Missing <sub> tags in tex4ht output

Question

When processing a LaTeX source with tex4ht, I can't seem to reliably convert subscripts in text mode to <sub> tags in the HTML output. My only solution so far is to switch to math mode. But for some reason, if I define the same math code as a macro with \newcommand (to avoid typos when typing long math expressions), the <sub> tags are gone again!

Example source:

\documentclass[10pt]{article}
\usepackage{subscript}
\newcommand{\tsub}{$a_b$}
\begin{document}
x\textsuperscript{n}
y\textsubscript{1}
$a_b$
\tsub{}
\end{document}

... which I process using:

htlatex example.tex 'html, charset=utf-8' ' -cunihtf -utf8'

Is there an easy way to make tex4ht honor \textsubscript or $_{}$ commands in \newcommand macros?

Thanks for any suggestion,

--Mathieu

Answer 1

It seems there is no configuration for subscript package, so you must create one. Configurations for packages are stored in files with extension .4ht, so for subscript create subscript.4ht:

\NewConfigure{textsubscript}{2}
\renewcommand\textsubscript[1]{%
\a:textsubscript#1\b:textsubscript
}
\Configure{textsubscript}{\Tg<sub>}{\Tg</sub>}

This file will be automatically loaded by tex4ht when you call \usepackage{subscript}