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 2EhjK5ioxWMFcAEAbAwnHQ (envelope-from ) for ; Mon, 16 Jan 2023 20:42:16 +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 eBSeKpioxWN6fQEAG6o9tA (envelope-from ) for ; Mon, 16 Jan 2023 20:42:16 +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 613CB2F5AD for ; Mon, 16 Jan 2023 20:42:16 +0100 (CET) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pHVMP-0008R0-5A; Mon, 16 Jan 2023 14:41:38 -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 1pHVMM-0008Qk-Nl for emacs-orgmode@gnu.org; Mon, 16 Jan 2023 14:41:35 -0500 Received: from mout02.posteo.de ([185.67.36.66]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pHVMI-0003Ck-8U for emacs-orgmode@gnu.org; Mon, 16 Jan 2023 14:41:33 -0500 Received: from submission (posteo.de [185.67.36.169]) by mout02.posteo.de (Postfix) with ESMTPS id 24FD124012E for ; Mon, 16 Jan 2023 20:41:27 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=posteo.net; s=2017; t=1673898088; bh=4lZLpbaME3trjIrnY+mba2yY3m+UwUwAb74zYKUpwA4=; h=From:To:Cc:Subject:Date:From; b=CvyCZQ4TFT6GvuhNgxX9+Rra/ybSgFbszO0DSCD3if5f0CY7ko0su6vEAe79xA8zf bUs0QjVj3lgiJpthnu0lw1uVerWz2Aa2axrk3y2htUipQjTlBktRfb6IbXNkfT6rRj mZYz5NYetcZvlS2+gdtyputX1pd3fjlexy8scgRcwiXEFyh+8ZjDfYxTU4RFfFwogH ln6M/y65Eb2HGlwuOqTeNRBTTdv0NPwPXqtTrn7qIXUWurR24r0V2GEJhuLJ+0VNRS ZSOZIWqp3rOVKU9SApJs1y73ymFYH0b6Foakn1kn62DctWnLG9mLpWYH2rQ9DiQ9aY RMNtAZWDVlw/w== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4Nwj7q2Lhhz6tmJ; Mon, 16 Jan 2023 20:41:27 +0100 (CET) From: Ihor Radchenko To: rjhorn@alum.mit.edu Cc: Daryl Manning , emacs-orgmode@gnu.org Subject: Re: [FEATURE REQUEST] Timezone support in org-mode datestamps and org-agenda In-Reply-To: References: <86zgamtv6o.fsf@gmail.com> <87tu0t1i0c.fsf@localhost> <63c2aa9e.170a0220.3bb49.9ef4@mx.google.com> <87pmbhz1x6.fsf@localhost> <87wn5mlo7f.fsf@localhost> <87pmbelnd0.fsf@localhost> <87fscajo2q.fsf@localhost> Date: Mon, 16 Jan 2023 19:41:53 +0000 Message-ID: <87cz7ejmgu.fsf@localhost> MIME-Version: 1.0 Content-Type: text/plain Received-SPF: pass client-ip=185.67.36.66; envelope-from=yantar92@posteo.net; helo=mout02.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, RCVD_IN_MSPIKE_H2=-0.001, 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=1673898136; a=rsa-sha256; cv=none; b=Hj9xkoiTiGtm7kv5cGYEFBB/lQMTqJxsHDcj8AMl56RTSLMPfOb+ToWiHtWqQLeYOrbMq+ GjLpUvLnHcARgd1o/E//2lc4BMwlQv5RC52P6XezJiyWRJ9QgzPSUTO8DlEa0LDJvea8Bz Vg5DFw7rYGZBg+IE6vPGa1CuijU6si4Ot8NnVTHVGBiUf4cWzSZGhf4PzWLgXwaOLo/mpd ACu8pcbXu/EZoSLEiL56kBBz41N6RJi5q2zzmP9XdGaZooO/A42Q0O8Q6zgSFEovnmsv66 a6txRmxQZ2MwjSd+KpQIkKOxWW2pJrKRJI3kqj9qpcsk7xuH/qnHMfUrk4bHZA== ARC-Authentication-Results: i=1; aspmx1.migadu.com; dkim=pass header.d=posteo.net header.s=2017 header.b=CvyCZQ4T; 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=1673898136; 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=QzS58Him97U1FEs/F4F/TDia3LyG7/XQ+/OGOwk07KU=; b=Q3oTbJ9mR+8T0uaLL/a8m9nG12JmN3Et/1ajb7T636glXyMWDCiyTJdDhtKgUeTmWR1QA8 xMOU2UZKrZtCpXmsZW2UBYzCKeatLkEmIDKTeGl87MCgSX5DPJc6em9X/rZZRDt3WdtivT 3LdsWpiEu0Xp+ZxEcHRPP5cGaTHA2ktRCBCGLc9hm92TLu5cVjwoVNwtYeQU496s008DXT ++uFN6TsIla8ERn46WS+Gv6TkppcWGxec7FRQHZLAThAhgyIo/08F9ePHaSrg7JFZbh83V 0WhGFpdVlMaLsbV86ceHrLEMf+B5b0aONpqV7P+M2bKAXEAtnyTV7Ecb241etQ== X-Migadu-Spam-Score: -4.57 X-Spam-Score: -4.57 X-Migadu-Queue-Id: 613CB2F5AD X-Migadu-Scanner: scn1.migadu.com Authentication-Results: aspmx1.migadu.com; dkim=pass header.d=posteo.net header.s=2017 header.b=CvyCZQ4T; 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-TUID: 1pHb7+9c1/4R Robert Horn writes: >> 1. Time (YYYY-MM-DD HH:MM) not continuous and may change arbitrarily at >> certain times a year or in future or in the past: >> - DST transitions are not stable and change from year to year >> according to strange rules that may involve Julian dates or >> counting weekdays >> - DST transition rules may change over time >> - The new year day itself is not necessarily fixed (England >> - Julian/Gregorian transitions happened at different times in >> different countries > > Note that as a result "time when it happened" has different rules than > "future time when it is scheduled". There are lots of other times that are > scheduled as "future local time, subject to changing DST rules". This > is particularly tricky for repeating times for regularly scheduled events. Not really. Countries may change DST at any moment in future. Or decide to switch calendars (consider countries near the day transition line). And "past local time, according to the DST rules in effect at the time" is also an option that might be useful in certain scenarios. >> 5. Leap seconds! 23:59:59 -> 23:59:60 -> 00:00:00, according to >> astronomical Earth observations > > Fortunately, the most recent vote reached majority for eliminating leap > seconds, hopefully within 8 years. But we will have to keep supporting all the leap seconds that already happened! So it does not really help all that much wrt timestamp design. -- Ihor Radchenko // yantar92, Org mode contributor, Learn more about Org mode at . Support Org development at , or support my work at