Re: Display of characters #xa0 and #xad in unibyte buffers

[Eli Zaretskii <eliz@gnu.org>]

> From: Kenichi Handa <handa@m17n.org>
> Cc: ulm@gentoo.org, emacs-devel@gnu.org
> Date: Mon, 28 Sep 2009 10:10:32 +0900
> 
> In article <83ws3ntmgv.fsf@gnu.org>, Eli Zaretskii <eliz@gnu.org> writes:
> 
> > > >> $ emacs -Q
> > > >> M-x toggle-enable-multibyte-characters RET C-q 240 RET C-q 255 RET
> > > >> 
> > > >> The characters are displayed as "_-" (approximately).
> > > >> 
> > > >> Shouldn't they be displayed as "\240\255", considering that these are
> > > >> raw bytes with no specific meaning?
> > > 
> > > > There are no ``raw bytes'' in a unibyte buffer.  Every byte there is
> > > > interpreted as a character, and shown as such.  This is the main
> > > > feature of unibyte buffers; otherwise, who'd want them?
> 
> I think the main feature of unibyte buffers is to handle
> raw-bytes as is.

How do we even know that they are raw bytes, and how do we
distinguish, in a unibyte buffer, ü from \374, say?  Just because they
were inserted by C-q NNN or by some other mechanism?

> For those who want to see a raw-byte as a character of their locale
> (language environment), we have
> unibyte-display-via-language-environment.

I thought bytes in unibyte buffers are always interpreted as
characters of the locale, as Emacs 19 did.  Are you saying that they
are by default always interpreted as raw bytes, unless
unibyte-display-via-language-environment is set?