From 8b909865f2b6ffeb4314622e1b9029e64aac7a8e Mon Sep 17 00:00:00 2001
From: Karl Berry <karl@freefriends.org>
Date: Wed, 11 Jan 2006 23:56:21 +0000
Subject: trunk/Master/texmf-dist/source/latex/preprint

git-svn-id: svn://tug.org/texlive/trunk@460 c570f23f-e606-0410-a88d-b1316a301751
---
 .../texmf-dist/source/latex/preprint/sublabel.dtx  | 729 +++++++++++++++++++++
 1 file changed, 729 insertions(+)
 create mode 100644 Master/texmf-dist/source/latex/preprint/sublabel.dtx

(limited to 'Master/texmf-dist/source/latex/preprint/sublabel.dtx')

diff --git a/Master/texmf-dist/source/latex/preprint/sublabel.dtx b/Master/texmf-dist/source/latex/preprint/sublabel.dtx
new file mode 100644
index 00000000000..7aad1f0ce68
--- /dev/null
+++ b/Master/texmf-dist/source/latex/preprint/sublabel.dtx
@@ -0,0 +1,729 @@
+% \iffalse      THIS IS A META-COMMENT
+%<*dtx>
+\ProvidesFile
+%========================================================================
+                       {SUBLABEL.DTX}
+%========================================================================
+%</dtx>
+%% Copyright 1993-1999 Patrick W Daly
+%% Max-Planck-Institut f\"ur Aeronomie
+%% Max-Planck-Str. 2
+%% D-37191 Katlenburg-Lindau
+%% Germany
+%% E-mail: daly@linmpi.mpg.de
+% 
+% This program can be 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 of the License, or any later version.
+%
+% This is a contributed file to the LaTeX2e system.
+% -------------------------------------------------
+%  This is a LaTeX package to permit figures, equations etc to be subnumbered
+%    as 4a, 4b, 4c etc.
+% Installation:
+%    LaTeX this file: creates docstrip installation file sublabel.ins
+%                         AND the (LaTeX2e) documentation
+%    (La)TeX sublabel.ins: creates package files sublabel.sty, and optionally
+%                         documentation driver sublabel.drv
+%    (sublabel.ins may be edited as needed)
+% Docstrip options available:
+%        package - to produce a (LaTeX2e) package .sty file 
+%        driver  - to produce a driver file to print the documentation
+%        209     - (with package) for package that runs under LaTeX 2.09 
+%        subpack - (with package) for coding included in other packages
+%        agu     - (with package,subpack) for inclusion in aguplus package
+%--------------------------------------------------------------------------
+%<*!subpack>
+%<package&209>\def\ProvidesPackage#1#2]
+%<package&209>  {\typeout{Style option `#1'#2]}}
+%
+%  *** Identify the package file:-
+%<package&!209>\NeedsTeXFormat{LaTeX2e}[1995/06/01]
+%<package>\ProvidesPackage{sublabel}
+%</!subpack>
+%
+%  *** Provide command to dislay module version
+%<package&subpack>\def\ModuleVersion#1[#2]{}
+%<package&subpack>    \ModuleVersion{sublabel}
+%
+%  *** Identify the driver file:-
+%<driver>\NeedsTeXFormat{LaTeX2e}
+%<driver>\ProvidesFile{sublabel.drv}
+%
+%  *** The DATE, VERSION, and other INFO
+%\fi
+%\ProvidesFile{sublabel}
+       [1999/02/23 4.5 (PWD)]
+% \changes{4.0}{1993 Jun  7}{Completely replacing the version based on
+%                              art-jgr; made more general and flexible}
+% \changes{4.1}{1993 July 20}{Initial release with {\tt docstrip}}
+% \changes{4.1}{1993 Jul 20}{Discover bug; sub labels previously prefixed
+%                              with `sub', but conflict with `subsection'}
+% \changes{4.1}{1993 Jul 20}{\cs{stepcounter} tests if subfoo exists}
+% \changes{4.2}{1993 Dec 17}{Adjust \cs{addtocounter} to step subcounter }
+% \changes{4.2a}{1994 Feb 25}{Must use the old \cs{addtocounter} in
+%      \cs{endeqnarray}}
+% \changes{4.3}{1994 May 16}{Convert to \LaTeXe}
+% \changes{4.3a}{1994 Jun 22}{Update to first official release of \LaTeXe}
+% \changes{4.3b}{1995 Jan 3}{Update documentation to PWD standard}
+% \changes{4.3c}{1995 Sep 18}{Fix \cs{DeclareOption} for \LaTeX\ of June 1995}
+% \changes{4.3d}{1997 Mar 16}{Fix copyright for subpackage and other minor
+%                                    things}
+% \changes{4.4}{1997 Apr 28}{Fix so it works with other packages that change
+%        \texttt{eqnarray}, like \texttt{amsmath}}
+% \changes{4.5}{1999 Feb 23}{Update copyright notice}
+%
+% \CheckSum{209}
+% \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         \~}
+%
+% \iffalse
+%<*install>
+%^^A =============================================
+%^^A    Here is the docstrip installation file
+%^^A    It is written on first LaTeX run if it 
+%^^A    does not already exist
+%^^A =============================================
+\begin{filecontents*}{sublabel.ins}
+% File: sublabel.ins
+% Copyright 1999 Patrick W. Daly
+%
+% This file can be 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 of the License, or any later version.
