%%
%% This is file 'bxbase.def'.
%%

%% file declaration
\NeedsTeXFormat{LaTeX2e}
\ProvidesFile{bxbase.def}[2023/02/23 v1.2a BX base library]
\def\bx@pkgname{BXbase} % bundle name

%% check intergrity
\edef\bxbz@tmpa{\@currname.\@currext}\def\bxbz@tmpb{bxbase.def}
\ifx\bxbz@tmpa\bxbz@tmpb\else
  \PackageError\bx@pkgname{Illegal load sequence}\@eha
\expandafter\endinput\fi\relax

%% code guards
\edef\bxbz@restore@codes{%
  \catcode33=\the\catcode33%
  \catcode34=\the\catcode34%
  \catcode39=\the\catcode39%
  \catcode43=\the\catcode43%
  \catcode45=\the\catcode45%
  \catcode46=\the\catcode46%
  \catcode47=\the\catcode47%
  \catcode58=\the\catcode58%
  \catcode60=\the\catcode60%
  \catcode62=\the\catcode62%
  \catcode94=\the\catcode94%
  \catcode96=\the\catcode96%
\relax}
\catcode33=12 % <!>
\catcode34=12 % <">
\catcode39=12 % <'>
\catcode43=12 % <+>
\catcode45=12 % <->
\catcode46=12 % <.>
\catcode47=12 % </>
\catcode58=12 % <:>
\catcode60=12 % <<>
\catcode62=12 % <>>
\catcode94=7 % <^>
\catcode96=12 % <`>
\AtEndOfPackage{%
  \bxbz@restore@codes
  \let\bxbz@restore@codes\@undefined}

%--------------------------------------- general

%% packages
\RequirePackage{bxtoolbox}[2017/05/29]

%% variables
\let\bxHex\relax      % result of \bxToHex...
\let\bxRes\relax      % result of \bxToLower
\ifundef\bxUcv{\newcount\bxUcv}{}   % argument of \bx@Ux

%% unique tokens
\def\bxbz@uniq{\bxbz@uniq@}

%% error messages
\def\bx@error{\PackageError\bx@pkgname}
\def\bx@warn{\PackageWarningNoLine\bx@pkgname}
\def\bx@err@nobbl{\bx@error{babel not yet loaded}\@eha}
\def\bx@err@nanbc{\bx@error{Non-BMP characters not supported}\@eha}
\def\bx@err@ilnfm{\bx@error{Illegal number format}\@eha}
\def\bx@err@uddrv#1{\bx@error{\string#1 is undefined}\@eha}
\def\bxbz@warn@depre#1#2{%
  \PackageWarning\bx@pkgname
   {The command '\string#1' is obsolete and\MessageBreak
    its use is deprecated%
    \ifx\relax#2\relax, \else
      \MessageBreak (use #2 instead),\MessageBreak
    \fi detected}}

%--------------------------------------- programming tools

%%<+> \bxCheckMA\CS <text> \bxEndCheckMA
% If this construct appears in moving arguments, it expands to
% an error message command.
\def\bxCheckMA{\let\bx@chkma@a\bx@chkma@a\noexpand}
\let\bxEndCheckMA\@empty \let\bx@chkma@z\relax
\def\bx@chkma@a#1{\bx@chkma@z\relax\bx@chkma@b}
\def\bx@chkma@b#1#2#3\bxEncCheckMA{\noexpand\bx@err@ivfrg#1#2}
\def\bx@err@ivfrg#1{\bx@error{Cannot use \string#1 here}\@eha}

%%<+D> \bxCheckCounterpart{<base_name>}
% Compares the version between the current file and <base_name>
% with the extension of current file, and if the latter file is
% already loaded and moreover turns out to be newer than the
% system aborts loading the current file.
\bxPreamble\newcommand*\bxCheckCounterpart[1]{%
  \PackageWarning\bx@pkgname
   {'\string\bxCheckCounterpart' is no more supported,%
    \MessageBreak detected}}

