<html><head><meta name="color-scheme" content="light dark"></head><body><pre style="word-wrap: break-word; white-space: pre-wrap;">%\iffalse
% makeindex -s gglo.ist -o xbmks.gls xbmks.glo
% makeindex -s gind.ist -o xbmks.ind xbmks.idx
%&lt;*copyright&gt;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% xbmks.sty package,                                    %%
%% Copyright (C) 2016--2018                              %%
%%   dpstory@uakron.edu                                  %%
%%                                                       %%
%% This program can redistributed and/or modified under  %%
%% the terms of the LaTeX Project Public License         %%
%% Distributed from CTAN archives in directory           %%
%% macros/latex/base/lppl.txt; either version 1.2 of the %%
%% License, or (at your option) any later version.       %%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%&lt;/copyright&gt;
%&lt;package&gt;\NeedsTeXFormat{LaTeX2e}[1997/12/01]
%&lt;package&gt;\ProvidesPackage{xbmks}
%&lt;package&gt; [2020/01/16 v2.0.3 xbmks: Cross-document bookmarks (dps)]
%&lt;*driver&gt;
\documentclass{ltxdoc}
\usepackage{xcolor}
\usepackage[colorlinks,hyperindex=false,bookmarksopen]{hyperref}
\usepackage{fancyvrb,array,calc}
\usepackage{xbmks}
\xbmksetup{colors={int=red},styles={intbf}}
%\pdfstringdefDisableCommands{\let\\\textbackslash}
\EnableCrossrefs
\CodelineIndex
\RecordChanges
\bgroup\ttfamily
\gdef\brpr#1{\char123\relax#1\char125\relax}\egroup
\let\darg\brpr
\let\env\texttt
\let\opt\texttt
\let\pkg\textsf
\let\app\textsf
\def\visispace{\symbol{32}}
%\def\hardspace{{\fontfamily{cmtt}\selectfont\symbol{32}}}
\def\ameta#1{\ensuremath{\langle\textit{\texttt{#1}}\rangle}}
\def\meta#1{\textsl{\texttt{#1}}}
\def\SUB#1{\ensuremath{{}_{\mbox{\scriptsize\ttfamily#1}}}}
\def\cs#1{\texttt{\bslash#1}}
\DeclareRobustCommand{\tmspace}[3]{%
  \ifmmode\mskip#1#2\else\kern#1#3\fi\relax}
\renewcommand{\,}{\tmspace+\thinmuskip{.1667em}}
\let\thinspace\,
\renewcommand{\!}{\tmspace-\thinmuskip{.1667em}}
\let\negthinspace\!
\renewcommand{\:}{\tmspace+\medmuskip{.2222em}}
\let\medspace\:
\newcommand{\negmedspace}{\tmspace-\medmuskip{.2222em}}
\renewcommand{\;}{\tmspace+\thickmuskip{.2777em}}
\let\thickspace\;
\newcommand{\negthickspace}{\tmspace-\thickmuskip{.2777em}}
\makeatletter
\renewcommand{\paragraph}
  {\@startsection{paragraph}{4}{0pt}{6pt}{-3pt}
  {\normalfont\normalsize\bfseries}}
\renewenvironment{quote}[1][]
 {\def\@rgi{#1}\ifx\@rgi\@empty
  \let\rghtm\@empty\else\def\rghtm{\rightmargin\leftmargin}\fi
  \list{}{\rghtm} %{\rightmargin\leftmargin}%
  \item\relax}
 {\endlist}
\makeatother
\InputIfFileExists{aebdocfmt.def}{\PackageInfo{xbmks}{Inputting aebdocfmt.def}}
  {\def\IndexOpt{\DescribeMacro}\def\IndexKey{\DescribeMacro}\let\setupFullwidth\relax
   \PackageInfo{xbmks}{aebdocfmt.def cannot be found}}
\begin{document}
\def\CMD#1{\textbackslash#1}
  \GetFileInfo{xbmks.sty}
  \title{\textsf{xbmks}: Cross-document bookmarks}
  \author{D. P. Story\\
    Email: \texttt{dpstory@acrotex.net}}
  \date{processed \today}
  \maketitle
  \tableofcontents
  \let\Email\texttt
  \DocInput{xbmks.dtx}
\IfFileExists{\jobname.ind}{\newpage\setupFullwidth\par\PrintIndex}{\paragraph*{Index} The index goes here.\\Execute
    \texttt{makeindex -s gind.ist -o xbmks.ind xbmks.idx}\\on the command line and recompile
    \texttt{xbmks.dtx}.}
\IfFileExists{\jobname.gls}{\PrintChanges}{\paragraph*{Change History} The list of changes goes here.\\Execute
    \texttt{makeindex -s gglo.ist -o xbmks.gls xbmks.glo}\\on the command line and recompile
    \texttt{xbmks.dtx}.}
\end{document}
%&lt;/driver&gt;
% \fi
% \MakeShortVerb{|}
%
% \InputIfFileExists{aebdonotindex.def}{\PackageInfo{web}{Inputting aebdonotindex.def}}
%    {\PackageInfo{web}{cannot find aebdonotindex.def}}
%
%    \begin{macrocode}
% Begin package
%&lt;*package&gt;
\RequirePackage{xkeyval}
\RequirePackage{ifpdf}[2006/02/20]
\RequirePackage{ifxetex}[2006/08/21]
%    \end{macrocode}
%
%\section{Description}
% More than a couple decades ago (counting back from 2018), I wrote two mathematics tutorials: \textsl{\href{http://www.math.uakron.edu/~dpstory/e-calculus.html}{eCalculus}} and
% \textsl{\href{http://www.math.uakron.edu/~dpstory/mpt_home.html}{Algebra Review in Ten Lessons}}. The tutorials consisted of a number of lessons, each in a separate PDF.
