[tex-eplain] \sidx not catcode-clean

[Dorai Sitaram]

Eplain's \sidx won't allow catcode changes in its argument.  E.g.,

% --- sidxtest.tex ---

\input eplain

\sidx{bye@\verbatim \bye|endverbatim}

\bye

% --- end sidxtest.tex ---

In contrast, \index in the corresponding LaTeX file does the right thing. 

% --- sidxtest.ltx ---

\documentclass{article}

\begin{document}

\index{bye@\verb+\bye+}

\end{document}

% --- end sidxtest.ltx ---

Allowing catcode changes within indexing commands is crucial, especially in
computer-science documentation where many indexed items require verbatim. 


Dorai