Re: character sets as they relate to “Raw” string literals for elisp

[Eli Zaretskii <eliz@gnu.org>]

> From: Stefan Kangas <stefankangas@gmail.com>
> Date: Thu, 7 Oct 2021 20:37:19 -0400
> Cc: rms@gnu.org, db48x@db48x.net, yuri.v.khan@gmail.com, emacs-devel@gnu.org, 
> 	monnier@iro.umontreal.ca, juri@linkov.net
> 
> >> What I mean is that I think it would be better if our manuals displayed
> >> em dash (written as "---") as they are displayed in the texinfo manual:
> >> "--" (HYPHEN-MINUS, HYPHEN-MINUS), instead of as "—" (EM DASH).  I find
> >> the former way to display this character easier to read in the monospace
> >> fonts that we typically use.
> >
> > Others disagreed at the time, and so we decided quite some time ago to
> > use @documentencoding UTF-8 in all our manuals.  (It was not only
> > about the dashes; UTF-8 encoding causes quite a lot of other Unicode
> > characters to be output by makeinfo.)  I see no reason to reverse that
> > decision (and start all those arguments all over again).
> 
> I also see no reason to reverse that decision, if the particular case of
> how em dash is displayed was already considered in detail as part of
> that discussion.
> 
> If that case was not considered in detail, perhaps we could discuss it
> now.

I'd rather not start another discussion of this, as opinions tend to
be polarized about it, and IME nothing can bridge over the differences
of opinions in this matter.  So I prefer a different way of handling
this, see below.

> I would hope that we could agree that how em dash is displayed is
> not necessarily strictly connected to "@documentencoding UTF-8"; and
> that it would be useful to continue using UTF-8 encoding, but also get
> the "old" way of displaying em dash.

Many people want to use and see Unicode punctuation characters in
human-readable text.  You can see that clearly in the Emacs mailing
lists: people use Unicode quotes “..”, dashes, Emoji, and other
special characters.  Since Info is largely such a human-readable text,
those people want to see the same there.  I don't see any way of
convincing them to change their views, nor do I think we should try.

> Maybe that would require us to use an existing option in texinfo, or
> maybe this would need the texinfo developers to provide a new option
> that could support it.

Even if such an option existed, it would still beg the question: how
to produce the Info manuals we provide as part of the Emacs release
tarballs?  The downside of any decision in this matter is that it is
imposed on everyone, no matter what their views on this.

So I'd prefer to deal with this differently: introduce a new
(buffer-local) minor mode, which will install a display-table, whereby
"problematic" Unicode characters will be displayed as their ASCII
equivalents or equivalent ASCII strings.  We already set that up
automatically on terminals that are incapable of displaying those
characters, but nothing precludes us from having such a feature on
demand for capable displays as well.  Then users who don't want the
effects of these characters on display could activate such a mode, and
solve their problems without affecting the actual contents of the Info
files.