% The bookmarks of each lessons contained the table of contents for the whole tutorial. A student, in theory, could then
% jump from one lesson to another by selecting an entry of interest from the bookmarks. In the intervening years I have not seen
% a {\LaTeX} package for merging the table of contents of a set of PDFs and merge them in this each member of the
% set. This package attempts to do just that.
%
% \section{Drivers and options}
% We support the drivers \app{dvips} (and \app{dvipsone}), \app{pdflatex}, \app{lualatex}, and \app{xelatex}; these
% options are then named \opt{dvipsone}, \opt{dvips}, \opt{pdftex}, \opt{luatex}, and \opt{xetex}.
% \changes{v1.1}{2018/06/13}{Fixed misspelling of drive command for pdfmark case}
%    \begin{macrocode}
\def\xbmk@driver{xbmks-pdfmark.def}
\DeclareOptionX{dvipsone}{\def\xbmk@driver{xbmks-pdfmark.def}}
\DeclareOptionX{dvips}{\def\xbmk@driver{xbmks-pdfmark.def}}
\DeclareOptionX{pdftex}{\def\xbmk@driver{xbmks-pdftex.def}}
\DeclareOptionX{luatex}{\def\xbmk@driver{xbmks-pdftex.def}}
\DeclareOptionX{xetex}{\def\xbmk@driver{xbmks-xetex.def}}
%    \end{macrocode}
%    \section{Process the options}
%    \changes{v2.0.3}{2020/01/16}{Modification to conform to the new \string\texttt{web.cfg} format}
%    \begin{macrocode}
\let\bWebCustomize\endinput
\let\eWebCustomize\relax
\ifpdf\ExecuteOptionsX{pdftex}\else
\ifxetex\ExecuteOptionsX{xetex}\else
  \let\ExecuteOptions@SAVE\ExecuteOptions
  \let\ExecuteOptions\ExecuteOptionsX
  \InputIfFileExists{web.cfg}{}
  {\@ifundefined{l@tex@@@@driver}{\ExecuteOptionsX{dvips}}
      {\ExecuteOptionsX{dvipsone}}}%
  \let\ExecuteOptions\ExecuteOptions@SAVE
\fi\fi
\ProcessOptionsX
%    \end{macrocode}
% \section{Requirements}
% The minimal requirement is \pkg{hyperref} and its built-in bookmark system. It is important to note that
% the \pkg{bookmark} package is not supported.
%    \begin{macrocode}
\RequirePackage{hyperref}
%    \end{macrocode}
%    \begin{macro}{\xbmksetup}
%    Set the cross-document options:
% \changes{v1.1}{2018/06/13}{Allow an empty value of docbundle, its value is set to \string\cs{jobname}}%
%\begin{quote}\ttfamily\obeylines
%\string\xbmksetup\darg{%
%\qquad docbundle=\darg{\ameta{doc\SUB1},\ameta{doc\SUB2},...,\ameta{doc\SUB{n}}},
%\qquad colors=\darg{int=\ameta{color},ext=\ameta{color}},
%\qquad styles=\darg{intbf,extbf,intit,extit}
%}
%\end{quote}
%This command must appear in one and only one of the document bundle, perhaps one
%of the documents you are calling the `main file'. It writes
%the key-values to the file \texttt{xbmks.cfg} which is then read back in by the other
%members of the document bundle, as specified by the \texttt{dobundle} key. The base names
%of the document bundle must match the name given to it by \cs{jobname}, exact spelling, case
%sensitive.
%
%\paragraph*{Key-values for \cs{xbmksetup}.} The keys belonging to the \texttt{xbmksetup} family:
%\IndexOpt{docbundle}\texttt{docbundle}, \IndexOpt{colors}\texttt{colors}, and \IndexOpt{styles}\texttt{styles}.