%--------------------------------------- TeX engine distinction

%%<+> \bxEngineTypeX / \bxEngineTypeY
% Numbers that signify what I am.
  % \bxEngineTypeX values
\chardef\bxETTeX=0     % none of those
\chardef\bxETpTeX=1    % pTeX-extended
\chardef\bxETXeTeX=2   % XeTeX-extended
\chardef\bxETOmega=3   % Omega-extended
  % \bxEngineTypeY values (plus \bxETTeX)
\chardef\bxETeTeX=1    % e-TeX-extended
\chardef\bxETpdfTeX=3  % pdfTeX-extended
\chardef\bxETLuaTeX=5  % LuaTeX-extended
  % (here old pdfTeX without e-TeX is ignored)
  %
  % Note:
  % Originally LuaTeX was supposed to be 'both pdfTeX- and Omega-
  % extended' (\bxEngineTypeX/Y = 3/3); however, It seems that
  % in today's LaTeX world LuaTeX is no longer seen as Omega-
  % extended (indeed, current LuaTeX drops many of the Omega-
  % specific features). So LuaTeX got relocated at \bxEngineTypeX/Y
  % = 0/5.
\ifbxinpTeX        \let\bxEngineTypeX\bxETpTeX
\else\ifbxinXeTeX  \let\bxEngineTypeX\bxETXeTeX
\else\ifbxinOmega  \let\bxEngineTypeX\bxETOmega
\else              \let\bxEngineTypeX\bxETTeX
\fi\fi\fi
\ifbxineTeX        \let\bxEngineTypeY\bxETeTeX
\else\ifbxinpdfTeX \let\bxEngineTypeY\bxETpdfTeX
\else\ifbxinLuaTeX \let\bxEngineTypeY\bxETLuaTeX
\else              \let\bxEngineTypeY\bxETTeX
\fi\fi\fi
\bxDebug{engine type = \the\bxEngineTypeX/\the\bxEngineTypeY}

%--------------------------------------- Babel something

%%<+> \bxBDHookBabel
% A begindocument-hook about Babel.
\newbool{bx@bbl@inuse}
\bxPreamble\def\bx@bbl@bdhook{}
\bxPreamble\newcommand*\bxBDHookBabel{%
  \AtBeginDocument{%
    \@ifpackageloaded{babel}{%
      \bx@bbl@inusetrue
      \ifx\bx@bbl@captlang\@undefined\else \bx@bbl@do@captlang \fi
      \bx@bbl@bdhook
    }{}}%
  \bxNullify\bxBDHookBabel}

%%<+> \bxAtBeginDocumentBabel{<text>}
% Register a begin-document hook that will be invoked only when babel
% is loaded.
\bxPreamble\newcommand\bxAtBeginDocumentBabel{%
  \g@addto@macro\bx@bbl@bdhook}

%% \bx@bbl@patch@sel@lang
% A patch to \select@language that disables automatic switching of
% caption language.
\bxPreamble\def\bx@bbl@patch@sel@lang{%
  \global\let\bx@bbl@patch@sel@lang\relax
  \global\let\bx@bbl@org@select@language\select@language
  \gdef\select@language##1{%
    \bx@bbl@copy{**C}{##1}\bx@bbl@copy{##1}{**Z}%
    \bx@bbl@org@select@language{##1}\bx@bbl@copy{##1}{**C}}}

%% \bx@bbl@do@captlang
% Sets the caption language of Babel according to the value of
% \bx@bbl@captlang.
\bxPreamble\def\bx@bbl@do@captlang{%
  \bxIfExpToEqual{\bx@bbl@captlang}{main}%
   {\let\bx@bbl@captlang\bbl@main@language}{}%
  \bxIfExpToEqual{\bx@bbl@captlang}{default}{}%else
   {\bxIfcsundef{l@\bx@bbl@captlang}{\@nolanerr\bx@bbl@captlang}%
     {\@nameuse{date\bx@bbl@captlang}%
      \@nameuse{captions\bx@bbl@captlang}}}}

%% \bx@bbl@copy{<lang1>}{<lang2>}
% Copies \captions... and \date... for save.
\def\bx@bbl@copy#1#2{%
  \csletcs{captions#1}{captions#2}%
  \csletcs{date#1}{date#2}}
\csdef{captions**Z}{\@empty}
\csdef{date**Z}{\@empty}

%%<*D> \fixcaptionlanguage{<lang>}
%%<+> \bxFixCaptionLanguage{<lang>}
% Change the caption language manually, with disabling automatic
% switching on it.
\bxPreamble\newcommand*\fixcaptionlanguage[1]{%
  \bxbz@warn@depre\fixcaptionlanguage{}%
  \bxFixCaptionLanguage{#1}}
\bxPreamble\newcommand*\bxFixCaptionLanguage[1]{%
  \@ifpackageloaded{babel}%
   {\bx@bbl@patch@sel@lang
    \xdef\bx@bbl@captlang{#1}}%
   {\bx@err@nobbl}}

%%<+> \bxProvideCaptionLanguage{<lang>}
\bxPreamble\newcommand*\bxProvideCaptionLanguage[1]{%
  \ifundef\bx@bbl@captlang
   {\bxFixCaptionLanguage{#1}}{}}

