RE2: Lots of undefined control sequences when using Arabic Babel

[outlook user]

I don't use XeTeX or `\beginR` in my code. I think it's rather a package that use that command under another command. I seem to understand that some packages are meant to be used under PDFLaTeX and no other (like here if they use `\beginR` where it's not meant for all engines. But it's probably Babel that use that command, or maybe Babel that makes the XeTeX switch happens that triggers all that. Because when I remove `[arabic]` all errors dissapears, so it's really Babel that input a change that makes lots of things not recognized

`\usepackage{babel}` with or without `\babelprovide{arabic}` doesn't output any Arabic, only latin text, where `\usepackage[arabic]{babel}` (with or without `\babelprovide{arabic}`) does output Arabic (and tons of errors listed in sequence of mails). In fact `babelprovide` doesn't change anything to the case here

________________________________________
De : David Carlisle <d.p.carlisle at gmail.com>
Envoyé : dimanche 12 mai 2024 15:56
À : outlook user <RACP at outlook.fr>
Cc : texhax at tug.org <texhax at tug.org>
Objet : Re: Lots of undefined control sequences when using Arabic Babel
 
\beginR is a xetex (tex-xet) command: it is not expected to be defined in luatex. Also as commented on your other message
you seem to have somehow forced xetex processing with lualatex as the inputenc error you showed should
only have occurred with xetex. If you use \usepackage{babel} \babelprovide{arabic} things should go more smoothly.

David


On Sun, 12 May 2024 at 14:43, outlook user <RACP at outlook.fr> wrote:
> The compiler is having trouble understanding a command you have used. Check that the command is  spelled correctly. If the command is part of a package, make sure you have included the package in your preamble using \usepackage{...}.
> Learn more
> \Arabi at rl@everypar ...setbox \z@ \lastbox \beginR 
>                                                    \usebox \z@ }\fi 
> l.1452 -
>       --
> The control sequence at the end of the top line
> of your error message was never \def'ed. If you have
> misspelled it (e.g., `\hobx'), type `I' and the correct
> spelling (e.g., `I\hbox'). Otherwise just continue,
> and I'll forget about whatever was undefined.


On version 1.16.0 of LuaHBTeX from TeX Live distribution version 2023 using LUALaTeX 2023.8.28. It appears when `\usepackage{babel}` is modified to `\usepackage[arabic]{babel}`

It seems like he expects all commands to be written in Arabic, or maybe he has lost TeX definitions and don't know any commands anymore, or is misinterpreting anything. Anyway, many classic La/TeX commands are interpreted as unknown control sequences