%    \begin{macrocode}
\define@key{xbmksetup}{docbundle}[]{\def\x@bmks@docs{#1}}
\let\x@bmks@docs\@empty
\define@key{xbmksetup}{colors}[]{\def\x@bmks@colors{#1}}
\let\x@bmks@colors\@empty
\define@key{xbmksetup}{styles}[]{\def\x@bmks@styles{#1}}
\let\x@bmks@styles\@empty
%    \end{macrocode}
%\subparagraph*{Values for the key \texttt{colors}.} The value recognized are
%\begin{quote}\ttfamily
%  colors=\darg{int=\ameta{color},ext=\ameta{color}}
%\end{quote}
%If the value of \texttt{int} or \texttt{ext} is empty, then the PDF viewer's default
%colors are using (black).
%    \begin{macrocode}
\define@key{xbmk@colors}{int}[]{%
  \HyColor@BookmarkColor{#1}{\xbmks@intC}{xbmks}{int}%
  \ifx\xbmks@intC\@empty\else
  \edef\xbmks@intC{/C[\xbmks@intC]}\fi
}
\let\xbmks@intC\@empty
\define@key{xbmk@colors}{ext}[]{%
  \HyColor@BookmarkColor{#1}{\xbmks@extC}{xbmks}{ext}%
  \ifx\xbmks@extC\@empty\else
  \edef\xbmks@extC{/C[\xbmks@extC]}\fi
}
\let\xbmks@extC\@empty
\let\xbmks@Yes=y \let\xbmks@No=n
%    \end{macrocode}
%\subparagraph*{Values for the key \texttt{colors}.} The value recognized are
%\begin{quote}\ttfamily
%  styles=\darg{intbf,intit,extbf,extit}
%\end{quote}
%These are valueless keys (Boolean keys, actually).  \texttt{intbf} means the interior document bookmarks
%are set in bold while \texttt{intbf,intit} creates bold and italic font.
%    \begin{macrocode}
\define@boolkey{xbmk@styles}{intbf}[true]{}
\define@boolkey{xbmk@styles}{extbf}[true]{}
\define@boolkey{xbmk@styles}{intit}[true]{}
\define@boolkey{xbmk@styles}{extit}[true]{}
%    \end{macrocode}
%    We evaluate the values of \cs{xbmksetup} by getting the values of
%    the \texttt{xbmksetup} family.
%    \begin{macrocode}
\newcommand{\xbmksetup}[1]{\setkeys{xbmksetup}{docbundle,#1}%
%    \end{macrocode}
%    \changes{v2.0.2}{2018/07/04}{Added an empty docbundle argument. This solves a problem
%    that the bookmarks not appearing after an even number of compiles.}
%    \begin{macrocode}
  \ifx\x@bmks@docs\@empty
%    \end{macrocode}
%     If there is no \texttt{docbundle} is specified, we use \cs{jobname} as its
%     value.
%    \begin{macrocode}
    \PackageInfo{xbmks}{The docbundle key of \string\xbmksetup\space
    is empty,\MessageBreak
    I will give it a value of `\jobname',\MessageBreak
    in hopes this is your intention}%
    \gdef\xbmk@cnt{1}%
    \def\xbmks@next{\write@xbmks@cfg{docbundle={\jobname},#1}}\else
    \def\xbmks@next{\write@xbmks@cfg{#1}}\fi\xbmks@next
}
%    \end{macrocode}
%    We write the key-values of \cs{xbmksetup} to the hard drive in the file
%    \texttt{xbmks.cfg}, this is \cs{xbmksetupi\darg{\ameta{KVPairs}}}. \cs{xbmksetupi}
%    is defined below, it is the command that actually does the heavy lifting in
%    processing the key-values.
%    \begin{macrocode}
\def\write@xbmks@cfg#1{%
  \newwrite\xbmks@setup \immediate\openout \xbmks@setup xbmks.cfg
  \set@display@protect
  \immediate\write\xbmks@setup{\protect\xbmksetupi{#1}}%
  \set@typeset@protect
  \immediate\closeout\xbmks@setup
}
%    \end{macrocode}
%    \cs{xbmksetupi} is an internal command that sets the key-values across all files in the \texttt{docbundle}.
%    \begin{macrocode}
\newcommand{\xbmksetupi}[1]{%
  \setkeys{xbmksetup}{#1}%
  \edef\x{\noexpand\x@docbundle{\x@bmks@docs}}\x
  \edef\x{\noexpand
    \setkeys{xbmk@colors}{\x@bmks@colors}}\x
  \edef\x{\noexpand
    \setkeys{xbmk@styles}{\x@bmks@styles}}\x
  \let\xbmk@intF\@empty
  \ifKV@xbmk@styles@intit
    \ifKV@xbmk@styles@intbf
      \def\xbmk@intF{/F 3}\else
      \def\xbmk@intF{/F 1}\fi
  \else
    \ifKV@xbmk@styles@intbf
      \def\xbmk@intF{/F 2}\fi
  \fi
  \let\xbmk@extF\@empty
  \ifKV@xbmk@styles@extit
    \ifKV@xbmk@styles@extbf
      \def\xbmk@extF{/F 3}\else
      \def\xbmk@extF{/F 1}\fi
  \else
    \ifKV@xbmk@styles@extbf
      \def\xbmk@extF{/F 2}\fi
  \fi
}
%    \end{macrocode}
%    \end{macro}
%    \begin{macro}{\x@docbundle}
%    is a comma-delimited list of document base names:
%\begin{quote}\ttfamily\obeylines
%\string\x@docbundle\darg{\ameta{doc\SUB1},\ameta{doc\SUB2},...,\ameta{doc\SUB{n}}}
%\end{quote}
%This command is called internally by \cs{xbmksetupi}.