+% 
+% It is an installation file for extracting package and driver
+% files from the original source file. Simply process it under
+% TeX or LaTeX. 
+
+\input docstrip
+
+\preamble
+=============================================
+IMPORTANT NOTICE:
+
+This program can be 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 of the License, or any later version.
+
+This is a generated file.
+It may not be distributed without the original source file \inFileName.
+
+Full documentation can be obtained by LaTeXing that original file.
+Only a few abbreviated comments remain here to describe the usage.
+=============================================
+\endpreamble
+\postamble
+
+<<<<< End of generated file <<<<<<
+\endpostamble
+
+\declarepreamble\driver
+============================================
+This is the driver file to produce the LaTeX documentation 
+from the original source file \inFileName.
+
+Make changes to it as needed. (Never change the file \inFileName!)
+============================================
+\endpreamble
+
+\declarepostamble\driverq
+
+End of documentation driver file.
+\endpostamble
+
+\keepsilent
+\askforoverwritefalse
+
+\generate{\file{sublabel.sty}{\from{sublabel.dtx}{package}}
+          \file{sublabel.drv}{\usepreamble\driver\usepostamble\driverq
+                           \from{sublabel.dtx}{driver}}
+         }
+
+\obeyspaces
+\Msg{*******************************************}%
+\Msg{* For documentation, process sublabel.dtx *}%
+\Msg{*    or the driver file      sublabel.drv *}%
+\Msg{*******************************************}
+
+\endbatchfile
+\end{filecontents*}
+%</install>
+%<*driver>
+\documentclass{ltxdoc}
+%<driver>%\documentclass[twoside]{ltxdoc}
+%<driver>%\documentclass[a4paper]{ltxdoc}
+%<driver>%\documentclass[twoside,a4paper]{ltxdoc}
+\raggedbottom
+
+ %** To include the detailed explanation of the coding, comment out
+ %**   the next line
+\OnlyDescription
+
+ %** To produce a command index: add the following line for one run,
+ %**   then run  makeindex -s gind.ist natbib
+ %**   and reprocess, with or without this line (much faster without)
+%<driver>% \EnableCrossrefs\CodelineIndex 
+
+ %** To produce a change history: add the following line for one run,
+ %**   then run  makeindex -s gglo.ist -o natbib.gls natbib.glo
+ %**   and reprocess, with or without this line (faster without)
+%<driver>% \RecordChanges 
+
+\DisableCrossrefs %May stay; zapped by \EnableCrossrefs
+\CodelineNumbered %May stay
+
+\begin{document}
+   \DocInput{sublabel.dtx}
+\end{document}
+%</driver>
+%\fi
+%
+% \DoNotIndex{\begin,\CodelineIndex,\CodelineNumbered,\def,\DisableCrossrefs}
+% \DoNotIndex{\DocInput,\documentclass,\EnableCrossrefs,\end,\GetFileInfo}
+% \DoNotIndex{\NeedsTeXFormat,\OnlyDescription,\RecordChanges,\usepackage}
+% \DoNotIndex{\ProvidesClass,\ProvidesPackage,\ProvidesFile,\RequirePackage}
+% \DoNotIndex{\LoadClass,\PassOptionsToClass,\PassOptionsToPackage}
+% \DoNotIndex{\DeclareOption,\CurrentOption,\ProcessOptions,\ExecuteOptions}
+% \DoNotIndex{\AtEndOfClass,\AtEndOfPackage,\AtBeginDocument,\AtEndDocument}
+% \DoNotIndex{\InputIfFileExists,\IfFileExists,\ClassError,\PackageError}
