plainsection.tex

% plainsection.tex
% Dorai Sitaram
% Last change 2016-12-21

\let\maybeendinput\relax
\ifx\shipout\UnDeFiNeD
  \let\maybeendinput\endinput
\fi\maybeendinput

\edef\atcatcodebeforeplainsection{%
  \noexpand\catcode`\noexpand\@=\the\catcode`\@}
\catcode`\@11

% Sections

\def\tracksectionchangeatlevel#1{%
  \expandafter\let\expandafter\thiscount
    \csname sectionnumber#1\endcsname
  \ifx\thiscount\relax
    \expandafter\expandafter\csname newcount\endcsname
      \csname sectionnumber#1\endcsname
    \csname sectionnumber#1\endcsname=0
  \fi
  \expandafter\advance\csname sectionnumber#1\endcsname by 1
  \ifx\doingappendix0%
    \edef\@currentlabel{\the\csname sectionnumber1\endcsname}%
  \else
    \edef\@currentlabel{\appendixchar{\the\csname
      sectionnumber1\endcsname}}%
  \fi
  \count255=0
  \loop
    \advance\count255 by 1
    \ifnum\count255=1
    \else\edef\@currentlabel{\@currentlabel.\the\csname
      sectionnumber\the\count255\endcsname}%
    \fi
  \ifnum\count255<#1%
  \repeat
  \loop
    \advance\count255 by 1
    \expandafter\let\expandafter\nextcount\csname
      sectionnumber\the\count255\endcsname
    \ifx\nextcount\relax
      \let\continue0%
    \else
      \csname sectionnumber\the\count255\endcsname=0
      \let\continue1\fi
  \ifx\continue1%
  \repeat}

\def\appendixchar#1{\ifcase#1\or A\or B\or C\or D\or E\or F\or
G\or H\or I\or J\or K\or L\or M\or N\or O\or P\or Q\or R\or S\or
T\or U\or V\or W\or X\or Y\or Z\else AA\fi}

\newcount\secnumdepth

\secnumdepth=3

\def\sectiond#1{\count255=#1%
  \ifx\usingchapters1\advance\count255 by 1 \fi
  \edef\sectiondlvl{\the\count255 }%
  \futurelet\sectionnextchar\sectiondispatch}

\def\sectiondispatch{\ifx\sectionnextchar*%
  \def\sectioncontinue{\sectionstar{\sectiondlvl}}\else
  \ifnum\sectiondlvl>\secnumdepth
  \def\sectioncontinue{\sectionhelp{\sectiondlvl}{}}\else
  \tracksectionchangeatlevel{\sectiondlvl}%
  \def\sectioncontinue{\sectionhelp{\sectiondlvl}%
    {\@currentlabel}}\fi\fi
  \sectioncontinue}

\def\sectionstar#1*{\sectionhelp{#1}{}}

\def\sectionhelp#1#2{%
  \edef\sectiondepth{#1}%
  \def\sectionnr{#2}%
  \immediate\openout\sectionQscratchfileport Z-sec-temp
  \begingroup
  \def\do##1{\catcode`##1=11 }\dospecials
  \catcode`\{=1 \catcode`\}= 2
  \sectionheader}

% Vanilla section-header look -- change this macro for new look

\def\sectionheader#1{\endgroup
  \immediate\write\sectionQscratchfileport {#1}%
  \immediate\closeout\sectionQscratchfileport
  \vskip -\lastskip
  \ifnum\sectiondepth>\tocdepth\else
  \writenumberedtocline{\sectiondepth}{\sectionnr}{#1}%
  \fi
  \vskip1.5\bigskipamount
  \goodbreak %???
  \noindent
  \hbox{\vtop{\pretolerance 10000
    \raggedright
    \noindent\bf
    \ifx\sectionnr\empty\else
      \sectionnr\enspace\fi
    \input Z-sec-temp }}%
  \nobreak
  \smallskip
  %\noindent
  }

% \edef\temp{\write\tocout{\string\hskip#1\space em\string\relax\space #2%
%    \string\vtop{\string\hsize=.7\string\hsize
%    \string\noindent\string\raggedright\space #3}\string\par}}\temp

