bug#59341: 29.0.50; Lisp files with other encoding than UTF-8?

[Eli Zaretskii]

> From: Stefan Kangas <stefankangas@gmail.com>
> Date: Thu, 17 Nov 2022 20:14:09 -0800
> Cc: 59341@debbugs.gnu.org
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > No.  AFAIR, they are in utf-8-emacs because they include characters
> > beyond the Unicode range, which UTF-8 cannot encode.  See, for
> > example, the codepoints that start around line 645 in ind-util.el,
> > which are used for converting between IS 13194 (ISCII) and Unicode.
> 
> I see, thanks.
> 
> Do we need these characters to be raw bytes in the source code though?

(They are not raw bytes, they are UTF-8 encoded sequences, except that
the encoding uses more bytes than the "official" UTF-8 allows.  IOW,
we have there encoded codepoints beyond u+0010FFFF, not raw bytes.)

Yes we need them to appear as characters, because then they will be
displayed as glyphs if you have a suitable font, and in the context
such as this one it is very important to _see_ the character, if only
understand the mapping and to detect mistakes in it.

However, I think we should add a note in the Commentary section about
these subtleties, so that whoever next is bothered about this will be
able to have their questions answered.

> This change would also avoid confusing external tools.  For example, the
> code is completely unreadable in many external viewers, such as:
> 
> https://github.com/emacs-mirror/emacs/blob/master/lisp/language/ind-util.el#L647

I'm not too bothered about this.  Emacs sources are best viewed with
Emacs, and there's no way around this.