%%<*> \setmainlanguage{<lang>}
% Changes the 'main' language (one that is effective at beginning).
\bxPreamble\newcommand*\setmainlanguage[1]{%
  \bxIfcsundef{date#1}{\@nolanerr{#1}}{}%
  \xdef\bbl@main@language{#1}}

%%<+> \bxTrivLangDef{<lang>}
% Makes a fake language option.
\bxPreamble\newcommand*\bxTrivLangDef[1]{%
  \bxIfcsundefX{date#1}{%
    \bxIfcsundefX{l@#1}%
      {\expandafter\chardef\csname l@#1\endcsname\z@}{}%
    \csdef{date#1}{\relax}%
    \csdef{captions#1}{\relax}%
    \csdef{extras#1}{\relax}%
    \csdef{noextras#1}{\relax}%
    \csdef{date#1}{\relax}%
  }{}}

%--------------------------------------- input through code values

%%<+> \bxBDHookUnicode
% A begindocument-hook about Unicode (& CID) input.
\bxPreamble\newcommand*\bxBDHookUnicode{%
  \AtBeginDocument{\bx@assign@Ux}%
  \bxNullify\bxBDHookUnicode}

%%<+> \bxBDHookJisInput
% A begindocument-hook about JIS-code input.
\bxPreamble\newcommand*\bxBDHookJisInput{%
  \AtBeginDocument{\bx@assign@JI}%
  \bxNullify\bxBDHookJisInput}

%%<+> \bxFallbackSym{<code>}
\newcommand*\bxFallbackSym[1]{%
  \leavevmode\bx@fbs@fnt{\dimen@=\bx@junit\relax
  \hb@xt@\dimen@{\hss\vrule\@width\z@\@height.88\dimen@\@depth.12\dimen@
  \frame{\lower.04\dimen@\hb@xt@.84\dimen@{\hss\vbox to.84\dimen@{\vss
  \hsize=.84\dimen@\baselineskip\z@\lineskip.01\dimen@\parskip\z@skip
  \leftskip\@flushglue\rightskip\@flushglue\parfillskip\z@skip
  \parindent\z@\let\\\bx@fbs@c\leavevmode\let\sml=\bx@fbs@fs\bx@fbs@f
  #1\unskip\par\vss}\hss}}\hss}}}
\edef\bx@junit{\ifnum\bxEngineTypeX=\@ne 1zw\else 1em\fi}
\def\bx@fbs@c{\unskip\par\ignorespaces}
\def\bx@fbs@fnt{\global\let\bx@fbs@fnt\relax
  \global\font\bx@fbs@fs=phvr at 2.4pt
  \global\font\bx@fbs@f=phvr at 3.6pt}

%%<+> \bxCodeValueSeq\CS{<text>}
% Dispatcher for code value sequences.
\newcommand*\bxCodeValueSeq{%
  \let\bx@cvseq@branch\bx@cvseq@branch@hex
  \bx@cvseq@a}
\def\bx@cvseq@a#1#2{%
  {\catcode33=12%
   \xdef\bx@gtmpa{\uppercase{\def\noexpand\bx@tmpa{#2}}}}%
  \let\bx@cvseq@do=#1\bx@gtmpa\relax
  \expandafter\bx@cvseq@b\bx@tmpa,!\@nil}
\def\bx@cvseq@b{\futurelet\bx@toka\bx@cvseq@branch}
\def\bx@cvseq@branch@hex{%
  \if      !\bx@toka \let\bx@nxt\bx@cvseq@fin
  \else\if "\bx@toka \let\bx@nxt\bx@cvseq@pfx
  \else\if '\bx@toka \let\bx@nxt\bx@cvseq@pfx
  \else\if +\bx@toka \let\bx@nxt\bx@cvseq@pfx
  \else \let\bx@nxt\bx@cvseq@hex \fi\fi\fi\fi
  \bx@nxt}
\def\bx@cvseq@pfx{%
  \afterassignment\bx@cvseq@post \bxUcv=}
\def\bx@cvseq@hex{%
  \afterassignment\bx@cvseq@post \bxUcv="0}
\def\bx@cvseq@post#1{%
  \if ,#1\expandafter\bx@cvseq@post@a
  \else \bx@err@ilnfm \expandafter\bx@cvseq@fin \fi}
\def\bx@cvseq@post@a{%
  \bx@cvseq@do \bx@cvseq@b}
\def\bx@cvseq@fin#1\@nil{}

