Re: Supporting stylistic sets

[Eli Zaretskii <eliz@gnu.org>]

> From: Yuri Khan <yuri.v.khan@gmail.com>
> Date: Tue, 27 Sep 2022 02:06:35 +0700
> Cc: Nicolas Ouellet-payeur <nicolaso@google.com>, lumarzeli30@gmail.com, emacs-devel@gnu.org
> 
> On Tue, 27 Sept 2022 at 01:55, Eli Zaretskii <eliz@gnu.org> wrote:
> 
> > And second, it is not good enough to have the property on the "-:---"
> > part, because that's where the input-method mnemonics are displayed,
> > and those frequently do need ligations, if they use characters from
> > scripts which require that.
> 
> Maybe just put a zwnj between every two directly adjacent fields to
> prevent ligation?

It's possible.  But then (1) we'd need to always have the ZWNJ there;
(2) some mode-line constructs are produced by formatting text with
tricky format specs, and some could come from the user or some Lisp
program that are utterly unaware of these subtleties; and (3) Emacs by
default displays ZWNJ as a thin space.  So this is not the best
solution, IMO.

I tend to think this is just one aspect of a more general problem,
which is: how do users/Lisp programs control which characters will or
will not ligate in what situations?  For example, take ffi: you might
not want the characters f f i to ligate in a variable name, or in some
major modes as opposed to others, etc.  When we figure out how to
specify when to ligate, we need that specification support the mode
line and other places (like maybe be tab bar/tab line).