path: root/macros/latex/contrib/eqparbox/eqparbox.dtx

% \iffalse meta-comment
%
% Copyright (C) 2017 Scott Pakin <scott+eqp@pakin.org>
% ----------------------------------------------------
%
% This package may be distributed and/or modified under the
% conditions of the LaTeX Project Public License, either version 1.3c
% of this license or (at your option) any later version.
% The latest version of this license is in
%    http://www.latex-project.org/lppl.txt
% and version 1.3c or later is part of all distributions of LaTeX
% version 2008/05/04 or later.
%
% \fi
%
% \iffalse
%<*driver>
\ProvidesFile{eqparbox.dtx}
%</driver>
%<package>\NeedsTeXFormat{LaTeX2e}[1999/12/01]
%<package>\ProvidesPackage{eqparbox}
%<*package>
    [2017/09/03 v4.1 Create equal-widthed boxes]
%</package>
%
%<*driver>
\documentclass{ltxdoc}
\usepackage{eqparbox}
\usepackage{calligra}
\usepackage{array}
\usepackage{boxedminipage}
\usepackage{needspace}
\usepackage{ifmtarg}
\usepackage[subrefformat=parens,labelformat=parens]{subfig}
\usepackage[bookmarksopen]{hyperref}
\EnableCrossrefs
\CodelineIndex
\RecordChanges

% Uncomment the following line if you don't want to include a
% source-code listing.
%\OnlyDescription

\begin{document}
  \sloppy
  \DocInput{eqparbox.dtx}
  \Needspace{10\baselineskip}
  \phantomsection\addcontentsline{toc}{section}{Change History}
  \PrintChanges
  \makeatletter
  \let\orig@index@prologue=\index@prologue
  \def\index@prologue{%
    \phantomsection\addcontentsline{toc}{section}{Index}
    \orig@index@prologue
  }%
  \makeatother
  \Needspace{12\baselineskip}
  \PrintIndex
\end{document}
%</driver>
% \fi
%
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% \CheckSum{536}
%
% \CharacterTable
%  {Upper-case    \A\B\C\D\E\F\G\H\I\J\K\L\M\N\O\P\Q\R\S\T\U\V\W\X\Y\Z
%   Lower-case    \a\b\c\d\e\f\g\h\i\j\k\l\m\n\o\p\q\r\s\t\u\v\w\x\y\z
%   Digits        \0\1\2\3\4\5\6\7\8\9
%   Exclamation   \!     Double quote  \"     Hash (number) \#
%   Dollar        \$     Percent       \%     Ampersand     \&
%   Acute accent  \'     Left paren    \(     Right paren   \)
%   Asterisk      \*     Plus          \+     Comma         \,
%   Minus         \-     Point         \.     Solidus       \/
%   Colon         \:     Semicolon     \;     Less than     \<
%   Equals        \=     Greater than  \>     Question mark \?
%   Commercial at \@     Left bracket  \[     Backslash     \\
%   Right bracket \]     Circumflex    \^     Underscore    \_
%   Grave accent  \`     Left brace    \{     Vertical bar  \|
%   Right brace   \}     Tilde         \~}
%
% \changes{v1.0}{2001/04/19}{Initial version}
% \changes{v2.0}{2004/07/31}{Rewrote to use only two \meta{dimen}s total
%   and the rest macros (problem reported by Gilles P\'erez-Lambert and
%   Plamen Tanovski; solution suggested by David Kastrup and Donald
%   Arseneau)}
%
% \GetFileInfo{eqparbox.dtx}
%
% \DoNotIndex{\@auxout,\@cons,\@ifnextchar,\@ifundefined,\@ne,\@tempboxa}
% \DoNotIndex{\@tempdima,\DeclareRobustCommand,\\,\advance,\begin}
% \DoNotIndex{\begingroup,\bgroup,\box,\csname,\def,\egroup,\else,\end}
% \DoNotIndex{\endcsname,\endgroup,\expandafter,\fi,\gdef,\global,\hbox}
% \DoNotIndex{\ifdim,\ifnum,\ifx,\immediate,\let,\long,\m@ne,\mbox}
% \DoNotIndex{\newcommand,\newdimen,\newif,\newlength,\noexpand,\relax}
% \DoNotIndex{\renewcommand,\renewenvironment,\romannumeral,\sbox,\setbox}
% \DoNotIndex{\space,\string,\the,\wd,\xdef,\z@}
%
% ^^A  The following environment, which typesets a declaration of a command
% ^^A  in a box set out into the margin, was copied almost verbatim from
% ^^A  ltxguide.cls.
% \newenvironment{decl}[1][]^^A
%     {\par\small\addvspace{4.5ex plus 1ex}^^A
%      \vskip -\parskip
%      \ifx\relax#1\relax
%         \def\@decl@date{}^^A
%      \else
%         \def\@decl@date{\NEWfeature{#1}}^^A
%      \fi
%      \noindent\hspace{-\leftmargini}^^A
%      \begin{tabular}{|l|}\hline\ignorespaces}^^A
%     {\\\hline\end{tabular}\nobreak\@decl@date\par\nobreak
%      \vspace{2.3ex}\vskip -\parskip}
%
% ^^A  Define a style for typesetting package names.
% \DeclareRobustCommand{\pkgname}[1]{^^A
%   \textsf{#1}\index{#1=\textsf{#1} (package)}}
%
% ^^A  Give LaTeX some more leeway in placing floats
% ^^A  (suggested by Donald Arseneau <asnd@triumf.ca>).
% \renewcommand{\topfraction}{0.85}
% \renewcommand{\bottomfraction}{0.7}
% \renewcommand{\textfraction}{0.15}
% \renewcommand{\floatpagefraction}{0.66}
% \renewcommand{\dbltopfraction}{0.66}
% \renewcommand{\dblfloatpagefraction}{0.66}
% \setcounter{topnumber}{9}
% \setcounter{bottomnumber}{9}
% \setcounter{totalnumber}{20}
% \setcounter{dbltopnumber}{9}
%
% ^^A  Because we put table captions *above* tables, we should add a
% ^^A  little extra space between the caption and the table.
% \setlength{\belowcaptionskip}{2ex}
%
% ^^A  Properly hyphenate Rob Verhoeven's name.
% \hyphenation{Ver-hoe-ven}
%
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% \title{The \pkgname{eqparbox} package\thanks{This document
%   corresponds to \pkgname{eqparbox}~\fileversion, dated \filedate.}}
% \author{Scott Pakin \\ \textit{scott+eqp@pakin.org}}
% \hypersetup{^^A
%   pdftitle={The eqparbox package},
%   pdfauthor={Scott Pakin <scott+eqp@pakin.org>},
%   pdfsubject={LaTeX package for typesetting text in equal-widthed boxes},
%   pdfkeywords={LaTeX2e, parbox, makebox, framebox, savebox, boxes, automatic width, largest}
% }
%
% \maketitle
%
% \begin{abstract}
%   The \pkgname{eqparbox} package makes it easy to define a group of
%   boxes (such as those produced by |\parbox| or |\makebox|) whose
%   members all have the same width, the natural width of the widest
%   member.  A document can contain any number of groups, and each group
%   can contain any number of members.  This simple, equal-width
%   mechanism can be used for a variety of alignment purposes, as is
%   evidenced by the examples in this document.
% \end{abstract}
%
% \section{Motivation}
% \label{sec:motivation}
%
% Let's start with a little test.  How would you typeset
% Figure~\ref{fig:quotations}, in which the names of the quotations'
% authors are left-justified relative to each other but as a group abut
% the right margin?  And second, how would you typeset the r\'esum\'e
% excerpt shown in Figure~\ref{fig:resume-excerpt} while meeting the
% following requirements:
%
% \begin{enumerate}
%   \item The header columns must be left-justified relative to each
%         other.
%   \item The header columns should be evenly spaced across the page.
%   \item Page breaks should be allowed within the r\'esum\'e.
% \end{enumerate}
%
% \begin{figure}[htbp]
%   \centering
%   \makeatletter
%   \newcommand{\showquote}[2]{^^A
%     \begin{flushright}
%       ---~\eqparbox{quotebox}{\sffamily#1}^^A
%       \@ifnotmtarg{#2}{\\
%         \mbox{}\phantom{---}~\eqparbox{quotebox}{\sffamily\itshape#2}^^A
%       }^^A
%     \end{flushright}^^A
%     \par
%   }
%   \makeatother
%   \begin{boxedminipage}{\linewidth}
%     The only medicine for suffering, crime, and all other woes of mankind,
%     is wisdom. Teach a man to read and write, and you have put into his
%     hands the great keys of the wisdom box. But it is quite another thing
%     to open the box.
%     \showquote{Thomas Huxley}{}
%
%     I would like a simple life \\
%     yet all night I am laying \\
%     poems away in a long box. \par
%     \bigskip
%     It is my immortality box, \\
%     my lay-away plan, \\
%     my coffin.