%    \begin{macrocode}
\def\xbmkcsarg#1#2{\expandafter#1\csname#2\endcsname}
\xdef\xbmk@cnt{0}
\newcommand{\x@docbundle}[1]{\bgroup
  \def\thisDoc{\jobname}\count\z@=0 %
  \edef\@tmpexp{\noexpand\@for\noexpand\@arg:=#1}%
  \@tmpexp\do{\advance\count\z@ by 1\relax
    \edef\x{\noexpand\xbmk@recordDoc{\@arg}}\x
    \edef\x{\noexpand\xbmk@docID{\@arg}}\x
  }%
  \xdef\xbmk@cnt{\the\count\z@}\egroup
}
\newcommand{\xbmk@recordDoc}[1]{%
  \xbmkcsarg\xdef{xbmk@doc\the\count\z@}{#1}}
%    \end{macrocode}
%    Because we are bringing in multiple outline files, there may be duplicate anchor names.
%    We assign each file in the document bundle a unique ID `\texttt{x1\ameta{anchor}}', `\texttt{x2\ameta{anchor}}', etc.
%    The IDs are ultimately assigned through \cs{pdfbookmarkx}.
%    \begin{macrocode}
\newcommand{\xbmk@docID}[1]{%
  \xbmkcsarg\xdef{x#1}{x\the\count\z@}}
\xbmkcsarg\xdef{x\jobname}{x0}
%    \end{macrocode}
%    \end{macro}
%
%    \section{Extending bookmarks to arbitrary actions}
%
%    It is possible to create bookmarks with arbitrary actions, just as the \pkg{bookmark}
%    package, does. Here we try to use \pkg{hyperref}'s native bookmark support. The
%    \pkg{hyperref} commands \cs{pdfbookmark}, \cs{currentbookmark}, \cs{subpdfbookmark}, and
%    \cs{belowpdfbookmark} are modified.
%    \begin{macro}{\pdfbookmarkx}\hskip-\marginparsep\,
%    \texttt{[\ameta{level}]\darg{\ameta{text}}[\ameta{xbmkskeys-kvp}]\darg{\ameta{name}}}\\
%    Defines a bookmark at \ameta{level}. If \ameta{level} is not provided, the level 1 is assumed.
%    We write to the outline file the action desired for this bookmark.
%    \cs{currentAction} is defined below. We do not set an anchor; if the
%    document author wants an anchor, he should use \cs{pdfbookmark}. As with
%    \cs{pdfbookmark}, the \cs{pdfbookmarkx} should not normally be directly
%    used.
%    \paragraph*{Key-values for the `\cs{...bookmarkx}' commands.} Recognized keys are
%    \IndexKey{action}\texttt{action}, \IndexKey{color}\texttt{color}, and \IndexKey{style}\texttt{style}.
%    Note that these keys are singular, as opposed to \texttt{colors} and \texttt{styles} defined in the
%    \texttt{xbmksetup} family. This is the \texttt{xbmkskeys} family.
%    \changes{v2.0}{2018/06/21}{Added `\string\cs{...bookmarkx} commands}
%    \changes{v2.0.1}{2018/06/25}{Added key-values for action, color, and style for custom `\string\cs{...bookmarkx} commands}
%    \begin{macrocode}
\define@key{xbmkskeys}{action}{\def\x@bmks@action{#1}}
\let\x@bmks@action\@empty
\define@key{xbmkskeys}{color}[]{%
  \HyColor@BookmarkColor{#1}{\x@bmks@C}{xbmks}{color}%
  \ifx\x@bmks@C\@empty\else
  \edef\x@bmks@C{/C[\x@bmks@C]}\fi
}
\let\x@bmks@C\@empty
\define@key{xbmkskeys}{style}[]{%
  \edef\x{\noexpand\setkeys{xbmks@style}{#1}}\x
  \let\x@bmks@F\@empty
  \ifKV@xbmks@style@it
    \ifKV@xbmks@style@bf
      \def\x@bmks@F{/F 3}\else
      \def\x@bmks@F{/F 1}\fi
  \else
    \ifKV@xbmks@style@bf
      \def\x@bmks@F{/F 2}\fi
  \fi
}
\let\x@bmks@F\@empty
%    \end{macrocode}
%    The \texttt{style} key takes zero, one, or two values, these are \texttt{bf} and \texttt{it}.