+% \DoNotIndex{\ClassWarning,\PackageWarning,\ClassWarningNoLine}
+% \DoNotIndex{\PackageWarningNoLine,\ClassInfo,\PackageInfo,\MessageBreak}
+% \DoNotIndex{\space,\protect,\DeclareRobustCommand,\CheckCommand}
+% \DoNotIndex{\newcommand,\renewcommand,\providecommand\newenvironment}
+% \DoNotIndex{\renewenvironment,\newif,\newlength,\newcounter,\setlength}
+% \DoNotIndex{\setcounter,\if,\ifx,\ifcase,\ifnum,\ifdim,\else,\fi}
+% \DoNotIndex{\texttt,\textbf,\textrm,\textsl,\textsc}
+% \DoNotIndex{\textup,\textit,\textmd,\textsf,\emph}
+% \DoNotIndex{\ttfamily,\rmfamily,\sffamily,\mdseries,\bfseries,\upshape}
+% \DoNotIndex{\slshape,\scshape,\itshape,\em,\LaTeX,\LaTeXe}
+% \DoNotIndex{\filename,\fileversion,\filedate,\let}
+% \DoNotIndex{\@@warning,\@bsphack,\@currenvir,\@eha,\@esphack,\@ifundefined}
+% \DoNotIndex{\@latexerr,\@nameuse,\@tempa,\@warning,\alph,\bf,\endcsname}
+% \DoNotIndex{\expandafter,\gdef,\global,\it,\newcount,\null,\relax,\thepage}
+%
+% \setcounter{IndexColumns}{2}
+% \setlength{\IndexMin}{10cm}
+% \setcounter{StandardModuleDepth}{1}
+%
+% \GetFileInfo{sublabel}
+%
+% \title{\bfseries A Package to Subnumber \LaTeX{} Counters}
+%    
+% \author{Patrick W. Daly}
+%         
+% \date{This paper describes package \texttt{\filename}\\
+%       version \fileversion{} from \filedate\\[1ex]
+%     \textsl{It is part of the \texttt{preprint} collection of packages}
+%  }
+% 
+% \maketitle
+%
+% \pagestyle{myheadings}
+% \markboth{P. W. Daly}{SUBNUMBERING FIGURES, TABLES, EQUATIONS}
+% 
+%^^A In order to keep all marginal notes on the one (left) side:
+%^^A (otherwise they switch sides disasterously with twoside option)
+% \makeatletter \@mparswitchfalse \makeatother 
+%
+%\begin{small}\begin{center}\textbf{Summary}\end{center}
+% The stripped version of this file contains the following brief description:
+%\iffalse
+%<*package&!subpack>
+%\fi
+% \begin{verbatim}
+ % To change a counter foo so that it has sublabels (4a 4b 4c ...) 
+ % give the command \sublabon{foo}... \sublaboff{foo}
+ % 
+ % The style of the sublabel is given by command \substyle, which takes one
+ % argument, a counter. It may be redefined in the document to be whatever
+ % style is wanted. 
+%<209> % Default is {\it\alph{#1}}, ie italic lowercase numbers.
+%<*!209>
+ % Default is {\itshape\alph{#1}}, ie italic lowercase numbers.
+ %
+ % Options for LaTeX2e:
+ %   roman   the style of sublabels is small roman letter
+ %   italic  the style is small italic letter (default)
+%</!209>
+% \end{verbatim}
+%\iffalse
+ %-----------------------------------------------------------
+%</package&!subpack>
+%\fi
+%\end{small}
+%
+% \section{Introduction}
+% The macros in this package allow all counters to be subnumbered, as for
+% example 4{\itshape a}, 4{\itshape b}, 4{\itshape c}, simply by
+% bracketting the objects to be so numbered with appropriate on/off
+% commands. These commands specify which counters are to be subnumbered,
+% and they are of global effect. This means that they will work with any
+% user-defined counters too, and that their effect goes beyond any current
+% environment.