%     \showquote{Anne Sexton}{The Ambition Bird}
%
%     \bigskip
%
%     We have four boxes with which to defend our freedom: the soap box, the
%     ballot box, the jury box, and the cartridge box.
%     \showquote{Larry McDonald}{}
%
%     \bigskip
%
%     I saw the Count lying within the box upon the earth, some of which the
%     rude falling from the cart had scattered over him. He was deathly
%     pale, just like a waxen image, and the red eyes glared with the
%     horrible vindictive look which I knew so well.
%     \showquote{Bram Stoker}{Dracula}
%
%     \bigskip
%
%     Life in a box is better than no life at all, I expect. You'd
%     have a chance, at least. You could lie there thinking, ``Well,
%     at least I'm not dead.''
%     \showquote{Tom Stoppard}{Rosencrantz~\& Guildenstern Are Dead}
%
%     \bigskip
%
%     Alla fin del gioco tanto va nel sacco il re quanto la pedina. \\
%     \textit{(After the game, the king and pawn go into the same box.)}
%     \showquote{Italian proverb}{}
%   \end{boxedminipage}
%   \caption{Quotations with left-aligned attributions}
%   \label{fig:quotations}
% \end{figure}
%
% \begin{figure}[htbp]
% \bigskip\noindent\rule{\linewidth}{1pt}\bigskip\par
% \noindent
% \eqparbox{place}{\textbf{Widgets, Inc.}} \hfill
% \eqparbox{title}{\textbf{Senior Widget Designer}} \hfill
% \eqparbox{dates}{\textbf{1/95--present}}
%
% \begin{itemize}
%   \item Supervised the development of the new orange and blue widget lines.
%   \item Improved the design of various widgets, making them less sticky
%         and far less likely to explode.
%   \item Made widget management ten times more cost-effective.
% \end{itemize}
%
% \noindent
% \eqparbox{place}{\textbf{Thingamabobs, Ltd.}} \hfill
% \eqparbox{title}{\textbf{Lead Engineer}} \hfill
% \eqparbox{dates}{\textbf{9/92--12/94}}
%
% \begin{itemize}
%   \item Found a way to make thingamabobs run on solar power.
%   \item Drafted a blueprint for a new doohickey-compatibility module for
%         all cool-mint thingamabobs.
%   \item Upgraded superthingamabob specification document from Microsoft
%         Word to \LaTeXe.
% \end{itemize}
% \noindent\rule{\linewidth}{1pt}
% \caption{Excerpt from a sample r\'esum\'e}
% \label{fig:resume-excerpt}
% \end{figure}
%
% The two questions can be answered the same way: by putting various
% blocks of text into equal-widthed boxes.  If the author names in
% Figure~\ref{fig:quotations} are placed within a |flushright|
% environment and in |\parbox|es as wide as the widest text
% (``Rosencrantz~\& Guildenstern Are Dead''), they will appear as
% desired.  Similarly, if the company names in
% Figure~\ref{fig:resume-excerpt} are both put in a |\parbox| as wide as
% ``Thingamabobs, Ltd.,'' the job titles in a |\parbox| as wide as
% ``Senior Widget Designer,'' and the dates in a |\parbox| as wide as
% ``1/95--present,'' then they can be spaced evenly by separating them
% with |\hfill|s.
%
% The problem is in choosing the width for each set of |\parbox|es.
% Considering for now just Figure~\ref{fig:resume-excerpt}, the user
% must typeset the r\'esum\'e once to see which entry in each column is
% the widest and then assign lengths appropriately:
%
% \begin{verbatim}
%     \newlength{\placewidth}
%     \settowidth{\placewidth}{Thingamabobs, Ltd.}         % Employment 2
%     \newlength{\jobtitlewidth}
%     \settowidth{\jobtitlewidth}{Senior Widget Designer}  % Employment 1
%     \newlength{\dateswidth}
%     \settowidth{\dateswidth}{1/95--present}              % Employment 1
% \end{verbatim}
%
% \noindent
% Every time a piece of information changes, it must be changed in two
% places: in the r\'esum\'e itself and in the |\settowidth|
% command.  When employment information is added or deleted, the
% |\settowidth| commands must be modified to reflect the new
% maximum-widthed entry in each column.  If only there were a simpler
% way to keep a set of |\parbox|es as wide as the widest entry in the
% set\,\dots
%
% That simpler way is the \pkgname{eqparbox} package.
% \pkgname{eqparbox} exports an |\eqparbox| macro that works just like
% |\parbox|, except that instead of specifying the width of the box, one
% specifies the group that the box belongs to.  All boxes in the same
% group will be typeset as wide as the widest member of the group.  In
% that sense, an |\eqparbox| behaves like a cell in an~|l|, |c|, or~|r|
% column in a |tabular|; |\eqparbox|es in the same group are analogous
% to cells in the same column.  Unlike the cells in a |tabular| column,
% however, a group of |\eqparbox|es can be spread throughout the
% document.
%
% \section{Usage}
% \label{sec:usage}
%
% \begin{decl}
%   |\eqparbox| \oarg{pos} \oarg{height} \oarg{inner-pos} \marg{tag} \marg{text} \\
%   |\eqmakebox| \oarg{tag} \oarg{pos} \marg{text} \\
%   |\eqframebox| \oarg{tag} \oarg{pos} \marg{text} \\
%   |\eqsavebox| \marg{cmd} \oarg{tag} \oarg{pos} \marg{text} \\[1ex]
%   |\begin{eqminipage}| \oarg{pos} \oarg{height} \oarg{inner-pos} \marg{tag} \\
%   \quad \meta{text} \\
%   |\end{eqminipage}|
% \end{decl}
%
% These are almost identical to, respectively, the |\parbox|,
% |\makebox|, |\framebox|, and |\savebox| macros and the |minipage|
% environment.  The key difference is that the \meta{width} argument is
% replaced by a \meta{tag} argument.  (For a description of the
% remaining arguments, look up |\parbox|, |\makebox|, |\framebox|,
% |\savebox|, and |minipage| in any \LaTeXe\ book or in the
% \texttt{usrguide.pdf} file that comes with all \TeX\ distributions.)
% \meta{tag} can be any valid identifier.  All boxes produced using the
% same tag are typeset in a box wide enough to hold the widest of them.
% Discounting \TeX's limitations, any number of tags can be used in the
% same document, and any number of boxes can share a tag.  The only
% catch is that \texttt{latex} will need to be run a second time for the
% various box widths to stabilize.
%
% \begin{decl}
% |\eqboxwidth| \marg{tag}
% \end{decl}
%
% It is sometimes useful to take the width of a box produced by one of
% the preceding commands.  While the width can be determined by creating
% an |\eqparbox| and using |\settowidth| to measure it, the
% \pkgname{eqparbox} package defines a convenience routine called
% |\eqboxwidth| that achieves the same result.
%
% |\eqboxwidth| makes it easy to typeset something like
% Table~\ref{tbl:mixed-tabular}.  Table~\ref{tbl:mixed-tabular}'s only
% column expands to fit the widest cell in the column, excluding the
% final cell.  The final cell's text word-wraps within whatever space is
% allocated to it.  In a sense, the first four cells behave as if they
% were typeset in an~|l| column, while the final cell behaves as if it
% were typeset in a~|p| column.  In actuality, the column is an~|l|
% column; an |\eqparbox| for the first four cells ensures the column
% stretches appropriately while a |\parbox| of width
% |\eqboxwidth{|\meta{tag}|}| in the final cell ensures that the final
% cell word-wraps.
%
% Section~\ref{sec:tabular-l-p} presents a more general version of this
% approach that doesn't require cells to be divided explicitly into
% |\eqparbox| cells and |\parbox| cells.
%
% \begin{table}[htbp]
% \centering
% \caption{A \texttt{tabular} that stretches to fit some cells while
% forcing others to wrap}
% \label{tbl:mixed-tabular}
% \DeleteShortVerb{\|}
% \begin{tabular}{|@{}l@{}|}
%   \hline
%   \eqparbox[b]{wtab}{Wide} \\ \hline
%   \eqparbox[b]{wtab}{Wider} \\ \hline
%   \eqparbox[b]{wtab}{Wider than that} \\ \hline
%   \eqparbox[b]{wtab}{This is a fairly wide cell} \\ \hline
%   \parbox[b]{\eqboxwidth{wtab}}{\strut
%     While this cell's text wraps, the previous cells (whose text
%     doesn't wrap) determine the width of the column.} \\ \hline
% \end{tabular}
% \MakeShortVerb{\|}
% \end{table}
%
% \begin{decl}
%   |\eqsetminwidth| \marg{tag} \marg{width} \\
%   |\eqsetmaxwidth| \marg{tag} \marg{width}
% \end{decl}
%
% These macros override the width calculation for boxes associated with
% tag \meta{tag}, ensuring that they are no narrower than a given
% minimum (|\eqsetminwidth|) and no wider than a given maximum
% (|\eqsetmaxwidth|).