%    \begin{macrocode}
\define@boolkey{xbmks@style}{bf}[true]{}
\define@boolkey{xbmks@style}{it}[true]{}
\def\x@rollCFIntoActionBmrk#1{%
  \xbmkcsarg\ifx{X_#1}\relax
    \let\x@bmks@C\@empty\let\x@bmks@F\@empty\fi
  \ifx\xbmk@J\xbmk@filename
    \ifx\x@bmks@C\@empty\let\thisCol\xbmks@intC\else
      \let\thisCol\x@bmks@C\fi
    \ifx\x@bmks@F\@empty\let\thisF\xbmk@intF\else
      \let\thisF\x@bmks@F\fi
  \else
    \ifx\x@bmks@C\@empty\let\thisCol\xbmks@extC\else
      \let\thisCol\x@bmks@C\fi
    \ifx\x@bmks@F\@empty\let\thisF\xbmk@extF\else
      \let\thisF\x@bmks@F\fi
  \fi
  \global\let\x@bmks@C\@empty\global\let\x@bmks@F\@empty
}
%    \end{macrocode}
%    We finally arrive at \cs{pdfbookmarkx} command.
%    \begin{macrocode}
\newcommand\pdfbookmarkx[2][0]{%
  \@ifnextchar[%]
    {\pdfbookmarkx@i{#1}{#2}}
    {\pdfbookmarkx@i{#1}{#2}[]}}
\def\pdfbookmarkx@i#1#2[#3]#4{% level, title, action, name
  \def\x@rgiii{#3}\ifx\x@rgiii\@empty
%    \end{macrocode}
% if there is no action, treat as a destination
%    \begin{macrocode}
    \Hy@writebookmark{}{#2}{#4.#1}{#1}{toc}%
    \hyper@anchorstart{#4.#1}\hyper@anchorend
  \else
  \protected@write\@outlinefile{}{%
    \string\nextAction% assign doc ID
      {\@nameuse{x\jobname}#4.#1}{#3}}%
  \Hy@writebookmark{}{#2}{\@nameuse{x\jobname}#4.#1}{#1}{toc}%
  \fi
}
%    \end{macrocode}
%    \end{macro}
%    \begin{macro}{\currentpdfbookmarkx}
%    \hskip-\marginparsep\,\texttt{\darg{\ameta{text}}[\ameta{xbmkskeys-kvp}]\darg{\ameta{name}}}\\
%    The \texttt{action=\ameta{action}} is raw PDF code, for example,
%\begin{quote}\ttfamily
%\string\currentpdfbookmarkx[/S/URI/URI(http://www.acrotex.net)]\\\null
%\qquad\darg{http://www.acrotex.net}\darg{home}
%\end{quote}
%   The command creates a bookmark at the current
%   bookmark level in the outline tree and associates the specified \ameta{action}. The argument
%   \ameta{text} appears in the bookmark panel. The \ameta{name} is used for identification purposes.
%    \begin{macrocode}
\newcommand{\currentpdfbookmarkx}[1]{%
  \@ifnextchar[%]
    {\currentpdfbookmarkx@i{#1}}
    {\currentpdfbookmarkx@i{#1}[]}}
\def\currentpdfbookmarkx@i#1[#2]#3{%
  \pdfbookmarkx[\Hy@currentbookmarklevel]{#1}[{#2}]{#3}}
%    \end{macrocode}
%    \end{macro}
%    \begin{macro}{\subpdfbookmarkx}
%    \hskip-\marginparsep\,\texttt{\darg{\ameta{text}}[\ameta{\ameta{xbmkskeys-kvp}}]\darg{\ameta{name}}}\\
%    Reduces the current bookmark level by one, then creates
%    the bookmark at that level. The reduced level is the new current
%    bookmark level.
%    \begin{macrocode}
\newcommand{\subpdfbookmarkx}[1]{%
  \@ifnextchar[%]
    {\subpdfbookmarkx@i{#1}}
    {\subpdfbookmarkx@i{#1}[]}}
\def\subpdfbookmarkx@i#1[#2]#3{%
  \@tempcnta\Hy@currentbookmarklevel
  \Hy@StepCount\@tempcnta
  \expandafter
  \pdfbookmarkx\expandafter[\the\@tempcnta]{#1}[{#2}]{#3}}
%    \end{macrocode}
%    \end{macro}
%    \begin{macro}{\belowpdfbookmarkx}
%    \hskip-\marginparsep\,\texttt{\darg{\ameta{text}}[\ameta{xbmkskeys-kvp}]\darg{\ameta{name}}}\\
%    Creates a bookmark at one level below the current
%    bookmark level without changing the value of the current bookmark
%    level.
