From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mp11.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 qOeaL5Njz2MyVQAAbAwnHQ (envelope-from ) for ; Tue, 24 Jan 2023 05:50:27 +0100 Received: from aspmx1.migadu.com ([2001:41d0:2:4a6f::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by mp11.migadu.com with LMTPS id EOilL5Njz2Nd+gAA9RJhRA (envelope-from ) for ; Tue, 24 Jan 2023 05:50:27 +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 9363EC378 for ; Tue, 24 Jan 2023 05:50:24 +0100 (CET) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pKBEz-00014H-Hq; Mon, 23 Jan 2023 23:49:01 -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 1pKBEx-0000p9-V4 for emacs-orgmode@gnu.org; Mon, 23 Jan 2023 23:48:59 -0500 Received: from ciao.gmane.io ([116.202.254.214]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pKBEw-00058a-89 for emacs-orgmode@gnu.org; Mon, 23 Jan 2023 23:48:59 -0500 Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1pKBEa-0007wz-Pw for emacs-orgmode@gnu.org; Tue, 24 Jan 2023 05:48:36 +0100 X-Injected-Via-Gmane: http://gmane.org/ To: emacs-orgmode@gnu.org From: Max Nikulin Subject: Re: UTC or not UTC for timestamps in the past ([FEATURE REQUEST] Timezone support in org-mode) Date: Tue, 24 Jan 2023 11:48:30 +0700 Message-ID: References: <87lelxk87a.fsf@tsdye.online> <63ca5101.630a0220.b2298.3363@mx.google.com> <63cb2d0b.630a0220.f919a.6174@mx.google.com> <63cc5983.620a0220.a7d40.68f6@mx.google.com> <87r0vnhxj6.fsf@tsdye.online> <87ilgyiid8.fsf@tsdye.online> <87edrli4sr.fsf@tsdye.online> <871qnkiqwu.fsf@tsdye.online> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.2 Content-Language: en-US In-Reply-To: <871qnkiqwu.fsf@tsdye.online> Received-SPF: pass client-ip=116.202.254.214; envelope-from=geo-emacs-orgmode@m.gmane-mx.org; helo=ciao.gmane.io X-Spam_score_int: 16 X-Spam_score: 1.6 X-Spam_bar: + X-Spam_report: (1.6 / 5.0 requ) BAYES_00=-1.9, DKIM_ADSP_CUSTOM_MED=0.001, FORGED_GMAIL_RCVD=1, FORGED_MUA_MOZILLA=2.309, FREEMAIL_FORGED_FROMDOMAIN=0.149, FREEMAIL_FROM=0.001, HEADER_FROM_DIFFERENT_DOMAINS=0.248, NICE_REPLY_A=-1.147, NML_ADSP_CUSTOM_MED=0.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 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-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=yhetil.org; s=key1; t=1674535824; 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=OYKxEIZ2E58wLWTsAyOaLNBPG6JFDLeUEs3vmPAB59Q=; b=qOpOpAA6bHTiGgWv9KqMpy+nyjanKeS3Dc0ElgtwQJ0xk2pxbEQg/F2XPf3ohFc16VRuy5 XBEUOQKFb1ZE5HHUjwS8/3iqtdx2LER5zhMx5Lmjc7v5pxUcAXT6OH5v3NAe3qU0K9+LWA prc4Mc4eRdf2yKsp4aOjTAUX5S2A0PEyO8TsTIm8f6zAgmzQPp9jdfqEKMyQdynWO2H1t0 +oDO1/mBrmR7aDE3rDMGpGTtcbXG2ItGCTOCq5NFsWFonutLFW+imqyF857ylY/gvS+LO9 icX21GiwBOcx+3JjedV0CLKas3TFzykBdNHMVpu3/79X2XF7JzZZ6FFdejeTvA== ARC-Authentication-Results: i=1; aspmx1.migadu.com; dkim=none; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=gmail.com (policy=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" ARC-Seal: i=1; s=key1; d=yhetil.org; t=1674535824; a=rsa-sha256; cv=none; b=u48MAvh+QJxMxGQg3JFrunAWsyzOkHPBhWZ4n1wsvF2OVMS2sC4nfO28N9kjDr7EcBuCJ5 320AGgFODzHpW69VtefPsEZd2TaQYJTzdqqlU5u0xyQJ0R69LiNSes6CXeuvwHWypTwc74 t93r+KtKBueP7W+pXnV5lpNnpWQ155NmSVb0l5SDvFZGTxZHJ4m08eVX36Mxm4OvCOnR9r nUOIn8OTfS0ZHMauzL+V5HhUYenvIoFeePsiTZjaFM4mAJcxy3/7d5EYJckCju0O5+oxVY cL3oCU79YNunTRZXG8/dVB8Uhjdsbm8x3JbWOMQAMzvGlezd2O07NKnVfn8HzQ== Authentication-Results: aspmx1.migadu.com; dkim=none; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=gmail.com (policy=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" X-Migadu-Spam-Score: -0.79 X-Spam-Score: -0.79 X-Migadu-Queue-Id: 9363EC378 X-Migadu-Scanner: scn1.migadu.com X-TUID: I8SSOknzm8/k On 24/01/2023 09:44, Thomas S. Dye wrote: > Max Nikulin writes: >> >> I believed that [2023-01-22 Sun 08:29@+1100] unambiguously suggests >> offset from UTC. > > Not for a casual programmer like me. The timestamp alone might easily be > read as 11 hours ahead of local time. Nevertheless, Org is certainly > free to interpret it as relative to UTC. My primary concern is that I might be wrong assuming that format like [2023-01-22 Sun 08:29@+1100] with offset in respect to UTC is reciprocal identity mapping to UTC. Of course there are a lot of people unaware of UTC. Org users may be educated by the manual and by hints in UI pushing toward time fixed in respect to UTC when "global" timestamp should be added. (In the sense of e.g. Lunar eclipse or an on-line meeting, not to confuse with set of events appointed on specific date but starting at the same local time in each location). I am afraid of confusion with repeater intervals, but syntax has not fixed yet. So we had different types of ambiguity in mind. Base time for offset was unclear for you, I was writing about mapping to UTC. Your point should be taken into account during consideration of storage format. I still believe that something like [2023-01-21 Sat 21:29:00Z] and [2023-01-22 Sun 08:29@+1100] may be used to store timestamps interchangeably. >> Are there local references that may confuse users? I mean something >> like 9 hours >> ahead of Moscow (Asia/Kamchatka) used in USSR. > > I think 9 hours ahead of a timezone with a potentially variable offset > from UTC has the potential to sow confusion, yes. If someone has examples of local time offsets (unrelated to UTC) widely used in some area, please, post them. MSK+3 style was not a real issue because daylight saving time was active during the same period in the whole country and iron curtain was efficiently isolating most of people form variety of DST rules in other areas.