%
% \begin{decl}
%   |\eqsetminwidthto| \marg{tag} \marg{text} \\
%   |\eqsetmaxwidthto| \marg{tag} \marg{text}
% \end{decl}
%
% These macros are analogous to |\eqsetminwidth| and |\eqsetmaxwidth|
% but automatically compute the natural width of the given text and use
% that as the minimum (|\eqsetminwidthto|) or maximum
% (|\eqsetmaxwidthto|) width for boxes using tag \meta{tag}.
%
%
% \section{Examples}
% \label{sec:examples}
%
% This section presents some sample uses of the macros described in
% Section~\ref{sec:usage}.
%
% \subsection{Figures and tables from previous sections}
% \label{sec:prev-figs-tabs}
%
% Figure~\ref{fig:quotations} was typeset using an |\eqparbox|-based
% helper macro, |\showquote|:
%
% \begin{verbatim}
%     \usepackage{ifmtarg}
%     \makeatletter
%     \newcommand{\showquote}[2]{%
%       \begin{flushright}
%         ---~\eqparbox{quotebox}{\sffamily#1}%
%         \@ifnotmtarg{#2}{\\
%           \mbox{}\phantom{---}~\eqparbox{quotebox}{\sffamily\itshape#2}%
%         }%
%       \end{flushright}%
%       \par
%     }
%     \makeatother
% \end{verbatim}
% \centerline{$\vdots$}
% \begin{verbatim}
%     Alla fin del gioco tanto va nel sacco il re quanto la pedina. \\
%     \textit{(After the game, the king and pawn go into the same box.)}
%     \showquote{Italian proverb}{}
% \end{verbatim}
%
% Figure~\ref{fig:resume-excerpt}'s headings were typeset with the
% following code:
%
% \begin{verbatim}
%     \noindent
%     \eqparbox{place}{\textbf{Widgets, Inc.}} \hfill
%     \eqparbox{title}{\textbf{Senior Widget Designer}} \hfill
%     \eqparbox{dates}{\textbf{1/95--present}}
% \end{verbatim}
% \centerline{$\vdots$}
% \begin{verbatim}
%     \noindent
%     \eqparbox{place}{\textbf{Thingamabobs, Ltd.}} \hfill
%     \eqparbox{title}{\textbf{Lead Engineer}} \hfill
%     \eqparbox{dates}{\textbf{9/92--12/94}}
% \end{verbatim}
% \centerline{$\vdots$}
% \bigskip
%
% Finally, Table~\ref{tbl:mixed-tabular} was typeset using the
% following code:
%
% \begin{verbatim}
%     \begin{tabular}{|@{}l@{}|}
%       \hline
%       \eqparbox[b]{wtab}{Wide} \\ \hline
%       \eqparbox[b]{wtab}{Wider} \\ \hline
%       \eqparbox[b]{wtab}{Wider than that} \\ \hline
%       \eqparbox[b]{wtab}{This is a fairly wide cell} \\ \hline
%       \parbox[b]{\eqboxwidth{wtab}}{\strut
%         While this cell's text wraps, the previous cells (whose text
%         doesn't wrap) determine the width of the column.} \\ \hline
%     \end{tabular}
% \end{verbatim}
%
% \subsection{Lists within \texttt{tabular}s}
% \label{sec:lists-tabulars}
%
% List environments (|itemize|, |enumerate|, etc.) cannot appear
% directly within a |tabular| cell.  Instead, they must be wrapped
% within a |\parbox|.  The problem is that the |\parbox| width must be
% specified; it can't be determined automatically.  Fortunately, as of
% version~4.0 of \pkgname{eqparbox}, the |\eqparbox| macro can contain
% list environments, and these are automatically sized to their widest
% item, just like any other |\eqparbox| contents.
% Table~\ref{tbl:lists-tabular} presents an example of |enumerate| lists
% appearing within |tabular| cells.  The code for this is
% straightforward, thanks to \pkgname{eqparbox}:
%
% \begin{table}[tbp]
%   \centering
%   \caption{Lists within a \texttt{tabular}}
%   \label{tbl:lists-tabular}
%   \begin{tabular}{c|c}
%     \textbf{Meeting date} & \textbf{Topics discussed} \\
%     \hline
%     2017-02-22
%     & \eqparbox{topiclist}{^^A
%         \begin{enumerate}
%           \item Hardware upgrades
%           \item Barbara's retirement
%           \item Revised 27B/6 paperwork
%         \end{enumerate}
%       }^^A
%     \\ \hline
%     2017-03-01
%     & \eqparbox{topiclist}{^^A
%         \begin{enumerate}
%           \item Printer low on toner
%           \item Message from the V.P.
%         \end{enumerate}
%     }^^A
%     \\ \hline
%     2017-03-08
%     & \eqparbox{topiclist}{^^A
%         \begin{enumerate}
%           \item Product to ship next week
%           \item Floors to be recarpeted
%           \item Too many meetings
%         \end{enumerate}
%       }^^A
%   \end{tabular}
% \end{table}
%
% \begin{verbatim}
%     2017-02-22 & \eqparbox{topiclist}{%
%                    \begin{enumerate}
%                      \item Hardware upgrades
%                      \item Barbara's retirement
%                      \item Revised 27B/6 paperwork
%                    \end{enumerate}
%                   } \\ \hline
% \end{verbatim}
%
% \subsection{Hanging indentation}
% \label{sec:hang-indent}
%
% Consider the paragraphs depicted in Figure~\ref{fig:hang-indent}.
% We'd like the paragraph labels set on the left, as shown, but we'd
% also like to allow both intra-~and inter-paragraph page breaks.  Of
% course, if the labels are made wider or narrower, we'd like the
% paragraph widths to adjust automatically.  By using a custom |list|
% environment that typesets its labels with |\eqparbox| this is fairly
% straightforward:
%
% \begin{verbatim}
%     \begin{list}{}{%
%       \renewcommand{\makelabel}[1]{\eqparbox[b]{listlab}{#1}}%
%       \setlength{\labelwidth}{\eqboxwidth{listlab}}%
%       \setlength{\labelsep}{2em}%
%       \setlength{\parsep}{2ex plus 2pt minus 1pt}%
%       \setlength{\itemsep}{0pt}%
%       \setlength{\leftmargin}{\labelwidth+\labelsep}%
%       \setlength{\rightmargin}{0pt}}
%
%       \item[Stuff about me]  I am great.  Blah, blah, blah, ...
%
%       \item[More stuff]  I am wonderful.  Blah, blah, blah, ...
%
%       \item[The final exciting thing]  I am fantastic.  Blah,
%          blah, blah, ...
%     \end{list}
% \end{verbatim}
%
% \begin{figure}[htbp]
% \rule{\linewidth}{1pt}
% \begin{list}{}{^^A
%   \renewcommand{\makelabel}[1]{\eqparbox[b]{listlab}{#1}}^^A
%   \setlength{\labelwidth}{\eqboxwidth{listlab}}^^A
%   \setlength{\labelsep}{2em}^^A
%   \setlength{\parsep}{2ex plus 2pt minus 1pt}^^A
%   \setlength{\itemsep}{0pt}^^A
%   \setlength{\leftmargin}{\labelwidth}^^A
%   \addtolength{\leftmargin}{\labelsep}^^A
%   \setlength{\rightmargin}{0pt}}
%
%   \item[Stuff about me] I am great.  Blah, blah, blah, blah, blah,
%   blah, blah, blah, blah, blah, blah, blah, blah, blah, blah, blah,
%   blah, blah, blah, blah, blah, blah, blah, blah, blah, blah, blah,
%   blah, blah, blah, blah, blah, blah, blah, blah, blah, blah, blah,
%   blah.
%
%   \item[More stuff] I am wonderful.  Blah, blah, blah, blah, blah,
%   blah, blah, blah, blah, blah, blah, blah, blah, blah, blah, blah,
%   blah, blah, blah, blah, blah, blah, blah, blah, blah, blah, blah,
%   blah.
%
%   Did I mention that blah, blah, blah, blah, blah, blah, blah, blah,
%   blah, blah, blah, blah, blah, blah, blah?
%
%   \item[The final exciting thing] I am fantastic.  Blah, blah, blah,
%   blah, blah, blah, blah, blah, blah, blah, blah, blah, blah, blah,
%   blah, blah, blah, blah, blah, blah, blah, blah, blah.
% \end{list}
% \rule{\linewidth}{1pt}
% \caption{Paragraphs with hanging indentation}
% \label{fig:hang-indent}
% \end{figure}
%
% \subsection{Justified, parallel text}
% \label{sec:parallel-text}
%
% Consider line-by-line transcription of a piece of text as illustrated
% by the mockup in Figure~\ref{fig:line-by-line}.  The idea is to
% juxtapose a scanned piece of handwritten text with its typeset version
% (or, similarly, to typeset a piece of text in one language alongside a
% line-by-line translation into another language).  The challenge is in
% ensuring that (1)~the same words appear on corresponding lines of text
% and that (2)~the typeset text is fully justified.  While the
% \pkgname{parallel} package can typeset fully justified paragraphs
% aligned in parallel columns, it does not support the alignment of
% individual lines.  |tabular| and |minipage| environments provide
% control of line breaks but do not support full justification of the
% text when explicit line breaks are used.
