From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: =?ISO-8859-1?Q?Nordl=F6w?= Newsgroups: gmane.emacs.help Subject: Seeking Understanding about Symbols, Strings, Structure and Storage Date: Fri, 6 Nov 2009 01:54:36 -0800 (PST) Organization: http://groups.google.com Message-ID: NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Trace: ger.gmane.org 1257504076 19734 80.91.229.12 (6 Nov 2009 10:41:16 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 6 Nov 2009 10:41:16 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Fri Nov 06 11:41:01 2009 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([199.232.76.165]) by lo.gmane.org with esmtp (Exim 4.50) id 1N6MFY-0001tx-Im for geh-help-gnu-emacs@m.gmane.org; Fri, 06 Nov 2009 11:41:00 +0100 Original-Received: from localhost ([127.0.0.1]:40213 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1N6MFX-0005aJ-RA for geh-help-gnu-emacs@m.gmane.org; Fri, 06 Nov 2009 05:40:59 -0500 Original-Path: news.stanford.edu!usenet.stanford.edu!postnews.google.com!w19g2000yqk.googlegroups.com!not-for-mail Original-Newsgroups: gnu.emacs.help Original-Lines: 40 Original-NNTP-Posting-Host: 81.170.219.22 Original-X-Trace: posting.google.com 1257501276 19726 127.0.0.1 (6 Nov 2009 09:54:36 GMT) Original-X-Complaints-To: groups-abuse@google.com Original-NNTP-Posting-Date: Fri, 6 Nov 2009 09:54:36 +0000 (UTC) Complaints-To: groups-abuse@google.com Injection-Info: w19g2000yqk.googlegroups.com; posting-host=81.170.219.22; posting-account=ytJKAgoAAAA1tg4ScoRszebXiIldA5vg User-Agent: G2/1.0 X-HTTP-UserAgent: Mozilla/5.0 (X11; U; Linux i686; en-US) AppleWebKit/532.3 (KHTML, like Gecko) Chrome/4.0.226.0 Safari/532.3,gzip(gfe),gzip(gfe) Original-Xref: news.stanford.edu gnu.emacs.help:174461 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.help:69538 Archived-At: I am trying really hard to get a unified view about all the atomic types and containers/structures/links (e)lisp provides me with: What is the best (efficient) way to store symbols (references) extracted from an obarray? Should I intern them in a new array or should I store them in a sequence? Does interning symbols in an obarray require more memory than storing them in a vector? When should I intern symbols in an obarray?; My guess: When I need fast (hashed) lookup of them. If I store symbols in a list, say '(a b), are these symbols "free", compared to if I first intern them? I have heard the we should always prefer symbols before strings, when we can. Why?; I guess symbols require less memory because they don't carry string attributes. Are the any other reasons? If I want to build a tree or even a cyclic graph (I guess this is possible because there are rings) do we always need to construct these from cons-cells? If so how do we realize this?: I know that setcar,setcdr,setf can play a key-role here. What happens if I try to print such an expression using princ(), prin1()? For example how should we efficiently store a parse tree of tokens having properties?: My suggestion: As a cons-tree of symbols were the symbols are interned in an obarray having properties accessed using get() and put(). If I assign the same long symbol to many variables is it assigned by reference, kind of like pointers in C? Example: (setq x 'loooooooooooooooooooong y 'loooooooooooooooooooong) Is there some web-page out there that highlights the choices the (e) lisp designers made concerning these things? Thanks, Nordl=F6w