Right-to-left columns in Latin environment

[vafakhalighi]

---

Brief outline of the issue

Using columns inside a xepersian latin environment, the columns are in the wrong order (i.e., the first column is on the right-hand side of the page). In some cases, adding \LTRdblcol fixes this, but not always.

Specifically, when using makeidx's \printindex command, which prints a two-column index, in a latin environment, the columns are in the wrong order. The same problem occurs when using a multicols environment. In the case of makeidx, this can be resolved by using bidi's \LTRdblcol --- but this should not be necessary. Furthermore, \LTRdblcol does not fix the same issue in the multicols environment.

Check/indicate

• Relevant to the bidi package
• The bidi package issue tracker has been searched for similar issues?
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Minimal example showing the issue

% !TEX TS-program = XeLaTeX
% !TEX encoding = UTF-8 Unicode

\documentclass{article}

\usepackage{makeidx}
\usepackage{multicol}
\usepackage{xepersian}
\settextfont{IRXLotus}
\makeindex

\begin{document} 
\begin{latin}

\index{a}
\index{b}

% \LTRdblcol
\printindex

\begin{multicols}{2}
First column
\vfill\columnbreak
Second column
\end{multicols}

\end{latin}
\end{document}

Expected behavior

The first page should have an automatically generated two-column index, where the columns are populated left-to-right. The second page should have a two-column multicols environment, where the columns are populated left-to-right.

Instead, both are populated right-to-left. The \LTRdblcol command only solves the index, not the multicols environment.

Log and PDF files

xepersiancolumns.log

xepersiancolumns.pdf

Proposed Changes

It was indeed my expectation that any columns started in a latin environment would default to LTR. Using a single global option works fine for my document, where I only need one and the same column order throughout. I can see how switching between different column orders within the same document may actually be really confusing, but a RTL column order with LTR text (and vice versa) is, too. Perhaps it's best to leave the choice to the user, but emphasise that this choice exists --- e.g. \begin{...}[LTRcols] and \begin{...}[RTLcols] as additional, optional arguments for the latin and persian environments.