%
% \begin{figure}[htbp]
% \centering
% \DeleteShortVerb{\|}
% \newsavebox{\tstretchbox}
% \newcolumntype{S}[1]{^^A
%   >{\begin{lrbox}{\tstretchbox}}^^A
%   l^^A
%   <{\end{lrbox}^^A
%   \eqmakebox[#1][s]{\unhcopy\tstretchbox}}}
% \begin{tabular}{|l|l|}
%   \hline
%   \calligra
%   \begin{tabular}{S{handwritten}}
%     Lorem ipsum dolor sit amet,      \\
%     consectetur adipiscing elit.     \\
%     Phasellus volutpat, nibh sit     \\
%     amet mattis convallis, metus     \\
%     libero rhoncus justo, sed auctor \\
%     erat mauris sit amet tellus.     \\
%   \end{tabular}
%   &
%   \begin{tabular}{S{typeset}}
%     Lorem ipsum dolor sit amet,      \\
%     consectetur adipiscing elit.     \\
%     Phasellus volutpat, nibh sit     \\
%     amet mattis convallis, metus     \\
%     libero rhoncus justo, sed auctor \\
%     erat mauris sit amet tellus.     \\
%   \end{tabular} \\
%   \hline
% \end{tabular}
% \MakeShortVerb{\|}
% \caption{Line-by-line transcription of text with full justification}
% \label{fig:line-by-line}
% \end{figure}
%
% One solution is to use \pkgname{eqparbox}'s |\eqmakebox| macro.  Like
% |\makebox|, |\eqmakebox| supports the ``|s|'' (stretch) value for the
% \meta{pos} argument, which causes the \meta{text} argument to stretch
% to the width of the box.  However, while |\makebox| requires the width
% to be specified explicitly, |\eqmakebox| automatically sizes all boxes
% that use the same tag (in this case, each line of the input paragraph)
% to the widest text's natural width.  Here's how to use the
% \pkgname{array} package's |\newcolumntype| macro to define a new
% |tabular| column type, ``|S|'', that stretches whitespace as needed to
% fit the widest line in the column:
%
% \begin{verbatim}
%     \newsavebox{\tstretchbox}
%     \newcolumntype{S}[1]{%
%       >{\begin{lrbox}{\tstretchbox}}%
%       l%
%       <{\end{lrbox}%
%       \eqmakebox[#1][s]{\unhcopy\tstretchbox}}}
% \end{verbatim}
%
% \noindent
% That code works by storing the current cell's contents within a box
% called |\tstretchbox| then passing |\tstretchbox|'s contents to
% |\eqmakebox|.  (The |tabular| environment does not enable a cell's
% contents to be passed directly to a macro, hence the |lrbox|
% trickery.)  Note that the ``|S|'' column type takes an argument, which
% is the tag to pass to |\eqmakebox|.  Using the preceding definition we
% can typeset Figure~\ref{fig:line-by-line} as follows.  To simulate
% scanned handwriting in the left column we use the Calligra handwriting
% font provided by the \pkgname{calligra} package.
%
% \begin{verbatim}
%     \begin{tabular}{|l|l|}
%       \hline
%       \calligra
%       \begin{tabular}{S{handwritten}}
%         Lorem ipsum dolor sit amet,      \\
%         consectetur adipiscing elit.     \\
%         Phasellus volutpat, nibh sit     \\
%         amet mattis convallis, metus     \\
%         libero rhoncus justo, sed auctor \\
%         erat mauris sit amet tellus.     \\
%       \end{tabular}
%       &
%       \begin{tabular}{S{typeset}}
%         Lorem ipsum dolor sit amet,      \\
%         consectetur adipiscing elit.     \\
%         Phasellus volutpat, nibh sit     \\
%         amet mattis convallis, metus     \\
%         libero rhoncus justo, sed auctor \\
%         erat mauris sit amet tellus.     \\
%       \end{tabular} \\
%       \hline
%     \end{tabular}
% \end{verbatim}
%
% \subsection{Combining \texttt{l} and \texttt{p} column properties in a \texttt{tabular}}
% \label{sec:tabular-l-p}
%
% In a |tabular| environment, |l|~columns, which automatically fit the
% column to its contents, are good for short pieces of text.  Long
% pieces of text are best set within a |p|~column, which wraps text
% within a specified width.  But which column type should you use to
% typeset text whose width is unknown (e.g.,~if the text is generated
% programmatically)?  With the help of \pkgname{eqparbox}'s
% |\eqsetmaxwidth| macro (and the \pkgname{array} package's
% |\newcolumntype| macro), it is possible to define a column type that
% behaves like~|l| for short pieces of text and like~|p| for long pieces
% of text:
%
% \begin{verbatim}
%     \newcolumntype{M}[1]{%
%       >{\begin{lrbox}{\csname#1box\endcsname}}%
%       l%
%       <{\end{lrbox}%
%         \eqparbox[t]{#1}{\unhcopy\csname#1box\endcsname\strut}}%
%     }
% \end{verbatim}
%
% This can then be used as follows to produce the output shown in
% Figure~\subref*{fig:maxwd-narrow}:
%
% \begin{verbatim}
%     \eqsetmaxwidth{maybebig}{0.5\linewidth}
%     \newsavebox{\maybebigbox}
%     \begin{tabular}{|M{maybebig}|l|}
%       \hline
%       Very short & Good \\
%       A little bit longer & Okay \\
%     \end{tabular}
% \end{verbatim}
%
% \noindent
% Because the text in the first column is narrower than half the line
% width, the column behaves like an |l|~column.  Now observe what
% happens if we add a long piece of text to the column:
%
% \begin{verbatim}
%     \eqsetmaxwidth{maybebig}{0.5\linewidth}
%     \newsavebox{\maybebigbox}
%     \begin{tabular}{|M{maybebig}|l|}
%       \hline
%       Very short & Good \\
%       A little bit longer & Okay \\
%       Almost certainly excessively long, even given the point we're
%       trying to make about box widths & Bad \\
%     \end{tabular}
% \end{verbatim}
%
% \noindent
% As Figure~\subref*{fig:maxwd-wide} shows, the first column now behaves
% like a |p|~column, specifically |p{0.5\linewidth}|.
%
% \begin{figure}[htbp]
%   \centering
%   \subfloat[Output when the text is narrow\label{fig:maxwd-narrow}]{%
%     \begin{tabular}{|l|l|}
%       \hline
%       Very short & Good \\
%       A little bit longer & Okay \\
%       \hline
%     \end{tabular}%
%   }
%   \par
%   \subfloat[Output when the text is wide\label{fig:maxwd-wide}]{%
%     \begin{tabular}{|p{0.5\linewidth}|l|}
%       \hline
%       Very short & Good \\
%       A little bit longer & Okay \\
%       Almost certainly excessively long, even given the point we're
%       trying to make about box widths & Bad \\
%       \hline
%     \end{tabular}%
%   }
%   \caption{Combining the features of \texttt{l} and \texttt{p} columns}
%   \label{fig:maxwd}
% \end{figure}
%
% \subsection{Centering a column of right-justified data}
% \label{tbl:center-justified}
%
% The data in each of the Sales columns in Table~\ref{tbl:sales-data}
% are centered relative to their column header.  However, they are also
% right-justified relative to each other.  To achieve this effect we
% simply need to put the data in each column in a right-justified box
% using |\eqmakebox|\oarg{tag}|[r]|\marg{text} and center that:
%
% \begin{verbatim}
%     \begin{tabular}{@{}lccc@{}} \hline
%       & \multicolumn{3}{c}{Sales (in millions)} \\ \cline{2-4}
%       \multicolumn{1}{c}{\raisebox{1ex}[2ex]{Product}} &
%       October & November & December \\ \hline
%
%       Widgets      & \eqmakebox[oct][r]{           55.2} &
%                      \eqmakebox[nov][r]{\bfseries  89.2} &
%                      \eqmakebox[dec][r]{           57.9} \\
%       Doohickeys   & \eqmakebox[oct][r]{\bfseries  65.0} &
%                      \eqmakebox[nov][r]{\tiny       N/A} &
%                      \eqmakebox[dec][r]{            9.3} \\
%       Thingamabobs & \eqmakebox[oct][r]{           10.4} &
%                      \eqmakebox[nov][r]{            8.0} &
%                      \eqmakebox[dec][r]{\bfseries 109.7} \\ \hline
%     \end{tabular}
% \end{verbatim}
%
% \begin{table}[htbp]
% \centering
% \caption{Sample sales data}
% \label{tbl:sales-data}
% \begin{tabular}{@{}lccc@{}} \hline
%   & \multicolumn{3}{c}{Sales (in millions)} \\ \cline{2-4}
%   \multicolumn{1}{c}{\raisebox{1ex}[2ex]{Product}} &
%   October & November & December \\ \hline
%
%   Widgets      & \eqmakebox[oct][r]{           55.2} &
%                  \eqmakebox[nov][r]{\bfseries  89.2} &
%                  \eqmakebox[dec][r]{           57.9} \\
%   Doohickeys   & \eqmakebox[oct][r]{\bfseries  65.0} &
%                  \eqmakebox[nov][r]{\tiny       N/A} &
%                  \eqmakebox[dec][r]{            9.3} \\
%   Thingamabobs & \eqmakebox[oct][r]{           10.4} &
%                  \eqmakebox[nov][r]{            8.0} &
%                  \eqmakebox[dec][r]{\bfseries 109.7} \\ \hline
% \end{tabular}
% \end{table}
%
%
% \section{Limitations}
% \label{sec:limitations}
%
% Unfortunately, \pkgname{eqparbox}'s macros have a number of
% limitations not exhibited by the corresponding \LaTeXe\ commands.
