From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: "Pascal J. Bourguignon" Newsgroups: gmane.emacs.help Subject: Re: Why is booleanp defined this way? Date: Sat, 18 Apr 2015 02:41:51 +0200 Organization: Informatimago Message-ID: <87oammmfn4.fsf@kuiper.lan.informatimago.com> References: <87siby7au6.fsf@mbork.pl> <877ftapd6v.fsf@debian.uxu> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Trace: ger.gmane.org 1429318527 31756 80.91.229.3 (18 Apr 2015 00:55:27 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 18 Apr 2015 00:55:27 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Sat Apr 18 02:55:24 2015 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1YjH2Z-0004Fy-8H for geh-help-gnu-emacs@m.gmane.org; Sat, 18 Apr 2015 02:55:23 +0200 Original-Received: from localhost ([::1]:44116 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YjH2Y-0004Fl-5u for geh-help-gnu-emacs@m.gmane.org; Fri, 17 Apr 2015 20:55:22 -0400 Original-Path: usenet.stanford.edu!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail Original-Newsgroups: gnu.emacs.help Original-Lines: 48 Original-X-Trace: individual.net WiCH0KJcqXy2NLe0gPGt5wJIcX+wjARTQ1eLLTReV68/vb6oR3 Cancel-Lock: sha1:YzM0ODcyODUwMjgzMmY4MTZmNDMwZGYyMWEzYzZlYTFmYjgyOTcwMA== sha1:gL9lnLCJWDJephri2u25wlx7fCY= Face: iVBORw0KGgoAAAANSUhEUgAAADAAAAAwAQMAAABtzGvEAAAABlBMVEUAAAD///+l2Z/dAAAA oElEQVR4nK3OsRHCMAwF0O8YQufUNIQRGIAja9CxSA55AxZgFO4coMgYrEDDQZWPIlNAjwq9 033pbOBPtbXuB6PKNBn5gZkhGa86Z4x2wE67O+06WxGD/HCOGR0deY3f9Ijwwt7rNGNf6Oac l/GuZTF1wFGKiYYHKSFAkjIo1b6sCYS1sVmFhhhahKQssRjRT90ITWUk6vvK3RsPGs+M1RuR mV+hO/VvFAAAAABJRU5ErkJggg== X-Accept-Language: fr, es, en User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) Original-Xref: usenet.stanford.edu gnu.emacs.help:211507 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.help:103789 Archived-At: Emanuel Berg 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