From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Emanuel Berg Newsgroups: gmane.emacs.help Subject: Re: why are there [v e c t o r s] in Lisp? Date: Sat, 17 Oct 2015 06:22:03 +0200 Message-ID: <87oafyw2dw.fsf@debian.uxu> References: <87oafzpqfj.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 1445055198 2996 80.91.229.3 (17 Oct 2015 04:13:18 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 17 Oct 2015 04:13:18 +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 Oct 17 06:13:08 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 1ZnIrk-0006XF-0x for geh-help-gnu-emacs@m.gmane.org; Sat, 17 Oct 2015 06:13:08 +0200 Original-Received: from localhost ([::1]:56876 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZnIrj-00038q-By for geh-help-gnu-emacs@m.gmane.org; Sat, 17 Oct 2015 00:13:07 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:43616) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZnIrZ-00038l-GK for help-gnu-emacs@gnu.org; Sat, 17 Oct 2015 00:12:58 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZnIrW-0005KY-A0 for help-gnu-emacs@gnu.org; Sat, 17 Oct 2015 00:12:57 -0400 Original-Received: from plane.gmane.org ([80.91.229.3]:41889) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZnIrW-0005KK-2h for help-gnu-emacs@gnu.org; Sat, 17 Oct 2015 00:12:54 -0400 Original-Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1ZnIrT-0006Cd-EP for help-gnu-emacs@gnu.org; Sat, 17 Oct 2015 06:12:51 +0200 Original-Received: from nl106-137-244.student.uu.se ([130.243.137.244]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 17 Oct 2015 06:12:51 +0200 Original-Received: from embe8573 by nl106-137-244.student.uu.se with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 17 Oct 2015 06:12:51 +0200 X-Injected-Via-Gmane: http://gmane.org/ Mail-Followup-To: help-gnu-emacs@gnu.org Original-Lines: 37 Original-X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: nl106-137-244.student.uu.se Mail-Copies-To: never User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.4 (gnu/linux) Cancel-Lock: sha1:x0drUuGuvTONbH0vSYrqovt+Qyk= X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 80.91.229.3 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:107690 Archived-At: Aurélien Aptel writes: > The direction and the position you're talking about > are geometry concepts. Linear algebra is just a tool What do you mean "just" a tool? > that can be used to model many things e.g. > in mechanics to represent forces, in euclidian > geometry to represent positions *or* directions, you > can even used them to model text documents [1] etc. > In pure linear algebra, "direction" and "position" > are not defined for vectors. You could argue that > elisp is using vectors to model a specific concept > (constant time random access objects) and as such > deserves its own notation, different from the list. It seems to be like this: - in terms of linear algebra, a plain, finite list with one and the same base data type as elements is a vector as good as any - in terms of modeling, you can do all sorts of things with this concept - in terms of Elisp programming, the vector type shouldn't necessarily be thought of as a linear algebra concept but rather another data structure that can be used for many purposes, just like the Elisp list, only most often specific purposes are better suited for one or the other -- underground experts united http://user.it.uu.se/~embe8573