Motivation

My end goal is to include more Mathematica expressions in LaTeX-pdfs that are copy-paste-able back into Mathematica notebooks. For instance, the code

\usepackage{mmacells}...\begin{mmaCell}{Input}  \mmaSub{\(\pmb{\partial}\)}{x}\mmaSup{x}{2}\end{mmaCell}

yields

but if you copy that and paste it into a Mathematica notebook, it makes

instead of the 'correct'

This makes sense: the raw copied text is "∂ x x2". Other unicode characters generated by CellToTeX copy like "\[Pi]", one of Mathematica's auto expanding inputs (if you paste that string into a notebook, it'll show as π). There is some raw text that produces the correct Mathematica code, though:

\!\(\*SubscriptBox[\(\[PartialD]\), \(x\)]\*SuperscriptBox[\(x\), \(2\)]\)

Basically, \!\(...\) with the ! says to auto expand, and wrapping things in \(\) and with \* does other parsing stuff. So if that string was to be copied when selecting the stuff in the pdf, it would be pasted beautifully back into a notebook.

Question

Is there a good way or package to specify what is copied for some selected pdf content of some cells? Can I wrap the \begin{mmaCell}...\end{mmaCell} with something like a href{\\!\\(\\*SuperscriptBox...\\)}{...}, but instead of a link, change the copy-paste content? Or do I have to begin spelunking inside the TeXbook, but probably not that -- I might have to spelunk in pdflatex or something else. Correct me if I'm wrong, but the mmacells package is pretty much just styling, and can't help here.