+% 
+% \section{Invoking the Package}
+% The macros in this package are included in the main document 
+% with the |\usepackage| command of \LaTeXe,
+% \begin{quote}
+% |\documentclass[..]{...}|\\
+% |\usepackage[|\emph{options}|]{|\texttt{\filename}|}|
+% \end{quote}
+% where the possible \emph{options} are:
+% \begin{description}
+% \item[\tt italic] to have subnumbers as italic lowercase letters
+%       (default);
+% \item[\tt roman] to have the subnumbers as Roman lowercase letters, as
+%       4{\rmfamily a}.
+% \end{description}
+%
+% Alternatively, the name of the package is added as an option to the
+% |\documentstyle| command in \LaTeX~2.09 compatibility mode, as
+% \begin{quote}
+% |\documentstyle[..|\texttt{\filename}|..]{...}|
+% \end{quote}
+% In this case, no options are possible.
+% 
+% \section{Usage}
+% \DescribeMacro{\sublabon}
+% \DescribeMacro{\sublaboff}
+% In order to number equations, figures, plates, and tables automatically
+% with subnumbers (e.g.\ 4{\itshape a}, 4{\itshape b}, 4{\itshape c}) use
+% the commands |\sublabon| and |\sublaboff|. These commands take as
+% argument the name of the counter that is to be subnumbered, i.e.
+% \texttt{equation}, \texttt{figure}, or \texttt{table}. The on and off
+% versions bracket the objects that are to be labelled with the same number
+% but different letters. For example,
+% 
+% \begin{quote}
+% \begin{verbatim}
+% \sublabon{figure}
+% \begin{figure}
+%   \caption{Text of Fig. 4a}
+% \end{figure}
+% \begin{figure}
+%   \caption{Text of Fig. 4b}
+% \end{figure}
+% \sublaboff{figure}
+% \end{verbatim}
+% \end{quote}
+% 
+% These commands also work for the |equation| environment in the same way. 
+% For the |eqnarray| environment, some care must be taken. The 
+% |\sublabon| command is to be given {\em in} the first equation to be 
+% bracketted, before the |\label| and |\\| commands, while the 
+% |\sublaboff| command is given after the |\\| of the last equation 
+% in the group. If necessary, it must come after |\end{eqnarray}|.
+% \begin{quote}
+% \begin{verbatim}
+% \begin{eqnarray}
+%   x & = & a \label{eq:x}\\%--> 1
+%   \sublabon{equation}
+%   y & = & b \label{eq:y}\\%--> 2a
+%   z & = & c \label{eq:z}\\%--> 2b
+%   \sublaboff{equation}
+%   w & = & d \label{eq:w}  %--> 3
+% \end{eqnarray}
+% \end{verbatim}
+% \end{quote}
+% 
+% If two groups appear adjacently, it is only necessary to give 
+% |\sublabon| between them.
+%
+% \DescribeMacro{\substyle}
+% The style in which the sublabels are written is determined by a command
+% |\substyle|. Its default definition is as italic lowercase
+% letters.\footnote{In \LaTeXe, if the option \texttt{roman} is added to
+% the \texttt{\bslash usepackage} command, then the default is upright
+% lowercase letters.} If
+% one wishes, this may be changed in the document itself. It must take an
+% argument that is a counter. For example, to change the style of sublabels
+% to be as 5--A, 5--B, 5--C, give
+% \begin{quote}
+% |\renewcommand{\substyle}[1]{--\Alph{#1}}|
+% \end{quote}
+% \section{Interference with Other Options}
+% If both |sublabel| and |figcaps| packages are to be used together, then 
+% |sublabel| must be input first. This is because
+% |figcaps| makes modifications so that the sublabelling also works on the page
+% of figure captions.
+%
+% Other packages (like \texttt{amsmath}) also modify some of the commands
+% redefined here. As of version~4.4, the redefinitions are delayed until 
+% after all packages are loaded, so that this conflict is avoided. For
+% earlier versions, things went wrong if \texttt{amsmath} were loaded after
+% \texttt{filename}.
