%%% ===================================================================
%%%  @LaTeX-file{
%%%     filename = "commalg.dtx",
%%%     version  = "1.0b",
%%%     date     = "1998/01/30",
%%%     time     = "17:37:42 WST",
%%%     checksum = "63934 452 1774 18680"
%%%     author   = "Greg Gamble",
%%%     address  = "Department of Mathematics,
%%%                 University of Western Australia,
%%%                 Nedlands, W.A. 6907,
%%%                 Australia",
%%%     telephone = "+61 8 9380 3340,"
%%%     FAX       = "+61 8 9380 1028",
%%%     copyright = "Copyright (C) 1996 Greg Gamble,
%%%                  all rights reserved.  Copying of this file is
%%%                  authorised only if either:
%%%                   (1) you make absolutely no changes to your copy,
%%%                       including name; OR
%%%                   (2) if you do make changes, you first rename it
%%%                       to some other name.",
%%%     email     = "gregg@maths.uwa.edu.au (Internet)",
%%%     codetable = "ISO/ASCII",
%%%     keywords  = "latex, amslatex, ams-latex, installation",
%%%     supported = "yes",
%%%     abstract  = "This is class \cls{commalg}. It is built on the
%%%                  standard \latex/ \cls{article} class.
%%%                  It provides a document class for typesetting
%%%                  articles to comply with specifications for
%%%                  the journal Communications in Algebra."
%%%     docstring = "The checksum field above contains a CRC-16
%%%                  checksum as the first value, followed by the
%%%                  equivalent of the standard UNIX wc (word
%%%                  count) utility output of lines, words, and
%%%                  characters.  This is produced by Robert
%%%                  Solovay's checksum utility.",
%%%  }
%%% ===================================================================
%
% \iffalse
%<*driver>
\documentclass{amsdtx}
\EnableCrossrefs
\CodelineIndex
\RecordChanges
\begin{document}
\title{The \cls{commalg} class}
\author{Greg Gamble}
\date{Version \fileversion, \filedate}
\hDocInput{commalg.dtx}
\end{document}
%</driver>
% \fi
%
% \maketitle
% \tableofcontents
% \markboth{THE \cls{COMMALG} CLASS}{}
%
% \changes{v1.0}{96/08/29}{First release}
% \changes{v1.0a}{97/02/24}{Provided \opt{draft} option which
%                           prints the word: \emph{Draft}, the 
%                           date and page number on each page}
% \changes{v1.0a}{97/02/25}{Cleaned up some hacky code that
%                           set the page parameters}
% \changes{v1.0a}{97/02/28}{Provided a modified \texttt{headings}
%                           \cn{pagestyle}}
% \changes{v1.0b}{98/01/30}{Fixed \cn{thanks}. Previously, no error
%                           was signalled but no footnote text
%                           appeared.}
% \changes{v1.0b}{98/01/30}{The \texttt{headings} \cn{pagestyle}
%                           is no longer redefined to be 
%                           \texttt{empty} when the \opt{draft}
%                           option is \emph{not} active.}
% \changes{v1.0b}{98/01/30}{Corrected the captioning for figures
%                           so that caption begins FIG.}
%
% \makeatletter
% \DoNotIndex{\@addpunct,\@address,\@addtoreset,\@arabic}
% \DoNotIndex{\@author,\@biblabel,\@date,\@dblarg,\@empty}
% \DoNotIndex{\@fnsymbol,\@gobbletwo,\@latex@warning,\@m}
% \DoNotIndex{\@makecaption,\@makefnmark,\@makefntext}
% \DoNotIndex{\@maketitle,\@minipagefalse,\@noitemerr,\@nx}
% \DoNotIndex{\@openbib@code,\@plus,\@setaddress,\@tempboxa}
% \DoNotIndex{\@textsuperscript,\@thefnmark,\@title}
% \DoNotIndex{\@topnum,\@xp,\c@enumiv,\c@footnote,\g@addto@macro}
% \DoNotIndex{\hb@xt@,\p@,\p@enumiv,\tw@,\z@}
% \DoNotIndex{\@draftfalse,\@drafttrue,\@evenfoot,\@evenhead}
% \DoNotIndex{\@mkboth,\@oddfoot,\@oddhead,\if@draft}
% \DoNotIndex{\ps@draft,\ps@empty,\ps@headings,\reset@font}
% \DoNotIndex{\@MM,\@currentlabel,\@footnotetext,\@par}
% \DoNotIndex{\@parboxrestore,\@setthanks,\@width,\m@th}
% \DoNotIndex{\p@footnote,\ps@firstpage}
% \makeatother
%
% \section{Introduction}
%    The file \fn{commalg.dtx} is the master file for the \latex/
%    class, \cls{commalg}, which provides an article class for 
%    submissions to the journal Communications in Algebra.