\def\section{\sectiond1}
\def\subsection{\sectiond2}
\def\subsubsection{\sectiond3}
\def\paragraph{\sectiond4}
\def\subparagraph{\sectiond5}

\let\usingchapters0

\def\chapter{\global\let\usingchapters1%
\global\footnotenumber=0
\futurelet\chapternextchar\chapterdispatch}

\def\chapterdispatch{\ifx\chapternextchar*%
  \let\chaptercontinue\chapterstar\else
  \tracksectionchangeatlevel{1}%
  \def\chaptercontinue{\chapterhelp{\@currentlabel}}\fi
  \chaptercontinue}

\def\chapterstar*{\chapterhelp{}}

\def\chapterhelp#1{%
  % #1=number #2=heading-text
  \def\chapternr{#1}%
  \immediate\openout\sectionQscratchfileport Z-sec-temp
  \begingroup
  \def\do##1{\catcode`##1=11 }\dospecials
  \catcode`\{=1 \catcode`\}=2
  \chapterheader}

\def\chapterheader#1{\endgroup
  \immediate\write\sectionQscratchfileport {#1}%
  \immediate\closeout\sectionQscratchfileport
  \writenumberedtocline{1}{\chapternr}{#1}%
  \vfill\eject
  \null\vskip3em
  \noindent
  \ifx\chapternr\empty\hbox{~}\else
  \ifx\doingappendix0%
    \hbox{\bf Chapter \chapternr}\else
  \hbox{\bf Appendix \chapternr}\fi\fi
  \vskip 1em
  \noindent
  \hbox{\bf\vtop{%\hsize=.7\hsize
    \pretolerance 10000
    \noindent\raggedright\input Z-sec-temp }}%
  \nobreak\vskip3em
  %\noindent
  }

\let\doingappendix=0

\def\appendix{\let\doingappendix=1
  \csname sectionnumber1\endcsname=0
  \relax}

% enumerate

\def\enumerate{\par\begingroup
  \advance\@itemdepth by 1
  \expandafter\csname newcount\endcsname\enumeratenumber
  \enumeratenumber=0
  \advance\leftskip\parindent
  \smallbreak
  \def\item{\smallbreak\noindent
    \advance\enumeratenumber by 1
    \ifnum\@itemdepth=1
      \edef\enumeratemark{\the\enumeratenumber.}\else
    \ifnum\@itemdepth=2
      \count255=\the\enumeratenumber
      \advance\count255 by -1 \advance\count255 by `a
      \edef\enumeratemark{(\noexpand\char\the\count255 )}\else
    \ifnum\@itemdepth=3
      \edef\enumeratemark{\noexpand\romannumeral\the\enumeratenumber.}\else
    \ifnum\@itemdepth=4
      \count255=\the\enumeratenumber
      \advance\count255 by -1 \advance\count255 by `A
      \edef\enumeratemark{\noexpand\char\the\count255 .}\else
    \edef\enumeratemark{\the\enumeratenumber.}\fi\fi\fi\fi
    \edef\@currentlabel{\enumeratemark}% needed?
    \llap{\enumeratemark\enspace}\ignorespaces}}

\def\endenumerate{\smallbreak\smallbreak\endgroup\par}

% itemize

\newcount\@itemdepth

\@itemdepth=0

\def\labelitemi{$\bullet$}
\def\labelitemii{$-$}
\def\labelitemiii{$\star$}
\def\labelitemiv{$\circ$}

\def\itemize{\par\begingroup
  \ifnum\@itemdepth>3
    \message{Too deeply nested.}%
  \fi
  \advance\@itemdepth by 1
  \advance\leftskip\parindent
  \smallbreak
  \def\item{\smallbreak\noindent
  \llap{\csname labelitem\romannumeral
    \the\@itemdepth\endcsname\enspace}%
  \ignorespaces}}

\def\enditemize{\smallbreak\smallbreak\endgroup\noindent}

\atcatcodebeforeplainsection

% end of file