% First, \pkgname{eqparbox}'s macros internally typeset the given text
% within a |tabular| environment---specifically, using ``|@{}l@{}|'' as
% the template---in order to determine the text's natural width.
% Consequently, commands not valid within such a |tabular|
% (e.g.,~|verbatim| environments) are also not valid within the
% \meta{text} argument of an \pkgname{eqparbox} macro.  As a corollary,
% the macros defined by the \pkgname{eqparbox} package can appear only
% where a |tabular| is also acceptable.
%
% A second limitation is that \pkgname{eqparbox}'s macros typeset their
% \meta{text} argument \emph{twice}: once within a |tabular| to
% determine the natural width and again within a box wide enough to hold
% all text associated with tag \meta{tag}.  This approach may cause
% unexpected results if \meta{text} is non-idempotent (i.e.,~has side
% effects).  For example, if \meta{text} increments a counter, the
% counter will be incremented twice per invocation of |\eqparbox|.
%
% \StopEventually{}
%
% \section{Implementation}
% \label{sec:implementation}
%
% The one-sentence summary of the implementation is, ``As
% \pkgname{eqparbox} goes along, it keeps track of the maximum width of
% each box type, and when it's finished, it writes those widths to
% the~|.aux| file for use on subsequent runs.''  If you're satisfied
% with that summary, then read no further.  Otherwise, get ready to
% tackle the following annotated code listing.
%
% \subsection{Preliminaries}
%
% \begin{macro}{\eqp@tempdima}
% \begin{macro}{\eqp@tempdimb}
% Define a couple temporary \meta{dimen}s for use in a variety of locations.
%    \begin{macrocode}
\newlength{\eqp@tempdima}
\newlength{\eqp@tempdimb}
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\eqp@taglist}
% Define a list of all of the tags we encountered in the author's document.
%    \begin{macrocode}
\def\eqp@taglist{}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\ifeqp@must@rerun}
% \begin{macro}{\eqp@must@reruntrue}
% \begin{macro}{\eqp@must@rerunfalse}
% If an |eqparbox| is wider than the maximum-width |eqparbox| with the
% same tag, we need to store the new maximum width and request that the
% user re-run |latex|.  We use |\ifeqp@must@rerun| and |\eqp@must@reruntrue|
% to assist with this.
%    \begin{macrocode}
\newif\ifeqp@must@rerun
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% The |\eqp@settowidth| macro requires the \pkgname{array} package's
% ability to inject code into every cell.
%    \begin{macrocode}
\RequirePackage{array}
%    \end{macrocode}
%
% \begin{macro}{\eqp@tabular@box}
% \begin{macro}{\eqp@list@box}
% The |\eqp@settowidth| macro requires a box, |\eqp@tabular@box|, in
% which to store the entire input text.  |\eqp@settowidth| also requires
% a box, |\eqp@list@box|, in which to store nested |list| environments.
%    \begin{macrocode}
\newsavebox{\eqp@tabular@box}
\newsavebox{\eqp@list@box}
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\eqp@list@indent}
% The |\eqp@settowidth| macro stores the accumulated |list| indentation
% in |\eqp@list@indent|.
%    \begin{macrocode}
\newlength{\eqp@list@indent}
%    \end{macrocode}
% \end{macro}
%
% The |eqminipage| environment requires the \pkgname{environ} package's
% |\Collect@Body|, which passes the body of an environment to a macro as
% a single argument.
%    \begin{macrocode}
\RequirePackage{environ}
%    \end{macrocode}
%
%
% \subsection{Width calculation}
%
% \begin{macro}{\eqp@storefont}
% \begin{macro}{\eqp@restorefont}
% To find the natural width of a piece of text, we put it in a table and
% take the width of that.  The problem is that font changes are not
% preserved across line breaks (table cells).  We therefore define an
% |\eqp@storefont| macro which itself defines an |\eqp@restorefont|
% macro that restores the current font and font size to its current
% state.
%    \begin{macrocode}
\newcommand*{\eqp@storefont}{%
  \xdef\eqp@restorefont{%
    \noexpand\usefont{\f@encoding}{\f@family}{\f@series}{\f@shape}%
    \noexpand\fontsize{\f@size}{\f@baselineskip}%
    \noexpand\selectfont
  }%
}
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\eqp@settowidth}
% This macro is just like |\settowidth|, but it puts its argument in a
% |tabular|, which means that it can contain |\\|.  We use the
% \pkgname{array} package's ``|>|'' and ``|<|'' template parameters to
% inject an |\eqp@restorefont| at the start of every cell and an
% |\eqp@storefont| at the end of every cell.  Doing so preserves fonts
% and font sizes across |\\| boundaries, just like |\parbox|.
%
% One catch is that lists cannot be included directly within a
% |tabular|.  True, they can be placed within a |\parbox| that itself is
% within a |tabular| cell, but the whole point is that we're trying to
% calculate how wide that |\parbox| should be, The trick we use here,
% therefore, is to redefine the |list| environment as a single-column
% |tabular| plus space for |\labelwidth| and |\labelsep|---we ignore all
% other list-formatting parameters---and |\item| as~|\\|.  There will be
% an extra row at the beginning, but all we care about here is computing
% a width, not a height, so that's acceptable.
% \changes{v2.0}{2004/08/01}{Modified to store and restore the font
%   across \texttt{\string\string\string\\}~boundaries (suggested by
%   Mike Shell)}
% \changes{v4.0}{2013/03/09}{Added support for list environments}
% \changes{v4.0}{2013/03/15}{Added support for multi-paragraph input}
%    \begin{macrocode}
\newcommand{\eqp@settowidth}[2]{%
  \begingroup
    \global\setbox\eqp@tabular@box=\hbox{%
%    \end{macrocode}
% \begin{macro}{\eqp@endings}
% Unfortunately, we can't simply redefine the |list| environment, which
% underlies |itemize|, |enumerate|, and |description| lists, because
% their definitions in the standard classes do not include a proper
% |\begin{list}|\dots\linebreak[0]|\end{list}|.  Instead, those parent
% environments call |\list| directly and
% |\let\end|\{|itemize|,\linebreak[0]|enumerate|,\linebreak[0]|description|\}|=\endlist|.
% Our workaround is to reissue those |\let| bindings after redefining
% |\list| and |\endlist| ourselves.
%    \begin{macrocode}
      \def\eqp@endings{}%
      \ifx\enditemize\endlist
        \g@addto@macro\eqp@endings{\let\enditemize=\endlist}%
      \fi
      \ifx\endenumerate\endlist
        \g@addto@macro\eqp@endings{\let\endenumerate=\endlist}%
      \fi
      \ifx\enddescription\endlist
        \g@addto@macro\eqp@endings{\let\enddescription=\endlist}%
      \fi
%    \end{macrocode}
% \begin{environment}{list}
% As described above, we locally redefine the |list| environment as a
% single-column |tabular| and the |\item| macro as~|\\|.  We begin by
% copying a block of code from |ltlists.dtx| that sets the default
% formatting parameters for a list of the current depth.  This is
% important because |trivlist| environments (e.g.,~|center| and
% |flushleft|) reset some of the parameters, which would otherwise screw
% up our width calculation.
%    \begin{macrocode}
      \renewenvironment{list}[2]{%
        \ifnum \@listdepth >5\relax
          \@toodeep
        \else
          \global\advance\@listdepth\@ne
        \fi
        \rightmargin\z@
        \listparindent\z@
        \itemindent\z@
        \csname @list\romannumeral\the\@listdepth\endcsname
        ##2\relax
%    \end{macrocode}
% \begin{macro}{\item}
% We locally redefine |\item| to start a new row of the |tabular|, then
% flush any nested lists from the previous |\item| at the current
% nesting level, and finally adjust the current indentation based on
% the item's label.