%    It is built on the standard \latex/ \cls{article} class.
%    A \opt{draft} option is provided that causes the word:
%    \emph{Draft}, the date and page number to be printed
%    on each page; by default, this data is printed
%    in the footline of each page, by using the \texttt{draft} 
%    \cn{pagestyle}, provided by this document class.
%    Also, when the \opt{draft} option is active,
%    the \texttt{headings} \cn{pagestyle} is adjusted
%    to put the word: \emph{Draft} and the date in the footline 
%    of each page and the abbreviated title (of the paper) 
%    and page number in the page header.
%    The final copy should have no page numbers --
%    the author must lightly mark page numbers with a blue
%    pencil before submission to the journal.
%    For this reason the default \cn{pagestyle} is \texttt{empty}.
%    In case users just like the style, but are not planning to
%    send their articles to the journal Communications in Algebra,
%    when the \opt{draft} option is \emph{not} active, one can
%    restore page numbers at the bottom for all but the first page
%    by using \cn{pagestyle} \texttt{plain}.
%
% \StopEventually{
%    \begin{thebibliography}{9}
%      \addcontentsline{toc}{section}{\numberline{}Bibliography}
%      \bibitem{AmSLaTeX} American Mathematical Society,
%        \emph{\amslatex/ Version 1.2 User's Guide} (Nov.\ 1996).
%        Filename: \fn{amsldoc.dvi}.
%      \bibitem{source2e} J.~Braams, D.~Carlisle, A.~Jeffrey, L.~Lamport,
%        F.~Mittelbach, C.~Rowley, and R.~Sch\"opf,
%        \emph{The \LaTeXe\ Sources} (Jun.\ 1996).
%        Filename: \fn{source2e.dvi}.
%      \bibitem{amsthm} M.~Downes,
%        \emph{The \pkg{amsthm} package} (Version 1.2a, Feb.\ 1995).
%        Filename: \fn{amsthm.dvi}.
%      \bibitem{uwamaths} G.~Gamble,
%        \emph{The \pkg{uwamaths} package},
%        (Version 1.0j, Oct.\ 1996).
%        Filename: \fn{uwamaths.dvi}.
%        Describes a general purpose package of macros for the
%        Mathematics Department of the
%        University of Western Australia.
%      \bibitem{Companion} M.~Goossens, F.~Mittelbach, and A.~Samarin,
%        \emph{The \latex/ Companion} (Addison-Wesley, 1994).
%      \bibitem{TeX} D.~E.~Knuth, 
%        \emph{The \tex/book}
%        (Addison-Wesley, 1984). Describes \tex/ in detail.
%      \bibitem{LaTeX} L.~Lamport, 
%        \emph{\latex/ -- A Document Preparation System} 
%        (Addison-Wesley, first ed., 1985). Describes \latex/ 2.09.
%      \bibitem{LaTeXe} L.~Lamport, 
%        \emph{\latex/ -- A Document Preparation System} 
%        (Addison-Wesley, second ed., 1994). Updated for \LaTeXe.
%      \bibitem{clsguide} The \latex/3 Project,
%        \emph{\LaTeXe\ for class and package writers} (Nov.\ 1996).
%        Filename: \fn{clsguide.dvi}.
%    \end{thebibliography}
%    \addcontentsline{toc}{section}{\numberline{}Index}
%    \DisableCrossrefs
%    \PrintIndex 
%    \addcontentsline{toc}{section}{\numberline{}Change History}
%    \PrintChanges
% }
%
% \section{Implementation}
%    The usual name, date, and version information.
%    \begin{macrocode}
\typeout{commalg 1.0b}
\NeedsTeXFormat{LaTeX2e}
\ProvidesClass{commalg}[1998/01/30 v1.0b]
%    \end{macrocode}
%    \enlargethispage*{1\baselineskip}
%    We build the class \cls{commalg} on top of \latex/'s
%    \cls{article} class.
