Re: Bug #25608 and the comment-cache branch

[Eli Zaretskii <eliz@gnu.org>]

> Date: Mon, 6 Feb 2017 20:01:16 +0000
> From: Alan Mackenzie <acm@muc.de>
> Cc: emacs-devel@gnu.org
> 
> The syntactic significance of a buffer position is not changed by
> any narrowing in force, no matter what the narrowing is "used for".

If that's what you think, you are not talking about Emacs.  Emacs
always behaved as if nothing existed outside of the current
narrowing.  Even the display engine behaves like that: e.g., by
suitable narrowing of bidirectional text you can completely change how
the accessible portion is displayed.

> That one or more multiple-mode attempts attempt to use narrowing that
> way is a fundamental problem in those modes which we should solve by
> providing a better method.

That's true, but it doesn't affect the basic fact that Emacs behaves
differently, and you cannot change that without significant changes on
levels below applications.

> Even if the user narrows to the string, it's still a string.

Emacs currently doesn't have any means of knowing that, because the
portions of the buffer outside the accessible region are simply not
accessible.