I try to use XeLaTeX to compile

      Hello World

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
 <inserted text> 
 l.1767       \int_case:nnn

Anything containing xepersian seems to generate the same error.

  • Have you compiled your code with XeLaTeX?
    – user78499
    Oct 30, 2017 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, 2017 at 22:31
  • You do not give many clues but I think your expl3 is too old, update your miktex packages Oct 30, 2017 at 22:41

1 Answer 1


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

enter image description here

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.

\settextfont{XB Niloofar}
    \noindent\lr{Hello World}\\
    سلام دنیا\\
خداحافظ دنیا

enter image description here

  • I don't get any output. I just get the error message.
    – Maesumi
    Oct 30, 2017 at 22:38
  • @Maesumi: Which distribution are you using?
    – user78499
    Oct 30, 2017 at 22:39
  • I am using MIKTEX.
    – Maesumi
    Oct 30, 2017 at 22:40
  • @Maesumi: Check your directory after compilation. Does LaTeX generate any pdf as the output, regardless of the error?
    – user78499
    Oct 30, 2017 at 22:41
  • Yes it does! And I noticed my package manager does not show an installation date for xepersian.
    – Maesumi
    Oct 30, 2017 at 22:47

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