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Research draft

calendar system

vr.tr.calendar-system · INF.KNW

Let an agent handle calendar systems by type, epoch, rules, conversion and use.

Thing Registry Information and virtual systems

Research draft, second pass

A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.

written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify

Researched by: Claude

Purpose and description

Let an agent handle calendar systems by type, epoch, rules, conversion and use.

A system for organising days into periods such as weeks, months and years, based on solar, lunar or lunisolar cycles, such as the Gregorian, Julian, Islamic, Hebrew, Chinese and traditional calendars.

What it is for: Scheduling, recording dates and religious and civil observances.

It can be convert dates between calendars; compute holidays; understand leap rules; read historical dates correctly.

Distinguishing features

Organises days into cycles

Solar, lunar or lunisolar

Has an epoch and leap rules

Many in parallel use

What it looks like

Tables, almanacs and date notations.

How it is recognised

Calendar names and eras

Month names and lengths

Record-keeping forms such as winter counts

Related models

is a kind of - category

chronology and conceptual system

defines - units

leap year and month

is represented in - standard

ISO 8601

is used for - application

holiday computation

In practice

Families and kinds

solar calendars such as Gregorian

lunar calendars such as Islamic

lunisolar calendars such as Hebrew and Chinese

historical calendars such as Julian

traditional record systems such as winter counts

Standards and regulation

ISO 8601 (Gregorian)

Unicode CLDR calendar data

National laws on official calendars

Failure modes and hazards

Conversion errors

Confusing Julian and Gregorian dates

Lunar calendars depending on sighting

Also called

Lukashian calendarwinter countconsulariaSchreibkalendertraditional calendar in VietnamJulian calendarreligious calendarbiodynamic calendarold calendarDirectoriumDiscordian calendarfastinew calendarfolk calendarcelestial calendarfiscal calendaracademic calendarLukashian calendar for Earthlegislative calendarTelugu calendar13 month calendar12 month calendarcalendar roundunspecified calendarlunar calendarMasonic calendarsolar calendarThai calendarZoroastrian calendarName days in FrancePregnancy CalendarLenten calendartraditional calendar in ChinaGermanic calendarInca calendarcivil calendarliturgical yeardecimal calendarCeltic calendarofficial calendar

+56

Where this came from

wikidata · CC0 1.0

Source repository Registry entry point

Drafted structure

Bundle to layer to finding to question, as the second pass will find it: 4 bundles · 8 layers · 8 findings · 16 questions.

System Which calendar.

Type and rules.

Type

Solar, lunar.

Type

Calendar type.

  1. Which calendar is used, and what kind is it? definition
  2. What is its epoch? provenance

Rules

Months and leaps.

Rules

Rules.

  1. How are months and leap periods determined? definition
  2. Are months fixed or based on sightings? boundary
Conversion Between calendars.

Conversion needs care.

Convert

Algorithm.

Convert

Conversion.

  1. What is this date in another calendar? measurement
  2. Which algorithm or authority? provenance

Historical

Old dates.

Historical

Historical dates.

  1. Was the date recorded in the Julian or another calendar? boundary
  2. When did the region switch? provenance
Observances Holidays.

Calendars define holidays.

Holidays

Dates.

Holidays

Holiday dates.

  1. When does this holiday fall this year? measurement
  2. According to which authority? provenance

Variation

Local differences.

Variation

Local variation.

  1. Does the date vary by region or community? boundary
  2. Why? definition
Software Implementation.

Software must support calendars.

Libraries

Support.

Libraries

Library support.

  1. Which libraries support this calendar? provenance
  2. Is CLDR data used? provenance

Display

Localisation.

Display

Localisation.

  1. How should dates be displayed for this locale? action
  2. Is the calendar shown explicitly? boundary

What the second pass must settle

  • Should each calendar be a separate entry?
  • How should conversion algorithms be linked?
  • How should sighting-based months be handled?
Draft as JSON