From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: "dskr@mac.com" Newsgroups: gmane.lisp.guile.user Subject: Re: What does #-3# mean? Date: Tue, 24 Aug 2010 16:46:58 -0400 Message-ID: <04CDA7A3-47B4-471E-9665-EE63ECDC0481@mac.com> References: <1282579402.2957.6.camel@debianrts.home> <87occsezkl.fsf@gnu.org> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Trace: dough.gmane.org 1282682865 30135 80.91.229.12 (24 Aug 2010 20:47:45 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Tue, 24 Aug 2010 20:47:45 +0000 (UTC) Cc: "guile-user@gnu.org" To: =?utf-8?Q?Ludovic_Court=C3=A8s?= Original-X-From: guile-user-bounces+guile-user=m.gmane.org@gnu.org Tue Aug 24 22:47:43 2010 Return-path: Envelope-to: guile-user@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 1Oo0PC-0008Rn-EA for guile-user@m.gmane.org; Tue, 24 Aug 2010 22:47:38 +0200 Original-Received: from localhost ([127.0.0.1]:50048 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Oo0PB-00082O-Gc for guile-user@m.gmane.org; Tue, 24 Aug 2010 16:47:37 -0400 Original-Received: from [140.186.70.92] (port=49095 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Oo0P6-00081M-Uq for guile-user@gnu.org; Tue, 24 Aug 2010 16:47:33 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1Oo0P5-0007Na-9W for guile-user@gnu.org; Tue, 24 Aug 2010 16:47:32 -0400 Original-Received: from asmtpout030.mac.com ([17.148.16.105]:34786) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1Oo0P5-0007NS-3o; Tue, 24 Aug 2010 16:47:31 -0400 Original-Received: from [10.0.1.5] (pool-70-106-32-253.hgrtmd.btas.verizon.net [70.106.32.253]) by asmtp030.mac.com (Sun Java(tm) System Messaging Server 6.3-8.01 (built Dec 16 2008; 32bit)) with ESMTPSA id <0L7O0059ECEL8J40@asmtp030.mac.com>; Tue, 24 Aug 2010 13:47:28 -0700 (PDT) X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 ipscore=0 phishscore=0 bulkscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx engine=6.0.2-1004200000 definitions=main-1008240146 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.0.10011,1.0.148,0.0.0000 definitions=2010-08-24_10:2010-08-24, 2010-08-24, 1970-01-01 signatures=0 In-reply-to: <87occsezkl.fsf@gnu.org> X-Mailer: iPad Mail (7B405) X-detected-operating-system: by eggs.gnu.org: Solaris 10 (1203?) X-BeenThere: guile-user@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: General Guile related discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: guile-user-bounces+guile-user=m.gmane.org@gnu.org Errors-To: guile-user-bounces+guile-user=m.gmane.org@gnu.org Xref: news.gmane.org gmane.lisp.guile.user:8097 Archived-At: I recall that the reader can be hash-extended to read these forms in a = hacky way. Extend on '-'. I don't recall exactly anymore. I long ago = patched the reader to read these natively. Perhaps there is some = enthusiasm for making these readable in the main line? Cheers, Dan On Aug 24, 2010, at 12:38 PM, ludo@gnu.org (Ludovic Court=C3=A8s) wrote: > Hi, >=20 > Richard Shann writes: >=20 >> I am displaying a structure that seems to be circular, and it shows >>=20 >> (x_LIST . #-3#) >>=20 >> x_LIST is my own symbol but what is the meaning of the other member = of the pair? >=20 > Indeed, it means it=E2=80=99s a circular list: >=20 > --8<---------------cut here---------------start------------->8--- > scheme@(guile-user)> (use-modules (srfi srfi-1)) > scheme@(guile-user)> (circular-list 1 2 3) > $1 =3D (1 2 3 . #-2#) > scheme@(guile-user)> (circular-list 1) > $2 =3D (1 . #0#) > --8<---------------cut here---------------end--------------->8--- >=20 >> And how does one track it down this notation in the guile manual? I = am >> sure I came across this before, but cannot locate it in the manual >> (again?) >=20 > It doesn=E2=80=99t seem to be documented but you get the idea. ;-) >=20 > Note that =E2=80=98read=E2=80=99 doesn=E2=80=99t understand it. >=20 > Thanks, > Ludo=E2=80=99. >=20 >=20