From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mp10.migadu.com ([2001:41d0:8:6d80::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by ms5.migadu.com with LMTPS id CLbnMXss2mMCJQAAbAwnHQ (envelope-from ) for ; Wed, 01 Feb 2023 10:10:19 +0100 Received: from aspmx1.migadu.com ([2001:41d0:8:6d80::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by mp10.migadu.com with LMTPS id sP/xMHss2mNopgAAG6o9tA (envelope-from ) for ; Wed, 01 Feb 2023 10:10:19 +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 579A13F458 for ; Wed, 1 Feb 2023 10:10:19 +0100 (CET) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pN94x-00053C-7H; Wed, 01 Feb 2023 04:06:55 -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 1pN94v-000532-LX for emacs-orgmode@gnu.org; Wed, 01 Feb 2023 04:06:53 -0500 Received: from basilikum.nobis-admin.de ([89.238.71.130]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pN94k-0008QR-5t for emacs-orgmode@gnu.org; Wed, 01 Feb 2023 04:06:53 -0500 From: Stefan Nobis DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=snobis.de; s=default; t=1675242377; bh=+e5B7MQiS4d2e3c5GkbHQRt5QApK1UuKvaXHLxWydbM=; h=From:To:Subject:References:Date:In-Reply-To:From; b=PXTdJ5knsZiW/eL0kXRKbyMAfo5sirZid6XoI1y+R7JIuvOBhEUvld8JL2eyUV4i9 tHCVa06+h1tA6J3r05KHQrDsRV5oQ+H9jzw+Ac8Evo1LSAv2eNPCWsiyJZ+trunoCQ uI8rZ3eZBvjWJ0xn8XfmUKI45aIzTe83MXhsGFWg= To: emacs-orgmode@gnu.org Subject: Re: [POLL] Proposed syntax for timestamps with time zone info References: <87tu0mjb24.fsf@tsdye.online> <63ca1283.170a0220.5bc81.0fdd@mx.google.com> <87pmb9k8oi.fsf@tsdye.online> <3035CDD5-41DD-4516-9E4E-9E0DF16BE2E0@gmail.com> <87lelo8c9r.fsf@localhost> <2150768.1675077958@archlinux> <87tu063ox2.fsf@localhost> <87h6w63jgg.fsf@localhost> Mail-Followup-To: emacs-orgmode@gnu.org Date: Wed, 01 Feb 2023 10:06:15 +0100 In-Reply-To: (tomas@tuxteam.de's message of "Wed, 1 Feb 2023 06:46:10 +0100") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (darwin) MIME-Version: 1.0 Content-Type: text/plain Received-SPF: pass client-ip=89.238.71.130; envelope-from=stefan-ml@snobis.de; helo=basilikum.nobis-admin.de X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham 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-Flow: FLOW_IN X-Migadu-Country: US ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=yhetil.org; s=key1; t=1675242619; 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:in-reply-to:in-reply-to: references:references:list-id:list-help:list-unsubscribe: list-subscribe:list-post:dkim-signature; bh=ahQWFkxKGd4XKXTHpZtdAAcBY9rdWxmMghU9FUL6vB4=; b=K6UPQLXcqJs7HP2z6UgMls6TXK2ufFTgWTX/GikDbgy2h7TinJSwaIwJrtTlwzGOjsSjig CAehMRe7QPx9r+VAhyD09RB6V/JZNo+7b1EYIy1mB09P1WI+pf4aAgVghkqM79QijqCq9m E5OlURmoMLBOC6JCV83LBdzqpHGmfePlffNW/66zyyTSyaRqGFagaDtqabCrJnuMCJQOhi 5pgmeyVnLYmfXYDjqAqoXhuHd9WxH8JdsfApf/qHLk/hCH2rFrfN1LwzBNwbZP6H+3iaIk Fj6Z6qT+yxDxLcSuH/M6o8HGr2ZRMKfjYa7GNa0ad+QG6bH0SE9MjQrJoeVxvA== ARC-Authentication-Results: i=1; aspmx1.migadu.com; dkim=pass header.d=snobis.de header.s=default header.b=PXTdJ5kn; 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=pass (policy=reject) header.from=snobis.de ARC-Seal: i=1; s=key1; d=yhetil.org; t=1675242619; a=rsa-sha256; cv=none; b=BP7ItKycA5ehGUzdtg66Slq/Lr4rw5/IA2SVuY5fuj2FW+ttSl3FNtktbT7GUTivOWHWDW GQhCbHH7fQ02V42AO7JlUj7u7hh0hPKf9m7ZRml9CVIYhhQC8sE5bHUv8u3w/ns9x9aZ0L F+i4bsmVtOLTDU+z74cVGum1Vao7HaDt8cMFESVsEnc1fYCSkIinYz6vAIgzW8Gu7+G5gT yb9ZfTD15rryxvJEOKu0ztqzJKeGk7M2uY3brSVmzPxjeXuOlFqp4cyGrGnakxprgmL2LI j7ndKiv4iKksbA82MYop/8tPB1omdzxIa7Avb3si6UrjYA4BumpnRgmvhxFv6A== Authentication-Results: aspmx1.migadu.com; dkim=pass header.d=snobis.de header.s=default header.b=PXTdJ5kn; 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=pass (policy=reject) header.from=snobis.de X-Migadu-Scanner: scn0.migadu.com X-Spam-Score: -4.38 X-Migadu-Queue-Id: 579A13F458 X-Migadu-Spam-Score: -4.38 X-TUID: UgsTibdi30C2 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. 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. -- Until the next mail..., Stefan.