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

[Stefan Monnier]

> Part of the inspiration for adding more things to some modes has been
> that of the p-s-alist in tuareg.el:
> https://github.com/ocaml/tuareg/blob/master/tuareg.el#L468

FWIW, I don't much like the new "not" and "sqrt" thingies either, tho
I wasn't bothered enough to turn them off either, so I can clearly live
with them.

I like ¬ in tuareg-mode, OTOH.  Not sure exactly why my reaction is
different in those two cases.  Maybe the parentheses make a difference,
or maybe it's the tradition to use longish names (and hence indent
differently) in Lisp vs the tradition to use shortish names in ML?

>> It seems a bit intrusive because I have never seen that notation before.
>> While I do know the sqrt notation √, I can imagine this being a source of
>> confusion/annoyance for some people.

I personally dislike the √ notation in all major modes because in most
of the fonts I use it looks more like a check-mark, and because for me,
the √ mathematical notation would require the attached horizontal
overline bar to make sense.

But I can't remember the last time I used `sqrt` in any programming
language, so my opinion is not really relevant.

> In any case, I don't feel strongly about it.  One thing I just thought
> of is making a mode's foo-prettify-symbols-alist a defcustom--perhaps
> that will be nicer.

There's a clear need for some customization, indeed.  There isn't any
right now partly because I couldn't come up with a good idea (e.g. the
format of prettify-symbols-alist is likely to be extended in ways which
are inconvenient for an end-user, and if the end-user customizes his
var he won't benefit from later improved defaults).

At some point I was tempted to add a `prettify-symbols-inhibit` which
would contain a list of chars.  E.g. I'd personally put √ globally in
that list.


        Stefan