%%<+> \bxCodeValueSeqD\CS{<text>}
% Same as \bxCodeValueSeq, except that it defaults to decimal.
\newcommand*\bxCodeValueSeqD{%
  \let\bx@cvseq@branch\bx@cvseq@branch@dec \bx@cvseq@a}
\def\bx@cvseq@branch@dec{%
  \if      !\bx@toka \let\bx@nxt\bx@cvseq@fin
  \else    \let\bx@nxt\bx@cvseq@pfx \fi
  \bx@nxt}

%%<*> \bxUx, \bxUI, \bxAJ, \bxJI, \bxKI
% The prefixed names for \Ux, etc. They are (more likely to be)
% collision-safe.
\bxNewrobustcmd*\bxUx{\bxCodeValueSeq\bx@Ux}
\bxNewrobustcmd*\bxUI{\bxCodeValueSeq\bx@UI}
\bxNewrobustcmd*\bxAJ{\bxCodeValueSeqD\bx@AJ}
\bxNewrobustcmd*\bxJI{\bxCodeValueSeq\bx@JI}
\bxNewrobustcmd*\bxKI{\bxCodeValueSeqD\bx@KI}

%%<+> \bxUHex{<value>}, \bxUInt{<value>}
% Alternative entry points for \Ux. The code value is specified in
% hexadecimal (\bxUHex) / decimal (\bxUInt) numerals.
\def\bxbz@tmpa{\bxUIntDummyBxutfx}
\bxIfx{\bxUInt\bxbz@tmpa}{\undef\bxUInt}{}
\def\bxbz@tmpa{\bxUHexDummyBxutf}
\bxIfx{\bxUHex\bxbz@tmpa}{\undef\bxUHex}{}
\newcommand*\bxUHex{\protect\bx@Uxh}
\newcommand*\bxUInt{\protect\bx@UInt}
\def\bx@UInt#1{\bxUcv=#1\relax\bx@Ux}

%% \bx@UIh@fb, \bx@AJ@fb
\def\bx@UIh@fb#1{\bxUcv="#1\relax\bxToHexFive\bxUcv
  \expandafter\bx@b@fb@five\bxHex[Ux]}
\def\bx@AJ@fb{\bxToDecFive\bxUcv
  \expandafter\bx@b@fb@five\bxHex[AJ]}
\def\bx@JI@fb{\bxToHexFour\bxUcv
  \expandafter\bx@b@fb@four\bxHex[JI]}
\def\bx@KI@fb{\bxToDecFive\bxUcv
  \expandafter\bx@b@fb@five\bxHex[KI]}
\def\bx@b@fb@five#1#2#3#4#5#6[#7]{%
  \bxFallbackSym{{\sml#7}\\\bx@hx@supzero#1#2#3\\#4#5}}
\def\bx@b@fb@four#1#2#3#4#5[#6]{%
  \bxFallbackSym{{\sml#6}\\#1#2\\#3#4}}
\def\bx@hx@supzero#1{\ifx0#1\else\expandafter#1\fi}

