From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Arun Isaac Newsgroups: gmane.lisp.guile.bugs Subject: bug#30145: [PATCH] doc: Document unspecified?. Date: Sun, 21 Jan 2018 23:52:08 +0530 Message-ID: References: <20180117175204.1381-1-arunisaac@systemreboot.net> <20180118062029.5655-1-arunisaac@systemreboot.net> <87wp0bmfmx.fsf@netris.org> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: blaine.gmane.org 1516558891 26616 195.159.176.226 (21 Jan 2018 18:21:31 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sun, 21 Jan 2018 18:21:31 +0000 (UTC) Cc: 30145-done@debbugs.gnu.org To: Mark H Weaver Original-X-From: bug-guile-bounces+guile-bugs=m.gmane.org@gnu.org Sun Jan 21 19:21:26 2018 Return-path: Envelope-to: guile-bugs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1edKF9-0006S7-IO for guile-bugs@m.gmane.org; Sun, 21 Jan 2018 19:21:23 +0100 Original-Received: from localhost ([::1]:41478 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1edKH9-0006Sl-V9 for guile-bugs@m.gmane.org; Sun, 21 Jan 2018 13:23:27 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:42192) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1edKGo-0006If-1R for bug-guile@gnu.org; Sun, 21 Jan 2018 13:23:07 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1edKGk-0001Xt-TS for bug-guile@gnu.org; Sun, 21 Jan 2018 13:23:06 -0500 Original-Received: from debbugs.gnu.org ([208.118.235.43]:57668) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1edKGk-0001Xf-MQ for bug-guile@gnu.org; Sun, 21 Jan 2018 13:23:02 -0500 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1edKGk-0005EP-GJ for bug-guile@gnu.org; Sun, 21 Jan 2018 13:23:02 -0500 Resent-From: Arun Isaac Original-Sender: "Debbugs-submit" Resent-To: bug-guile@gnu.org Resent-Date: Sun, 21 Jan 2018 18:23:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: cc-closed 30145 X-GNU-PR-Package: guile X-GNU-PR-Keywords: patch Mail-Followup-To: 30145@debbugs.gnu.org, arunisaac@systemreboot.net, arunisaac@systemreboot.net Original-Received: via spool by 30145-done@debbugs.gnu.org id=D30145.151655894720044 (code D ref 30145); Sun, 21 Jan 2018 18:23:02 +0000 Original-Received: (at 30145-done) by debbugs.gnu.org; 21 Jan 2018 18:22:27 +0000 Original-Received: from localhost ([127.0.0.1]:37330 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1edKGB-0005DE-Hw for submit@debbugs.gnu.org; Sun, 21 Jan 2018 13:22:27 -0500 Original-Received: from vultr.systemreboot.net ([45.77.148.100]:34246) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1edKG8-0005Cy-G3 for 30145-done@debbugs.gnu.org; Sun, 21 Jan 2018 13:22:25 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=systemreboot.net; s=default; h=Content-Type:MIME-Version:Message-ID:Date: References:In-Reply-To:Subject:Cc:To:From:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=rmyKhiUkMbEB2r6emObvsrkt1VBLMxHIWb2fO1mjeW0=; b=m+Lg5/Qu0p3dd5UUJG3fujQx6 BjG2E2A5VtD0lmZ7U8a1Rzz919zGd9AiTwGLz4lOkvG34ll6Yyfx+OOKcgvGfdIR0zAmJFFavGUGi vh7KY8nZ4bNJiJYliRkEKodkkhUIMyAnQvpbDZBGLbsumBrd3mPuFMcKeoXYJgV9pAepk=; Original-Received: from [103.61.74.183] (helo=steel) by systemreboot.net with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90) (envelope-from ) id 1edKFu-0006Ql-UL; Sun, 21 Jan 2018 23:52:10 +0530 In-Reply-To: <87wp0bmfmx.fsf@netris.org> X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 208.118.235.43 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" Xref: news.gmane.org gmane.lisp.guile.bugs:8978 Archived-At: Mark H Weaver writes: About undefined?: That was a typo. I mentioned that in a later message. > It's nonsensical to ask whether a given object is "unspecified". When > the Scheme standards say that the result of a computation is an > unspecified value, that means that *any* Scheme object could be > returned. > > In Guile, for historical reasons, we usually return a particular object > SCM_UNSPECIFIED (a.k.a. *unspecified*) in cases where the specification > says that the result is unspecified. However, we make no promises that > this will remain the case in future versions of Guile. > > The number of legitimate uses for 'unspecified?' is extremely small. In > fact, I can think of only one: when a REPL prints the result of a user's > computation, it is nice to avoid printing "*unspecified*" and instead > print nothing in that case. > > In almost every other case, use of 'unspecified?' implies an assumption > that it's possible to detect when a value is an "unspecified" value, > when in fact that is fundamentally impossible. > > What do you think? I agree. I didn't put very much thought into the matter before I sent the patch. I needed unspecified? for a patch to GNU Guix. I found the info documentation missing for unspecified? and thought I'll write it. Later, it turned out unspecified? was not necessary for the Guix patch after all. But, I had already documented unspecified?. So, I sent it here. Anyways, I'll close this bug report.