%    \begin{macrocode}
\newcommand{\belowpdfbookmarkx}[1]{%
  \@ifnextchar[%]
    {\belowpdfbookmarkx@i{#1}}
    {\belowpdfbookmarkx@i{#1}[]}}
\def\belowpdfbookmarkx@i#1[#2]#3{%
  \@tempcnta\Hy@currentbookmarklevel
  \Hy@StepCount\@tempcnta
  \expandafter
  \pdfbookmarkx\expandafter[\the\@tempcnta]{#1}[{#2}]{#3}%
  \advance\@tempcnta by -1 %
  \xdef\Hy@currentbookmarklevel{\the\@tempcnta}}
%    \end{macrocode}
%    \end{macro}
%    \begin{macro}{\nextAction@i}
%     \hskip-\marginparsep\,\texttt{\darg{\ameta{anchor.level}}\darg{\ameta{xbmkskeys-kvp}}}\\
%     This command is used internally, the document author need not do anything.
%     The command \cs{nextAction} is \cs{let} to \cs{nextAction@i} just prior to when
%     the outline file is input; and is \cs{let} to \cs{@gobbletwo}, otherwise.
%    \begin{macrocode}
\def\nextAction@i#1#2{\@ifundefined{X_#1}{%
    \setkeys{xbmkskeys}{#2}%
    \xbmkcsarg\xdef{X_#1}{\x@bmks@action}%
    }{\global\xbmkcsarg\let{X_#1}\relax
    \PackageWarning{xbmks}
    {The anchor name `#1' is already defined,\MessageBreak
    change this name, the bookmark will be created\MessageBreak
    but it will have no associated action}}}
%    \end{macrocode}
%    \end{macro}
%    \begin{macrocode}
\def\x@outWarningMsg{\PackageWarningNoLine{xbmks}{%
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@\MessageBreak
@@ Outline files were not input, compile again @@\MessageBreak
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@}}%
%    \end{macrocode}
%    These commands are implemented in the driver dependent sections.
%    \begin{macrocode}
% End package
%&lt;/package&gt;
%&lt;*pdfmark&gt;
%    \end{macrocode}
%    \section{Driver dependent code}
%    \subsection{The pdfmark driver}
%    We redefine/modify the \cs{ReadBookmarks} command of \pkg{hyperref},
%    this definition is driver dependent.
%    \begin{macrocode}
\def\ReadBookmarks{%
  \pdf@ifdraftmode{}{%
    \begingroup\def\\{\@backslashchar\@backslashchar}% dps
      \def\calc@bm@number##1{%
      \@tempcnta=\check@bm@number{##1}\relax
      \advance\@tempcnta by 1 %
      \expandafter\edef\csname B_##1\endcsname{\the\@tempcnta}%
      }%
      \def\do##1{%
        \ifnum\catcode`##1=\active
          \@makeother##1%
        \else
          \ifnum\catcode`##1=6 %
            \@makeother##1%
          \fi
        \fi
      }%
      \dospecials
      \Hy@safe@activestrue
      \escapechar=`\\%
      \ifx\WriteBookmarks\relax
        \global\let\WriteBookmarks\relax
      \fi
      \begingroup
        \def\WriteBookmarks{0}%
        \count\z@=0\relax
        \edef\xbmk@J{\jobname}%
        \@whilenum \count\z@&lt;\xbmk@cnt\relax\do{%
          \advance\count\z@ by 1 %
          \edef\xbmk@thisdoc{xbmk@doc\the\count\z@}%
          \edef\xbmk@filename{\@nameuse{\xbmk@thisdoc}}%
          \@onelevel@sanitize\xbmk@filename
          \bgroup
          \def\@@BOOKMARK[##1][##2]##3##4##5{%
            \calc@bm@number{##5}%
          }%
          \let\nextAction\@gobbletwo
          \InputIfFileExists{\xbmk@filename.out}{}{\x@outWarningMsg}%
          \def\@@BOOKMARK[##1][##2]##3##4##5{%
            \def\Hy@temp{##4}%
%    \end{macrocode}
%    If `\texttt{X\_\#\#3}' is undefined (\cs{relax}), it is a  normal bookmark.
%    \begin{macrocode}
            \xbmkcsarg\ifx{X_##3}\relax
              \ifx\xbmk@J\xbmk@filename
                \pdfmark{%
                  pdfmark=/OUT,%
                  Count={##2\check@bm@number{##3}},%
                  Raw={\xbmks@intC\xbmk@intF},%
                  Dest={##3},%
                  Title=\expandafter\strip@prefix\meaning\Hy@temp
                }%
              \else
                \pdfmark{%
                  pdfmark=/OUT,%
                  Count={##2\check@bm@number{##3}},%
                  Raw={\xbmks@extC\xbmk@extF},%
                  Action=/GoToR,%
                  File={\xbmk@filename.pdf},%
                  Dest={##3},%
                  Title=\expandafter\strip@prefix\meaning\Hy@temp
                }%
              \fi
            \else
%    \end{macrocode}
%    The anchor has an `\texttt{X\_}' definition, it is a bookmark created
%    from one of the `\texttt{bookmarkx}' commands. We treat this as a separate case.
