LaTeX reader sometimes omits expressions containing square brackets [

[nilaykumar]

In LaTeX, I have an expression [d,\delta]=0 that I've placed in an equation* environment. Upon converting to HTML, all I see is "=0" (see screenshot below), even if we were to get rid of MathJax. When placed in the \[ \] environment, however, the expression converts correctly.

The following is a working example:

\documentclass{article}
\begin{document}
\noindent With the arguments
\begin{verbatim}
pandoc test.tex -f latex -t html --mathjax -s -o out.html
\end{verbatim}
the code
\begin{verbatim}
\begin{equation*}
  [d,\delta]=0.
\end{equation*}
\end{verbatim}
results in
\begin{equation*}
  [d,\delta]=0.
\end{equation*}
but the code
\begin{verbatim}
\[ [d,\delta] = 0\]
\end{verbatim}
results in
\[ [d,\delta]=0.\]
\end{document}

resulting in

Interestingly, throwing a character a[d,\delta]=0 in front of the opening square bracket in the equation* environment solves the problem. Is this a bug or a feature that I should work around? Thanks!

Version: I'm running pandoc version 2.14.1 on macOS Big Sur 11.4 on a Macbook Air (M1 2020).

[jgm]

The issue is shown a bit more clearly by:

% pandoc --mathjax -t html  -f latex
\begin{equation*}
[d,\delta]=0.
\end{equation*}
^D
<p><span class="math display">\[=0.\]</span></p>

[jgm]

I think what's happening here is that there's some code in the LaTeX reader's generic environment parser that skips over bracketed optional arguments that some environments have. This is obviously not wanted for the equation* environment! Escaping the square brackets should be a workaround.

[jgm]

More workarounds:

{}[d,\delta]=0

{[d,\delta]}=0

[jgm]

I've modified the title because this isn't specific to HTML output or mathjax.

% pandoc -t native -f latex
\begin{equation*}
[d,\delta]=0.
\end{equation*}
^D
[Para [Math DisplayMath "=0."]]

[fedeinthemix]

I would like to provide another example where this happens: In the following table the first entry in the second row (starts with [) is dropped by pandoc while it's present if the file is processed with LaTeX.

\documentclass{article}
\begin{document}
\begin{table}[htb]
  \centering
  \begin{tabular}{|c|c|c|c|c|c|c|}
       $W$      & $N_S$ & $L$  & $L$  & rel. err. & $L$  & rel. err. \\[0mm]
       [$\mu$m] & [-]   & [nH] & [nH] & [\%]      & [nH] & [\%]\\
    \hline\hline
    1.00 & 32 & 0.2871 & 0.293 & 2.06 & 0.294 & 2.40 \\
    2.00 & 32 & 0.2616 & 0.266 & 1.68 & 0.269 & 2.83 \\
  \end{tabular}
\end{table}
\end{document}

Note that the commands \\ and \\* do have an optional argument that in the example is used.