# nicematrix with fontspec

Why don't the nicematrix and fontspec package play well together?

Here is a MWE:

\documentclass{article}

\usepackage{nicematrix}
\usepackage{fontspec}
\usepackage{lipsum}

\begin{document}
\lipsum*[1-3]
$\begin{pNiceMatrix}a&b\\0&0\end{pNiceMatrix}$
\end{document}


When you comment out either the fontspec package or the nicematrix package (and the corresponding environment) the compilation runs fine. As is, if you put in a NiceMatrix environment, it still compiles, but throws the error LaTeX Error: Missing \begin{document}.

• I have no such problem, compiling with xelatex as well as with lualatex. Is your installation up-to-date? – Bernard Sep 20 at 21:04
• Interesting; I did update my installation before posting the question. My system is a Mac running TeX Live 2019. I can provide the log file if that would help. – tim Sep 20 at 21:16
• Quite strange… And you have the error message with this very code? – Bernard Sep 20 at 21:19
• Yep! Here's the link to the log file. Apparently the error occurs immediately when loading the nicematrix package. – tim Sep 20 at 21:28
• I see you have the very latest version of nicematrix (3.2), whereas MiKTeX (my distribution) still has version 3.1. That's the only difference I notice. Maybe a problem with latest version. Just in case: try changing the loading order. – Bernard Sep 20 at 21:43

## 1 Answer

In the latest update of the nicematrix package there is a zero width space

U+feff ZERO WIDTH NO-BREAK SPACE


at the start of line 21 before the % this is clearly an error, you should report to the package author.

You can save a local copy of the file, deleting the line

% \iffalse meta-comment


and it will run without error

• I just mailed the author with a link to this post. – David Carlisle Sep 20 at 22:22
• Awesome; I was just about to do that too. Thank you! – tim Sep 20 at 22:24
• Thanks. I will post a corrected version of the package nicematrix on CTAN today. – F. Pantigny Sep 21 at 4:36
• I have posted on CTAN a corrected version (3.2a). – F. Pantigny Sep 21 at 15:59
• @F.Pantigny thanks! – David Carlisle Sep 21 at 16:07