[Aleph] And boxes (was \parshape and \hangindent)

Thu Aug 19 10:33:34 CEST 2004

Hello,

> 1. What should be the effects of local commands like \pardir TRT
> & \textdir TRT?
>
> 2. What changes do LaTeX and ConTeXt need to make to fully accomodate
> bidirectionality?

In some sense, both, but I think the TeX code must be the
same and independent from the direction. For example, if
I wanted to indent a paragraph and then to place a label,
I would write.

\leftskip2pc
\noindent
\llap{\hbox to 2pc{1.\hfil}}

Why should I say explicitly the direction here? Note
boxes are used very often in order to make small (or
not so small) adjustements of this kind (for example,
in \llap). If you need an expecial case, then you can
set explicitly the direction with \hbox dir TLT{...},
but otherwise we would be forced to write two versions
of these macros or to append sistematically dir XXX to
every box, thus making even more difficult to handle
special cases.

> As I learned in a complicated bi-directional project recently, the answers are
> not necessarily trivial.

Not at all, indeed, but at least one should be allowed
to write macros with some degree of abstraction (or for
that very reason). If we mix horizontal and vertical
writing things are a lot more complicated---note
Omega has nothing for that yet, and although some code
to turn text with metafont has been devised, page
breaking is still miles away, afaik.

Cheers
Javier