~a~macro }
            \__hook_patch_check:NNnn \__hook_if_public_command:NTF #1 { expl3 }
              {
                \__hook_patch_debug:x { ++~macro~is~not~private }
                \robust@command@act
                  \g_hook_patch_action_list_tl #1
                  \__hook_retokenize_patch:Nnn { #1 {#2} {#3} }
              }
          }
      }
  }
\cs_new_protected:Npn \__hook_patch_check:NNnn #1 #2 #3 #4
  {
    #1 #2 {#4}
      {
        \msg_error:nnxx { hooks } { cant-patch }
          { \token_to_str:N #2 } {#3}
      }
  }
\use:x
  {
    \prg_new_protected_conditional:Npnn
        \exp_not:N \__hook_if_public_command:N ##1 { TF }
      {
        \exp_not:N \exp_last_unbraced:Nf
          \exp_not:N \__hook_if_public_command:w
            { \exp_not:N \cs_to_str:N ##1 }
          \tl_to_str:n { _ _ } \s__hook_mark
      }
  }
\exp_last_unbraced:NNNNo
\cs_new_protected:Npn \__hook_if_public_command:w
    #1 \tl_to_str:n { _ _ } #2 \s__hook_mark
  {
    \tl_if_empty:nTF {#2}
      { \prg_return_true: }
      { \prg_return_false: }
  }
\tl_gset:Nn \g_hook_patch_action_list_tl
  {
    { \@if@DeclareRobustCommand \__hook_patch_DeclareRobustCommand:Nnn }
    { \@if@newcommand \__hook_patch_newcommand:Nnn }
    { \__kernel_cmd_if_xparse:NTF \__hook_cmd_patch_xparse:Nnn }
  }
\cs_new_protected:Npn \__hook_patch_DeclareRobustCommand:Nnn #1
  {
    \exp_args:Nc \__hook_patch_DeclareRobustCommand_aux:Nnn
      { \cs_to_str:N #1 ~ }
  }
\cs_new_protected:Npn \__hook_patch_DeclareRobustCommand_aux:Nnn #1
  {
    \robust@command@chk@safe #1
      { \@if@newcommand #1 }
      { \use_ii:nn }
        { \__hook_patch_newcommand:Nnn }
        { \__hook_patch_expand_redefine:NNnn \c_false_bool }
          #1
  }
\cs_new_protected:Npn \__hook_patch_newcommand:Nnn #1
  {
    \exp_args:NNc \__hook_patch_expand_redefine:NNnn \c_true_bool
      { \c_backslash_str \cs_to_str:N #1 }
  }
\cs_new_protected:Npn \__hook_cmd_patch_xparse:Nnn #1
  {
    \exp_args:NNc \__hook_patch_expand_redefine:NNnn \c_false_bool
      { \cs_to_str:N #1 ~ code }
  }
\cs_new_protected:Npn \__hook_patch_expand_redefine:NNnn #1 #2 #3 #4
  {
    \__hook_patch_debug:x { ++~command~can~be~patched~without~rescanning }
    \int_set:Nn \l__hook_patch_num_args_int
      {
        \exp_args:Nf \str_count:n { \cs_argument_spec:N #2 } / 2
        \bool_if:NT #1 { -1 }
      }
    \int_compare:nNnTF { \l__hook_patch_num_args_int } > { \c_zero_int }
      {
        \tl_set:Nx \l__hook_tmpa_tl { \bool_if:NTF #1 { [ ] } { { } } }
        \int_step_inline:nnn { 2 } { \l__hook_patch_num_args_int }
          { \tl_put_right:Nn \l__hook_tmpa_tl { { } } }
        \exp_args:NNo \exp_args:No \__hook_if_has_hash:nTF
            { \exp_after:wN #2 \l__hook_tmpa_tl }
          { \cs_set_eq:NN \__hook_exp_not:n \exp_not:n }
          { \cs_set_eq:NN \__hook_exp_not:n \use:n }
        \cs_set_protected:Npn \__hook_tmp:w ##1 ##2
          {
            ##1 \l__hook_param_text_tl   { \use:n ##2 }
            ##1 \l__hook_replace_text_tl { \__hook_exp_not:n {##2} }
          }
        \bool_if:NTF #1
          { \__hook_tmp:w \tl_set:Nx { [ \c__hook_hash_tl 1 ] } }
          { \__hook_tmp:w \tl_set:Nx { { \c__hook_hash_tl 1 } } }
        \int_step_inline:nnn { 2 } { \l__hook_patch_num_args_int }
          { \__hook_tmp:w \tl_put_right:Nx { { \c__hook_hash_tl ##1 } } }
        \tl_set:Nx \l__hook_replace_text_tl
          { \exp_not:N #2 \exp_not:V \l__hook_replace_text_tl }
        \tl_set:Nx \l__hook_replace_text_tl
          {
            \token_if_eq_meaning:NNTF \__hook_exp_not:n \exp_not:n
              { \exp_args:NNV \exp_args:No \__hook_double_hashes:n }