%% \bx@assign@Ux
% Picks up appropriate drivers \bx@Ux etc. according to current
% load-states of packages.
% [driver]  [purpose]      [argument]    [default]
% \bx@Ux    Unicode        \bxUcv        go to \bx@UI
% \bx@Uxh   Unicode        #1(hex)       go to \bx@UIh
% \bx@UI    Unicode-ideo.  \bxUcv        go to \bx@UIh
% \bx@UIh   Unicode-ideo.  #1(hex)       fallback
% \bx@AJ    Adobe-Japan1   \bxUcv        fallback
% From the default value it can be said:
%  - Implemetations for \bx@Ux(h) must fallback on \bx@UI(h) when
%    they cannot be handle the given character, unless such fallback
%    is known to be useless.
%  - When you implement one of \bx@Ux or \bx@Uxh, then you must also
%    implement the other.
%  - When you implement \bx@UI, then you must also implement \bx@UIh.
%    (But you can implement only \bx@UIh.)
  % Initial values
\def\bx@Ux{\bx@UI}          % pass to \bx@UI
\def\bx@Uxh{\bx@UIh}        % pass to \bx@UIh
\def\bx@UI{\bxToHexUC\bxUcv\bx@UIh\bxHex} % pass to \bx@UIh
\let\bx@UIh\bx@UIh@fb       % 'fallback' driver
\let\bx@AJ\bx@AJ@fb         % 'fallback' driver
  % some helpers
  % one more step put so that \UTF could be redefined
\def\bx@UIh@otf{\UTF}
  % \UMS with the argument expanded
\def\bx@UIh@ums#1{\expandafter\UMS\expandafter{#1}}
  % \CID with \bxUcv
\def\bx@AJ@otf{\CID\bxUcv}
\bxPreamble\def\bx@assign@Ux{%
  % If I have bxucs, then set \bx@Ux to \bx@Ux@ucs
  % (which fallbacks on \bx@UI in failure).
  \@ifpackageloaded{bxucs}{%
    \let\bx@Ux\bx@Ux@ucs\let\bx@Uxh\bx@Uxh@ucs}{}%
  % If I have ums or bxsuika then I use \UMS as \bx@UIh driver.
  \@ifpackageloaded{ums}{\bxOktrue}{\bxOkfalse}
  \@ifpackageloaded{bxsuika}{\bxOktrue}{}
  \ifbxOk \let\bx@UIh\bx@UIh@UMS \fi
  % If I have utf or otf then I use \UTF as \bx@UIh driver.
  \@ifpackageloaded{utf}{\bxOktrue}{\bxOkfalse}
  \@ifpackageloaded{otf}{\bxOktrue}{}
  \ifbxOk \let\bx@UIh\bx@UIh@otf \let\bx@AJ\bx@AJ@otf \fi
  % pxotf is same as otf, except that it also provides a direct
  % way to \bx@UI and \bx@AJ.
  \@ifpackageloaded{pxotf}{%
    \let\bx@UIh\bxUIh@otf \let\bx@UI\pxUcvUTF \let\bx@AJ\pxUcvCID}{}%
  % If I am upTeX I use \kchar.
  \ifbxinupTeX
    \def\bx@UI{\kchar\bxUcv}\def\bx@UIh##1{\kchar"##1\relax}%
  % If I am a Unicode-aware engine, then...
  \else\ifnum\bxEngineTypeX>\@ne % 
    \def\bx@UI{\char\bxUcv}\def\bx@UIh##1{\char"##1\relax}%
    \let\bx@Ux\bx@UI \let\bx@Uxh\bx@UIh
    % zxjatype provides better handling of \UI & \Ux.
    \@ifpackageloaded{zxjatype}{%
      \let\bx@UI\zxjt@UI \let\bx@UIh\zxjt@UIh
      \let\bx@Ux\zxjt@Ux \let\bx@Uxh\zxjt@Uxh}{}%
    % zxotf provides \CID comamnd.
    \@ifpackageloaded{zxotf}{%
      \def\bx@AJ{\CID\bxUcv}}{}%
  \fi\fi
  % If \bx@UIh@usr is known I use it.
  \ifx\bx@UIh@usr\@undefined\else \let\bx@UIh\bx@UIh@usr \fi
  \let\bx@setuidriver@a\bx@setuidriver@b
  \ifx\bx@AJ@usr\@undefined\else \let\bx@AJ\bx@AJ@usr \fi
  \let\bx@setajdriver@a\bx@setajdriver@b
}

%%<*> \setUIdriver\CS
\newcommand*\setUIdriver[1]{%
  \ifx#1\@undefined \bx@err@uddrv#1%
  \else \bx@setuidriver@a#1\fi}
\def\bx@setuidriver@a#1{\let\bx@UIh@usr#1}
\def\bx@setuidriver@b#1{\let\bx@UIh#1}

%%<*> \setAJdriver\CS
\newcommand*\setAJdriver[1]{%
  \ifx#1\@undefined \bx@err@uddrv#1%
  \else \bx@setajdriver@a#1\fi}
\def\bx@setajdriver@a#1{\let\bx@AJ@usr#1}
\def\bx@setajdriver@b#1{\let\bx@AJ#1}

