bug#71429: Inconsistent y-or-n-p prompt behavior in Emacs Lisp

[Eli Zaretskii <eliz@gnu.org>]

> From: Stephen Berman <stephen.berman@gmx.net>
> Cc: Stefan Monnier <monnier@iro.umontreal.ca>,  gabriele@medialab.sissa.it,
>   stefankangas@gmail.com,  71429@debbugs.gnu.org
> Date: Sat, 08 Jun 2024 17:47:04 +0200
> 
> On Sat, 08 Jun 2024 17:58:17 +0300 Eli Zaretskii <eliz@gnu.org> wrote:
> 
> >> Without the backslashes the cond-clause in substitute-command-keys
> >> handling sequences starting with "\" is skipped, so "y" and "n" do not
> >> get the help-key-binding face property.
> >
> > This should be explained in a comment in y-or-n-p.
> 
> Since this effect of using a backslash is part of what
> substitute-command-keys does (and it's commented there: ";; 1C. \`f' is
> replaced with a fontified f."), would adding a comment to y-or-n-p be an
> exception or would all callers of substitute-command-keys that use this
> handling of the backslash also need to have such a comment?

Not necessarily all the callers, but some definitely.  This is an
unusual convention, which is mentioned in the doc string of
substitute-command-keys, but not in the ELisp manual, and is used in
our tree not too many times.  The fact that I didn't know about it
should already speak volumes.  And in this case, how can the reader
guess that `y' and `n' are meant as key bindings, not as simple
characters?