\documentclass{ltxdoc}
\CodelineIndex
\EnableCrossrefs
\DeclareTextFontCommand\word\em          % refer to a word as a word
\DeclareTextFontCommand\term\slshape     % technical term
\DeclareTextFontCommand\env\ttfamily     % environment
\DeclareTextFontCommand\package\slshape  % name of LaTeX package
\DeclareTextFontCommand\program\ttfamily % generic name of computer program
\DeclareTextFontCommand\class\slshape    % name of LaTeX class
\DeclareTextFontCommand\file\ttfamily    % name of disk file
\DeclareTextFontCommand\ext\ttfamily     % name of file extension
\begin{document}
\providecommand\ALaTeX{A\LaTeX}
\date{Version:  1.0 \\Documentation revision: 1996/01/21}
\author{Matt Swift \texttt{<swift@bu.edu>}}
\title{\ALaTeX{} and its Standard Metaclass}
\maketitle
\DocInput{alatex.dtx}
\clearpage
\PrintIndex
\end{document}
