```% pandoc -f latex -t native\newcommand\foo{+}Testing: $\mu\foo\eta$.^D[ Para [ Str "Testing:" , Space , Math InlineMath "\\mu+\\eta" , Str "." ]]```
<!-- It would be nice to handle this case, but I don't
know how:
```% pandoc -f latex -t native\newcommand{\vecx}{a + b}$\hat\vecx$^D[Para [Math InlineMath "\\hat{a+b}"]]```
-->