From: Andreas Schwab <schwab@linux-m68k.org>
To: Robert Pluim <rpluim@gmail.com>
Cc: "Michael Albinus" <michael.albinus@gmx.de>,
emacs-devel@gnu.org, "Mattias Engdegård" <mattiase@acm.org>
Subject: Re: master 6ebce84ff2b: Use t for non-nil default values in boolean defcustom declarations
Date: Tue, 02 May 2023 18:42:07 +0200 [thread overview]
Message-ID: <87zg6mvg68.fsf@igel.home> (raw)
In-Reply-To: <87fs8fyxbv.fsf@gmail.com> (Robert Pluim's message of "Tue, 02 May 2023 10:03:16 +0200")
On Mai 02 2023, Robert Pluim wrote:
>>>>>> On Sat, 29 Apr 2023 13:23:42 +0200, Andreas Schwab <schwab@linux-m68k.org> said:
>
> Andreas> On Apr 29 2023, Michael Albinus wrote:
> >> Mattias Engdegård <mattiase@acm.org> writes:
> >>
> >> Hi Mattias,
> >>
> >>> Use t for non-nil default values in boolean defcustom declarations
> >>>
> >>> +(defcustom viper-ms-style-os-p
> >>> + (not (not (memq system-type '(ms-dos windows-nt))))
> >>
> >> I'm just curious. Is there an advantage in using the (not (not ...))
> >> pattern?
>
> Andreas> Logically, (not (null ...)) would fit better.
>
> Andreas> (not is just an alias of null, so both are the same, of course).
>
> Yes, but (not (not ...)) maps nicely to '!!' in C
C doesn't have lists, and memq returns a list.
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
"And now for something completely different."
prev parent reply other threads:[~2023-05-02 16:42 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <168268729579.28551.10245924430337302769@vcs2.savannah.gnu.org>
[not found] ` <20230428130816.81449C22A07@vcs2.savannah.gnu.org>
2023-04-29 7:39 ` master 6ebce84ff2b: Use t for non-nil default values in boolean defcustom declarations Michael Albinus
2023-04-29 9:03 ` Mattias Engdegård
2023-04-29 11:07 ` Michael Albinus
2023-04-29 11:23 ` Andreas Schwab
2023-05-02 8:03 ` Robert Pluim
2023-05-02 16:42 ` Andreas Schwab [this message]
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