From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Lars Ingebrigtsen Newsgroups: gmane.emacs.bugs Subject: bug#49944: parse-partial-sexp fails to signal an error when (> START LIMIT). Date: Tue, 10 Aug 2021 16:54:59 +0200 Message-ID: <87o8a5xscc.fsf@gnus.org> References: <87r1f36by6.fsf@gnus.org> <87pmum4wnm.fsf@gnus.org> <87a6lpz9vq.fsf@gnus.org> <83mtppflcu.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="2910"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) Cc: acm@muc.de, 49944@debbugs.gnu.org To: Stefan Monnier Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Tue Aug 10 16:58:44 2021 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1mDTDH-0000Sc-Fq for geb-bug-gnu-emacs@m.gmane-mx.org; Tue, 10 Aug 2021 16:58:43 +0200 Original-Received: from localhost ([::1]:51310 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mDTDG-0004Cl-Ce for geb-bug-gnu-emacs@m.gmane-mx.org; Tue, 10 Aug 2021 10:58:42 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:34990) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mDTAg-0006D7-Iz for bug-gnu-emacs@gnu.org; Tue, 10 Aug 2021 10:56:02 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:48754) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1mDTAg-0001hk-9L for bug-gnu-emacs@gnu.org; Tue, 10 Aug 2021 10:56:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1mDTAg-00051G-8Z for bug-gnu-emacs@gnu.org; Tue, 10 Aug 2021 10:56:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Lars Ingebrigtsen Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Tue, 10 Aug 2021 14:56:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 49944 X-GNU-PR-Package: emacs Original-Received: via spool by 49944-submit@debbugs.gnu.org id=B49944.162860731419216 (code B ref 49944); Tue, 10 Aug 2021 14:56:02 +0000 Original-Received: (at 49944) by debbugs.gnu.org; 10 Aug 2021 14:55:14 +0000 Original-Received: from localhost ([127.0.0.1]:60296 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1mDT9u-0004zs-Gs for submit@debbugs.gnu.org; Tue, 10 Aug 2021 10:55:14 -0400 Original-Received: from quimby.gnus.org ([95.216.78.240]:48618) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1mDT9s-0004zb-LS for 49944@debbugs.gnu.org; Tue, 10 Aug 2021 10:55:13 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnus.org; s=20200322; h=Content-Type:MIME-Version:Message-ID:In-Reply-To:Date: References: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=eNmMYBJaYxMp9VlQu7FUSAQbQbRENrnAVEPQqH0JCXI=; b=hslxxLcCiBAeQVx/C5xDq4jknF G16+zfDusz0XbeTvWYgaSsNkFEUatCuaqcwXvGmLSOJSv5/NMIfZBBWn7b5I8zaUCJsJlYl+RKL/c P2MW2zAjHU9WrPBqtw/RbQDIhEZ2Y6QSRvrtaEOOXRTx170lbjW98qCZz097OIu+VGcI=; Original-Received: from [84.212.220.105] (helo=elva) by quimby.gnus.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1mDT9g-0003Ie-HE; Tue, 10 Aug 2021 16:55:04 +0200 In-Reply-To: (Stefan Monnier's message of "Tue, 10 Aug 2021 10:41:30 -0400") X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.io gmane.emacs.bugs:211510 Archived-At: Stefan Monnier writes: > I think the case of `parse-partial-sexp` is different because it > receives the argument OLDSTATE which provides the parser's state which > should apply at START. If START and END are swapped you'll generally > get an incorrect result. > > So, I don't care if we signal an error when START > END or if we "do > nothing" (as is customary in some language's `for` loops), but we should > always consider that OLDSTATE is the state that belongs with START and > hence we can't start parsing at END towards START because we don't know > what parsing state to use at END. Ah; thanks for the explanation. But I guess you'll get incorrect results if you pass in any OLDSTATE that doesn't belong to START, not just when START and END are swapped? It's just that if START/END obviously wrong (i.e., END is smaller than START), then the function here "helpfully" swaps them and things get even more confusing than they would normally be if you pass in a wrong OLDSTATE (or wrong START). So perhaps signalling an error here is the correct thing after all? (Or just not doing any swapping.) -- (domestic pets only, the antidote for overdose, milk.) bloggy blog: http://lars.ingebrigtsen.no