%    \begin{macrocode}
              \x@rollCFIntoActionBmrk{##3}%
              \pdfmark{%
                pdfmark=/OUT,%
                Count={##2\check@bm@number{##3}},%
                Raw={/Action&lt;&lt;\@nameuse{X_##3}&gt;&gt;\thisCol\thisF},%
                Title=\expandafter\strip@prefix\meaning\Hy@temp
              }%
            \fi
          }% bookmark
          \let\nextAction\nextAction@i
          \InputIfFileExists{\xbmk@filename.out}{}{}%
          \egroup
        }% \@whilenum
      \endgroup
    \endgroup
  }%
  \ifx\WriteBookmarks\relax\else
    \if@filesw
      \newwrite\@outlinefile
      \Hy@OutlineRerunCheck
     \immediate\openout\@outlinefile=\jobname.out\relax
      \ifHy@typexml
        \immediate\write\@outlinefile{&lt;relaxxml&gt;\relax}%
      \fi
    \fi
  \fi
}
%&lt;/pdfmark&gt;
%    \end{macrocode}
%    \subsection{Code for pdftex/luatex driver}
%    We redefine/modify the \cs{ReadBookmarks} command of \pkg{hyperref},
%    this definition is driver dependent.
%    \begin{macrocode}
%&lt;*pdftex&gt;
\def\ReadBookmarks{%
  \pdf@ifdraftmode{}{%
    \begingroup\def\\{\@backslashchar\@backslashchar}% dps
    \def\calc@bm@number##1{%
      \@tempcnta=\check@bm@number{##1}\relax
      \advance\@tempcnta by 1 %
      \expandafter\edef\csname B_##1\endcsname{\the\@tempcnta}%
    }%
    \def\Hy@OutlineName##1##2##3##4{\def\@rgi{##1}%
      \expandafter\pdfoutline\ifx\@rgi\@empty\else
      attr {##1} \fi
      user {##2} count##3{##4}%
    %  goto name{#2} count#3{#4}%
    }%
    \def\do##1{%
      \ifnum\catcode`##1=\active
        \@makeother##1%
      \else
        \ifnum\catcode`##1=6 %
          \@makeother##1%
        \fi
      \fi
    }%
    \dospecials
    \Hy@safe@activestrue
    \escapechar=`\\%
    \ifx\WriteBookmarks\relax
      \global\let\WriteBookmarks\relax
    \fi
    \begingroup
    \def\WriteBookmarks{0}%
    \count\z@=0\relax
    \edef\xbmk@J{\jobname}%
    \@whilenum \count\z@&lt;\xbmk@cnt\relax\do{%
      \advance\count\z@ by 1 %
      \edef\xbmk@thisdoc{xbmk@doc\the\count\z@}%
      \edef\xbmk@filename{\@nameuse{\xbmk@thisdoc}}%
      \@onelevel@sanitize\xbmk@filename
      \bgroup
      \gdef\@@BOOKMARK[##1][##2]##3##4##5{%
        \calc@bm@number{##5}%
      }%
      \let\nextAction\@gobbletwo
      \InputIfFileExists{\xbmk@filename.out}{}{\x@outWarningMsg}%
      \gdef\@@BOOKMARK[##1][##2]##3##4##5{%
        \def\Hy@temp{##4}%
        \Hy@pstringdef\Hy@pstringName{\HyperDestNameFilter{##3}}%
        \xbmkcsarg\ifx{X_##3}\relax
%    \end{macrocode}
%     Ordinary bookmark
%    \begin{macrocode}
          \ifx\xbmk@J\xbmk@filename
            \Hy@OutlineName{\xbmks@intC\xbmk@intF}{&lt;&lt;/S/GoTo%
              /D(\Hy@pstringName)&gt;&gt;}{%
              ##2\check@bm@number{\Hy@pstringName}%
            }{%
              \expandafter\strip@prefix\meaning\Hy@temp
            }%
          \else
            \Hy@OutlineName{\xbmks@extC\xbmk@extF}{&lt;&lt;/S/GoToR%
              /F(\xbmk@filename.pdf)/D(\Hy@pstringName)&gt;&gt;}{%
              ##2\check@bm@number{##3}%
            }{%
              \expandafter\strip@prefix\meaning\Hy@temp
            }%
          \fi
        \else
%    \end{macrocode}
%     Bookmark created by one of the `\texttt{...bookmarkx} commands
%    \begin{macrocode}
          \x@rollCFIntoActionBmrk{##3}%
          \Hy@OutlineName{\thisCol\thisF}
          {&lt;&lt;\@nameuse{X_##3}&gt;&gt;}{%
              ##2\check@bm@number{\Hy@pstringName}%
          }{%
            \expandafter\strip@prefix\meaning\Hy@temp
          }%
        \fi
      }% bookmark
      \let\nextAction\nextAction@i
      \InputIfFileExists{\xbmk@filename.out}{}{}%
      \egroup
    } % \@whilenum
    \endgroup
  }%
  \ifx\WriteBookmarks\relax
  \else
    \if@filesw
      \newwrite\@outlinefile
      \Hy@OutlineRerunCheck
      \immediate\openout\@outlinefile=\jobname.out\relax
      \ifHy@typexml
        \immediate\write\@outlinefile{&lt;relaxxml&gt;\relax}%
      \fi
    \fi
  \fi
}
%&lt;/pdftex&gt;
%&lt;*xetex&gt;
%    \end{macrocode}
%    \subsection{Code for xetex driver}
%    We redefine/modify the \cs{ReadBookmarks} command of \pkg{hyperref},
%    this definition is driver dependent.
