RE: problems with Emacs 28

[Drew Adams]

> > What is that bang (explication mark) syntax BTW?
> 
> That comes from the scheme tradition: it is used for functions that
> modify something (state), unlike "pure" functions that "only" calculate
> a return value.  E.g. `+', `car' vs. `setcar!' etc., you get it.

FWIW, I think it's a mistake for Emacs to adopt
that convention now, or at least it's a mistake
to adopt it only partially.

If users can't depend on it, to let them know
if a function might modify data destructively,
then it can mislead, and so be even more
"dangerous".  Now, we really need a giant sign
saying that you can't rely on a destructive
function's name having a suffix of `!'.
___

Same thing for Scheme's `?' suffix, to indicate
a predicate.  Elisp uses the more traditional
Lisp suffix of `p' for a predicate.  Introducing
`?' now, in only a partial way, wouldn't help,
and it might confuse.  Of course, that's trivial
compared with the effect of possible confusion
over destructive modification.  (Yes, I know `?'
hasn't been proposed as a suffix for predicates.
Just sayin.)