Re: Unicode support

[Roozbeh Pournader]

On Tue, 24 Jul 2001, Eli Zaretskii wrote:

> This was considered, but it is not easy.  All the implementations of
> the Unicode bidi algorithm known to me process characters en masse, in
> more-or-less large blocks.  That is, you hand them a buffer of text in
> logical order, and get back that text reordered for display (``visual
> order'').  By contrast, the current design principle, as suggested by
> Gerd based on his intuition about the display engine, calls for an
> algorithm that could be called sequentially, once for each character
> that is being converted into a glyph.  This requires to turn a typical
> implementation of UTR#9 ``inside out''.

Sorry Eli, it seems that I always forget this (at least when I'm
advocating Fribidi ;-)). Yes, we certainly need an *incremental* bidi
algorithm, equivalent to the original one. But this is exactly what I call
academic research. And no one has worked on this yet. Well, there is a
Haskell implementation of Bidi, but first of all, it does not implement
some parts of the algorithm, like the limited stack size, and second of
all, it is in Haskell, which I can't understand even a bit, so I don't
even know how it works. See:

        http://www.cs.fit.edu/~satkin/docs/bidi.pdf

(Beware, the paper should not be your best reference for comparing bidi
implementations, it containcs many errors.)

Without an incremental *algorithm*, we will get nowhere. I'm CC-ing the
Fribidi mailing list. Anyone with some spare time and a little academic
support for a joint effort?

roozbeh