[luatex] \predisplaydirection from etex in luatex has no effect

[Taco Hoekwater]

Diederick C. Niehorster wrote:
> 
> It still sounds to me like there is a need for
> 1) flexibility, that is, some might want to follow Khaled, others
> might want to use \mathdir instead
> 2) sensible defaults, Khaled's sound good
> 
> I guess this means at the luatex level things should be flexible
> (independent primitives) and then a package like bidi could implement
> sensible defaults and an interface for the user to change them.

With the proposals by Khaled and Vafa, combined with allowing the
user to force a swap by setting \predisplaydirection=-1, there should
be enough flexibility and the actual location becomes just a matter of
macro programming.

A macro package could use \everydisplay to query \mathdir and/or
\pardir and adjust \predisplaydirection according to its taste
(the primitive name \predisplaydirection becomes somewhat of a
misnomer, though).

Best wishes,
Taco