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%%% ====================================================================
%%% @LaTeX-doc-source-file{
%%% filename = "ifoption.dtx",
%%% version = "1.02",
%%% date = "2002/03/04",
%%% time = "16:33:16 EST",
%%% author = "Michael J Downes",
%%% address = "American Mathematical Society,
%%% Publications Technical Group,
%%% PO Box 6248,
%%% Providence, RI 02940,
%%% USA",
%%% email = "tech-support@ams.org",
%%% URL = "http://www.ams.org/",
%%% abstract = "",
%%% checksum = "06695 170 563 5432",
%%% docstring = "The checksum field, produced by Robert Solovay's
%%% checksum utility, gives CRC-16 checksum, lines,
%%% words, and characters.",
%%% }
%%% ====================================================================
% \iffalse
%<*driver>
\NeedsTeXFormat{LaTeX2e}
\documentclass{amsdtx}
\providecommand{\mdash}{\textemdash}
\newcommand{\xt}[1]{\texttt{#1}}
\providecommand{\qq}[1]{``#1''}
\providecommand{\lat}[1]{\protect\LaTeX{}}
\begin{document}
\title{The \pkg{ifoption} package}
\author{Michael~J. Downes\\American Mathematical Society}
\date{Version \fileversion, \filedate}
\hDocInput{ifoption.dtx}
\end{document}
%</driver>
% \fi
%
% \maketitle
% \section{Introduction}
%
% The \pkg{ifoption} package provides an \cn{IfOption} command that
% has certain advantages over the \cs{@ifpackagewith} command\mdash
% e.g., default options specified with \cs{ExecuteOptions} test as
% true rather than false. In order for this to work properly,
% mutually exclusive options should be specified with
% \cs{DeclareExclusiveOptions}, another command defined by the
% \pkg{ifoption} package.
% \StopEventually{}
%
% \section{Implementation}
% \subsection{Package info}
%
% Standard declaration of package name and date.
% \begin{macrocode}
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{ifoption}[2002/03/04 v1.02]
% \end{macrocode}
%
% \subsection{Some utility functions}
%
% \begin{macrocode}
\let\@xp\expandafter \let\@nx\noexpand
% \end{macrocode}
%
% \begin{macrocode}
\def\@True{00}
\def\@False{01}
% \end{macrocode}
%
% \subsection{Background}
% See the definitions of \cs{@onefilewithoptions} and
% \cs{@pushfilename} in the \lat/ kernel.
%
% When we have
%\begin{verbatim}
%\DeclareOption{foo}{some code}
%\end{verbatim}
% in a file named \fn{bar.sty}, \lat/ defines \cs{ds@foo} to contain
% \emph{some code}. Then if the package is invoked with
%\begin{verbatim}
%\usepackage[foo]{bar}
%\end{verbatim}
% there are two consequences: \opt{foo} is added to the options list
% for package \pkg{bar}, which is the control sequence
% \cs{opt@bar.sty}; and when \cs{ProcessOptions} is called, it
% executes \cs{ds@option-name} for each option found in the list.
% When it is finished running the options, \cs{ProcessOptions}
% undefines all the \cs{ds@whatever} for the current package, which
% are listed in the control sequence \cs{@declaredoptions}. At the
% end of \fn{bar.sty}, \cs{@declaredoptions} is globally reset to
% empty. Thus subordinate packages with options cannot be loaded in
% the \qq{first half} of a package that also has options, where first half
% means the area leading up to the \cs{ProcessOptions} call.
%
% For mutually exclusive options \xt{a}, \xt{b}, \xt{c}, when option
% \xt{b} is invoked it should remove all of its sibling options from
% the options-actually-used list and add itself to the list. For this
% task we make use of the fact that \cs{ProcessOptions} ends by
% undefining all the declared options of the current package or
% documentclass.
%
% \begin{macrocode}
\def\CurrentPackage{\@currname}
\let\CurrentClass\CurrentPackage
% \end{macrocode}
%
% \begin{macrocode}
\newcommand{\IfOption}{}
\def\IfPackageOption{\@ifpackagewith}
\def\IfClassOption{\@ifclasswith}
\def\IfOption{%
\ifx\@currext\@pkgextension \@xp\IfPackageOption
\else \@xp\IfClassOption
\fi
\@currname
}
% \end{macrocode}
%
% \begin{macrocode}
\newcommand{\DeclareExclusiveOptions}[1]{%
\xdef\@declaredoptions{\@declaredoptions,#1}%
\gdef\ProcessExclusiveOptions{\relax}%
\@for\CurrOption:=#1\do{%
\@xp\deo@a\csname ds@\CurrOption\@xp\endcsname\@xp{\CurrOption}{#1}%
}%
}
\def\DeclareBooleanOption{\DeclareExclusiveOptions}
% \end{macrocode}
%
% \begin{macrocode}
\def\deo@a#1#2#3{%
\def#1{%
\g@addto@macro\ProcessExclusiveOptions{\OptionsFalseTrue{#3}{#2}}%
}%
}
% \end{macrocode}
%
% \begin{macrocode}
\def\cull@options#1,{%
\@xp\ifx\csname ds@#1\@gobble\@percentchar\@empty\endcsname\@False
\else #1,\fi
\cull@options
}
\newcommand{\OptionsFalseTrue}[2]{%
\begingroup
\@for\CurrentOption:=#1\do{%
\@xp\let\csname ds@\CurrentOption\endcsname\@False
}%
\let\ds@\@False
\@xp\xdef\csname opt@\@currname.\@currext\endcsname{%
\@xp\@xp\@xp\cull@options\csname opt@\@currname.\@currext\endcsname
% \end{macrocode}
% Lacking \cs{@secondofthree} and not keen on defining it \ldots
% \begin{macrocode}
,\@firstoftwo\@firstoftwo,#2%
}%
\endgroup
}
% \end{macrocode}
%
% The usual \cs{endinput} to ensure that random garbage at the end of
% the file doesn't get copied by \fn{docstrip}.
% \begin{macrocode}
\endinput
% \end{macrocode}
%
% \CheckSum{112}
% \Finale
|