%%%% \bx@assign@JI
% Picks up appropriate drivers \bx@JI etc.
% [driver]  [purpose]      [argument]    [default]
% \bx@JI    JIS-code       \bxUcv        fallback
% \bx@KI    Kuten-code     \bxUcv        fallback
\def\bx@JI{\bx@JI@fb}
\def\bx@KI{\bx@KI@fb}
\bxPreamble\def\bx@assign@JI{%
  % \JI & \KI are available only in (u)pTeX
  \ifnum\bxEngineTypeX=\@ne
    \def\bx@JI{\char\jis\bxUcv\relax}\let\bx@KI\bx@KI@pTeX
  \fi
}
\ifnum\bxEngineTypeX=\@ne     %----<*pTeX>
%% \bx@KI@pTeX
  % \KI{2????} (0213 plane 2) works only when kanji-internal=sjis
\mathchardef\bx@ki@max=\ifnum\jis"2121="8140 30000\else 20000\fi\relax
\mathchardef\bx@ki@myr=10000
\mathchardef\bx@ki@bas="2020
\let\bx@ki@char=\char
\ifx\kchar\@undefined\else \let\bx@ki@char=\kchar \fi
\def\bx@KI@pTeX{%
  \ifnum\bxUcv<\bx@ki@max\else \bxUcv=\z@ \fi
  \ifnum\bxUcv<\bx@ki@myr \advance\bxUcv\bx@ki@myr \fi
  \expandafter\bx@ki@ptex@a\the\bxUcv\@nil
  \bx@ki@char\jis\bxUcv\relax}
\begingroup \@tempcnta=94
  \@for\bx@tmpa:=01,08,03,04,05,12,13,14,15\do{\advance\@tempcnta\@ne
    \expandafter\xdef\csname bx@JSH/\bx@tmpa\endcsname{\the\@tempcnta}}
  \@tempcntb=77 \loop
    \advance\@tempcnta\@ne \advance\@tempcntb\@ne
    \expandafter\xdef\csname bx@JSH/\the\@tempcntb\endcsname
     {\the\@tempcnta}%
  \ifnum\@tempcntb<94 \repeat
\endgroup
\def\bx@ki@ptex@a#1#2#3#4#5#6\@nil{%
  \ifnum#1=\@ne \bxUcv=#2#3\relax
  \else \bxUcv=0\csname bx@JSH/#2#3\endcsname\relax \fi
  \multiply\bxUcv\@cclvi \advance\bxUcv#4#5\relax
  \advance\bxUcv\bx@ki@bas}
\fi                           %----</pTeX>

%--------------------------------------- "safe-caret" module

%% variables
\newbool{bx@acr@ok}
\newbool{bx@acr@needed}
\newbool{bx@safecaret}

\catcode`\^=13                %---- make caret active

%%<*> \safecaret
\bxPreamble\newcommand*\safecaret{%
  \bx@safecarettrue}

%%<+> \bxEnableSafeCaret
\bxPreamble\newcommand*\bxEnableSafeCaret{%
  \bx@acr@neededtrue}

%% \bx@acr@defbytes
\bxPreamble\def\bx@acr@defbytes{%
  \bgroup\@tempcnta128\lccode`\Z=`\B\catcode`\^\active
    \@whilenum\@tempcnta<256 \do{%
      \lccode`\^\@tempcnta \chardef\bx@acr@tok\@tempcnta
      \expandafter\bx@acr@defbytes@do@a\meaning\bx@acr@tok\@nil
      \advance\@tempcnta\@ne}\egroup}
\bxPreamble\def\bx@acr@defbytes@do@a#1"#2\@nil{% name is bx@acr@B/ab etc.
  \lowercase{\expandafter\gdef\csname bx@acr@Z/#2\endcsname{^}}}
\@onlypreamble\bx@acr@defbytes
\@onlypreamble\bx@acr@defbytes@do@a

%% \bx@acr@caret
% This command should be \let'd to active <^>.
\def\bx@acr@caret{%
  \let\bx@acr@out\@empty \bx@acr@caret@a}
\def\bx@acr@caret@a{%
  \bx@acr@nextcaret{\bx@acr@caret@b}{\bx@acr@finish{\bx@acr@nxc}}}
\def\bx@acr@caret@b#1{%
  \let\bx@acr@hex\@empty
  \bx@acr@nexthexdgt{\bx@acr@caret@c}{\bx@acr@finish{\bx@acr@nxdc}}}
\def\bx@acr@caret@c#1{%
  \edef\bx@acr@hex{#1}%
  \bx@acr@nexthexdgt{\bx@acr@caret@d}{\bx@acr@finish{\bx@acr@nxdc\bx@acr@hex}}}
\def\bx@acr@caret@d#1{%
  \edef\bx@acr@hex{\bx@acr@hex#1}%
  \expandafter\bx@acr@caret@e\csname bx@acr@B/\bx@acr@hex\endcsname
  \bx@acr@ifok{\bx@acr@nextcaret{\bx@acr@caret@g}{\bx@acr@finish{}}}%
    {\bx@acr@finish{\bx@acr@nxdc\bx@acr@hex}}}
\def\bx@acr@caret@e#1{%
  \ifx#1\relax \bx@acr@okfalse
  \else \bx@acr@oktrue \expandafter\bx@acr@caret@f#1\fi}
\def\bx@acr@caret@f#1{%
  \expandafter\def\expandafter\bx@acr@out\expandafter{\bx@acr@out#1}}
\def\bx@acr@caret@g#1{\bx@acr@caret@a}
\def\bx@acr@nxc{\noexpand^}
\def\bx@acr@nxdc{\noexpand^\noexpand^}
\def\bx@acr@nextcaret#1#2{%
  \def\bx@acr@tmpa{#1}\def\bx@acr@tmpb{#2}%
  \futurelet\bx@acr@tok\bx@acr@nextcaret@a}
\def\bx@acr@nextcaret@a{%
  \let\bx@acr@nxt\bx@acr@tmpb
  \ifx^\bx@acr@tok \let\bx@acr@nxt\bx@acr@tmpa
  \fi \bx@acr@nxt}
\def\bx@acr@nexthexdgt#1#2{%
  \def\bx@acr@tmpa{#1}\def\bx@acr@tmpb{#2}%
  \futurelet\bx@acr@tok\bx@acr@nexthexdgt@a}
\def\bx@acr@nexthexdgt@a{%
  \let\bx@acr@nxt\bx@acr@tmpb
  \ifcat @\noexpand\bx@acr@tok \let\bx@acr@nxt\bx@acr@tmpa \fi
  \ifcat "\noexpand\bx@acr@tok \let\bx@acr@nxt\bx@acr@tmpa \fi
  \bx@acr@nxt}
\def\bx@acr@ifok{%
  \ifbx@acr@ok \expandafter\@firstoftwo \else \expandafter \@secondoftwo \fi}
\def\bx@acr@finish#1{%
  \edef\bx@acr@nxt{#1}%
  \ifx\bx@acr@out\@empty \bx@acr@oktrue \else \bx@acr@okfalse \fi
  \bx@acr@ifok{\expandafter\bx@acr@finish@a\bx@acr@nxt\@nil}%
    {\expandafter\bx@acr@out\bx@acr@nxt}}
\def\bx@acr@finish@a#1#2\@nil{%
    % replace first ^ with normal one to avoid loop
  \bx@acr@normcaret #2}
\let\bx@acr@normcaret\sp % this does not mean much