%    \begin{macrocode}
        \renewcommand*{\item}[1][]{%
          \mbox{}\\
          \box\eqp@list@box\mbox{} \\
          \sbox\@tempboxa{\makelabel{####1}}%
          \ifdim\wd\@tempboxa>\labelwidth
            \advance\eqp@list@indent by -\labelwidth
            \advance\eqp@list@indent by \wd\@tempboxa
          \fi
          \hspace*{\eqp@list@indent}%
        }%
%    \end{macrocode}
% To measure the width of a |list| we introduce a single-column
% |tabular| that includes |\eqp@list@indent|'s worth of padding
% ($=$~|\leftmargin|~$+$ |\rightmargin|~$+$ |\itemindent|)
% to mimic the width of the original |list| environment.
%    \begin{macrocode}
        \hspace*{-\eqp@list@indent}%
        \advance\eqp@list@indent by \leftmargin
        \advance\eqp@list@indent by \rightmargin
        \advance\eqp@list@indent by \itemindent
        \global\setbox\eqp@list@box=\hbox\bgroup
        \begin{tabular}{@{}l@{}}%
      }{%
        \item[]%
        \end{tabular}%
        \egroup
        \global\advance\@listdepth\m@ne
      }%
      \eqp@endings
%    \end{macrocode}
% Finally, we place the given text---list or not---within a |tabular| so
% the preceding |\settowidth| can measure its width.  Because the text
% may contain paragraph breaks we redefine |\par| as~|\\| to turn them
% into line breaks and restore |\par|'s original definition when the
% |tabular| ends.
%    \begin{macrocode}
      \global\let\eqp@par=\par
      \eqp@storefont
      \begin{tabular}{@{}>{\eqp@restorefont}l<{\eqp@storefont}@{}}%
        \global\@setpar{\\}%
        #2%
        \\ \box\eqp@list@box
      \end{tabular}%
      \global\@restorepar
    }%
  \endgroup
%    \end{macrocode}
% Now that we've constructed a |tabular| with lines of the input text as
% cells we can use \LaTeX's |\settowidth| macro to take its width.
%    \begin{macrocode}
  \settowidth{#1}{\box\eqp@tabular@box}%
}
%    \end{macrocode}
% \end{macro}
% \end{environment}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\eqp@compute@width}
% The following function does all the real work for the
% \pkgname{eqparbox} package.  It takes two parameters---\meta{tag} and
% \meta{text}---and ensures that all boxes with the same tag will be as
% wide as the widest box with that tag.  It ends by passing \meta{tag}
% and \meta{text} to the |\eqp@produce@box| command, which was defined
% by the calling macro to produce a box using one of the existing
% \LaTeXe\ commands.
%
% To keep track of box widths, |\eqp@compute@width| makes use of two global
% variables for each tag: |\eqp@this@|\meta{tag} and
% |\eqp@next|\meta{tag}.  |\eqp@this@|\meta{tag} is the maximum width
% ever seen for tag \meta{tag}, including in previous |latex| runs.
% |\eqp@next@|\meta{tag} works the same way but is always initialized
% to~|0.0pt|.  It represents the maximum width to assume in
% \emph{subsequent} |latex| runs.  It is needed to detect whether the
% widest text with tag \meta{tag} has been removed/shrunk.  At the end of
% a run, \pkgname{eqparbox} prepares the next run (via the~|.aux| file)
% to initialize |\eqp@this@|\meta{tag} to the final value of
% |\eqp@next@|\meta{tag}.
% \changes{v2.0}{2004/07/30}{Removed extraneous \texttt{\string\string\string\global}s
%   (suggested by David Kastrup)}
% \changes{v3.1}{2010/01/01}{Restructured the package to make all
%   user-callable functions eventually call
%   \texttt{\string\string\string\eqp@compute@width}, which does the
%   bulk of the work}
%    \begin{macrocode}
\long\def\eqp@compute@width#1#2{%
  \eqp@settowidth{\eqp@tempdimb}{#2}%
%    \end{macrocode}
% We first clamp the box width, currently in |\eqp@tempdimb|, to the
% range [|\eqp@minwd@|\meta{tag}, |\eqp@maxwd@|\meta{tag}].  As these
% bounds are not necessarily defined we first have to check for their
% existence.
%    \begin{macrocode}
  \@ifundefined{eqp@minwd@#1}{}{%
    \ifdim\eqp@tempdimb<\csname eqp@minwd@#1\endcsname
      \eqp@tempdimb=\csname eqp@minwd@#1\endcsname
    \fi
  }%
  \@ifundefined{eqp@maxwd@#1}{}{%
    \ifdim\eqp@tempdimb>\csname eqp@maxwd@#1\endcsname
      \eqp@tempdimb=\csname eqp@maxwd@#1\endcsname
    \fi
  }%
  \expandafter
  \ifx\csname eqp@this@#1\endcsname\relax
%    \end{macrocode}
% If we get here, then we've never encountered tag \meta{tag}, even in
% a previous |latex| run.  We request that the user re-run |latex|.
% This is not always necessary (e.g.,~when all uses of the |\eqparbox|
% with tag \meta{tag} are left-justified), but it's better to be safe
% than sorry.
%    \begin{macrocode}
    \global\eqp@must@reruntrue
    \expandafter\xdef\csname eqp@this@#1\endcsname{\the\eqp@tempdimb}%
    \expandafter\xdef\csname eqp@next@#1\endcsname{\the\eqp@tempdimb}%
  \else
%    \end{macrocode}
% If we get here, then we \emph{have} previously seen tag \meta{tag}.
% We just have to keep track of the maximum text width associated with
% it.
%    \begin{macrocode}
    \eqp@tempdima=\csname eqp@this@#1\endcsname\relax
    \ifdim\eqp@tempdima<\eqp@tempdimb
      \expandafter\xdef\csname eqp@this@#1\endcsname{\the\eqp@tempdimb}%
      \global\eqp@must@reruntrue
    \fi
%    \end{macrocode}
%    \begin{macrocode}
    \eqp@tempdima=\csname eqp@next@#1\endcsname\relax
    \ifdim\eqp@tempdima<\eqp@tempdimb
      \expandafter\xdef\csname eqp@next@#1\endcsname{\the\eqp@tempdimb}%
    \fi
  \fi
%    \end{macrocode}
%
% The first time we encounter tag \meta{tag} in the current document we
% ensure \LaTeX{} will notify the user if he needs to re-run |latex| on
% account of that tag.
%    \begin{macrocode}
  \@ifundefined{eqp@seen@#1}{%
    \expandafter\gdef\csname eqp@seen@#1\endcsname{}%
    \@cons\eqp@taglist{{#1}}%
  }{}%
%    \end{macrocode}
%
% Finally, we can call |\eqp@produce@box|.  We pass it
% |\eqp@this@|\meta{tag} for its \meta{width} argument and |#2| for its
% \meta{text} argument.
%    \begin{macrocode}
  \eqp@tempdima=\csname eqp@this@#1\endcsname\relax
  \eqp@produce@box{\eqp@tempdima}{#2}%
}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\eqp@set@min@width}
% Given a tag and a textual length, ensure that |\eqp@this@|\meta{tag}
% represents a width of at least \meta{length}.
% \changes{v4.1}{2017/09/03}{Introduced this helper macro for
%   \texttt{\string\string\string\eqsetminwidth} and
%   \texttt{\string\string\string\eqsetminwidthto}}
%    \begin{macrocode}
\def\eqp@set@min@width#1#2{%
  \expandafter\ifx\csname eqp@this@#1\endcsname\relax
%    \end{macrocode}
% If we get here, then we've never encountered tag \meta{tag}, even in
% a previous |latex| run.  We assign a value to \meta{tag} and request
% that the user re-run |latex|.
%    \begin{macrocode}
    \global\eqp@must@reruntrue
    \expandafter\xdef\csname eqp@this@#1\endcsname{#2}%
    \expandafter\xdef\csname eqp@next@#1\endcsname{#2}%
  \else
%    \end{macrocode}
% If we get here, then we \emph{have} previously seen tag \meta{tag}.
% We ensure its width is at least~|#2|.
%    \begin{macrocode}
    \eqp@tempdima=\csname eqp@this@#1\endcsname\relax
    \eqp@tempdimb=#2\relax
    \ifdim\eqp@tempdima<\eqp@tempdimb
      \expandafter\xdef\csname eqp@this@#1\endcsname{\the\eqp@tempdimb}%
    \fi
    \eqp@tempdima=\csname eqp@next@#1\endcsname\relax
    \ifdim\eqp@tempdima<\eqp@tempdimb
      \expandafter\xdef\csname eqp@next@#1\endcsname{\the\eqp@tempdimb}%
    \fi
  \fi
  \@ifundefined{eqp@seen@#1}{%
    \expandafter\gdef\csname eqp@seen@#1\endcsname{}%
    \@cons\eqp@taglist{{#1}}%
  }{}%
}
%    \end{macrocode}
% \end{macro}
%
%
% \subsection{Author macros}
%
% \begin{macro}{\eqparbox}
% We want |\eqparbox| to take the same arguments as |\parbox|, with the
% same default values for the optional arguments.  The only difference
% in argument processing is that |\eqparbox| has a \meta{tag} argument
% where |\parbox| has \meta{width}.
