From: "Andreas Röhler" <andreas.roehler@easy-emacs.de>
To: help-gnu-emacs@gnu.org
Subject: Re: Rationale behind conversion of a nil prefix arg to numeric 1
Date: Tue, 6 Sep 2016 13:27:39 +0200 [thread overview]
Message-ID: <afaf96a1-9e5c-957d-1b47-8e5ce6248ac4@easy-emacs.de> (raw)
In-Reply-To: <87inu98ipz.fsf@bertrandrussell.Speedport_W_723V_1_40_000>
On 06.09.2016 11:45, Florian v. Savigny wrote:
> > Alternatively, for Andreas the axiom "the default value is always 0"
> > holds ;-P
>
> I do sympathise with him, because my question started out supposing
> exactly the same thing. It just seems intuitive that nil translates to
> the number 0, if any, and when things are intuitive, this is (I think)
> generally good.
>
> It all becomes immediately clear when you understand that the numeric
> prefix arg has a special purpose, i.e. is conceived as a repeat
> counter (and NOT simply a number), but only then. In other words,
> `prefix-arg-as-repeat-counter' might be the kind of name that would be
> more readily understandable (and would even arguably be more accurate)
> than `prefix-numeric-value'.
IIUC `prefix-numeric-value' is a more complex thing than providing a
repeat counter - which it does for lower p.
prefix-numeric-value of C-u is 4 in contrast.
But let's go back to the simplest case of lower p in interactive spec:
What is easier to read/grasp
(setq counter (or arg 1)
or
(setq counter (prefix-numeric-value arg))
IOW: in favor of avoiding these complex, tricky things. Let's have the
code as explicit as possible.
next prev parent reply other threads:[~2016-09-06 11:27 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-04 12:23 Rationale behind conversion of a nil prefix arg to numeric 1 Florian v. Savigny
2016-09-04 14:23 ` Eli Zaretskii
2016-09-04 17:11 ` Andreas Röhler
2016-09-04 18:33 ` Eli Zaretskii
2016-09-05 7:16 ` Andreas Röhler
2016-09-05 14:56 ` Eli Zaretskii
2016-09-05 15:22 ` Kaushal Modi
2016-09-05 16:32 ` Drew Adams
2016-09-05 18:41 ` Andreas Röhler
2016-09-05 19:02 ` Eli Zaretskii
2016-09-06 7:10 ` tomas
2016-09-06 9:45 ` Florian v. Savigny
2016-09-06 10:27 ` tomas
2016-09-06 11:27 ` Andreas Röhler [this message]
2016-09-06 13:27 ` Florian v. Savigny
2016-09-06 15:22 ` Drew Adams
2016-09-06 14:20 ` Kaushal Modi
2016-09-06 16:44 ` Andreas Röhler
2016-09-06 16:41 ` Kaushal Modi
2016-09-07 23:11 ` Charles Millar
2016-09-08 13:10 ` Kaushal Modi
2016-09-08 14:42 ` Charles Millar
2016-09-08 15:40 ` Drew Adams
2016-09-06 7:22 ` Andreas Röhler
2016-09-05 17:04 ` Drew Adams
2016-09-05 21:39 ` Florian v. Savigny
[not found] ` <<877faqvxfp.fsf@bertrandrussell.Speedport_W_723V_1_40_000>
2016-09-05 23:32 ` Drew Adams
2016-09-06 3:45 ` B.V. Raghav
2016-09-04 22:53 ` Florian v. Savigny
[not found] ` <<87d1kjjmys.fsf@bertrandrussell.Speedport_W_723V_1_40_000>
2016-09-05 0:52 ` Drew Adams
2016-09-15 12:47 ` Thien-Thi Nguyen
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