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 YHLeCHKd32MRuQAAbAwnHQ (envelope-from ) for ; Sun, 05 Feb 2023 13:13:38 +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 4OoECHKd32MLkgAAG6o9tA (envelope-from ) for ; Sun, 05 Feb 2023 13:13:38 +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 DFDDD13899 for ; Sun, 5 Feb 2023 13:13:37 +0100 (CET) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pOdsn-0008Hl-4c; Sun, 05 Feb 2023 07:12:33 -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 1pOdsh-0008GH-PN for emacs-orgmode@gnu.org; Sun, 05 Feb 2023 07:12:29 -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 1pOdsf-0006ZQ-Ta for emacs-orgmode@gnu.org; Sun, 05 Feb 2023 07:12:27 -0500 Received: from localhost ([::ffff:102.83.69.138]) (AUTH: PLAIN admin, TLS: TLS1.3,256bits,ECDHE_RSA_AES_256_GCM_SHA384) by stw1.rcdrun.com with ESMTPSA id 0000000000055D79.0000000063DF9D2C.00002BE3; Sun, 05 Feb 2023 05:12:27 -0700 Date: Sun, 5 Feb 2023 15:12:00 +0300 From: Jean Louis To: Ihor Radchenko Cc: Ypo , Org-mode Subject: Re: [POLL] Proposed syntax for timestamps with time zone info (was: [FEATURE REQUEST] Timezone support in org-mode datestamps and org-agenda) Message-ID: Mail-Followup-To: Ihor Radchenko , Ypo , Org-mode References: <87lelce6iu.fsf@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: <87lelce6iu.fsf@localhost> 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: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, 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-Country: US X-Migadu-Flow: FLOW_IN ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=yhetil.org; s=key1; t=1675599217; 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: 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=828bYl+j/Muxg0x5nXy3xWjCDaE8zEpakmlB+EpvUHQ=; b=T5YPxg3qPD80Ype+3qUnxKKMJqGeMHUA3aXYh7QwNuvm/MZlGvX0T29D1lM9yGA9QNF+jH gjIy6tUIEc5XfQtouw+XxyQdddBHDYEzSlFrHf25GNc0b3PYNWfVcC9Mq/3gCP1GocGuTc ycuk/rTprtbDUA0oJ3SU4TQqlLcHAxO+3WDIdGOxZ3q+qjmsUWYkKzAYekQ4Djx2XiQ0Vg bSDfGASh1AXa/ry91ve6U+vrOCQL3Xmch3WC51o5+mjTHD56c82nzG1rW3+HTM5GOTbEal yx37A6Qz13g6XFkXofJ/mWHDQ7rLk01OxHhnehF7GuxZt0QWHnatwjelYbi6wg== 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-Seal: i=1; s=key1; d=yhetil.org; t=1675599217; a=rsa-sha256; cv=none; b=PEmXhdLLhaBczQRsvxeZmtd0xgtOOJPYIjHQfzOiwOBazI12zvYqQxEy7FUJVOXwl30OmC zLVyjppocnG2HTF5QIh3LkrFvVx7KrCprrpXQCl8i3yucC2+S1BJaijw9ED9+Jg1gP+mTR 2QdCARlaLSJjOkIFx2lKQg6arFM9STF7gN5mC80swlV137aS7xbjdPCRBD3+MEhWqVInvi 6b8+FWfIFaZMTEXI0uW5iceP7HMByn0M1oWEzacnHqLcE9E5e5m22wZoPtX4ChxLqsdtfl EwhF4V+GIlRZezdPTqNOV9le5jVr9cmTU9aQeuXSdBQ/KiZcknxgRJgKa8+rUw== X-Migadu-Spam-Score: -2.39 X-Spam-Score: -2.39 X-Migadu-Queue-Id: DFDDD13899 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-TUID: h0wxhnxUNZ/2 * Ihor Radchenko [2023-02-05 13:45]: > [2024-02-04 12:00 @-08,America/Vancouver] will use fixed -8 offset What does that mean practically? Provide example for better understanding. - The UTC offset is not certain to remain fixed in the future. - If you do not have the time of creation of the timestamp above, you cannot know with certainty what was the offset in past, to calculate new UTC offset in case it changed - As not even time zone is certain to remain in existence in future, you will need to use time zone, in order to derive that future UTC offset correctly. As it could change in mean time. What is meaning of "fixed -8 offset"? > [2024-02-04 12:00 @-08] will also use fixed -8 offset That type of timestamp does not clearly show the time zone, that one may only be understood as timestamp with UTC offset. UTC time may be derived from such timestamp. That offset should remain fixed, as there is no time zone associated. It is UTC time represented with offset. > [2024-02-04 12:00 @America/Vancouver] will use @America/Vancouver time > zone, as it is be defined in you OS time zone database. If you do not keep UTC offset, you will miss changes in future and generate errors. > [2024-02-04 12:00 @-08,!America/Vancouver] (note "!") will use fixed -8 > offset, but also calculate America/Vancouver time from TZ database, > compare it with the time coming from -8 offset, and warn you if there is > inconsistency. The UTC offset is the log what was the UTC offset at the time point when timestamp was created, as future UTC offset cannot be known. Making it "fixed" does not fix it in real time, you are then introducing something new than what other programs do with time. I do not think that you need "!", you are creating work not necessary for users. If users wish to get some warnings, let them customize single option. Not timestamp by timestamp. -- Jean Take action in Free Software Foundation campaigns: https://www.fsf.org/campaigns In support of Richard M. Stallman https://stallmansupport.org/