Re: how reliable is rendering of complex scripts?

[Eli Zaretskii <eliz@gnu.org>]

> From: "John Wiegley" <johnw@newartisans.com>
> Date: Sun, 04 Oct 2015 11:06:32 -0700
> 
> Just FYI, I use Emacs to write in Arabic script fairly often (chatting in
> Persian via ERC). I haven't noticed any specific rendering or right-to-left
> issues yet, but do count me as someone with knowledge of and concern for these
> issues.

Thanks.

One of the things that always bothered me are the composition rules
for Arabic and Persian (see the end of lisp/language/misc-lang.el).
Perhaps you could take a look at them, in particular the ZWJ and ZWNJ
related rules, and other similar stuff.  I think someone said in the
past we lack some rules there.

Also, the Harfbuzz test suite includes several text files that are
supposed to exercise Arabic and Persian shaping, so if you know what
is the correct display in all of the cases there, perhaps you could
see if Emacs displays them correctly.