Re: Can watermarking Unicode text using invisible differences sneak through Emacs, or can Emacs detect it?

[Kévin Le Gouguec]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Richard Stallman <rms@gnu.org>
>> Cc: eliz@gnu.org, psainty@orcon.net.nz, luangruo@yahoo.com,
>>      emacs-devel@gnu.org, kevin.legouguec@gmail.com
>> Date: Wed, 26 Jan 2022 23:13:47 -0500
>> 
>> When it is impossible to display the character's ligature, it would be
>> more useful to display the two ASCII characters than to display an
>> unhelpful diamond.
>> 
>> We should try to do what is most helpful, not be quick to give up.
>
> Would it be good enough to have a command that will arrange for these
> ligatures to be displayed as their ASCII equivalents, using the
> facilities in latin1-disp.el?  Such a command could be invoked either
> manually or from your init file.  latin1-disp.el also provides a
> special face to display such equivalents, so you could have them stand
> out on display if you want.

Reading the documentation of the various glyphless-* knobs, I wonder if
it would make sense to provide another group for
glyphless-char-display-control?  'no-font is not helpful on my TTY, IIUC
because terminal-coding-system says "utf-8-unix"?).

Maybe 'no-display, meaning (null (char-displayable-p CHAR))?  That would
at least allow users to tell Emacs to use the 'hex-code method, which
would be more immediately informative than the diamond.

Though not by a lot.  Maybe adding a new method?  Something like
'char-name?  Obviously it'd be ugly to see…

> Please refer to the o\N{LATIN SMALL LIGATURE FFI}cial documentation

… but (1) it would be more informative (though maybe not less confusing)
than "Please refer to the o◆cial documentation", (2) it would also serve
as a decent fallback for symbols and emojis, which we see more and more
on this list.

I'm thinking of situations like <E1mxiYQ-0002ul-5B@fencepost.gnu.org>;
not saying we should encourage using symbols over words, but TTY users
would probably appreciate this kind of fallback?


(I hope at least some of this message makes sense; apologies if not)