              { \exp_args:NV \exp_not:o }
                  \l__hook_replace_text_tl
          }
        \cs_set_eq:NN \__hook_def_cmd:w \tex_gdef:D
        \cs_set_eq:NN \__hook_exp_not:NN \prg_do_nothing:
      }
      {
        \tl_clear:N \l__hook_param_text_tl
        \tl_set_eq:NN \l__hook_replace_text_tl #2
        \cs_set_eq:NN \__hook_def_cmd:w \tex_xdef:D
        \cs_set:Npn \__hook_exp_not:NN ##1 { \exp_not:N ##1 \exp_not:N }
      }
    \group_begin:
      \int_set:Nn \tex_escapechar:D { `\/ }
      \use:x
        {
    \group_end:
    \tl_set:Nx \exp_not:N \l__hook_patch_prefixes_tl
      { \exp_not:N \__hook_make_prefixes:w \cs_prefix_spec:N #2 / / }
        }
    \use:x
      {
        \__hook_redefine_with_hooks:Nnnn \exp_not:N #2
        \str_if_eq:nnTF {#4} { after }
          { \use_ii_i:nn }
          { \use:nn }
            { { \__hook_exp_not:NN \exp_not:N \UseHook { cmd / #3 / #4 } } }
            { { } }
            { \__hook_exp_not:NN \exp_not:V \l__hook_replace_text_tl }
      }
  }
\cs_new_protected:Npn \__hook_redefine_with_hooks:Nnnn #1 #2 #3 #4
  {
    \l__hook_patch_prefixes_tl
      \exp_after:wN \__hook_def_cmd:w
        \exp_after:wN #1 \l__hook_param_text_tl
      { #2  #4  #3 }
  }
\cs_new:Npn \__hook_make_prefixes:w / #1 /
  {
    \tl_if_empty:nF {#1}
      {
        \exp_not:c { tex_ \tl_trim_spaces:n {#1} :D }
        \__hook_make_prefixes:w /
      }
  }
\prg_new_conditional:Npnn \__hook_if_has_hash:n #1 { TF }
  { \__hook_if_has_hash:w #1 ## \s__hook_mark }
\cs_new:Npn \__hook_if_has_hash:w #1
  {
    \tl_if_single_token:nTF {#1}
      {
        \token_if_eq_catcode:NNTF ## #1
          { \__hook_if_has_hash_check:w }
          { \__hook_if_has_hash:w }
      }
      { \__hook_if_has_hash:w #1 }
  }
\cs_new:Npn \__hook_if_has_hash_check:w #1 \s__hook_mark
  { \tl_if_empty:nTF {#1} { \prg_return_false: } { \prg_return_true: } }
\cs_new:Npn \__hook_double_hashes:n #1
  { \__hook_double_hashes:w #1 \q__hook_recursion_tail \q__hook_recursion_stop }
\cs_new:Npn \__hook_double_hashes:w #1 \q__hook_recursion_stop
  {
    \tl_if_head_is_N_type:nTF {#1}
      { \__hook_double_hashes_output:N }
      {
        \tl_if_head_is_group:nTF {#1}
          { \__hook_double_hashes_group:n }
          { \__hook_double_hashes_space:w }
      }
    #1 \q__hook_recursion_stop
  }
\cs_new:Npn \__hook_double_hashes_output:N #1
  {
    \if_meaning:w \q__hook_recursion_tail #1
      \__hook_double_hashes_stop:w
    \fi:
    \if_meaning:w \c__hook_hash_tl #1
      \use_i:nnnn
    \fi:
    \use:n
      {
        \if_catcode:w ## \exp_not:N #1
          \exp_after:wN \use_ii:nnnn
        \fi:
        \use_none:n
          { \exp_not:n { #1 #1 } }
      }
    \exp_not:N #1
    \__hook_double_hashes:w
  }
\cs_new:Npn \__hook_double_hashes_stop:w #1 \q__hook_recursion_stop { \fi: }
\cs_new:Npn \__hook_double_hashes_group:n #1
  { { \__hook_double_hashes:n {#1} } \__hook_double_hashes:w }
\exp_last_unbraced:NNo
\cs_new:Npn \__hook_double_hashes_space:w \c_space_tl
  { ~ \__hook_double_hashes:w }
\cs_new_protected:Npn \__hook_retokenize_patch:Nnn #1 #2 #3
  {
    \__hook_patch_debug:x { ..~command~can~only~be~patched~by~rescanning }
    \str_if_eq:eeTF { \cs_argument_spec:N #1 } { }
      { \__hook_patch_expand_redefine:NNnn \c_false_bool #1 {#2} {#3} }
      {
        \tl_set:Nx \l__hook_tmpa_tl
          {
            \int_compare:nNnTF { \char_value_catcode:n {`\@ } } = { 12 }
              { \exp_not:N \makeatletter } { \exp_not:N \makeatother }
          }
        \tl_set:Nx \l__hook_tmpb_tl
          {
            \bool_if:NTF \l__kernel_expl_bool
              { \ExplSyntaxOff } { \ExplSyntaxOn }
