Patch for l3str-convert for (u)pLaTeX

pl3str-convert.sty

\NeedsTeXFormat{pLaTeX2e}
\ProvidesExplPackage{pl3str-convert}{2023-06-05}{}
  {Patch for l3str-convert for (u)pLaTeX}
% Check if pTeX is old.
% Needs pTeX p3.10.0 or latar.
\msg_new:nnn { pl3str-convert } { old-ptex }
  { Your~pTeX~is~too~old. }
\token_if_primitive:NF \toucs
  { \msg_error:nn { pl3str-convert } { old-ptex } }
% Check that the expl3 function definitions are what we expect.
\msg_new:nnn { pl3str-convert } { definition-mismatch }
  { Definition~of~function~`#1'~does~not~match. }
\cs_new:Npn \__plstr_original_decode_utf_viii_start:N #1
  {
    #1
    \if_int_compare:w `#1 < "C0 \exp_stop_f:
      \s__str
      \if_int_compare:w `#1 < "80 \exp_stop_f:
        \int_value:w `#1
      \else:
        \flag_raise:n { str_extra }
        \flag_raise:n { str_error }
        \int_use:N \c__str_replacement_char_int
      \fi:
    \else:
      \exp_after:wN \__str_decode_utf_viii_continuation:wwN
      \int_value:w \int_eval:n { `#1 - "C0 } \exp_after:wN
    \fi:
    \s__str
    \__str_use_none_delimit_by_s_stop:w {"80} {"800} {"10000} {"110000} \s__str_stop
    \__str_decode_utf_viii_start:N
  }
\cs_if_eq:NNF
    \__str_decode_utf_viii_start:N
    \__plstr_original_decode_utf_viii_start:N
  {
    \msg_error:nnn { pl3str-convert } { definition-mismatch }
      { __str_decode_utf_viii_start:N }
  }
% Make expl3's UTF-8 decoding function compatible with Japanese character tokens.
\cs_gset:Npn \__str_decode_utf_viii_start:N #1
  {
    #1
    \__plstr_if_jachar:NTF #1
      { \__plstr_decode_utf_viii_start_jachar:N #1 }
      { \__plstr_decode_utf_viii_start_alchar:N #1 }
    \__str_decode_utf_viii_start:N
  }
\cs_new:Npn \__plstr_decode_utf_viii_start_alchar:N #1
  {
    \if_int_compare:w `#1 < "C0 \exp_stop_f:
      \s__str
      \if_int_compare:w `#1 < "80 \exp_stop_f:
        \int_value:w `#1
      \else:
        \flag_raise:n { str_extra }
        \flag_raise:n { str_error }
        \int_use:N \c__str_replacement_char_int
      \fi:
    \else:
      \exp_after:wN \__str_decode_utf_viii_continuation:wwN
      \int_value:w \int_eval:n { `#1 - "C0 } \exp_after:wN
    \fi:
    \s__str
    \__str_use_none_delimit_by_s_stop:w {"80} {"800} {"10000} {"110000} \s__str_stop
  }
\cs_new:Npn \__plstr_decode_utf_viii_start_jachar:N #1
  {
    \s__str
    \tex_toucs:D `#1
    \s__str
  }
% Tests if internal kanji encoding is unicode.
\prg_new_conditional:Npnn \__plstr_if_encoding_unicode: { p , T , F , TF }
  {
    \if_int_compare:w \tex_jis:D "2121 = "3000 \exp_stop_f:
      \prg_return_true:
    \else:
      \prg_return_false:
    \fi:
  }
% Define Japanese character token whitch has specific kanji category code.
\group_begin:
  \cs_set:Npn \__plstr_tmp:w #1#2
    {
      \tex_kansujichar:D 0 = \tex_jis:D "2121 \scan_stop:
      \tex_kcatcode:D \tex_jis:D "2121 = #2 \scan_stop:
      \exp_after:wN \cs_new_eq:NN \exp_after:wN #1
        \tex_kansuji:D 0 \scan_stop:
    }
  \__plstr_tmp:w \c__plstr_kanji_token  { 16 }
  \__plstr_tmp:w \c__plstr_kana_token   { 17 }
  \__plstr_tmp:w \c__plstr_symbol_token { 18 }
  \sys_if_engine_uptex:T
    { \__plstr_tmp:w \c__plstr_hangul_token { 19 } }
\group_end:
% Tests whether the token is Japanese character.
\sys_if_engine_uptex:TF
  {
    \prg_new_conditional:Npnn \__plstr_if_jachar:N #1 { p , T , F , TF }
      {
        \if_catcode:w \exp_not:N #1 \c__plstr_kanji_token
          \prg_return_true:
        \else:
          \if_catcode:w \exp_not:N #1 \c__plstr_kana_token
            \prg_return_true:
          \else:
            \if_catcode:w \exp_not:N #1 \c__plstr_symbol_token
              \prg_return_true:
            \else:
              \if_catcode:w \exp_not:N #1 \c__plstr_hangul_token
                \prg_return_true:
              \else:
                \prg_return_false:
              \fi:
            \fi:
          \fi:
        \fi:
      }
  }
  {
    \prg_new_conditional:Npnn \__plstr_if_jachar:N #1 { p , T , F , TF }
      {
        \if_catcode:w \exp_not:N #1 \c__plstr_kanji_token
          \prg_return_true:
        \else:
          \if_catcode:w \exp_not:N #1 \c__plstr_kana_token
            \prg_return_true:
          \else:
            \if_catcode:w \exp_not:N #1 \c__plstr_symbol_token
              \prg_return_true:
            \else:
              \prg_return_false:
            \fi:
          \fi:
        \fi:
      }
  }