From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mp12.migadu.com ([2001:41d0:2:bcc0::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by ms5.migadu.com with LMTPS id SAlcOd0n2WMpFQAAbAwnHQ (envelope-from ) for ; Tue, 31 Jan 2023 15:38:22 +0100 Received: from aspmx1.migadu.com ([2001:41d0:2:bcc0::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by mp12.migadu.com with LMTPS id 4FgaOd0n2WNlhAAAauVa8A (envelope-from ) for ; Tue, 31 Jan 2023 15:38:21 +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 93F6036332 for ; Tue, 31 Jan 2023 15:38:21 +0100 (CET) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pMqxj-0004JV-UP; Tue, 31 Jan 2023 08:46:15 -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 1pMqxh-0004JE-GC for emacs-orgmode@gnu.org; Tue, 31 Jan 2023 08:46:13 -0500 Received: from mout01.posteo.de ([185.67.36.65]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pMqxd-00071Q-Fb for emacs-orgmode@gnu.org; Tue, 31 Jan 2023 08:46:13 -0500 Received: from submission (posteo.de [185.67.36.169]) by mout01.posteo.de (Postfix) with ESMTPS id 6E61124018B for ; Tue, 31 Jan 2023 14:46:05 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=posteo.net; s=2017; t=1675172767; bh=Mq765P1mgK5yrBr8nQhdzpTCPsF8fgo2DzsZF9g5x88=; h=From:To:Cc:Subject:Date:From; b=d20pwRdb4MGV2F5VrzABgU4JvJTEm2VwD/5sNMY1aQKTfjyrdZvLCzxMKctUA/CoR vPWlylbjnqd3N9BEbaA7X8PTNG2rkB+QOSTcZnbGtnnnd7EAQmm6/ml2Bm63C1oYSf 8yyyHvMtxxrcscA1Tx3h6T2pUqlm5W857zhebmtSd1MDP2UH26BO1E7+mgrqC6rjTH hcayejHAAZe7/yjpO0fdLR26gND/j1Zx/5g0Z9vkf3OrXWJYW6zDY7VXlZyVsRQUV2 WGOcRAnsCKftgaHyrOaOtl873f8j1OU2C+kWc2PumYshVhjgvKxvy5xdxNT+7mB0f5 SolKy6QGG0AEQ== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4P5mXq2Wy8z9rxK; Tue, 31 Jan 2023 14:46:03 +0100 (CET) From: Ihor Radchenko To: Jean Louis Cc: Greg Minshall , Sterling Hooten , "Thomas S. Dye" , Tim Cross , Daryl Manning , rjhorn@alum.mit.edu, emacs-orgmode@gnu.org Subject: Re: [POLL] Proposed syntax for timestamps with time zone info (was: [FEATURE REQUEST] Timezone support in org-mode datestamps and org-agenda) In-Reply-To: References: <63c9b654.170a0220.d82d2.4254@mx.google.com> <87mt6e86sr.fsf@tsdye.online> <63c9d976.620a0220.a7d40.113b@mx.google.com> <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> Date: Tue, 31 Jan 2023 13:46:39 +0000 Message-ID: <87h6w63jgg.fsf@localhost> MIME-Version: 1.0 Content-Type: text/plain Received-SPF: pass client-ip=185.67.36.65; envelope-from=yantar92@posteo.net; helo=mout01.posteo.de X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 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, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=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-Country: US X-Migadu-Flow: FLOW_IN ARC-Seal: i=1; s=key1; d=yhetil.org; t=1675175901; a=rsa-sha256; cv=none; b=qR1aJT6abGBBRCZG6Ilx9HjmLxVsfl7khY/5kVomrzsksixcBCGepc5Dq9kOZSW/3yizUq aYklGbBLX4ySxdXEMb1d7DtGRYj4uak8LnWQygV/DbsuxZzcUy1qKgQ1bk7DsjpzNpHl/z lTAxEZrGDgpfysyUnYpgg764yqLFYQ3JnoT6YE3gkJSaPjy12r8cUUORHMEbbgM3XjjQD/ of7/r9ZUUqSoB+9n8IGGQdJYv7GuamNHjOdDe4VNf7BfOAjIcDDwrju7Al2q9uPw205r4n ZzIcUFTmTAuXw+y2/50ab4R48spBTwPzEcH12qpr1KBFNzCRb/uyI7brcm1lEg== ARC-Authentication-Results: i=1; aspmx1.migadu.com; dkim=pass header.d=posteo.net header.s=2017 header.b=d20pwRdb; 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=none) header.from=posteo.net ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=yhetil.org; s=key1; t=1675175901; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc: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=NVbT2M33V4lWWfVpAU9Z/vJuuOHFmarI+vy5oeCPJ2c=; b=sFGxeFL4+jikBa9yNLep8udYJaeh7yQ85mCYBOzz5JvkhHlXSpRZJFgJhdVeX159NqbkKw eE6s7mlu36QZ+JH7zXqYhQXcRCqMQgQzoYYl8VAUNG7Bi8+aeoJNPyFr7ftI1OzzMPl/5o IMf/qos26e9/DqBMBFnRwoVB7eaTyv5DwRK2t6Kw8bW6bqJfZ/D5WgcNF9u5NFKlsIDrN0 wMGM86PFZbvI9A5ejy1q8NX72ye80vv91uFixv2CBbSmhUOkne6al968tB2YUYsqKqlZGp ewQaTHvGhskM+3pMmcsQ0ZcQ2OdB9yYrBVgz99RTcbodBKaLXm6q+UnyYGfi5g== Authentication-Results: aspmx1.migadu.com; dkim=pass header.d=posteo.net header.s=2017 header.b=d20pwRdb; 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=none) header.from=posteo.net X-Migadu-Scanner: scn1.migadu.com X-Migadu-Spam-Score: -4.54 X-Spam-Score: -4.54 X-Migadu-Queue-Id: 93F6036332 X-TUID: /u8vWLuWcGBl Jean Louis writes: >> For time ranges, we will only allow a single offset and time zone >> specifier for both start and end times: >> [2022-11-12 8:00-9:00+08] >> If different time zones are necessary to specify the start/end times, >> users can still use full timestamp range syntax >> [2022-11-12 8:00+03]--[2022-11-12 22:00+08] > > I have already explained today that above calculation cannot be > unambigous. Please verify my references and practical examples. When > user thinks that span is X hours, the real span could be X-1 or X+1 This has been discussed in the previous emails. Consider that you are running a scientific experiment around daylight saving time change: [2022-10-29 2:15-5:15+02]. You don't care that the government decided that the wall clock should go like 2:15 -> 2:59 -> [CEST -> CET] 2:00 -> 2:15 -> 2:59. Physics does not care. You just need to make sure that the experiment runs exactly 3 hours without trying to consider the currently used TZ rules. In contrast, writing [2022-10-29 2:15-5:15 @Europe/Berlin] is ambiguous as it may imply both 2:15CEST-5:15CET (4 hours) or 2:15CET-5:15CET (3 hours). Specifying just @Europe/Berlin is ambiguous around the daylight savings transition. To resolve the ambiguous, we should either introduce DST flag or simply allow specifying the UTC offset directly. Since DST is not guaranteed to be +-1 hour (it may be more, up to 1 full day), DST flag is more problematic than UTC offset. -- Ihor Radchenko // yantar92, Org mode contributor, Learn more about Org mode at . Support Org development at , or support my work at