Re: Emacs Lisp and Guile

[Eli Zaretskii]

On Sat, 3 Aug 2002, Simon Josefsson wrote:

>                               I think it would be nice if Emacs could
> take advantage of the work that went into libc for low-level non-ASCII
> manipulation, and into GNOME (GTK) for high-level non-ASCII display
> (e.g., bidirectional text), instead of re-implementing it all just for
> Emacs.  It doesn't seem very re-usable.

The display part of the bidirectional editing support must be 
reimplemented for Emacs because the Emacs display engine examines the 
buffer text one character at a time.  For each character examined, 
Emacs decides how to display it and also whether to examine more of the 
buffer.  By contrast, all the bidi libraries out there accept a buffer 
of text and return that buffer reordered for display.  Making the Emacs 
display work in such a batch-style manner means a total rewrite of the 
display code, and also loses over slow connections, which AFAIK we still 
want to support.

That's the main reason why Emacs development didn't use fribidi or some 
similar library, although people who (slowly) work on bidi Emacs are well 
aware of fribidi and similar efforts.