From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mp1 ([2001:41d0:2:4a6f::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by ms11 with LMTPS id QHAHB7dJ1l+kRQAA0tVLHw (envelope-from ) for ; Sun, 13 Dec 2020 17:04:55 +0000 Received: from aspmx1.migadu.com ([2001:41d0:2:4a6f::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by mp1 with LMTPS id 4JvHArdJ1l/oVwAAbx9fmQ (envelope-from ) for ; Sun, 13 Dec 2020 17:04:55 +0000 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 8B27B9403CB for ; Sun, 13 Dec 2020 17:04:54 +0000 (UTC) Received: from localhost ([::1]:38372 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1koUnl-0004cO-Fw for larch@yhetil.org; Sun, 13 Dec 2020 12:04:53 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:51270) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1koUmp-0004bE-RM for emacs-orgmode@gnu.org; Sun, 13 Dec 2020 12:03:55 -0500 Received: from static.214.254.202.116.clients.your-server.de ([116.202.254.214]:45576 helo=ciao.gmane.io) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1koUmo-0005m6-7L for emacs-orgmode@gnu.org; Sun, 13 Dec 2020 12:03:55 -0500 Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1koUmj-0006us-RR for emacs-orgmode@gnu.org; Sun, 13 Dec 2020 18:03:49 +0100 X-Injected-Via-Gmane: http://gmane.org/ To: emacs-orgmode@gnu.org From: Maxim Nikulin Subject: Re: org-table change time from UTC to other timezones Date: Mon, 14 Dec 2020 00:03:35 +0700 Message-ID: References: <87wnxrjjl2.fsf@gmail.com> <87lfe5ju0t.fsf@gmail.com> <871rfuvdh9.fsf@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 In-Reply-To: Content-Language: en-US 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: 28 X-Spam_score: 2.8 X-Spam_bar: ++ X-Spam_report: (2.8 / 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=0.25, FREEMAIL_FROM=0.001, HEADER_FROM_DIFFERENT_DOMAINS=0.249, NICE_REPLY_A=-0.001, 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: 2.1.23 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" X-Migadu-Flow: FLOW_IN X-Migadu-Spam-Score: -1.70 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@gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=emacs-orgmode-bounces@gnu.org X-Migadu-Queue-Id: 8B27B9403CB X-Spam-Score: -1.70 X-Migadu-Scanner: scn1.migadu.com X-TUID: gk59RGg8WmGe 2020-12-13 Alan E. Davis wrote: > > I think R would not be too unwieldy as a hammer here.  My use case  is a > humble one: just take a several clock times in HH:MM format (utc) and > adjust to  another timezone by adding or subtracting the relevant number > of hours.  The day of week is not important; i will have to deal with > it.  I did imagine a conditional subtraction by adding of subtracting > 24:00 as needed. Likely your approach is suitable for you and you could ignore my comments. I just live in a city having longitude that should be (and it was) the border between time zones, so majority do not like any decision. Since cancellation of DST 10 years ago, local time has been shifted 2 times... To get time offset for some timezone, it is necessary to specify timestamp, so a date is required in addition to time. Namely day of week is mostly irrelevant. Time transitions are usually arranged at night when most of people are not active. Astronomers is a different case, that is why their chance to face a timezone bug is higher. When operations with arbitrary time zones are not required and a process could be run with TZ variable set to desired time zone, libc functions should work correctly. I have not tried elisp functions https://www.gnu.org/software/emacs/manual/html_node/elisp/Time-Zone-Rules.html A bookmark for those who still hopes to avoid complications with time-related operations Falsehoods programmers believe about time https://infiniteundo.com/post/25326999628/falsehoods-programmers-believe-about-time