From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: ludo@gnu.org (Ludovic =?iso-8859-1?Q?Court=E8s?=) Newsgroups: gmane.lisp.guile.devel Subject: Re: rfi: immutable strings Date: Sat, 08 Jan 2011 22:57:00 +0100 Message-ID: <87d3o7f49f.fsf@gnu.org> References: <245692.94996.qm@web37905.mail.mud.yahoo.com> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Trace: dough.gmane.org 1294523848 12951 80.91.229.12 (8 Jan 2011 21:57:28 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Sat, 8 Jan 2011 21:57:28 +0000 (UTC) To: guile-devel@gnu.org Original-X-From: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Sat Jan 08 22:57:22 2011 Return-path: Envelope-to: guile-devel@m.gmane.org Original-Received: from lists.gnu.org ([199.232.76.165]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Pbgml-0007Uq-Fu for guile-devel@m.gmane.org; Sat, 08 Jan 2011 22:57:19 +0100 Original-Received: from localhost ([127.0.0.1]:44901 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Pbgml-0002Ne-3m for guile-devel@m.gmane.org; Sat, 08 Jan 2011 16:57:19 -0500 Original-Received: from [140.186.70.92] (port=41359 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Pbgmh-0002NK-9I for guile-devel@gnu.org; Sat, 08 Jan 2011 16:57:16 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Pbgmg-0003RD-2K for guile-devel@gnu.org; Sat, 08 Jan 2011 16:57:15 -0500 Original-Received: from lo.gmane.org ([80.91.229.12]:34622) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Pbgmf-0003Qp-Su for guile-devel@gnu.org; Sat, 08 Jan 2011 16:57:14 -0500 Original-Received: from list by lo.gmane.org with local (Exim 4.69) (envelope-from ) id 1Pbgmd-0007Q7-KU for guile-devel@gnu.org; Sat, 08 Jan 2011 22:57:11 +0100 Original-Received: from yoda.fdn.fr ([80.67.169.18]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 08 Jan 2011 22:57:11 +0100 Original-Received: from ludo by yoda.fdn.fr with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 08 Jan 2011 22:57:11 +0100 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 22 Original-X-Complaints-To: usenet@dough.gmane.org X-Gmane-NNTP-Posting-Host: yoda.fdn.fr X-URL: http://www.fdn.fr/~lcourtes/ X-Revolutionary-Date: 19 =?iso-8859-1?Q?Niv=F4se?= an 219 de la =?iso-8859-1?Q?R=E9volution?= X-PGP-Key-ID: 0xEA52ECF4 X-PGP-Key: http://www.fdn.fr/~lcourtes/ludovic.asc X-PGP-Fingerprint: 83C4 F8E5 10A3 3B4C 5BEA D15D 77DD 95E2 EA52 ECF4 X-OS: x86_64-unknown-linux-gnu User-Agent: Gnus/5.110011 (No Gnus v0.11) Emacs/23.2 (gnu/linux) Cancel-Lock: sha1:+/reUX5KsJrEQiFOMu7H6cxykPo= X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 3) X-BeenThere: guile-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Developers list for Guile, the GNU extensibility library" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Errors-To: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.lisp.guile.devel:11304 Archived-At: Hi! >> Guile needs immutable strings.  String literals should be immutable, so >> that its characters can come directly from objcode.  Also, the result of >> (symbol->string 'foo) should be immutable; currently symbol->string >> conses up a new shared substring every time. > > How is this different from read-only strings? Indeed, statically allocated stringbufs are immutable, for instance (see ‘SCM_IMMUTABLE_STRING’ in ‘snarf.h’.) Read-only strings are also used elsewhere: --8<---------------cut here---------------start------------->8--- scheme@(guile-user)> (string-set! (symbol->string 'foo) 2 #\x) ERROR: In procedure string-set!: ERROR: string is read-only: "foo" --8<---------------cut here---------------end--------------->8--- Thanks, Ludo’.