From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: David Kastrup Newsgroups: gmane.lisp.guile.bugs Subject: bug#17474: Ping? Date: Mon, 01 Jun 2015 16:04:25 +0200 Message-ID: <87twurcyom.fsf@fencepost.gnu.org> References: <87r43zuswp.fsf@fencepost.gnu.org> <87bnru81ke.fsf@fencepost.gnu.org> <874mxkrwff.fsf@yeeloong.lan> <87vbq05bw8.fsf@fencepost.gnu.org> <87vbq0qa28.fsf@yeeloong.lan> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1433167824 21287 80.91.229.3 (1 Jun 2015 14:10:24 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 1 Jun 2015 14:10:24 +0000 (UTC) Cc: 17474@debbugs.gnu.org To: Mark H Weaver Original-X-From: bug-guile-bounces+guile-bugs=m.gmane.org@gnu.org Mon Jun 01 16:10:13 2015 Return-path: Envelope-to: guile-bugs@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 1YzQPs-0005Iq-Hn for guile-bugs@m.gmane.org; Mon, 01 Jun 2015 16:10:12 +0200 Original-Received: from localhost ([::1]:52675 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YzQPr-0004qH-Vr for guile-bugs@m.gmane.org; Mon, 01 Jun 2015 10:10:11 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:35753) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YzQPn-0004mU-Ml for bug-guile@gnu.org; Mon, 01 Jun 2015 10:10:08 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YzQPl-0001wI-TL for bug-guile@gnu.org; Mon, 01 Jun 2015 10:10:07 -0400 Original-Received: from debbugs.gnu.org ([140.186.70.43]:54472) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YzQPl-0001vE-QP for bug-guile@gnu.org; Mon, 01 Jun 2015 10:10:05 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.80) (envelope-from ) id 1YzQPl-0000Td-A9 for bug-guile@gnu.org; Mon, 01 Jun 2015 10:10:05 -0400 X-Loop: help-debbugs@gnu.org Resent-From: David Kastrup Original-Sender: "Debbugs-submit" Resent-CC: bug-guile@gnu.org Resent-Date: Mon, 01 Jun 2015 14:10:04 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 17474 X-GNU-PR-Package: guile X-GNU-PR-Keywords: patch Original-Received: via spool by 17474-submit@debbugs.gnu.org id=B17474.14331677941811 (code B ref 17474); Mon, 01 Jun 2015 14:10:04 +0000 Original-Received: (at 17474) by debbugs.gnu.org; 1 Jun 2015 14:09:54 +0000 Original-Received: from localhost ([127.0.0.1]:36214 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1YzQPa-0000T8-9A for submit@debbugs.gnu.org; Mon, 01 Jun 2015 10:09:54 -0400 Original-Received: from fencepost.gnu.org ([208.118.235.10]:40855 ident=Debian-exim) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1YzQPX-0000T0-SS for 17474@debbugs.gnu.org; Mon, 01 Jun 2015 10:09:52 -0400 Original-Received: from localhost ([127.0.0.1]:50517 helo=lola) by fencepost.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YzQPW-0003ZU-VY; Mon, 01 Jun 2015 10:09:51 -0400 Original-Received: by lola (Postfix, from userid 1000) id 757A8DF4C9; Mon, 1 Jun 2015 16:04:25 +0200 (CEST) In-Reply-To: <87vbq0qa28.fsf@yeeloong.lan> (Mark H. Weaver's message of "Sun, 10 Aug 2014 18:00:47 -0400") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.0.50 (gnu/linux) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.15 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 140.186.70.43 X-BeenThere: bug-guile@gnu.org List-Id: "Bug reports for GUILE, GNU's Ubiquitous Extension Language" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-guile-bounces+guile-bugs=m.gmane.org@gnu.org Original-Sender: bug-guile-bounces+guile-bugs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.lisp.guile.bugs:7789 Archived-At: Mark H Weaver writes: > David Kastrup writes: >> So you think that it will be more "lightweight" if (values) does not >> have an immediate representation but rather creates a multiple-values >> object on the heap? > > I don't have time to continue this discussion, but I wanted to respond > to this one point: there should be a single global > statically-allocated instance of the multiple-values object containing > zero values, and the procedures that create multiple-values objects > would always use that one. So we are in agreement that a single object (I don't see a meaningful distinction between "immediate" and "single global statically-allocated" that is consistently being used) with SCM_NO_VALUES semantics makes sense. Where we don't agree is about making it the same as SCM_UNSPECIFIED. It is my contention that the concepts for SCM_NO_VALUES and SCM_UNSPECIFIED overlap too much to offer the user a meaningful distinction allowing him to make a qualified choice between returning one of the two. I consider it a good hint that the REPL already considers *unspecified* and (values) similar enough that it prints exactly the same for either input, namely nothing. So I'm pretty convinced that the user is better off without having to deal with two separate representations of "no useful value". -- David Kastrup