\leftline, \rightline and \centerline should be robust.

[Udi-Fogiel]

Brief outline of the issue

Check/indicate

• Relevant to the xepersian package
• The bidi package issue tracker has been searched for similar issues?
• The xepersian package issue tracker has been searched for similar issues?
• Links to <tex.stackexchange.com> discussion if appropriate
• Links to <qa.parsilatex.com> discussion if appropriate

Minimal example showing the issue

% !TEX TS-program = XeLaTeX
% !TEX encoding = UTF-8 Unicode
\documentclass{article} 
\usepackage{bidi}
\begin{document}
\meaning\leftline

\meaning\rightline

\meaning\centerline
\end{document}

[Udi-Fogiel]

Should be fixed by #28