+%
+% \StopEventually{\PrintIndex\PrintChanges}
+% 
+% \section{Options with \texttt{docstrip}}
+% The source \texttt{.dtx} file is meant to be processed with
+% \texttt{docstrip}, for which a number of options are available:
+% \begin{description}
+% \item[\tt package] to produce a \texttt{.sty} package file with most
+%     comments removed;
+% \item[\tt 209] for a package file that will also run under the older
+%     \LaTeX~2.09 and not just under the newer (mid-1994) \LaTeXe;
+% \item[\tt subpack] (together with \texttt{package}) for coding that is to
+%     be included inside a larger package; even more comments are removed,
+%     as well as \LaTeXe{} option handling and identification;
+% \item[\tt agu] (with \texttt{package,subpack}) for special coding for
+%     the \textsl{AGU$^{++}$} package;
+% \item[\tt driver] to produce a driver \texttt{.drv} file that will print
+%     out the documentation under \LaTeXe. The documentation cannot be
+%     printed under \LaTeX~2.09.
+% \end{description}
+% The source file \texttt{\filename.dtx} is itself a driver file and can
+% be processed directly by \LaTeXe.
+% 
+% \section{The Coding}
+% This section presents and explains the actual coding of the macros.
+% It is nested between |%<*package>| and |%</package>|, which
+% are indicators to \texttt{docstrip} that this coding belongs to the package 
+% file.
+%
+% The \texttt{docstrip} option |<subpack>| should only be called if the
+% coding is to be included as part of another package, in which case the 
+% announcement text and \LaTeXe{} options are suppressed.
+%
+% An inferior version of this coding is provided for running as a 
+% style file under \LaTeX~2.09. Code lines belonging to this are
+% indicated with guard |<209>|; those for LaTeXe{} only with |<!209>|.
+%
+% There is a problem if \texttt{\filename} is used with the package
+% \texttt{figcaps}, which makes modifications to the sublabelling
+% commands.  Thus \texttt{\filename} must be read in \emph{before}
+% \texttt{figcaps}. This is tested with the existence of the command
+% |\iffigcaps|, which should not be defined at this point.
+%    \begin{macrocode}
+%<*package>
+\@ifundefined{iffigcaps}{}
+%<*!209>
+  {\PackageWarningNoLine{sublabel}
+     {***********************************\MessageBreak
+      This package read in after `figcaps'\MessageBreak
+      There could be problems with sublabelled\MessageBreak
+      figure and table numbers.\MessageBreak
+      ***********************************}}
+%</!209>
+%<*209>
+ {\@@warning
+  {^^J ********************************^^J
+       `sublabel' read in after `figcaps'^^J
+       There could be problems with sublabelled^^J
+       figure and table numbers.^^J
+       ********************************}}
+%</209>
+%    \end{macrocode}
+%
+% \begin{macro}{\substyle}
+% \changes{4.3d}{1997 Mar 16}{Remove some superfluous lines}
+% The style of the sublabel, or subnumbering, is defined by |\substyle|.  A
+% default definition is provided as italic lowercase letters: 4{\itshape
+% a}, 4{\itshape b}, 4{\itshape b}, etc. This command may be redefined by
+% the user in the document or in a calling style.
+% 
+% For the \textsl{AGU$^{++}$} package, the default is upright letters.
+%
+%    \begin{macrocode}
+\newcommand{\substyle}{}
+%<*!subpack>
+%<209>\def\substyle#1{\it\alph{#1}}
+%    \end{macrocode}
+%
+% \begin{macro}{\DeclareOption}
+% \changes{4.3}{1994 May 16}{Add options \texttt{roman} and \texttt{italic}.}
+% \changes{4.3c}{1995 Sep 18}{Fix options \texttt{roman} and \texttt{italic}
+%    for kernel changes of 1995/06/01}
+% In \LaTeXe, the default depends on the option in the |\usepackage| command.
+%
+% Prior to \LaTeX\ of 1995/06/01, one needed |##| to specify arguments in the
+% |\DeclareOption| statement, but now only a single |#| is needed.