%
% Because |\eqparbox| has more than one optional argument, we can't use
% a single function defined by |\DeclareRobustCommand|.  Instead, we
% have to split |\eqparbox| into |\eqparbox|, |\eqparbox@i|,
% |\eqparbox@ii|, and |\eqparbox@iii| macros, which correspond to
% |\parbox|, |\@iparbox|, |\@iiparbox|, and |\@iiiparbox| in
% |ltboxes.dtx|.
%
% |\eqparbox| takes an optional \meta{pos} argument that defaults
% to~|c|.  It passes the value of this argument to |\eqparbox@i|.
%    \begin{macrocode}
\DeclareRobustCommand{\eqparbox}{%
  \@ifnextchar[%]
    {\eqparbox@i}%
    {\eqparbox@iii[c][\relax][s]}%
}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\eqparbox@i}
% |\eqparbox@i| takes a \meta{pos} argument followed by an optional
% \meta{height} argument that defaults to~|\relax|.  It passes both
% \meta{pos} and \meta{height} to |\eqparbox@ii|.
%    \begin{macrocode}
\def\eqparbox@i[#1]{%
  \@ifnextchar[%]
    {\eqparbox@ii[#1]}%
    {\eqparbox@iii[#1][\relax][s]}%
}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\eqparbox@ii}
% |\eqparbox@ii| takes \meta{pos} and \meta{height} arguments followed
% by an optional \meta{inner-pos} argument that defaults to \meta{pos}.
% It passes \meta{pos}, \meta{height}, and \meta{inner-pos} to
% |\eqparbox@iii|.
%    \begin{macrocode}
\def\eqparbox@ii[#1][#2]{%
  \@ifnextchar[%]
    {\eqparbox@iii[#1][#2]}%
    {\eqparbox@iii[#1][#2][#1]}%
}
%    \end{macrocode}
% \end{macro}
% \begin{macro}{\eqparbox@iii}
% \begin{macro}{\eqp@produce@box}
% |\eqparbox@iii| takes \meta{pos}, \meta{height} and \meta{inner-pos}
% arguments.  It defines an |\eqp@produce@box| macro that takes a
% \meta{width} argument and a \meta{text} argument and passes all of
% \meta{pos}, \meta{height}, \meta{inner-pos}, \meta{width}, and
% \meta{text} to \LaTeX's |\parbox| macro.  |\eqparbox@iii| ends by
% calling |\eqp@compute@width|, which will eventually invoke
% |\eqp@produce@box|.
%    \begin{macrocode}
\def\eqparbox@iii[#1][#2][#3]{%
  \long\gdef\eqp@produce@box##1##2{%
    \parbox[#1][#2][#3]{##1}{##2}%
  }%
  \eqp@compute@width
}
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{environment}{eqminipage}
% The |eqminipage| environment is implemented almost exactly like the
% |\eqparbox| macro above.  Just like |\eqparbox|, |eqminipage| takes an
% optional \meta{pos} argument that defaults to~|c|.  It passes the
% value of this argument to |\eqminipage@i|.
% \changes{v4.0}{2013/03/14}{Introduced this environment}
%    \begin{macrocode}
\DeclareRobustCommand{\eqminipage}{%
  \@ifnextchar[%]
    {\eqminipage@i}%
    {\eqminipage@iii[c][\relax][s]}%
}
\let\endeqpminipage=\relax
%    \end{macrocode}
% \end{environment}
%
% \begin{macro}{\eqminipage@i}
% |\eqminipage@i| takes a \meta{pos} argument followed by an optional
% \meta{height} argument that defaults to~|\relax|.  It passes both
% \meta{pos} and \meta{height} to |\eqminipage@ii|.
%    \begin{macrocode}
\long\def\eqminipage@i[#1]{%
  \@ifnextchar[%]
    {\eqminipage@ii[#1]}%
    {\eqminipage@iii[#1][\relax][s]}%
}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\eqminipage@ii}
% |\eqminipage@ii| takes \meta{pos} and \meta{height} arguments followed
% by an optional \meta{inner-pos} argument that defaults to \meta{pos}.
% It passes \meta{pos}, \meta{height}, and \meta{inner-pos} to
% |\eqminipage@iii|.
%    \begin{macrocode}
\def\eqminipage@ii[#1][#2]{%
  \@ifnextchar[%]
    {\eqminipage@iii[#1][#2]}%
    {\eqminipage@iii[#1][#2][#1]}%
}
%    \end{macrocode}
% \end{macro}
% \begin{macro}{\eqminipage@iii}
% This is where |eqminipage| differs from |\eqparbox|.  Like
% |\eqparbox@iii|, |\eqminipage@iii| takes \meta{pos}, \meta{height} and
% \meta{inner-pos} arguments.  However, while |\eqparbox@iii| expects to
% be followed by a tag and text, |\eqminipage@iii| consumes the tag
% itself.  |\eqminipage@iii| then uses \pkgname{environ}'s
% |\Collect@Body| macro to collect everything up to the
% |\end{eqminipage}| into a single argument, which it passes to
% |\eqminipage@iv|.
%    \begin{macrocode}
\def\eqminipage@iii[#1][#2][#3]#4{%
%    \end{macrocode}
% \begin{macro}{\eqminipage@iv}
% \begin{macro}{\eqp@produce@box}
% This code is a bit confusing due to the definition of a macro within a
% macro within a macro.  |\eqminipage@iv|, which is invoked by
% |\collect@body|, is passed the body of the |eqminipage| environment as
% an argument.  In then defines an |\eqp@produce@box| macro with the
% parameter list that |\eqp@compute@width| expects: a width (|####1|)
% and text (|####2|).  |\eqp@produce@box| typesets a |minipage| with
% that width and text and the formatting parameters provided to
% |\eqminipage@iii| (|#1|, |#2|, and~|#3|).  Finally, |\eqminipage@iv|
% invokes |\eqp@compute@width| with the tag passed to |\eqminipage@iii|
% as~|#4| and the text passed to |\eqminipage@iv| as~|##1|.
%    \begin{macrocode}
  \long\def\eqminipage@iv##1{%
    \long\gdef\eqp@produce@box####1####2{%
      \begin{minipage}[#1][#2][#3]{####1}%
        ####2%
      \end{minipage}%
    }%
    \eqp@compute@width{#4}{##1}%
  }%
  \Collect@Body\eqminipage@iv
}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\eqmakebox}
% |\eqmakebox| provides an automatic-width analogue to \LaTeX's
% |\makebox|.  It takes the same arguments as |\makebox| with the same
% default values for the optional arguments.  The only difference in
% argument processing is that |\eqmakebox| has a \meta{tag} argument
% where |\makebox| has \meta{width}.  Note that if \meta{width} is not
% specified, |\eqmakebox| simply invokes |\makebox|.
% \changes{v3.0}{2010/01/01}{Included Rob Verhoeven's
%   \texttt{\string\string\string\eqmakebox} macro}
% \changes{v3.1}{2010/01/01}{Modified the argument processing to match
%   \texttt{\string\string\string\makebox}'s}
%    \begin{macrocode}
\DeclareRobustCommand{\eqmakebox}{%
  \@ifnextchar[%]
    {\eqlrbox@i\makebox}%
    {\makebox}%
}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\eqframebox}
% |\eqframebox| provides an automatic-width analogue to \LaTeX's
% |\framebox|.  It takes the same arguments as |\framebox| with the same
% default values for the optional arguments.  The only difference in
% argument processing is that |\eqframebox| has a \meta{tag} argument
% where |\framebox| has \meta{width}.  Note that if \meta{width} is not
% specified, |\eqframebox| simply invokes |\framebox|.
% \changes{v3.1}{2010/01/01}{Introduced this macro}
%    \begin{macrocode}
\DeclareRobustCommand{\eqframebox}{%
  \@ifnextchar[%]
    {\eqlrbox@i\framebox}%
    {\framebox}%
}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\eqsavebox}
% |\eqsavebox| provides an automatic-width analogue to \LaTeX's
% |\savebox|.  It takes the same arguments as |\savebox| with the same
% default values for the optional arguments.  The only difference in
% argument processing is that |\eqsavebox| has a \meta{tag} argument
% where |\savebox| has \meta{width}.  Note that if \meta{width} is not
% specified, |\eqsavebox| simply invokes |\savebox|.
% \changes{v3.1}{2010/01/01}{Introduced this macro}
%    \begin{macrocode}
\DeclareRobustCommand{\eqsavebox}[1]{%
  \@ifnextchar[%]
    {\eqlrbox@i{\savebox{#1}}}%
    {\savebox{#1}}%
}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\eqlrbox@i}
% |\eqlrbox@i| takes a \marg{command} argument (one of |\makebox|,
% |\framebox|, or |\savebox|\marg{cmd}) and a \oarg{tag} argument and
% checks if those arguments are followed by a \oarg{pos} argument.  If
% not, then \meta{pos} defaults to ``|c|''.  All of \meta{command},
% \meta{tag}, and \meta{pos} are passed to |\eqlrbox@ii|.
