From mboxrd@z Thu Jan 1 00:00:00 1970 Path: main.gmane.org!not-for-mail From: Kevin Rodgers Newsgroups: gmane.emacs.devel Subject: Re: comma-dot ? Date: Thu, 29 May 2003 14:49:46 -0600 Sender: emacs-devel-bounces+emacs-devel=quimby.gnus.org@gnu.org Message-ID: <3ED6726A.9010802@yahoo.com> References: <200305292004.h4TK42nn017172@rum.cs.yale.edu> NNTP-Posting-Host: main.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Trace: main.gmane.org 1054241610 23019 80.91.224.249 (29 May 2003 20:53:30 GMT) X-Complaints-To: usenet@main.gmane.org NNTP-Posting-Date: Thu, 29 May 2003 20:53:30 +0000 (UTC) Original-X-From: emacs-devel-bounces+emacs-devel=quimby.gnus.org@gnu.org Thu May 29 22:53:26 2003 Return-path: Original-Received: from quimby.gnus.org ([80.91.224.244]) by main.gmane.org with esmtp (Exim 3.35 #1 (Debian)) id 19LUOO-0005wg-00 for ; Thu, 29 May 2003 22:52:56 +0200 Original-Received: from monty-python.gnu.org ([199.232.76.173]) by quimby.gnus.org with esmtp (Exim 3.12 #1 (Debian)) id 19LUdD-0001vu-00 for ; Thu, 29 May 2003 23:08:15 +0200 Original-Received: from localhost ([127.0.0.1] helo=monty-python.gnu.org) by monty-python.gnu.org with esmtp (Exim 4.20) id 19LUOb-0007Fn-02 for emacs-devel@quimby.gnus.org; Thu, 29 May 2003 16:53:09 -0400 Original-Received: from list by monty-python.gnu.org with tmda-scanned (Exim 4.20) id 19LUO2-00075C-FJ for emacs-devel@gnu.org; Thu, 29 May 2003 16:52:34 -0400 Original-Received: from mail by monty-python.gnu.org with spam-scanned (Exim 4.20) id 19LUN7-0005xy-C8 for emacs-devel@gnu.org; Thu, 29 May 2003 16:51:41 -0400 Original-Received: from main.gmane.org ([80.91.224.249]) by monty-python.gnu.org with esmtp (Exim 4.20) id 19LUMk-0005Pa-5J for emacs-devel@gnu.org; Thu, 29 May 2003 16:51:14 -0400 Original-Received: from list by main.gmane.org with local (Exim 3.35 #1 (Debian)) id 19LUK6-0005fu-00 for ; Thu, 29 May 2003 22:48:30 +0200 X-Injected-Via-Gmane: http://gmane.org/ Original-To: emacs-devel@gnu.org Original-Received: from news by main.gmane.org with local (Exim 3.35 #1 (Debian)) id 19LUJ7-0005aA-00 for ; Thu, 29 May 2003 22:47:29 +0200 Original-Lines: 18 Original-X-Complaints-To: usenet@main.gmane.org User-Agent: Mozilla/5.0 (X11; U; SunOS i86pc; en-US; rv:0.9.4.1) Gecko/20020406 Netscape6/6.2.2 X-Accept-Language: en-us X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1b5 Precedence: list List-Id: Emacs development discussions. List-Help: List-Post: List-Subscribe: , List-Archive: List-Unsubscribe: , Errors-To: emacs-devel-bounces+emacs-devel=quimby.gnus.org@gnu.org Xref: main.gmane.org gmane.emacs.devel:14426 X-Report-Spam: http://spam.gmane.org/gmane.emacs.devel:14426 Stefan Monnier wrote: > While looking at the lread.c code recently I bumped into > the comma-dot read syntax: the reader not only recognizes > , and ,@ but also ,. as a special thingy. > > Does anybody know what this is/was for ? Probably compatibility with Common Lisp: Anywhere ",@" may be used, ",." may be used instead to indicate that it is permissible to destroy the list produced by the form following the ",."; this may permit more efficient code, using nconc instead of append, for example. -- Kevin Rodgers