+%    \begin{macrocode}
+%<*!209>
+  \DeclareOption{italic}{\def\substyle#1{\itshape\alph{#1}}}
+  \DeclareOption{roman}{\def\substyle#1{\alph{#1}}}
+  \ExecuteOptions{italic}
+  \ProcessOptions
+%</!209>
+%</!subpack>
+%<subpack&!agu&209>\def\substyle#1{\it\alph{#1}}
+%<subpack&!agu&!209>\def\substyle#1{\itshape\alph{#1}}
+%<subpack&agu>\def\substyle#1{\alph{#1}}
+%    \end{macrocode}
+% \end{macro}\end{macro}
+%
+% \begin{macro}{\sublabon}
+% \changes{4.3a}{1994 Jun 22}{Use \cs{newcommand}}
+% The basic principle of this macro is that when |\sublabon{|\emph{ctr}|}|
+% is called, then a new counter called |sb@|\emph{ctr} is created, if it
+% does not already exist. That is, its internal name is |\c@sb@|\emph{ctr},
+% as is standard for \LaTeX{} counters. Its value is set to $0$ and the main
+% counter \emph{ctr} is incremented. The command that formats and prints
+% out the value of the main counter, |\the|\emph{ctr} is redefined to be
+% \begin{quote}
+% |\@ldthe|\emph{ctr}|{\substyle{sb@|\emph{ctr}|}}|
+% \end{quote}
+% where |\@ldthe|\emph{ctr} is the stored definition |\the|\emph{ctr} and
+% |\substyle| is a command that operates on a counter to format it.
+%
+% First |\sublabon| tests if there really is a counter with the given
+% name.
+%    \begin{macrocode}
+\newcommand{\sublabon}[1]{\@bsphack
+\@ifundefined{c@#1}{%
+%<209>    \@latexerr
+%<!209>    \PackageError{sublabel}
+  {\protect\sublabon\space called for a non-existent counter}{\@eha}}
+%    \end{macrocode}
+% Now test for the subcounter |sb@|\emph{ctr} and if it does not exist,
+% create it and set its value to $-1$.
+%    \begin{macrocode}
+ {\@ifundefined{c@sb@#1}{\expandafter\newcount\csname c@sb@#1\endcsname
+  \setcounter{sb@#1}{-1}}{}%
+%    \end{macrocode}
+% The value $-1$ means that the subcounter has not yet been used. This
+% value is set on creation, or by |\sublaboff| if the subcounter was never
+% stepped. This is the trick that allows multiple calls to |\sublabon|
+% without intervening |\sublaboff| calls. We have to avoid calling
+% |\sublaboff| when there was no stepping. Call it only if the current
+% value of the subcounter is 0 or more.
+%    \begin{macrocode}
+\ifnum\@nameuse{c@sb@#1}<0\else\sublaboff{#1}\fi
+%    \end{macrocode}
+% Set the counters \emph{ctr} and |sb@|\emph{ctr}.
+%    \begin{macrocode}
+\stepcounter{#1}%
+\setcounter{sb@#1}{0}%
+%    \end{macrocode}
+% A correction must be made for the |eqnarray| environment which
+% increments the |equation| counter immediately on entry and then after
+% each equation. That is, the |equation| counter already holds the value of
+% the \emph{next} equation. Thus we must set the two counters to the
+% values that they should have for the next equation. For example, let us
+% suppose the following:
+% \begin{quote}
+% We are outside the |eqnarray| environment, the last equation was
+% number~3, so the |equation| counter has the value |3|.
+% 
+% We enter |eqnarray|; the |equation| counter is incremented immediately to
+% |4|.
+% 
+% We write an equation; it obtains the number~4, and |equation| goes to
+% |5|.
+% 
+% We call |\sublabon{equation}|, and |equation| is set to |6| and
+% |sb@equation| to |0| (so far). Since the counter is stepped only 
+% \emph{after} the equation in this environment, this would mean that the next
+% equation would be numbered 6-0 instead of the desired 5-1. 
+% 
+% Hence the correction: decrement |equation| and set |sb@equation| to 1.
+% \end{quote}
+%    \begin{macrocode}
+\def\@tempa{eqnarray}\ifx \@tempa\@currenvir 
+    \addtocounter{equation}{-1}\setcounter{sb@equation}{1}\fi
+%    \end{macrocode}
+% Note that the above does not test if |#1| really is |equation|. However,
+% if |\sublabon| is used within |eqnarray|, then it only makes sense to
+% subnumber equations.
+%
+%  Now save the definition of |\the|\emph{ctr} as |\@ldthe|\emph{ctr}.
+%  (This combination of |\expandafter| is necessary. I have experimented
+%    with many other variations.)
+%    \begin{macrocode}
+\global\expandafter\let\csname @ldthe#1\expandafter\endcsname
+    \csname the#1\endcsname
+%    \end{macrocode}
+% and redefine |\the|\emph{ctr} to add |\substyle| with the subcounter.