%    \begin{macrocode}
\def\ReadBookmarks{%
  \pdf@ifdraftmode{}{%
    \begingroup\def\\{\@backslashchar\@backslashchar}% dps
      \def\calc@bm@number##1{%
        \@tempcnta=\check@bm@number{##1}\relax
        \advance\@tempcnta by 1 %
        \expandafter\edef\csname B_##1\endcsname{\the\@tempcnta}%
      }%
      \def\do##1{%
        \ifnum\catcode`##1=\active
          \@makeother##1%
        \else
          \ifnum\catcode`##1=6 %
            \@makeother##1%
          \fi
        \fi
      }%
      \dospecials
      \Hy@safe@activestrue
      \escapechar=`\\%
      \ifx\WriteBookmarks\relax
        \global\let\WriteBookmarks\relax
      \fi
      \begingroup
        \def\WriteBookmarks{0}%
        \count\z@=0\relax
        \edef\xbmk@J{\jobname}%
        \@whilenum \count\z@&lt;\xbmk@cnt\relax\do{%
          \advance\count\z@ by 1 %
          \edef\xbmk@thisdoc{xbmk@doc\the\count\z@}%
          \edef\xbmk@filename{\@nameuse{\xbmk@thisdoc}}%
          \@onelevel@sanitize\xbmk@filename
          \bgroup
          \def\@@BOOKMARK[##1][##2]##3##4##5{%
            \calc@bm@number{##5}%
          }%
          \let\nextAction\@gobbletwo
          \InputIfFileExists{\xbmk@filename.out}{}{\x@outWarningMsg}%
          \def\@@BOOKMARK[##1][##2]##3##4##5{%
            \def\Hy@temp{##4}%
            \Hy@pstringdef\Hy@pstringName{\HyperDestNameFilter{##3}}%
            \x@rollCFIntoActionBmrk{##3}%
            \@pdfm@mark{%
              outline \ifHy@DvipdfmxOutlineOpen
                [\ifnum##21&gt;\z@\else-\fi] \fi
              ##1&lt;&lt;%
              /Title(\expandafter\strip@prefix\meaning\Hy@temp)%
              \xbmkcsarg\ifx{X_##3}\relax
%    \end{macrocode}
%     Ordinary bookmark
%    \begin{macrocode}
                \ifx\xbmk@J\xbmk@filename
                  /A&lt;&lt;%
                    /S/GoTo%
                    /D(\Hy@pstringName)%
                  &gt;&gt;%
                \else
                  /A&lt;&lt;%
                    /S/GoToR/F(\xbmk@filename.pdf)%
                    /D(\Hy@pstringName)%
                  &gt;&gt;%
                \fi
              \else
%    \end{macrocode}
%     Bookmark created by one of the \texttt{\string\...bookmarkx} commands
%    \begin{macrocode}
                /A&lt;&lt;\@nameuse{X_##3}&gt;&gt;
              \fi
              \thisCol\thisF
              &gt;&gt;%
            }% \@pdfm@mark
            \let\thisC\@empty\let\thisF\@empty
          }% bookmark
          \let\nextAction\nextAction@i
          \InputIfFileExists{\xbmk@filename.out}{}{}%
          \egroup
        }% \@whilenum
      \endgroup
    \endgroup
  }%
  \ifx\WriteBookmarks\relax
  \else
    \if@filesw
      \newwrite\@outlinefile
      \Hy@OutlineRerunCheck
     \immediate\openout\@outlinefile=\jobname.out\relax
      \ifHy@typexml
        \immediate\write\@outlinefile{&lt;relaxxml&gt;\relax}%
      \fi
    \fi
  \fi
}
%&lt;/xetex&gt;
%&lt;*package&gt;
\InputIfFileExists{xbmks.cfg}{}{}
\@ifpackageloaded{bookmark}{\PackageWarningNoLine{xbmks}{The
  bookmark package is not supported;\MessageBreak
  this package does nothing, as a result}}
{\InputIfFileExists{\xbmk@driver}{}{}}
%&lt;/package&gt;
%    \end{macrocode}
%    \Finale
</pre></body></html>