polyglossia 的 \setotherlanguage 阻止 imakeindex 的 \indexprologue

Question

下面的 MWE（现在有一个！）\indexprologue没有输出。如果我注释掉阿拉伯语的语言设置，它就会输出。这里的问题是什么？我该如何解决？

\documentclass{book}
\usepackage{kantlipsum}
\usepackage{imakeidx}
\makeindex

\usepackage{polyglossia}

\setdefaultlanguage{english}


\setotherlanguage{arabic} % Comment this and the indexprologue appears


\begin{document}
\kant[1]
\index{entry}

\indexprologue{\kant[1]}
\printindex
\end{document}

Answer 1

bidi这是一个掌握主动权的问题，毫无理由地恢复了环境book的定义theindex。

\documentclass{book}
\usepackage{polyglossia}
\usepackage{kantlipsum}
\usepackage{imakeidx}

% nullify bidi redefinition
% this should go after polyglossia and imakeidx have been loaded
\let\imakeidxtheindex\theindex
\let\imakeidxendtheindex\endtheindex
\AtBeginDocument{%
  \let\theindex\imakeidxtheindex
  \let\endtheindex\imakeidxendtheindex
}

\makeindex

\setdefaultlanguage{english}
\setotherlanguage{arabic} % Comment this and the indexprologue appears

\begin{document}
\kant[1]
\index{entry}

\indexprologue{\kant[1]}
\printindex
\end{document}