%% \bx@acr@initialize
\bxPreamble\def\bx@acr@initialize{%
  \bx@acr@defbytes}

%% \bx@acr@annihilate
\bxPreamble\def\bx@acr@annihilate{%
  \let\bx@acr@caret\relax\let\bx@acr@caret@a\relax
  \let\bx@acr@caret@b\relax\let\bx@acr@caret@c\relax
  \let\bx@acr@caret@d\relax\let\bx@acr@caret@e\relax
  \let\bx@acr@caret@f\relax\let\bx@acr@caret@g\relax
  \let\bx@acr@nextcaret\relax\let\bx@acr@nextcaret@a\relax
  \let\bx@acr@nexthexdgt\relax\let\bx@acr@nexthexdgt@a\relax
  \let\bx@acr@finish\relax\let\bx@acr@finish@a\relax}

%% \bx@acr@babel@hookcaret
\bxPreamble\def\bx@acr@babel@hookcaret{%
  \expandafter\ifx\csname active@char\string^\endcsname\relax\else
    \declare@shorthand\system@group{^}{\bx@acr@caret}%
    \let\bx@acr@normcaret\bx@acr@babel@normcaret
    \bxEnableSafeCaret \fi}
\edef\bx@acr@babel@normcaret{%
  \expandafter\noexpand\csname normal@char\string^\endcsname}

%% \bx@acr@verbatim@hookcaret
\bxPreamble\def\bx@acr@verbatim@hookcaret{%
  \g@addto@macro\@noligs{\catcode`\^\active\let^\bx@acr@caret
    \let\bx@acr@normcaret\bx@acr@verb@normcaret}%
  \bxEnableSafeCaret}
\begingroup \catcode`\^=12
\global\let\bx@acr@verb@normcaret=^%
\endgroup

%%<+> \bxBDHookSafeCaret
% Begin-document hook.
\bxPreamble\newcommand*\bxBDHookSafeCaret{%
  \AtBeginDocument{%
  %% function activated by '\safecaret'
  \ifbx@safecaret
    \@ifpackageloaded{babel}{\bx@acr@babel@hookcaret}{}%
    \bx@acr@verbatim@hookcaret
  \fi
  %% initialize or annihilate...
  \ifbx@acr@needed \bx@acr@initialize
  \else \bx@acr@annihilate \fi
  \let\bxEnableSafeCaret\@undefined}%
  \bxNullify\bxBDHookSafeCaret}

\catcode`\^=7                 %---- make caret normal

%--------------------------------------- hyphenation something

%%<*> 'withnohyph' environment
\expandafter\ifx\csname l@nohyphenation\endcsname\relax
  \newlanguage\l@nohyphenation \fi
\def\withnohyph{\language\l@nohyphenation}
\let\endwithnohyph\relax

