From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mp10.migadu.com ([2001:41d0:2:4a6f::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by ms5.migadu.com with LMTPS id MKVnLEiJ2mN8WgEAbAwnHQ (envelope-from ) for ; Wed, 01 Feb 2023 16:46:16 +0100 Received: from aspmx1.migadu.com ([2001:41d0:2:4a6f::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by mp10.migadu.com with LMTPS id jYGHK0iJ2mP+dwAAG6o9tA (envelope-from ) for ; Wed, 01 Feb 2023 16:46:16 +0100 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by aspmx1.migadu.com (Postfix) with ESMTPS id 56AFC8000 for ; Wed, 1 Feb 2023 16:46:16 +0100 (CET) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pNFJC-0003bc-RX; Wed, 01 Feb 2023 10:46:02 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pNFIx-0003MP-Uu for emacs-orgmode@gnu.org; Wed, 01 Feb 2023 10:45:48 -0500 Received: from stw1.rcdrun.com ([217.170.207.13]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pNFIp-00028F-26 for emacs-orgmode@gnu.org; Wed, 01 Feb 2023 10:45:43 -0500 Received: from localhost ([::ffff:197.239.7.190]) (AUTH: PLAIN admin, TLS: TLS1.3,256bits,ECDHE_RSA_AES_256_GCM_SHA384) by stw1.rcdrun.com with ESMTPSA id 0000000000103A93.0000000063DA8919.0000518D; Wed, 01 Feb 2023 08:45:28 -0700 Date: Sun, 29 Oct 2023 04:02:44 +0300 From: Jean Louis To: emacs-orgmode@gnu.org Subject: Re: [POLL] Proposed syntax for timestamps with time zone info Message-ID: Mail-Followup-To: emacs-orgmode@gnu.org References: <87pmb9k8oi.fsf@tsdye.online> <3035CDD5-41DD-4516-9E4E-9E0DF16BE2E0@gmail.com> <87lelo8c9r.fsf@localhost> <2150768.1675077958@archlinux> <87tu063ox2.fsf@localhost> <87h6w63jgg.fsf@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/2.2.9+54 (af2080d) (2022-11-21) Received-SPF: pass client-ip=217.170.207.13; envelope-from=bugs@gnu.support; helo=stw1.rcdrun.com X-Spam_score_int: -17 X-Spam_score: -1.8 X-Spam_bar: - X-Spam_report: (-1.8 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_SBL=0.141, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001, T_DATE_IN_FUTURE_Q_PLUS=0.01 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-orgmode@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "General discussions about Org-mode." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-orgmode-bounces+larch=yhetil.org@gnu.org Sender: emacs-orgmode-bounces+larch=yhetil.org@gnu.org X-Migadu-Country: US X-Migadu-Flow: FLOW_IN ARC-Seal: i=1; s=key1; d=yhetil.org; t=1675266376; a=rsa-sha256; cv=none; b=qRP+2uXTVkEC//uOh4PGS0xRa/pr5CebTBsxZY0anhdtYdSqnGw1piebnWsgplXMRXg3bS NZDZgtK3dYroRWPHgy60f59tosbyG5rBt0caAE0RJPsQXiU4mwVgoa3F2mY5jU/U+S4ZRi sa+SgVJfN00Aw293ANVlJk6tiDBa55BPMsQbJBiUxD2Q6UzZDe51ddq9e26Rw2YoMXhe+H Y+Y+xSZz9MIACOoWjXT4TJtVtn04hLrmBr0TFnC95716jM8dTJq6t2At9qUMcbhzrrqt1r vCGn0mJozJaeOWLzuPSgz1FJtB6WIf4wj8HCDN+8bJlPkTf+UuC0rdi6FXlLlA== ARC-Authentication-Results: i=1; aspmx1.migadu.com; dkim=none; spf=pass (aspmx1.migadu.com: domain of "emacs-orgmode-bounces+larch=yhetil.org@gnu.org" designates 209.51.188.17 as permitted sender) smtp.mailfrom="emacs-orgmode-bounces+larch=yhetil.org@gnu.org"; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=yhetil.org; s=key1; t=1675266376; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:list-id:list-help: list-unsubscribe:list-subscribe:list-post; bh=OaMUC2QykWn3m/64j5isQJwPKYQgG9VLEN/MNfxlREQ=; b=KlW/tWLdAMq5sSKeDpRqOwn0nuznyPO/rvwC/RrnhGMl3jmekDJd+CF0sqqnvfRTrsdgME SXxOeCqH8ZqY54PnAA8hF/m9mw1JSNilZ4JSaC3InmM3Zlcyug/+VSEKB6ZtDMmvT+Tx2N ss856XDGdCi/Rsf7j5yRbS263QuLLQxULQ/VACvCTqYylj1e/4ygkuOlW2y/NJsOTBwGWY Dn+/ToY5zG+PMG2fAIkqtO+dZaaGNTonR5jk1ZAyvhOI7HrYb2LfQFRinvdjoBL4r0smPk XxPNAYrlnV9Jir3r/fNAqoD5aiaIzIb7uAbrpcEhjgas7X6378jlDFOIca5T9w== Authentication-Results: aspmx1.migadu.com; dkim=none; spf=pass (aspmx1.migadu.com: domain of "emacs-orgmode-bounces+larch=yhetil.org@gnu.org" designates 209.51.188.17 as permitted sender) smtp.mailfrom="emacs-orgmode-bounces+larch=yhetil.org@gnu.org"; dmarc=none X-Migadu-Scanner: scn1.migadu.com X-Migadu-Spam-Score: 5.92 X-Spam-Score: 5.92 X-Migadu-Queue-Id: 56AFC8000 X-TUID: xp2Wy1xR7J4n * Stefan Nobis [2023-02-01 12:13]: > writes: > > > 2023-03-23 02:30 @Europe/Berlin refers to /two/ points in time, thus > > it /is/ ambiguous. > > As far as I understand the definitions, the point in time "2023-03-23 > 02:30 @Europe/Berlin" is clearly defined as 2023-03-23 02:30 UTC+0100. > > A bit more problematic would be "2023-03-26 02:30 @Europe/Berlin". > Strictly speaking, this point in time does not exist, because in the > night from 2023-03-25 to 2023-03-26 the clock will jump from 02:00 > directly to 03:00 in the time zone Europe/Berlin. Therefore the > /interpretation/ of this timestamp is ambiguous. Thank you! The generation of invalid time stamps is programming bug. > The real problem would be e.g. "2023-10-29 02:30 @Europe/Berlin". This > point in time really exist twice, there is 02A:30 (02:30 UTC+0200) and > 02B:30 (02:30 UTC+0100) in this night of switching back from DST to > normal time! > > So, in general, only using the time zone name may indeed lead to > ambiguous interpretations of timestamps. Exactly! Thank you! With the correction that "this point in time really exists twice" -- well, not like that, you have specified 2 different time points by specifying different UTC offset, so those are different time points. Though I got your ▲ -- Jean Take action in Free Software Foundation campaigns: https://www.fsf.org/campaigns In support of Richard M. Stallman https://stallmansupport.org/