bug#69079: [PATCH] Add 'customize-toggle-option' command

[Philip Kaludercic]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Philip Kaludercic <philipk@posteo.net>
>> Cc: 69079@debbugs.gnu.org
>> Date: Mon, 12 Feb 2024 18:56:39 +0000
>> 
>> Eli Zaretskii <eliz@gnu.org> writes:
>> 
>> >> From: Philip Kaludercic <philipk@posteo.net>
>> >> Date: Mon, 12 Feb 2024 17:32:37 +0000
>> >> 
>> >> +;;;###autoload
>> >> +(defun customize-toggle-option (opt)
>> >> +  "Toggle the value of boolean option OPT for this session."
>> >> +  (interactive (let (opts)
>> >> +          (mapatoms
>> >> +           (lambda (sym)
>> >> +             (when (eq (get sym 'custom-type) 'boolean)
>> >> +               (push sym opts))))
>> >> +          (list (intern (completing-read "Option: " opts)))))
>> >> +  (message "%s user options '%s'."
>> >> +    (if (funcall (or (get opt 'custom-set) #'set-default)
>> >> +                 opt (not (funcall (or (get opt 'custom-get)
>> >> +                                       #'symbol-value)
>> >> +                                   opt)))
>> >> +        "Enabled" "Disabled")
>> >> +    opt))
>> >
>> > Shouldn't this have some validation? what if the argument OPT is
>> > not a
>> > boolean?
>> 
>> My assumption was that the command would only be invoked interactivly,
>> so I can either make that explicit with an `interactive-only' or repeat
>> the check.  What do you think would be better?
>
> I think an explicit test is better, since then we get to display a
> user-friendly error message, instead of relying on Lisp errors to
> explain themselves.
>
> Btw, are you sure that the users can never succeed in inputting a
> non-boolean option with the way you prompt them?

No, that was not ensured, and I think it is better not to.  I have
adjusted the patch to check and prompt the user if the user option is
non-boolean, in case they know what they are doing.  WDYT?

0001-Add-custom-variable-command.patch
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