+% \begin{macro}{\cmd}
+% \begin{macro}{\cs}
+% \begin{macrocode}
+\def\cmd#1{\expandafter\cmd@i\string#1\x}
+\def\cmd@i#1#2\x{\cs{#2}}
+\DeclareRobustCommand\cs[1]{\texttt{\char`\\#1}}
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}{\marg}
+% \begin{macro}{\oarg}
+% \begin{macro}{\parg}
+% \begin{macrocode}
+\def\@arg#1#2#3{\texttt{#1}\meta{#2}\texttt{#3}}
+\def\marg#1{\@arg{\char`\{}{#1}{\char`\}}}
+\def\oarg#1{\@arg{[}{#1}{]}}
+\def\parg#1{\@arg{(}{#1}{)}}
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+