From: Stephen Berman via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
To: Eli Zaretskii <eliz@gnu.org>
Cc: gabriele@medialab.sissa.it, 71429@debbugs.gnu.org,
Stefan Monnier <monnier@iro.umontreal.ca>,
stefankangas@gmail.com
Subject: bug#71429: Inconsistent y-or-n-p prompt behavior in Emacs Lisp
Date: Sat, 08 Jun 2024 17:47:04 +0200 [thread overview]
Message-ID: <878qzfl9mv.fsf@gmx.net> (raw)
In-Reply-To: <861q57cwhi.fsf@gnu.org> (Eli Zaretskii's message of "Sat, 08 Jun 2024 17:58:17 +0300")
On Sat, 08 Jun 2024 17:58:17 +0300 Eli Zaretskii <eliz@gnu.org> wrote:
>> From: Stephen Berman <stephen.berman@gmx.net>
>> Cc: Gabriele Nicolardi <gabriele@medialab.sissa.it>, Stefan Kangas
>> <stefankangas@gmail.com>, 71429@debbugs.gnu.org
>> Date: Sat, 08 Jun 2024 15:59:11 +0200
>>
>> >> I actually don't understand why we use \\`y' and \\`n' in y-or-n-p.
>> >> Why those backslashes, and not just `y' and `n'? That's your change
>> >> in commit a36ecc408a. If I remove the backslashes, the results are
>> >> identical whether or not search-spaces-regexp is let-bound.
>>
>> 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?
>> Stepping through substitute-command-keys in Edebug, I see that when the
>> regexp ends in '?' or '*' the sexp (key-valid-p k) in
>> substitute-command-keys returns nil for k set to "y" and then to "n", so
>> these strings do not get the help-key-binding face property and "(\\`y'
>> or \\`n') " is returned to y-or-n-p unaltered. When the regexp does not
>> end in '?' or '*', (key-valid-p k) returns t for "y" and "n" and these
>> strings get propertized.
>>
>> Stepping through key-valid-p, I see that when the regexp ends in '?' or
>> '*' the sexp (split-string keys " ") returns (#1="" "y" #1#) for keys
>> set to "y", and key-valid-p loops over this lists, and the first element
>> "" is an invalid key. When the regexp does not end in '?' or '*' the
>> split-string sexp in key-valid-p returns ("y"), and "y" is valid.
>
> Thanks. To me, this means that key-valid-p should bind
> search-spaces-regexp to nil, because otherwise the value will subvert
> its contract. Do you agree?
The value can break key-valid-p, e.g. by only optionally matching
whitespace. Maybe that's reason enough to have key-valid-p bind it to
nil. The OP's use case (mentioned the the stackexchange thread Drew
referred to) seems legitimate, but maybe it can be achieved without
changing search-spaces-regexp.
Steve Berman
next prev parent reply other threads:[~2024-06-08 15:47 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-08 7:03 bug#71429: Inconsistent y-or-n-p prompt behavior in Emacs Lisp Gabriele Nicolardi
2024-06-08 8:24 ` Eli Zaretskii
2024-06-08 9:20 ` Stephen Berman via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-06-08 13:59 ` Stephen Berman via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-06-08 14:58 ` Eli Zaretskii
2024-06-08 15:30 ` Drew Adams via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-06-08 15:38 ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-06-08 16:36 ` Eli Zaretskii
2024-06-08 17:41 ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-06-08 18:08 ` Eli Zaretskii
2024-06-09 11:02 ` Stefan Kangas
2024-06-08 15:47 ` Stephen Berman via Bug reports for GNU Emacs, the Swiss army knife of text editors [this message]
2024-06-08 16:44 ` Eli Zaretskii
2024-06-09 11:01 ` Stefan Kangas
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