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Dye" To: Max Nikulin Cc: emacs-orgmode@gnu.org Subject: Re: [FEATURE REQUEST] Timezone support in org-mode datestamps and org-agenda Date: Fri, 20 Jan 2023 10:37:10 -1000 In-reply-to: Message-ID: <87cz79j5gu.fsf@tsdye.online> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - box2035.bluehost.com X-AntiAbuse: Original Domain - gnu.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - tsdye.online X-BWhitelist: no X-Source-IP: 50.113.33.148 X-Source-L: No X-Exim-ID: 1pIyLD-0031QE-HU X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: cpe-50-113-33-148.hawaii.res.rr.com (poto-foou.tsdye.online) [50.113.33.148]:33420 X-Source-Auth: tsd@tsdye.online X-Email-Count: 2 X-Source-Cap: dHNkeWVvbmw7dHNkeWVvbmw7Ym94MjAzNS5ibHVlaG9zdC5jb20= X-Local-Domain: yes Received-SPF: pass client-ip=69.89.30.42; envelope-from=tsd@tsdye.online; helo=gproxy3-pub.mail.unifiedlayer.com X-Spam_score_int: -15 X-Spam_score: -1.6 X-Spam_bar: - X-Spam_report: (-1.6 / 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, FROM_SUSPICIOUS_NTLD=0.5, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_PDS_OTHER_BAD_TLD=0.01 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-Seal: i=1; s=key1; d=yhetil.org; t=1674247868; a=rsa-sha256; cv=none; b=tnXf02xlDuE0nVCDPu3oI4USBsGjGnCkUhNYDDeOeDHeGP2UGo3EinHrzpuNkbzlcJDRkd 1Cil1QfjYTV9F+J7Q5JqN7iyFWKAlk814DK7hV1UYj8xog3J4U73RKf2FizLYZGFOaiqS6 7fg/tzqeyXZCMZ/34raOsRwzb1sTqD94qBJ4LWgn+A+hK/V484w1sFBhdRPRobRaWMyclR Hu4aity0UchBdOkRVSE4+vMjBKuV5XH70LI5ygb/fjKUtpVGrVMx7Y5marZPTxFEMSK5+5 8sChllZMyO5jJyNnGZ/b1zRmOwBWhP+Ekebug2IrOC51fPfETXOjjL6SUloCFg== ARC-Authentication-Results: i=1; aspmx1.migadu.com; dkim=fail ("headers rsa verify failed") header.d=tsdye.online header.s=default header.b=OYlB0qOt; dmarc=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-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=yhetil.org; s=key1; t=1674247868; 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:dkim-signature; bh=jM3t8cM+z9RqSkDSUDawHxk5c3l9jRKOaEl/eJ2e8aw=; b=T6xB4IlB3Ev1iAL44XfRHp+86Df84cB25+X3eSubGskazpGvkDGCKQx3v4OfjUEQzTciIn ICpe5qT4WEsvARlPOqg19spGf4/NKvknhTj5zP6m6ws4ZzKhXzW/rN17ISdsvQZ6joc+SW xURNZAmnD8umKpEk4+Oj3rPNnLbk2mAb3LUYy8fJKjxiR3FmuIwuauYaiZCugxbTRKOTsZ cSUTPF/BNjjUDsKLGIst7h0iga/Brx17X5ehoyu5S4y1Cw/ee2hydhpyamPu18BOxPx6Hg lXi6b5Ldf2rVYUhq3mrqFoJNuZq22dB9zuk90LLjHHjCVH0hp4zftqQJZLfaig== X-Spam-Score: 1.79 X-Migadu-Queue-Id: CE5A52A21C Authentication-Results: aspmx1.migadu.com; dkim=fail ("headers rsa verify failed") header.d=tsdye.online header.s=default header.b=OYlB0qOt; dmarc=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-Scanner: scn0.migadu.com X-Migadu-Spam-Score: 1.79 X-TUID: du2aj1HBiZqs Aloha Max, Max Nikulin writes: > On 20/01/2023 23:09, Thomas S. Dye wrote: >> Max Nikulin writes: >> Now, if Amsterdam's timezone=20 >> arbitrarily changes its relation to UTC before the conference=20 >> takes place, >> then everyone who participates in the conference must notice=20 >> this (or miss the >> start of the conference). > > My point is that if timestamp is stored in UTC than it becomes=20 > incorrect in the > case of time offset change. If such timestamp is stored as local=20 > time + time > zone identifier then application presenting the timestamp to=20 > users will show > correct time as soon as zoneinfo data is updated. > >> A virtual conference is organized by someone in Amsterdam, who=20 >> sets a start >> time corresponding to 9AM in Amsterdam at a date some years in=20 >> the future and >> invites participants from all over the world.=C2=A0 Now, if=20 >> Amsterdam's timezone >> arbitrarily changes its relation to UTC before the conference=20 >> takes place, >> then must everyone notice this?=C2=A0 Or, should Org, from the time=20 >> the arbitrary=20 >> change is made public, simply adjust the conference time for=20 >> all the >> participants in the Amsterdam timezone? > > Both variants are possible and a planning application should=20 > support them. It is > matter of negotiation between the committee and the=20 > participants. Timestamp > should be stored in UTC only in one case. Agreed. So, IIUC, there are three cases: 1) Occurrence, where the timestamp includes UTC; 2) Event relative to user, where the timestamp does not include=20 UTC or a time zone; and=20 3) Event not relative to user, where the timestamp includes the=20 relevant time zone. For completeness, Case 3 might benefit from a procedure to change=20 the relevant time zone. For instance, when the boss has scheduled=20 time for you at 9:00 AM her time, but doesn't know where she will=20 be on that day. hth, Tom --=20 Thomas S. Dye https://tsdye.online/tsdye