bug#9571: 24.0.50; user option to turn off bidi, please

[Eli Zaretskii]

> From: Štěpán Němec
>       <stepnem@gmail.com>
> Date: Fri, 23 Sep 2011 12:39:19 +0200
> Cc: 9571@debbugs.gnu.org
> 
> On Fri, 23 Sep 2011 11:21:02 +0200
> Juanma Barranquero wrote:
> 
> > OOH, there was a time when suggesting that the user adds something to
> > .emacs, like
> >
> >   (setq-default bidi-display-reordering nil)
> >
> > was not considered obscure. Not everything must go through the
> > customization interface.
> 
> It's certainly good enough to me, but you won't find that advice in the
> current documentation either, AFAICT.

??? The variable and its effect are clearly documented in both the
user manual and the ELisp manual.  Which is more than I can say for
the other new features introduced in Emacs 24, because documentation
is generally finalized only during the pretest.  What else besides
documentation of the variable is needed to make it clear to users how
to turn a feature off?

> As it happens, Drew did complain.

His complaint is not helpful, because he explicitly declined to
provide any details about the situation where bidi slowed down Emacs
for him.

> Also, this is not (only) about making `bidi-display-reordering' a custom
> variable. It is about releasing Emacs 24 with still-not-widely-tested
> bidi support, which quite possibly adds zero value for most users[1],
> but does add significant problems at least in some (possibly as yet
> unknown) circumstances.

We are not releasing Emacs 24.1 yet.  We didn't yet enter the pretest,
and it's anyone's guess when the pretest will be over.  Pretest is the
time when such radical new features are supposed to be tested and any
problems in them fixed before Emacs 24.1 hits the street.  We had an
even more radical change in the display engine when Emacs 21.1 was
developed; the pretest took more than a year back then.