From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Thien-Thi Nguyen Newsgroups: gmane.emacs.devel Subject: emacs lisp syntax rfc: (cond (EXPR => (lambda (X) ...))) Date: Sun, 02 Jan 2011 22:45:56 +0100 Message-ID: <877hengesr.fsf@ambire.localdomain> 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 1294005087 5738 80.91.229.12 (2 Jan 2011 21:51:27 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Sun, 2 Jan 2011 21:51:27 +0000 (UTC) To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Sun Jan 02 22:51:23 2011 Return-path: Envelope-to: ged-emacs-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 1PZVph-0004Ik-Hq for ged-emacs-devel@m.gmane.org; Sun, 02 Jan 2011 22:51:21 +0100 Original-Received: from localhost ([127.0.0.1]:43002 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PZVpg-00089Q-PH for ged-emacs-devel@m.gmane.org; Sun, 02 Jan 2011 16:51:20 -0500 Original-Received: from [140.186.70.92] (port=45394 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PZVpZ-00088D-B6 for emacs-devel@gnu.org; Sun, 02 Jan 2011 16:51:14 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PZVpT-0003Ku-MZ for emacs-devel@gnu.org; Sun, 02 Jan 2011 16:51:13 -0500 Original-Received: from smtp206.alice.it ([82.57.200.102]:57505) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PZVpT-0003K8-Hd for emacs-devel@gnu.org; Sun, 02 Jan 2011 16:51:07 -0500 Original-Received: from ambire.localdomain (95.245.72.7) by smtp206.alice.it (8.5.124.08) id 4C1A268C0E1B6B8D for emacs-devel@gnu.org; Sun, 2 Jan 2011 22:51:05 +0100 Original-Received: from ttn by ambire.localdomain with local (Exim 4.69) (envelope-from ) id 1PZVkS-0005rx-5G for emacs-devel@gnu.org; Sun, 02 Jan 2011 22:45:56 +0100 User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.0.50 (gnu/linux) X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:134176 Archived-At: In Scheme, the expression: (cond (EXPR =3D> (lambda (X) ...))) provides the lambda expression parameter X with the non-false value computed from evaluating EXPR. However, if EXPR evaluates to false, control falls through to the next =E2=80=98cond=E2=80=99 clause, = as usual. The syntax requires the symbol =E2=80=98=3D>=E2=80=99 between EXPR = and the lambda expression, without which the non-false value is discarded (i.e., the status quo). What do people think of adding this to Emacs Lisp? (I would be grateful for pointers to any previous discussion on the matter.)