%--------------------------------------- patch for 'ucs' package

%% \bxBDHookUcsFastErrors
% The begin-document hook, which forces the 'fasterrors' option
% of 'ucs' package when running on pTeX.
\bxPreamble\newcommand*\bxBDHookUcsFastErrors{%
  \ifbxinpTeX
    \AtBeginDocument{%
      \@ifpackageloaded{ucs}{%
        \let\UnicodeOptionfasterrorsfalse\UnicodeOptionfasterrorstrue
        \UnicodeOptionfasterrorstrue}{}}%
  \fi
  \bxNullify\bxBDHookUcsFastErrors}

%--------------------------------------- DVI-specials

%%<*D> \usejapanesepdfstring
\bxPreamble\newcommand*\usejapanesepdfstring{}
\if s\bxInternalJaEncoding
  \def\usejapanesepdfstring{%  why use CP932??
    \bx@docspec@urgent{pdf:tounicode 90ms-RKSJ-UCS2}%
    \bxNullify\usejapanesepdfstring}
\else\if e\bxInternalJaEncoding
  \def\usejapanesepdfstring{%
    \bx@docspec@urgent{pdf:tounicode EUC-UCS2}%
    \bxNullify\usejapanesepdfstring}
\else\if u\bxInternalJaEncoding
  \def\usejapanesepdfstring{%
    \bx@docspec@urgent{pdf:tounicode UTF8-UCS2}%
    \bxNullify\usejapanesepdfstring}
\else
  \def\usejapanesepdfstring{%
    \bx@warn{\string\usejapanesepdfstring\space ignored,\MessageBreak
      since internal encoding is unknown}%
    \bxNullify\usejapanesepdfstring}
\fi\fi\fi
\preto\usejapanesepdfstring{%
  \bxbz@warn@depre\usejapanesepdfstring{'pxjahyper' package}}

%%<*D> \recordpapersize
\bxPreamble\newcommand*\recordpapersize{%
  \bxbz@warn@depre\recordpapersize{'bxpapersize' package}%
  \bxDocumentSpecial{papersize=\the\paperwidth,\the\paperheight}%
  \bxNullify\recordpapersize}

%%<*D> \dvipdfmxmapline{<text>}
%%<*D> \dvipdfmxmapfile{<text>}
\bxPreamble\newcommand*\dvipdfmxmapline[1]{%
  \bxbz@warn@depre@dpxmap
  \bxDocumentSpecial{pdf:mapline #1}}
\bxPreamble\newcommand*\dvipdfmxmapfile[1]{%
  \bxbz@warn@depre@dpxmap
  \bxDocumentSpecial{pdf:mapfile #1}}
\def\bxbz@warn@depre@dpxmap{%
  \bxbz@warn@depre\dvipdfmxmapfile{'pxchfon' package}%
  \global\let\bxbz@warn@depre@dpxmap\relax}

%--------------------------------------- CJK font scaling

%% \bxbz@doc@class@type
%%<+D> \pxDocClassType
% 1 = pLaTeX standard class
% 2 = New standard classes by Okumura
% 0 = otherwise
\bxUcv=\z@
\@ifclassloaded{jarticle}{\bxUcv=\@ne}{}
\@ifclassloaded{jreport}{\bxUcv=\@ne}{}
\@ifclassloaded{jbook}{\bxUcv=\@ne}{}
\@ifclassloaded{tarticle}{\bxUcv=\@ne}{}
\@ifclassloaded{treport}{\bxUcv=\@ne}{}
\@ifclassloaded{tbook}{\bxUcv=\@ne}{}
\@ifclassloaded{ujarticle}{\bxUcv=\@ne}{}
\@ifclassloaded{ujreport}{\bxUcv=\@ne}{}
\@ifclassloaded{ujbook}{\bxUcv=\@ne}{}
\@ifclassloaded{utarticle}{\bxUcv=\@ne}{}
\@ifclassloaded{utreport}{\bxUcv=\@ne}{}
\@ifclassloaded{utbook}{\bxUcv=\@ne}{}
\@ifclassloaded{jsarticle}{\bxUcv=\tw@}{}
\@ifclassloaded{jsreport}{\bxUcv=\tw@}{}
\@ifclassloaded{jsbook}{\bxUcv=\tw@}{}
\chardef\bxbz@doc@class@type=\bxUcv
\chardef\pxDocClassType=\bxUcv

%%<+> \pxUpScale
\edef\pxUpScale{%
  \ifx\Cjascale\@undefined
    \ifcase\bxbz@doc@class@type 1\or 0.962216\or 0.924690\else 1\fi
  \else \Cjascale \fi}

%--------------------------------------- all done
\endinput
%% EOF