+%    \begin{macrocode}
+\expandafter\gdef\csname the#1\endcsname{%
+   \@nameuse{@ldthe#1}{\substyle{sb@#1}}}
+}\@esphack}
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\sublaboff}
+% \changes{4.3a}{1994 Jun 22}{Use \cs{newcommand}}
+% The command that turns off the sublabelling tests if there is such a
+% counter, and if there exists a subcounter for it. If both tests pass,
+% then it checks that the subcounter has a non-negative value, for if it
+% does not, then there was no corresponding |\sublabon| command. That is,
+% the on/off commands are not nested properly. These tests are necessary to
+% check for typing errors.
+%    \begin{macrocode}
+\newcommand{\sublaboff}[1]{\@bsphack
+\@ifundefined{c@#1}{%
+%<209>    \@latexerr
+%<!209>    \PackageError{sublabel}
+  {\protect\sublaboff\space called for a non-existent counter}{\@eha}}
+ {\@ifundefined{c@sb@#1}{%
+%<209>    \@warning
+%<!209>    \PackageWarning{sublabel}
+ {\protect\sublaboff{#1} called without any previous
+%<209>    ^^J
+%<!209>    \MessageBreak
+  \protect\sublabon{#1} command}}
+ {\ifnum\@nameuse{c@sb@#1}<0
+%<209>    \@warning
+%<!209>    \PackageWarning{sublabel}
+ {\protect\sublaboff{#1} called without a previous
+%<209>    ^^J
+%<!209>    \MessageBreak
+  \protect\sublabon{#1} command being active}\else
+%    \end{macrocode}
+% However, if the subcounter has a 0 value, then |\sublabon| was indeed
+% called, but the counter was never stepped with |\stepcounter|. This is
+% not an error, but it means that the old value of \emph{ctr} should be
+% restored. The subcounter is set to $-1$ to indicate this to the next
+% call to |\sublabon|. The numbering goes on as if |\sublabon| and 
+% |\sublaboff| had never been given.
+%    \begin{macrocode}
+\ifnum\@nameuse{c@sb@#1}=0\addtocounter{#1}{-1}\fi
+\setcounter{sb@#1}{-1}%
+%    \end{macrocode}
+%  Re-establish the definition of |\the|\emph{ctr} stored in
+% |\@ldthe|\emph{ctr}.
+%    \begin{macrocode}
+\global\expandafter\let\csname the#1\expandafter\endcsname
+    \csname @ldthe#1\endcsname
+%    \end{macrocode}
+%  Finally, if |\sublaboff| is called within the |eqnarray| environment,
+% then the |equation| counter must be corrected again, to hold the number
+% for the next equation.
+%    \begin{macrocode}
+\def\@tempa{eqnarray}\ifx \@tempa\@currenvir
+    \stepcounter{equation}\fi
+\fi}}\@esphack}
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\ref}
+% \changes{4.3}{1994 May 16}{Use definition from \LaTeXe{} for NFSS with 2.09}
+% \begin{macro}{\pageref}
+% \changes{4.3}{1994 May 16}{Use definition from \LaTeXe{} for NFSS with 2.09}
+%
+% The font command within |\substyle| means that it is transferred to the
+% auxiliary file in a |\newlabel| command. This causes problems under the
+% New Font Selection Scheme (NFSS) when all the tokens are expanded too
+% early. This problem does not exist with \LaTeX~2.09 without NFSS, nor 
+% with the NFSS in \LaTeXe. To get around this, I add the revised
+% definitions of |\ref| and |\pageref| from \LaTeXe, but implement them
+% only for NFSS under 2.09.
+%    \begin{macrocode}
+%<*209>
+\@ifundefined{selectfont}{}{%
+\def\@setref#1#2#3{%
+  \ifx#1\relax {\reset@font\bf ??}%
+   \@warning{Reference `#3' on page \thepage \space undefined}%
+  \else
+   \expandafter#2#1\null
+  \fi}
+\def\ref#1{\expandafter\@setref\csname r@#1\endcsname\@firstoftwo{#1}}
+\def\pageref#1{\expandafter\@setref\csname r@#1\endcsname
+     \@secondoftwo{#1}}
+\def\@firstoftwo#1#2{#1}
+\def\@secondoftwo#1#2{#2}
+}
+%    \end{macrocode}
+% \end{macro}\end{macro}
+%
+% \begin{macro}{\reset@font}
+% For older implementations of \LaTeX~2.09 (before December, 1991) the
+% |\reset@font| command does not exist. It is defined to be |\relax| under
+% normal \LaTeX{}, but does more under NFSS. In case it is not defined, add
+% it here.
