\documentclass{jsarticle}
\usepackage{at,makeidx}
\newatcommand sec[1]{\section{#1}}
\newatcommand ssec[1]{\subsection{#1}}
\newatcommand sssec[1]{\subsubsection{#1}}
\makeindex
\newatcommand showindex{\printindex}
\atdef|#1|{\texttt{#1}}
\begin{document}
@sec{ほげ}
@/hogehoge/ @@
@ssec{ほげほげ}
@*hogehoge*
@sssec{ほげほげほげ}
@|TypeWriter|, Hoge@i{hoge} is @I{hoge}.
@showindex
\end{document}
