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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.



  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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