Re: bidi-display-reordering is now non-nil by default

[Eli Zaretskii <eliz@gnu.org>]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: Eli Zaretskii <eliz@gnu.org>,  emacs-devel@gnu.org
> Date: Thu, 18 Aug 2011 23:16:13 -0400
> 
> > Obviously, there is a trade-off: exploiting font-lock means more
> > "magically correct" segmenting; using a hack (like marking chars
> > special) means less dependence on the font-lock machinery.  I don't
> > think the latter is worth it.
> 
> The problem is not jit-lock-defer-time but the fact that font-lock may
> be turned off.

Right, I mentioned that as well.

> We could do it in syntax-propertize, of course, but it's not great
> either (e.g. syntax-propertize is applied to all the text before
> window-start whether that text will ever be displayed or not).

So are you saying that using text properties for this is not a good
idea at all?  If so, what other Emacs features do we have to mark
segments of text for "special" reordering?  Markers, perhaps?

I think we should also think how will we use this feature if it
existed, before we go out to implement the feature.  What specific
segments of text we would want to mark, and in what kinds of
buffers/strings?  What mechanisms can be used to compute where to put
these markers, and how these mechanisms will be triggered?  How
exactly to handle HTML/XML with such a feature?  Etc., etc. -- all of
these questions can have a profound effect on the details of the
implementation, or even show that the idea is stillborn.