%    \begin{macrocode}
\newif\if@draft
\DeclareOption{draft}{\@drafttrue}
\DeclareOption{final}{\@draftfalse}
%    \end{macrocode}
%    \pagebreak
%    \begin{macrocode}
\DeclareOption*{\PassOptionsToClass{\CurrentOption}{article}}
\ProcessOptions\relax
\LoadClass[a4paper]{article}
%    \end{macrocode}
%    The following code is a modified version of the \cls{amsbook}
%    class macro of the same name.
%    \begin{macrocode}
\def\calclayout{%
  \oddsidemargin\paperwidth
  \advance\oddsidemargin -\textwidth
  \divide\oddsidemargin\tw@
  \ifdim\oddsidemargin<.5truein \oddsidemargin.5truein \fi
  \advance\oddsidemargin -1truein
  \evensidemargin\oddsidemargin
  \advance\topmargin -\headheight \advance\topmargin -\headsep
  \advance\topmargin -1truein\relax%
  }
%    \end{macrocode}
%    Now we set the page parameters. If a user wishes to reset
%    these, it is recommended that they do so in the following
%    way and in the following order. In particular, take note
%    of what parameters are set \emph{before} and \emph{after}
%    the \cn{calclayout} command.
%    The journal Communications in Algebra specifies the text
%    area should be $5.5\,$in by $8.5\,$in.
%    \begin{macrocode}
\normalsize
\setlength{\textheight}{8.5in}
\setlength{\textwidth}{5.5in}
\setlength{\topmargin}{1in}
\calclayout
\setlength{\marginparsep}{4mm}
\setlength{\marginparwidth}{12mm}
%    \end{macrocode}
%    We now define the \texttt{draft} \cn{pagestyle} and
%    redefine the \texttt{headings} \cn{pagestyle} in the
%    way described in the Introduction.
%    \begin{macrocode}
\def\shortdate{\number\day/\number\month/\number\year}
\def\ps@draft{\let\@mkboth\@gobbletwo\let\@oddhead\@empty%
              \def\@oddfoot{\reset@font\rlap{\textsl{Draft: \shortdate}}%
                            \hfil\thepage\hfil}%
              \let\@evenhead\@empty\let\@evenfoot\@oddfoot}
\def\ps@firstpage{\let\@mkboth\@gobbletwo\let\@oddhead\@empty%
                  \def\@oddfoot{\normalfont\scriptsize}
                  \let\@evenhead\@empty\let\@evenfoot\@oddfoot}
\if@draft%
  \def\ps@headings{%
    \def\@oddfoot{\reset@font\rlap{\textsl{Draft: \shortdate}}\hfil}
    \def\@oddhead{{\slshape\MakeUppercase\shorttitle}\hfil\thepage}}%
\fi%
\if@draft\pagestyle{draft}\else\pagestyle{empty}\fi%
%    \end{macrocode}
%    We ensure that the \amslatex/ packages 
%    \pkg{amsmath} \cite{AmSLaTeX},
%    \pkg{amsfonts} and \pkg{amsthm} \cite{amsthm} are loaded.
%    The latter of these provides more developed theorem environments
%    than standard \latex/.
%    You get still more if you use
%    the \pkg{uwamaths} package \cite{uwamaths}.
%    The \env{proof} environment is redefined to give a
%    \textbf{bold} header (it's done in the same way as
%    the \pkg{uwamaths} package \cite{uwamaths}).
%    \begin{macrocode}
\RequirePackage{amsmath}\relax
\ifx\relax\mathfrak \@xp\@gobbletwo \else \let\mathfrak\relax \fi
\RequirePackage{amsfonts}\relax
\RequirePackage{amsthm}\relax
\renewenvironment{proof}[1][\proofname]{\par 
  \normalfont
  \topsep6\p@\@plus6\p@ \trivlist 
  \item[\hskip\labelsep\bfseries
    #1\@addpunct{.}]\ignorespaces
  }{%
  \qed\endtrivlist
  }%
%    \end{macrocode}
%    The following \amslatex/ command tells \latex/ to allow breaks 
%    within maths displays but to avoid them as much as possible.
%    \begin{macrocode}
\allowdisplaybreaks[1]
%    \end{macrocode}
%    We redefine \cn{title} to accept an optional shorter
%    argument as for the \amslatex/ \cls{amsbook} class. This
%    is only useful for drafts where under the \opt{draft} option
%    the \cn{pagestyle} might be changed to \texttt{headings} 
%    before submission to the journal.
