From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Richard Stallman Newsgroups: gmane.emacs.devel Subject: Re: if-let and when-let: parallel or sequential Date: Mon, 11 Aug 2014 23:15:27 -0400 Message-ID: References: Reply-To: rms@gnu.org NNTP-Posting-Host: plane.gmane.org Content-Type: text/plain; charset=ISO-8859-15 X-Trace: ger.gmane.org 1407813345 3859 80.91.229.3 (12 Aug 2014 03:15:45 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 12 Aug 2014 03:15:45 +0000 (UTC) Cc: john.b.mastro@gmail.com, bozhidar.batsov@gmail.com, emacs-devel@gnu.org To: Stefan Monnier Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Aug 12 05:15:39 2014 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1XH2Yk-0001TI-1G for ged-emacs-devel@m.gmane.org; Tue, 12 Aug 2014 05:15:38 +0200 Original-Received: from localhost ([::1]:38922 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XH2Yj-0005CT-He for ged-emacs-devel@m.gmane.org; Mon, 11 Aug 2014 23:15:37 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:47706) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XH2Yc-0005BS-1u for emacs-devel@gnu.org; Mon, 11 Aug 2014 23:15:30 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XH2Ya-0005V5-N5 for emacs-devel@gnu.org; Mon, 11 Aug 2014 23:15:29 -0400 Original-Received: from fencepost.gnu.org ([2001:4830:134:3::e]:59691) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XH2Ya-0005Td-JV for emacs-devel@gnu.org; Mon, 11 Aug 2014 23:15:28 -0400 Original-Received: from rms by fencepost.gnu.org with local (Exim 4.71) (envelope-from ) id 1XH2YZ-0001HM-NB; Mon, 11 Aug 2014 23:15:27 -0400 In-reply-to: (message from Stefan Monnier on Mon, 11 Aug 2014 10:42:19 -0400) X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-Received-From: 2001:4830:134:3::e X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:173587 Archived-At: [[[ To any NSA and FBI agents reading my email: please consider ]]] [[[ whether defending the US Constitution against all enemies, ]]] [[[ foreign or domestic, requires you to follow Snowden's example. ]]] > if-let and when-let don t make much sense with more than one binding > form. Why do you think so? If they only work for a single binding, the benefit is really minor. It's only when you use several bindings that the benefit becomes more significant (the alternative being either a very deeply nested code, or separating the var's declarations from their initialization). With several sequential bindings, the alternative is (let* ...bindings... (if ...)) Thus, if-let saves just one level of nesting even if there are several bindings. -- Dr Richard Stallman President, Free Software Foundation 51 Franklin St Boston MA 02110 USA www.fsf.org www.gnu.org Skype: No way! That's nonfree (freedom-denying) software. Use Ekiga or an ordinary phone call.