Re: Emacs Lisp's future

[Eli Zaretskii]

> From: David Kastrup <address@hidden>
> Cc: Eli Zaretskii <address@hidden>,  Kenichi Handa <address@hidden>,  
> address@hidden,  address@hidden
> Date: Sat, 27 Sep 2014 13:13:26 +0200
> 
> However, the problems specific to R->L typesetting are mostly not in the
> character set and string handling area but rather concern the display
> algorithms where we already found that supporting all the functionality
> of Emacs is not well-supported by industry-standard solutions like
> Pango.

Only people who don't speak any of the R2L languages can seriously
claim that using Pango/Cairo is the way to support R2L in Emacs.
There are just too many quirks that Emacs needs for user satisfaction
that an external GP renderer can never provide.

Using Pango also means you are at the mercy of their developers as far
as bidi is concerned.  And it doesn't help that the development in
that area is not really "alive and kicking" as one would hope; e.g.,
the latest changes in UAX#9, released with Unicode 6.3 a year ago, are
still not supported in Pango or FriBidi.

Besides, using Pango means no bidi in text-mode frames.  (Some people
say this should be delegated to bidi-aware terminal emulators, like
PuTTY and some Linux-based emulator whose name I don't remember, but
that's again only because those people don't use the R2L scripts.
Doing bidi display for TTY Emacs this way is simply unworkable.)