          }
        \use:x
          {
            \exp_not:N \__hook_try_patch_with_catcodes:Nnnnw
                \exp_not:n { #1 {#2} {#3} }
              { \prg_do_nothing: }
              { \exp_not:V \l__hook_tmpa_tl } % @
              { \exp_not:V \l__hook_tmpb_tl } % _:
              {
                \exp_not:V \l__hook_tmpa_tl   % @
                \exp_not:V \l__hook_tmpb_tl   % _:
              }
          }
              \q_recursion_tail \q_recursion_stop
          {
            \msg_error:nnxx { hooks } { cant-patch }
              { \c_backslash_str #2 } { retok }
          }
      }
  }
\cs_new_protected:Npn \__hook_try_patch_with_catcodes:Nnnnw #1 #2 #3 #4
  {
    \quark_if_recursion_tail_stop_do:nn {#4} { \use:n }
    \__hook_patch_debug:x { ++~trying~to~patch~by~retokenization }
    \__hook_cmd_if_scanable:NnTF {#1} {#4}
      {
        \__hook_patch_debug:x { ++~macro~can~be~retokenized~cleanly }
        \__hook_patch_debug:x { ==~retokenizing~macro~now }
        \__hook_patch_retokenize:Nnnn #1 {#2} {#3} {#4}
        \use_i_delimit_by_q_recursion_stop:nw \use_none:n
      }
      {
        \__hook_patch_debug:x { --~macro~cannot~be~retokenized~cleanly }
        \__hook_try_patch_with_catcodes:Nnnnw #1 {#2} {#3}
      }
  }
\cs_new_eq:NN \kerneltmpDoNotUse !
\cs_new_protected:Npn \__hook_patch_required_catcodes:
  {
    \char_set_catcode_escape:N \\
    \char_set_catcode_group_begin:N \{
    \char_set_catcode_group_end:N \}
    \char_set_catcode_parameter:N \#
    % \int_set:Nn \tex_endlinechar:D { -1 }
    % \int_set:Nn \tex_newlinechar:D { -1 }
  }
\prg_new_protected_conditional:Npnn \__hook_cmd_if_scanable:Nn #1 #2 { TF }
  {
    \cs_set_eq:NN \kerneltmpDoNotUse \scan_stop:
    \cs_set_eq:NN \__hook_tmp:w \scan_stop:
    \use:x
      {
        \cs_set:Npn \__hook_tmp:w
            ####1 \tl_to_str:n { macro: } ####2 -> ####3 \s__hook_mark
          { ####1 \def \kerneltmpDoNotUse ####2   {####3} }
        \tl_set:Nx \exp_not:N \l__hook_tmpa_tl
          { \exp_not:N \__hook_tmp:w \token_to_meaning:N #1 \s__hook_mark }
      }
    \tl_rescan:nV { #2 \__hook_patch_required_catcodes: } \l__hook_tmpa_tl
    \token_if_eq_meaning:NNTF #1 \kerneltmpDoNotUse
      { \prg_return_true: }
      { \prg_return_false: }
  }
\cs_new_protected:Npn \__hook_patch_retokenize:Nnnn #1 #2 #3 #4
  {
    \cs_set_eq:NN \kerneltmpDoNotUse \scan_stop:
    \cs_set_eq:NN \__hook_tmp:w \scan_stop:
    \use:x
      {
        \cs_set:Npn \__hook_tmp:w
            ####1 \tl_to_str:n { macro: } ####2 -> ####3 \s__hook_mark
          {
            ####1 \def \kerneltmpDoNotUse ####2
              {
                \str_if_eq:nnT {#3} { before }
                  { \token_to_str:N \UseHook { cmd / #2 / #3 } }
                ####3
                \str_if_eq:nnT {#3} { after }
                  { \token_to_str:N \UseHook { cmd / #2 / #3 } }
              }
          }
        \tl_set:Nx \exp_not:N \l__hook_tmpa_tl
          { \exp_not:N \__hook_tmp:w \token_to_meaning:N #1 \s__hook_mark }
      }
    \tl_rescan:nV { #4 \__hook_patch_required_catcodes: } \l__hook_tmpa_tl
    \cs_gset_eq:NN #1 \kerneltmpDoNotUse
  }
\msg_new:nnnn { hooks } { cant-patch }
  {
    Generic~hooks~cannot~be~added~to~'#1'.
  }
  {
    You~tried~to~add~a~hook~to~'#1',~but~LaTeX~was~unable~to~
    patch~the~command~because~it~\__hook_unpatchable_cases:n {#2}.
  }
\cs_new:Npn \__hook_unpatchable_cases:n #1
  {
    \str_case:nn {#1}
      {
        { undef } { doesn't~exist }
        { macro } { is~not~a~macro }
        { expl3 } { is~a~private~expl3~macro }
        { retok } { can't~be~retokenized~cleanly }
      }
  }

\endinput