Re: ¬ notation for not? Ref: Add a couple cells to lisp-prettify-symbols-alist

[Stefan Monnier]

> (defvar prettify-mode-tagsets '(emacs-lisp-mode (general . (?λ ...)) ... )
>                                (ocaml-mode (math . (?¬ ...)) ... ))

Sounds complicated as well.  Maybe we could just get away with having
prettify-symbols-alist have 2 lists: a basic one and an extended one.
Users can then choose to use the basic set or the extended set (for the
users in search of more visual thrills) (or nothing at all for the more
conservative users).

If we add the ability to inhibit specific chars, it should be flexible
enough in practice, not too hard to implement, and understandable for
the end-user.


        Stefan