# Having trouble with running xepersian

I try to use XeLaTeX to compile

     \documentclass{article}
\usepackage{xepersian}
\begin{document}
Hello World
\end{document}


And I get the following error:

 Runaway argument?
{\dim_set:Nn ##1{\fontdimen ##2##3}\dim_compare:nNnT ##1={0pt}{\settoheight\ETC.
! Forbidden control sequence found while scanning use of \__cs_generate_from_si
gnature:nnNNNn.
<inserted text>
\par
l.1767       \int_case:nnn
#2


Anything containing xepersian seems to generate the same error.

• Have you compiled your code with XeLaTeX? – Roboticist Oct 30 '17 at 22:23
• @Roboticist Yes compiled with XeLaTeX. If I comment out '\usepackage{xepersian}' it works with XeLaTeX, but including the package creates the error. – Maesumi Oct 30 '17 at 22:31
• You do not give many clues but I think your expl3 is too old, update your miktex packages – David Carlisle Oct 30 '17 at 22:41

If you compile your code with XeLaTeX, you should end up with something like this:

which is pretty predictable because your left-to-right text is inverted by the right-to-left xepersian.

To fix the issue, you can use \lr{} to change the direction temporarily. Outside of \lr{} everything will be right-to-left again.

\documentclass{article}
\usepackage{xepersian}
\settextfont{XB Niloofar}
\begin{document}
\noindent\lr{Hello World}\\
سلام دنیا\\
خداحافظ دنیا
\end{document}


• I don't get any output. I just get the error message. – Maesumi Oct 30 '17 at 22:38
• @Maesumi: Which distribution are you using? – Roboticist Oct 30 '17 at 22:39
• I am using MIKTEX. – Maesumi Oct 30 '17 at 22:40
• @Maesumi: Check your directory after compilation. Does LaTeX generate any pdf as the output, regardless of the error? – Roboticist Oct 30 '17 at 22:41
• Yes it does! And I noticed my package manager does not show an installation date for xepersian. – Maesumi Oct 30 '17 at 22:47