From: Stefan Monnier <monnier@IRO.UMontreal.CA>
To: "Nelson H. F. Beebe" <beebe@math.utah.edu>
Cc: 5700@debbugs.gnu.org
Subject: bug#5700: emacs-23 and 8-bit characters in 128..255
Date: Tue, 09 Mar 2010 17:02:14 -0500 [thread overview]
Message-ID: <jwvy6i19n4v.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: <CMM.0.95.0.1268164291.beebe@psi.math.utah.edu> (Nelson H. F. Beebe's message of "Tue, 9 Mar 2010 12:51:31 -0700 (MST)")
> This morning, I set out to track down the source of one of the
> problems in a function that I use a lot, and eventually narrowed it to
> the failure of functions like these:
> (string-equal (buffer-substring (point) (1+ (point))) "\377")
Indeed, we have a problem:
(string-equal "\377" (string-to-multibyte "\377"))
returned t in Emacs-22 but returns nil in Emacs-23. Another (somewhat
related) problem is that under Emacs-22, we had:
"\377" prints as "\377"
"\xff" prints as "\xff"
(multibyte-string-p "\377") prints as "\xff"
which seems acceptable, whereas under Emacs-23 we have:
"\377" prints as "ÿ"
"\xff" prints as "ÿ"
(multibyte-string-p "\377") prints as "\377"
which looks rather confusing.
> (looking-at "\377")
This is probably a separate bug.
> The internal encoding used for buffers and strings is now
> Unicode-based and called `utf-8-emacs' (`emacs-internal' is an alias
It is related, but only to the extent that a lot of the code that
handles multibyte chars (and especially "eight-bit chars") was
completely rewritten, and this is a very delicate area.
Stefan
next prev parent reply other threads:[~2010-03-09 22:02 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-09 19:51 bug#5700: emacs-23 and 8-bit characters in 128..255 Nelson H. F. Beebe
2010-03-09 22:02 ` Stefan Monnier [this message]
2016-07-06 23:52 ` npostavs
2016-07-07 16:21 ` Eli Zaretskii
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