[XeTeX] Are the new etex changes reflected in XeTeX? (was XeTeX bugs in bidirectional typesetting)

[Jonathan Kew]

On 20/11/2016 03:55, Vafa Khalighi wrote:
> Hi
>
>
> When I discussed the TeX--XeT issues with Peter Bre­it­en­lohner, he
> made few changes in etex. Are these changes applied to XeTeX?

> 2) Better handling of right to left text
>
>
> This is quite important since he changed TeX--XeT model into a new
> version where the order of whatsit nodes is no longer reversed.

This is very interesting, I didn't know Peter had done that. I think 
this is the right way forward (for an etex-based engine such as xetex), 
and had been hoping to find the time to work on essentially the same 
idea in xetex, but so far the code exists only in my head.

Unfortunately, xetex is no longer built on top of tex.web + etex.ch etc, 
but has its own separate xetex.web (I think Peter made this change 
around 2012), and so subsequent improvements in etex won't have 
automatically become part of the xetex build; they would (I presume) 
have to be ported over to xetex.web. But that should be relatively 
straightforward, I hope, and should save me needing to reinvent that 
particular wheel.

JK