From: Emanuel Berg <embe8573@student.uu.se>
To: help-gnu-emacs@gnu.org
Subject: Re: Why is booleanp defined this way?
Date: Sat, 18 Apr 2015 03:06:02 +0200 [thread overview]
Message-ID: <871tjint39.fsf@debian.uxu> (raw)
In-Reply-To: 87oammmfn4.fsf@kuiper.lan.informatimago.com
"Pascal J. Bourguignon" <pjb@informatimago.com>
writes:
> 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))
... you mean 'g?
Are you saying (not (not x)) generates more efficient
byte-code? I hate to break it to you, but the
Commodore 64 demo era is long gone :)
>> 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!
If that is "of course" then what are we talking about?
--
underground experts united
http://user.it.uu.se/~embe8573
next prev parent reply other threads:[~2015-04-18 1:06 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
2015-04-18 1:06 ` Emanuel Berg [this message]
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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