From: "Pascal J. Bourguignon" <pjb@informatimago.com>
To: help-gnu-emacs@gnu.org
Subject: Re: Why is booleanp defined this way?
Date: Sat, 18 Apr 2015 02:41:51 +0200 [thread overview]
Message-ID: <87oammmfn4.fsf@kuiper.lan.informatimago.com> (raw)
In-Reply-To: 877ftapd6v.fsf@debian.uxu
Emanuel Berg <embe8573@student.uu.se> writes:
> The "normalization" of which you speak should rather
> look something like this:
>
> (defun normalize-boolean (obj)
> (if obj t) ) ; implicit (if obj t nil)
>
> (normalize-boolean 1) ; t
> (normalize-boolean nil) ; nil
You may want to compare:
(defun normalize-boolean (obj)
(if obj t))
(disassemble (byte-compile 'normalize-boolean))
byte code:
args: (obj)
0 varref obj
1 goto-if-nil-else-pop 1
4 constant t
5:1 return
with:
(defun g (x) (not (not x)))
byte code:
args: (x)
0 varref x
1 not
2 not
3 return
(disassemble (byte-compile 'f))
> So I think `booleanp' shouldn't be thought of as
> a normalizer but rather as a type predicate, much like
> them `stringp', `integerp', and so on.
Of course. That's what the "p" in "booleanp" means!
--
__Pascal Bourguignon__ http://www.informatimago.com/
“The factory of the future will have only two employees, a man and a
dog. The man will be there to feed the dog. The dog will be there to
keep the man from touching the equipment.” -- Carl Bass CEO Autodesk
next prev parent reply other threads:[~2015-04-18 0:41 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-17 20:34 Why is booleanp defined this way? Marcin Borkowski
2015-04-17 20:49 ` Jorge A. Alfaro-Murillo
[not found] ` <mailman.962.1429303822.904.help-gnu-emacs@gnu.org>
2015-04-17 23:06 ` Emanuel Berg
2015-04-18 0:41 ` Pascal J. Bourguignon [this message]
2015-04-18 1:06 ` Emanuel Berg
2015-04-18 1:23 ` Pascal J. Bourguignon
2015-04-18 7:44 ` Marcin Borkowski
2015-04-18 8:37 ` Stefan Nobis
2015-04-19 23:15 ` Emanuel Berg
2015-04-18 2:37 ` Drew Adams
2015-04-18 6:13 ` Tassilo Horn
[not found] <mailman.946.1429302909.904.help-gnu-emacs@gnu.org>
2015-04-17 20:55 ` Pascal J. Bourguignon
2015-04-17 23:20 ` Barry Margolin
2015-04-17 23:30 ` Emanuel Berg
2015-04-18 0:43 ` Pascal J. Bourguignon
2015-04-18 3:13 ` Barry Margolin
2015-04-18 3:12 ` Barry Margolin
2015-04-18 2:01 ` Rusi
2015-04-18 2:23 ` Emanuel Berg
2015-04-18 2:33 ` Rusi
2015-04-18 2:55 ` Emanuel Berg
2015-04-18 3:11 ` Barry Margolin
2015-04-18 3:35 ` Rusi
2015-04-18 4:56 ` Barry Margolin
2015-04-19 23:08 ` Emanuel Berg
2015-04-19 23:00 ` Emanuel Berg
2015-04-18 21:24 ` Emanuel Berg
2015-04-18 7:52 ` Marcin Borkowski
[not found] ` <mailman.997.1429343558.904.help-gnu-emacs@gnu.org>
2015-04-18 12:43 ` Rusi
2015-04-18 4:09 ` Pascal J. Bourguignon
2015-04-18 5:00 ` Rusi
2015-04-18 3:50 ` Pascal J. Bourguignon
2015-04-18 5:03 ` Stefan Monnier
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