%    The \verb+\pagestyle{headings}+ declaration
%    need not be removed before submission to the journal, since
%    if the \opt{draft} option is not active the \texttt{headings}
%    \cn{pagestyle} is redefined to be the same as the \texttt{empty}
%    \cn{pagestyle}.
%    \begin{macrocode}
\renewcommand{\title}[2][]{\gdef\shorttitle{#1}\gdef\@title{#2}}
\edef\title{\@nx\@dblarg
  \@xp\@nx\csname\string\title\endcsname}
%    \end{macrocode}
%    We redefine \cn{author} as per the \cls{amsbook} class to
%    accept an optional abbreviated argument \dots (this is
%    \emph{not at all} useful; however the intention in the future
%    is to support multiple authors -- the real reason for using
%    a hack of the \cls{amsbook} macro.)
%    We create also \cn{address} and supporting macros. Again,
%    at the moment a single author with a single address only
%    is supported. (The \cn{author} macro can though be used \emph{once}
%    for a list of authors, if those authors have a \emph{common}
%    address.
%    \begin{macrocode}
\renewcommand{\author}[2][]{%
  \ifx\@empty\authors
    \gdef\shortauthors{#1}\gdef\authors{#2}%
  \else
    \g@addto@macro\shortauthors{\and#1}%
    \g@addto@macro\authors{\and#2}%
  \fi}
\edef\author{\@nx\@dblarg
  \@xp\@nx\csname\string\author\endcsname}
\let\shortauthors\@empty   \let\authors\@empty
\let\thankses\@empty
\def\@setaddress{\def\address##1{\par##1\@addpunct.}\@address}
\newcommand{\address}[1]{\let\@address\@empty
			 \g@addto@macro\@address{\address{#1}}}
\renewcommand{\thanks}[1]{\g@addto@macro\thankses{\thanks{#1}}}
\def\@setthanks{\def\thanks##1{\par##1\@addpunct.}\thankses}
%    \end{macrocode}
%    Now we adjust the \cn{maketitle} macro from the \cls{article}
%    class to be in keeping with the journal specifications.
%    \begin{macrocode}
\renewcommand\maketitle{\par
  \begingroup
    \renewcommand\thefootnote{\@fnsymbol\c@footnote}%
    \let\thanks\footnote
    \newpage
    \global\@topnum\z@   % Prevents figures from going at top of page.
    \@maketitle
    \if@draft\thispagestyle{draft}\else\thispagestyle{firstpage}\fi%
  \endgroup
  \setcounter{footnote}{0}%
  \global\let\thanks\relax
  \global\let\thankses\relax
  \global\let\maketitle\relax
  \global\let\@maketitle\relax
  \global\let\@author\@empty
  \global\let\@address\@empty
  \global\let\@date\@empty
  \global\let\@title\@empty
  \global\let\title\relax
  \global\let\author\relax
  \global\let\date\relax
  \global\let\and\relax
}
\def\@maketitle{%
  \newpage
  \null
  \vskip 11mm%
  \begin{center}%
  \ifx\@empty\thankses\else \@footnotetext{%
      \def\par{\let\par\@par}\@setthanks}\fi
  \renewcommand{\baselinestretch}{\normalstretch}
    {\LARGE\MakeUppercase\@title\par}%
    \vskip 2\baselineskip%
    {\normalsize
      \authors
      \vskip \baselineskip%
      {\renewcommand{\baselinestretch}{1}\normalsize%
       \ifx\@empty\@address\else\@setaddress\\\fi}}
  \end{center}%
  \renewcommand{\baselinestretch}{\normalstretch}\normalsize
  \par
  \vskip 4\baselineskip}
\def\footnoterule{\kern-.4\p@
        \hrule\@width 5pc\kern11\p@\kern-\footnotesep}
\def\@makefnmark{\hbox{$\m@th^{\@thefnmark}$}}
\def\@makefntext{\indent\@makefnmark}
\long\def\@footnotetext#1{\insert\footins{%
  \normalfont\footnotesize
  \interlinepenalty\interfootnotelinepenalty
  \splittopskip\footnotesep \splitmaxdepth \dp\strutbox
  \floatingpenalty\@MM \hsize\columnwidth
  \@parboxrestore \parindent\parindent \sloppy
  \edef\@currentlabel{\p@footnote\@thefnmark}%
  \@makefntext{\rule\z@\footnotesep\ignorespaces#1\unskip\strut\par}}}
%    \end{macrocode}
%    We now create the \env{acknowledgements} environment.
