\def\filedate{1996/07/22}
\def\docdate {1995/04/14}
\def\fileversion{2.5}
%
% \iffalse
% File: nameref.dtx Copyright (C) 1995 Sebastian Rahtz
% 
%  This package is distributed in the hope that it will be useful,
%  but WITHOUT ANY WARRANTY; without even the implied warranty of
%  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
%
%<*driver>
\documentclass{ltxdoc}
\begin{document}
 \title{Section name references in \LaTeX\thanks{This file
        has version number \fileversion, last
        revised \filedate.}}
 \author{Sebastian Rahtz}
 \date{\filedate}
 \maketitle
 \tableofcontents
 \DocInput{nameref.dtx}
\end{document}
%</driver>
% \fi
% \CheckSum{721}
% \section{Introduction}
% Cross-referencing to include the \emph{name} of the section, rather than
% just the number or page. This works by redefining some of the inside
% \LaTeX\ macros, so it is vulnerable to future changes.
% \section{History}
% Sebastian Rahtz, for Lou Burnard, March 15th 1994
% SPQR CERN July 1994
% Last mod. Sept. 3th MG, 
% Sept. 19th SPQR
% April 11th 1995 SPQR (added section formatting hook)
% April 14th 1995 SPQR (compatibility with hyperref)
% June 22 1995 SPQR (removed typeout from Sectionformat)
%    \begin{macrocode}
%<*package>
\ProvidesPackage{nameref}[\filedate\space Cross-referencing by name of section]
\RequirePackage{ifthen}
%    \end{macrocode}
%
% We redefine |\label| so that it also writes the name of the 
% current section to the .aux file; if the name ends in a dot, 
% we zap it. To allow for the hyperref package, also write
% a fourth field (empty by default).
%    \begin{macrocode}
\def\strip@period#1.\relax#2\@@@{#1}
\def\label#1{%
  \@bsphack
  \bgroup
  \let\label\@gobble
  \def\ref{\protect\ref}%
  \edef\@currentlabstr{\expandafter\strip@prefix\meaning\@currentlabelname}%
  \protected@write\@auxout{}%
         {\string\newlabel{#1}{%
            {\@currentlabel}%
            {\thepage}%
            {\expandafter\strip@period\@currentlabstr\relax.\relax\@@@}%
            {\@currentHref}%
          }}%
  \egroup
  \@esphack
}
\let\ltx@label\label
%    \end{macrocode}
% Needed for the \emph{subeqnarray} package.
%    \begin{macrocode}
\@ifundefined{slabel}{}{%
\def\slabel#1{%
  \@bsphack
  \if@filesw
    {\let\label\@gobble
     \def\ref{\protect\ref}%
     \edef\@currentlabstr{\expandafter\strip@prefix\meaning\@currentlabelname}%
     \let\thepage\relax
     \def\protect{\noexpand\noexpand\noexpand}%
     \edef\@tempa{\write\@auxout{\string
        \newlabel{#1}{%
            {\thesubequation}%
            {\thepage}%
            {\expandafter\strip@period\@currentlabstr\relax.\relax\@@@}%
            {\@currentHref}%
            }}}%
     \expandafter}\@tempa
     \if@nobreak \ifvmode\nobreak\fi\fi
  \fi\@esphack}}
%    \end{macrocode}
% Overload an AMS \LaTeX\ command, which uses |\newlabel|. Sigh!
%    \begin{macrocode}
\def\@writetocindents{%
  \begingroup
  \@for\@tempa:=-1,0,1,2,3\do{%
    \immediate\write\@auxout{%
      \string\newlabel{tocindent\@tempa}{%
        \csname r@tocindent\@tempa\endcsname}{}{}}%
  }%
  \endgroup}
%    \end{macrocode}
% Add to the underlying section heading macros so that they
% note the section name for use by label. 
%
% If a section heading or the like has a |\label| in it,
% we need to extract it, or subsequent processing breaks.
% This is done by the label-writing routine.
%    
% First the numbered sections. While we are about it, put in
% a useful section formatting macro.
%    \begin{macrocode}
\let\old@sect\@sect
\def\@sect#1#2#3#4#5#6[#7]#8{%
 \def\@currentlabelname{#7}%
 \old@sect{#1}{#2}{#3}{#4}{#5}{#6}[{#7}]{\Sectionformat{#8}{#2}}%
}
%    \end{macrocode}
% and now the unnumbered ones
%    \begin{macrocode}
\let\old@ssect\@ssect
\def\@ssect#1#2#3#4#5{%
 \def\@currentlabelname{#5}%
 \old@ssect{#1}{#2}{#3}{#4}{\Sectionformat{#5}{#1}}%
}
%    \end{macrocode}
%
% Parts and chapters are treated differently. sigh.
%
%    \begin{macrocode}
\let\old@part\@part
\def\@part[#1]#2{%
  \def\@currentlabelname{#1}%
  \old@part[{#1}]{#2}%
}
\let\old@chapter\@chapter
\def\@chapter[#1]#2{%
  \def\@currentlabelname{#1}%
  \old@chapter[{#1}]{#2}%
}
\let\old@schapter\@schapter
\def\@schapter#1{%
  \def\@currentlabelname{#1}%
  \old@schapter{#1}%
}
%    \end{macrocode}
% We default the label and hypertext reference to be empty.
%    \begin{macrocode}
\def\@currentlabelname{}
\def\@currentHref{}
%    \end{macrocode}
% Since the second part of the preserved reference now has four parts
% (number, page, name and hypertext reference), we need extra utility
% macros:
%    \begin{macrocode}
\long\def\@firstoffour#1#2#3#4{#1}
\long\def\@secondoffour#1#2#3#4{#2}
\long\def\@thirdoffour#1#2#3#4{#3}
\long\def\@fourthoffour#1#2#3#4{#4}
%    \end{macrocode}
% We have to redefine |\ref| and |\pageref| to know about extra
% reference elements. Make them robust.
%    \begin{macrocode}
\def\T@ref#1{\expandafter\@setref\csname r@#1\endcsname\@firstoffour{#1}}
\def\T@pageref#1{\expandafter\@setref\csname r@#1\endcsname
                                     \@secondoffour{#1}}
\def\ref{\protect\T@ref}
\def\pageref{\protect\T@pageref}
%    \end{macrocode}
% \section{Usage and frontend}
% Access the (third) name part with |\nameref|;
%    \begin{macrocode}
\def\T@nameref#1{\expandafter\@setref\csname r@#1\endcsname 
 \@thirdoffour{#1}}
\def\nameref{\protect\T@nameref}
%    \end{macrocode}
% An extended form which gives title and page number.
%    \begin{macrocode}
\def\Nameref#1{`\nameref{#1}' on page~\pageref{#1}}
%    \end{macrocode}
%
% The default for |\Sectionformat|
%    \begin{macrocode}
\def\Sectionformat#1#2{#1}
%    \end{macrocode}
% an example alternative for BNC book for Lou Burnard:
%    \begin{macrocode}
\def\LouSectionformat#1#2{%
   \ifnum#2=1
     \if@twoside
       \ifthenelse{\isodd{\thepage}}%
         {\raggedright}%
         {\raggedleft}%
     \else
      \raggedleft 
     \fi
     #1 \\[2pt]\rule{\columnwidth}{1.5pt}
   \else
    #1
   \fi
}
%</package>
%    \end{macrocode}
%
% \Finale