+%    \begin{macrocode}
+\@ifundefined{reset@font}{\def\reset@font{\relax}}{}
+%</209>
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\stepcounter}
+% \changes{4.3a}{1994 Jun 22}{Use \cs{renewcommand}}
+% \changes{4.4}{1997 Apr 28}{Put into \cs{AtBeginDocument}}
+% A very important matter has still to be done: redefine |\stepcounter| so
+% that it increments the subcounter and not the main one. It is not
+% necessary to redefine |\refstepcounter| since it calls |\stepcounter|
+% itself. The existing definition of |\stepcounter| is saved and used in
+% the new definition.
+%
+% This is done at the start of the document, not immediately, in case some
+% other package is loaded that alters |\setcounter|. This also applies to 
+% |\addtocounter| and |\endeqnarray|. For example, the \texttt{amsmath}
+% package makes such changes, so if it is loaded after \texttt{\filename}
+% it clobbers these new definitions if they are not delayed. (This used to
+% happen when \textsl{AGU$^{++}$} is used with \texttt{amsmath}.)
+% Do this only for \LaTeXe.
+%
+%    \begin{macrocode}
+%<!209>\AtBeginDocument{%
+\let\@ldstepcounter=\stepcounter
+\renewcommand{\stepcounter}[1]
+ {\@ifundefined{c@sb@#1}{\@ldstepcounter{#1}}{\ifnum
+  \@nameuse{c@sb@#1}<0\relax
+  \@ldstepcounter{#1}\else \@ldstepcounter{sb@#1}\fi}%
+}
+%    \end{macrocode}
+% \end{macro}
+% 
+% \begin{macro}{\addtocounter}
+% \changes{4.2}{1993 Dec 17}{Add to allow for macros that might fiddle with
+%        counters}
+% \changes{4.3a}{1994 Jun 22}{Use \cs{renewcommand}}
+% \changes{4.4}{1997 Apr 28}{Put into \cs{AtBeginDocument}}
+% A similar refinement must be done to |\addtocounter| to allow for any
+% macros that fiddle with counters. (The \texttt{planotable} environment of
+% the AGU styles does this, for example.) If the fiddling is done
+% explicitly (by giving |\c@|\emph{ctr} a new value) then we are lost.
+% It might also be necessary to refine |\setcounter|, but at the moment I
+% cannot foresee any reason for using that command where sublabels might be
+% used.
+%    \begin{macrocode}
+\let\@ldaddtoctr=\addtocounter
+\renewcommand{\addtocounter}[2]
+ {\@ifundefined{c@sb@#1}{\@ldaddtoctr{#1}{#2}}{\ifnum
+  \@nameuse{c@sb@#1}<0\relax
+  \@ldaddtoctr{#1}{#2}\else \@ldaddtoctr{sb@#1}{#2}\fi}%
+}
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\endeqnarray}
+% Lastly, the |eqnarray| environment itself must be altered to allow for
+% the case where it is ended while |\sublabon{equation}| is
+% active. (The example above was for when |\sublabon| is given within the
+% environment.) The normal |\endeqnarray| command explicitly decrements the
+% |equation| counter (not with |\stepcounter|) so that it now points to the
+% last equation, as usual. However if the subnumbering is on at this point,
+% the |equation| must be re-incremented and |sb@equation| decremented
+% instead.
+% \changes{4.2a}{1994 Feb 25}{Use original \cs{addtocounter}}
+% \changes{4.3a}{1994 Jun 22}{Use \cs{renewcommand}}
+% \changes{4.4}{1997 Apr 28}{Put into \cs{AtBeginDocument}}
+%    \begin{macrocode}
+\let\@ldendeqnarray=\endeqnarray
+\renewcommand{\endeqnarray}{\@ldendeqnarray
+  \@ifundefined{c@sb@equation}{}{\ifnum\c@sb@equation<0\else
+  \@ldaddtoctr{equation}{1}\@ldaddtoctr{sb@equation}{-1}\fi}}
+%<!209>}
+%</package>
+%    \end{macrocode}
+% \end{macro}
+%
+% \Finale
-- 
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