Support href inside math expressions

[fred-wang]

Minimal testcase:

\documentclass{article}
\usepackage{amsmath}
\usepackage{hyperref}
\begin{document}
  $$\binom{k}{n} = \frac{\href{https://en.wikipedia.org/wiki/Factorial}{n!}}{k!{(n-k)!}}$$
\end{document}

This works with pdflatex / xelatex. LaTeXML returns error regarding malformed XML output and the final MathML uses HTML hyperlink instead of the href attribute.

[brucemiller]

Surprisingly less straightforward than you'd think. Not clear how to adjust LaTeXML's schema to record the url (on what?). And your example highlights that the url applies to the whole subtree of n!; presumably the href should be on the m:mrow (which isn't guaranteed to exist in general).

[brucemiller]

Well, the solution was relatively easy, even though it makes me slightly uncomfortable; just allow href attribute on XMath elements. I'd have generalized further to allow idref and labelref, but am concerned about the clash with the different meaning of those on shared elements.

Hopefully better late than never; Thanks for the request!