%    \begin{macrocode}
\def\eqlrbox@i#1[#2]{%
  \@ifnextchar[%]
    {\eqlrbox@ii{#1}[#2]}%
    {\eqlrbox@ii{#1}[#2][c]}%
}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\eqlrbox@ii}
% \begin{macro}{\eqp@produce@box}
% |\eqlrbox@i| takes a \marg{command} argument (one of |\makebox|,
% |\framebox|, or |\savebox|\marg{cmd}), a \oarg{tag} argument, and a
% \oarg{pos} argument.  It defines |\eqp@produce@box| to take a
% \meta{width} argument and a \meta{text} argument and invoke
% \meta{command}\oarg{width}\oarg{pos}\marg{text}.  |\eqlrbox@ii| ends
% by calling |\eqp@compute@width|, which will eventually invoke
% |\eqp@produce@box|.
%    \begin{macrocode}
\def\eqlrbox@ii#1[#2][#3]{%
  \long\gdef\eqp@produce@box##1##2{%
    #1[##1][#3]{##2}%
  }%
  \eqp@compute@width{#2}%
}
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\eqboxwidth}
% For the times that the user wants to make something other than a box to
% match an |\eqparbox|'s width, we provide |\eqboxwidth|.  |\eqboxwidth|
% returns the width of a box corresponding to a given tag.  More
% precisely, if |\eqp@this@|\meta{tag} is defined, it's returned.
% Otherwise,~|0pt| is returned.
% \changes{v2.1}{2004/08/02}{Rewrote so as to be compatible with the
%   \pkgname{calc} package's \texttt{\string\string\string\setlength}
%   command (problem initially reported by Gary L. Gray and narrowed
%   down by Martin Vaeth)}
%    \begin{macrocode}
\newcommand*{\eqboxwidth}[1]{%
  \@ifundefined{eqp@this@#1}{0pt}{\csname eqp@this@#1\endcsname}%
}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\eqsetminwidth}
% The |\eqsetminwidth| macro accepts a tag and a length and records that
% the user wants the associated box to be no narrower than the given
% length.
% \changes{v4.0}{2013/03/04}{Introduced this macro}
% \changes{v4.1}{2017/09/03}{Define
%   \texttt{\string\string\string\eqp@this@}\meta{tag} and
%   \texttt{\string\string\string\eqp@next@}\meta{tag} appropriately}
%    \begin{macrocode}
\newcommand{\eqsetminwidth}[2]{%
  \@tempdima=#2\relax
  \expandafter\xdef\csname eqp@minwd@#1\endcsname{\the\@tempdima}%
  \eqp@set@min@width{#1}{\csname eqp@minwd@#1\endcsname}%
}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\eqsetmaxwidth}
% The |\eqsetmaxwidth| macro accepts a tag and a length and records that
% the user wants the associated box to be no wider than the given
% length.
% \changes{v4.0}{2013/03/04}{Introduced this macro}
%    \begin{macrocode}
\newcommand{\eqsetmaxwidth}[2]{%
  \@tempdima=#2\relax
  \expandafter\xdef\csname eqp@maxwd@#1\endcsname{\the\@tempdima}%
}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\eqsetminwidthto}
% The |\eqsetminwidthto| macro accepts a tag and a piece of text and
% records that the user wants the associated box to be no narrower than
% the text, typeset at its natural width.
% \changes{v4.0}{2013/03/04}{Introduced this macro}
% \changes{v4.1}{2017/09/03}{Define
%   \texttt{\string\string\string\eqp@this@}\meta{tag} and
%   \texttt{\string\string\string\eqp@next@}\meta{tag} appropriately}
%    \begin{macrocode}
\newcommand{\eqsetminwidthto}[2]{%
  \eqp@settowidth{\@tempdima}{#2}%
  \expandafter\xdef\csname eqp@minwd@#1\endcsname{\the\@tempdima}%
  \eqp@set@min@width{#1}{\csname eqp@minwd@#1\endcsname}%
}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\eqsetmaxwidthto}
% The |\eqsetmaxwidthto| macro accepts a tag and a piece of text and
% records that the user wants the associated box to be no wider than
% the text, typeset at its natural width.
% \changes{v4.0}{2013/03/04}{Introduced this macro}
%    \begin{macrocode}
\newcommand{\eqsetmaxwidthto}[2]{%
  \eqp@settowidth{\@tempdima}{#2}%
  \expandafter\xdef\csname eqp@maxwd@#1\endcsname{\the\@tempdima}%
}
%    \end{macrocode}
% \end{macro}
%
% \subsection{End-of-document processing}
%
% At the |\end{document}|, for each tag \meta{tag} we see if
% |\eqp@next@|\meta{tag}, which was initialized to~|0.0pt|, is different
% from |\eqp@this@|\meta{tag}, which was initialized to the maximum box
% width from the previous run.  If so, we issue an informational
% message.  In any case, we initialize the next run's
% |\eqp@this@|\meta{tag} to |\eqp@next@|\meta{tag} and the next run's
% |\eqp@next@|\meta{tag} to |0pt|.
%    \begin{macrocode}
\AtEndDocument{%
  \begingroup
%    \end{macrocode}
% \begin{macro}{\@elt}
% The |\eqp@taglist| list is of the form ``|\@elt| |{|\meta{tag$_1$}|}|
% |\@elt| |{|\meta{tag$_2$}|}|~\ldots''.  We therefore locally define
% |\@elt| to take the name of a tag and perform all of the checking
% described above and then merely execute |\eqp@taglist|.
% \changes{v2.0}{2004/08/01}{Modified to allow numbers in tag names
%   (suggested by Martin Vaeth)}
% \changes{v4.0}{2013/03/04}{Modified to honor minimum and maximum
%   text widths, as set by
%   \texttt{\string\string\string\eqset}\{\texttt{max},\texttt{min}\}\texttt{width} and
%   \texttt{\string\string\string\eqset}\{\texttt{max},\texttt{min}\}\texttt{widthto}}
%    \begin{macrocode}
    \def\@elt#1{%
%    \end{macrocode}
% Complain if the tag's minimum width is greater than its maximum width.
%    \begin{macrocode}
      \@ifundefined{eqp@minwd@#1}{}{%
        \@ifundefined{eqp@maxwd@#1}{}{%
          \ifdim\csname eqp@minwd@#1\endcsname>\csname eqp@maxwd@#1\endcsname
            \PackageWarning{eqparbox}{For tag `#1',
              minimum width (\csname eqp@minwd@#1\endcsname) >
              maximum width (\csname eqp@maxwd@#1\endcsname)}%
          \fi
        }%
      }%
%    \end{macrocode}
% Make the |.aux| file define |\eqp@this@|\meta{tag} to the current
% value of |\eqp@next@|\meta{tag} and |\eqp@next@|\meta{tag} to |0pt|.
%    \begin{macrocode}
      \eqp@tempdima\csname eqp@this@#1\endcsname\relax
      \eqp@tempdimb\csname eqp@next@#1\endcsname\relax
      \ifdim\eqp@tempdima=\eqp@tempdimb
      \else
        \@latex@warning@no@line{Rerun to correct the width of eqparbox `#1'}%
      \fi
      \immediate\write\@auxout{%
        \string\expandafter\string\gdef\string\csname\space
        eqp@this@#1\string\endcsname{%
          \csname eqp@next@#1\endcsname
        }%
        ^^J%
        \string\expandafter\string\gdef\string\csname\space
         eqp@next@#1\string\endcsname{0pt}%
      }%
%    \end{macrocode}
% Also make the |.aux| file define |\eqp@minwd@|\meta{tag} and
% |\eqp@maxwd@|\meta{tag} to their current value, if any.
%    \begin{macrocode}
      \@ifundefined{eqp@minwd@#1}{}{%
        \immediate\write\@auxout{%
          \string\expandafter\string\gdef\string\csname\space
          eqp@minwd@#1\string\endcsname{%
            \csname eqp@minwd@#1\endcsname
          }%
        }%
      }%
      \@ifundefined{eqp@maxwd@#1}{}{%
        \immediate\write\@auxout{%
          \string\expandafter\string\gdef\string\csname\space
          eqp@maxwd@#1\string\endcsname{%
            \csname eqp@maxwd@#1\endcsname
          }%
        }%
      }%
    }%
    \eqp@taglist
  \endgroup
%    \end{macrocode}
% We output a generic ``rerun |latex|'' message if we encountered a
% tag that was not present on the previous run.  (This is always the
% case on the first run or the first run after deleting the
% corresponding |.aux| file.
%    \begin{macrocode}
  \ifeqp@must@rerun
    \@latex@warning@no@line{Rerun to correct eqparbox widths}
  \fi
}
%    \end{macrocode}
% \end{macro}
%
% \Finale
\endinput