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

Diederick C. Niehorster dcnieho at gmail.com
Thu Apr 8 15:32:51 CEST 2010

On Thu, Apr 8, 2010 at 9:18 PM, Khaled Hosny <khaledhosny at eglug.org> wrote:
> On Thu, Apr 08, 2010 at 02:11:39PM +0200, Taco Hoekwater wrote:
>> Khaled Hosny wrote:
>> >
>> > May preference is to treat left and right as "start of the line" and
>> > "end of the line", so that existing macro code will give the logically
>> > expected result when one switches direction (one setting equation number
>> > to the right is actually expecting it at the start of the line).
>> Ok, but that leaves the question whether \pardir or \mathdir decides
>> on start/end. Vafa clearly prefers \mathdir, but I am not so sure myself.
> I think, the equation number is related to paragraph and not math
> direction as it is a general layout item i.e. if I'm setting a RTL math
> equation inside a LTR document, I'll want all equation numbers to be on
> the same side regardless of the actual direction of the equation itself.

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.

Anyway, I'm somewhat of an outsider in this, not an experienced user,
so I'll be quiet from now on ;)


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