From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: Double unquote/unquote-splicing Date: Mon, 04 Nov 2013 15:41:57 -0500 Message-ID: References: <87wqko6z8g.fsf@nbtrap.com> <874n7sf3pi.fsf@nbtrap.com> <87habsdlwo.fsf@nbtrap.com> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1383597736 5806 80.91.229.3 (4 Nov 2013 20:42:16 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 4 Nov 2013 20:42:16 +0000 (UTC) Cc: emacs-devel@gnu.org To: Nathan Trapuzzano Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Mon Nov 04 21:42:20 2013 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 1VdQyY-0003K0-Fz for ged-emacs-devel@m.gmane.org; Mon, 04 Nov 2013 21:42:18 +0100 Original-Received: from localhost ([::1]:51958 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VdQyY-0007H9-3J for ged-emacs-devel@m.gmane.org; Mon, 04 Nov 2013 15:42:18 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:55896) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VdQyN-0007Gq-MB for emacs-devel@gnu.org; Mon, 04 Nov 2013 15:42:15 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VdQyG-0001ji-CH for emacs-devel@gnu.org; Mon, 04 Nov 2013 15:42:07 -0500 Original-Received: from ironport2-out.teksavvy.com ([206.248.154.182]:35981) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VdQyG-0001jb-8L for emacs-devel@gnu.org; Mon, 04 Nov 2013 15:42:00 -0500 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Av4EABK/CFFFxLzd/2dsb2JhbABEvw4Xc4IeAQEEAVYjBQsLDiYSFBgNJIgeBsEtkQoDiGGcGYFegxU X-IPAS-Result: Av4EABK/CFFFxLzd/2dsb2JhbABEvw4Xc4IeAQEEAVYjBQsLDiYSFBgNJIgeBsEtkQoDiGGcGYFegxU X-IronPort-AV: E=Sophos;i="4.84,565,1355115600"; d="scan'208";a="37076495" Original-Received: from 69-196-188-221.dsl.teksavvy.com (HELO pastel.home) ([69.196.188.221]) by ironport2-out.teksavvy.com with ESMTP/TLS/ADH-AES256-SHA; 04 Nov 2013 15:41:58 -0500 Original-Received: by pastel.home (Postfix, from userid 20848) id 7D8DF60D75; Mon, 4 Nov 2013 15:41:57 -0500 (EST) In-Reply-To: <87habsdlwo.fsf@nbtrap.com> (Nathan Trapuzzano's message of "Mon, 04 Nov 2013 14:09:11 -0500") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3.50 (gnu/linux) X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 206.248.154.182 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:164943 Archived-At: > In fact, I just built from trunk with two lines of code from > backquote.el changed (using your helpful comments), and it seems to work > precisely like that. In other words, this doesn't seem to require any > extra work. I know (obviously), but I rather dislike this weird intermediate state, which doesn't fit cleanly in the usual semantics of unquote (whose special syntax makes it clear that it's supposed to have just one argument). The fact that Common-Lisp found a way to extend the semantics in a way that makes some sense is fine for Common-Lips, but not enough to convince me. Your example was the first concrete example I've seen where such a ,,@foo construct was used and as you've seen it's trivially replaced by ,@(list ,@foo) (which is true because ,foo is equivalent to ,@(list foo). So ,,@ is not a very compelling use. Maybe ,@,@ would be more compelling, but I haven't seen any concrete use for it yet, so I can't comment. Stefan