%    \begin{macrocode}
\def\ackname{Acknowledgments}
\newenvironment{acknowledgements}%
   {\subsection*{\centering\normalfont\MakeUppercase\ackname}}{}
%    \end{macrocode}
%    We adjust the heading for the bibliography to be 
%    centred and capitalised.
%    \begin{macrocode}
\renewenvironment{thebibliography}[1]
     {\section*{\centering\MakeUppercase\refname}%
      \list{\@biblabel{\@arabic\c@enumiv}}%
           {\settowidth\labelwidth{\@biblabel{#1}}%
            \leftmargin\labelwidth
            \advance\leftmargin\labelsep
            \@openbib@code
            \usecounter{enumiv}%
            \let\p@enumiv\@empty
            \renewcommand\theenumiv{\@arabic\c@enumiv}}%
      \sloppy\clubpenalty4000\widowpenalty4000%
      \sfcode`\.\@m}
     {\def\@noitemerr
       {\@latex@warning{Empty `thebibliography' environment}}%
      \endlist}
%    \end{macrocode}
%    We set the normal interline spacing to be approximately
%    $1\frac12$-spacing (as required by the journal).
%    \begin{macrocode}
\def\normalstretch{1.24}
\renewcommand{\baselinestretch}{\normalstretch}\normalsize
%    \end{macrocode}
%    We make available some spacing macros. 
%    The amounts of stretch are those specified
%    for $12\,$pt by the \emph{\latex/ Companion} \cite{Companion}.
%    Other font sizes differ from these only marginally.
%    See the \pkg{uwamaths} package \cite{uwamaths}
%    where the same macros are defined, for further discussion
%    of these macros.
%    \begin{macrocode}
\newcommand{\singlespacing}{\renewcommand{\baselinestretch}{1}}
\newcommand{\oneandhalfspacing}{\renewcommand{\baselinestretch}{1.24}}
\newcommand{\doublespacing}{\renewcommand{\baselinestretch}{1.66}}
%    \end{macrocode}
%    The following macro is used in the setting of captions. It is
%    adjusted to capitalise the word TABLE or FIG. Also, we adjust
%    \cn{figurename} to be \texttt{Fig.} (the \cls{article} class
%    ordinarily defines the \cn{figurename} to be unabbreviated),
%    as dictated by the journal style.
%    \begin{macrocode}
\long\def\@makecaption#1#2{%
  \vskip\abovecaptionskip
  \sbox\@tempboxa{#1: #2}%
  \ifdim \wd\@tempboxa >\hsize
    \MakeUppercase#1: #2\par
  \else
    \global \@minipagefalse
    \hb@xt@\hsize{\hfil\box\@tempboxa\hfil}%
  \fi
  \vskip\belowcaptionskip}
\figurename{Fig.}
%    \end{macrocode}
%    \amslatex/ defines a macro \cn{numberwithin}
%    which doesn't work as desired in the case where a counter is already
%    numbered within a sectional unit -- one can end up with duplicate chapter
%    numbers for a table, for example. Hence we provide a macro
%    \cn{numberin} which otherwise works in the manner described for
%    \cn{numberwithin} in \cite{AmSLaTeX}, e.g.
%    \begin{quote}\slshape
%      \verb+\numberin{table}{section}+
%    \end{quote}
%    will cause \env{table}s to be numbered within \texttt{section}s.
%    To get the order of the arguments right, read the above command
%    this way: \emph{number} \env{table} \emph{in} \texttt{section}.
%    (You will get strange effects if you get the arguments the wrong way 
%    round.)
%    \begin{macrocode}
\newcommand{\numberin}[2]{%
     \@addtoreset{#1}{#2}%
     \@xp\@xp\@xp\renewcommand\@xp{\csname the#1\endcsname}{%
                        \csname the#2\endcsname.\arabic{#1}}}
%    \end{macrocode}
%    (For those curious about what \cn{@xp} does: \cn{@xp} is an
%    \amslatex/ abbreviation for \tex/'s \cn{expandafter}.
%    The above configuration of \cn{expandafter} commands is described
%    in \cite[page 374]{TeX}.)
%
%    \begin{macrocode}
\endinput
%    \end{macrocode}
% \CheckSum{515}
% \Finale