EDTF

[10] EDTF は、曖昧性を含む日時や期間の記述形式です。

[11] 2012年に米国議会図書館によって制定されました >>1。

[12] その後 ISO に提出されて非互換変更が加えられ、 2019年2月に ISO 8601-2:2019 の一部として出版されました >>9。

仕様書#✎

[18] >>5 昔はもっとちゃんとした仕様書があったのに ISO 版 (有料) が出版されて削除されてる。普及させたいのかさせたくないのかわからん。

歴史#✎

[8] オリジナル版 >>1 と ISO 版 >>9, >>5 で非互換変更があって問題となりました >>6, >>7。

[1] Extended Date/Time Format (EDTF) 1.0 Submission ( (9/11/2012, 3:28:54 PM 版)) http://www.loc.gov/standards/datetime/pre-submission.html

[2] Extended Date Time Format (Library of Congress) ( (10/31/2012, 1:06:22 PM 版)) http://www.loc.gov/standards/datetime/

[3] Top-level Elements and Attributes (MODS Ver. 3 User Guidelines: Metadata Object Description Schema, Library of Congress) (7/21/2016, 9:48:40 PM) https://www.loc.gov/standards/mods/userguide/generalapp.html

edtf – This value is used for dates coded according to Extended Date/Time Format which in consistent with ISO 8601 but extends it to express special forms of dates that are not covered by w3cdtf and iso8601, such as open ended ranges.
<dateOther encoding="edtf">unknown/2009</dateOther>

[4] Extended Date Time Format (Library of Congress) (9/16/2015, 1:24:55 PM) http://www.loc.gov/standards/datetime/

[6] biblatex/CHANGES.md at dev · plk/biblatex (5/8/2019, 9:06:17 AM) https://github.com/plk/biblatex/blob/dev/doc/latex/biblatex/CHANGES.md#release-notes-for-version-310

The recent ISO8601:201x standard supersedes the draft EDTF (Extended Date Time Format) extensions. Biblatex therefore now supports the ISO8601-2 Clause 4, Level 1 Extended Format which is equivalent to the draft EDTF standard but with different syntax. This syntax is in some cases not backwards compatible. Biblatex will not support backwards compatibility for the draft EDTF syntax because it is too messy to do so and few people were using this anyway since it is a relatively new and specialised feature.

[7] Datetimes. The draft ISO 8601-201x and EDTF. · Issue #656 · plk/biblatex (5/8/2019, 9:14:31 AM) https://github.com/plk/biblatex/issues/656

[13] GitHub - inukshuk/edtf.js: Extended Date Time Format (ISO 8601-2 / EDTF) Parser for JavaScript, 3/1/2021, 4:39:29 AM https://github.com/inukshuk/edtf.js

[14] Year zero not treated as a leap year · Issue #21 · inukshuk/edtf.js · GitHub, 6/28/2022, 2:55:32 AM https://github.com/inukshuk/edtf.js/issues/21

[15] >>14 これ ISO 8601暦への理解も JavaScript Date への理解も不十分なままライブラリー作っちゃったってことなのかなあ (まあ作り始めた当時の EDTF が ISO 8601暦だったのかどうかは知らんが)、不安感あるなあ

[16] 未修正のまま何年も放置されてるのがやばい

[17] season range not recognized · Issue #12 · inukshuk/edtf.js · GitHub, 6/28/2022, 3:04:45 AM https://github.com/inukshuk/edtf.js/issues/12