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ReferenceTime and calendar

LanguageValues and typesStandard typesTime and calendar

RecurrenceRule

On this page

When something repeats, in the calendar standard's own text.

Use it for repeating events, such as every Monday at 09:30. temporal.occurrences gives the next ones. For a shop's weekly hours, use OpeningHours.

Shape

One value, held as text in one set form, with no parts: DTSTART;VALUE=DATE:20240229 RRULE:FREQ=YEARLY.

Example

example
RecurrenceRule("DTSTART;TZID=Europe/London:20261026T093000\nRRULE:FREQ=WEEKLY;BYDAY=MO")

RecurrenceRule(raw) checks the text, and text that isn't one breaks the format rule.

text.parse(raw, as: RecurrenceRule) reads one from text that comes from outside. Text that isn't one at all fails malformed, such as FREQ=WEEKLY;BYDAY=MO.

Good to know

  • It holds its first time on one line and its rule on the next, with the zone in the first, so daylight saving is kept right.
  • == tells you whether two are the same. < and list.sort_by don't take it.

In JSON

A string, in a request, a response or json.write:

json
"DTSTART;TZID=Europe/London:20261026T093000\nRRULE:FREQ=WEEKLY;BYDAY=MO""DTSTART;TZID=America/New_York:20260310T090000\nRRULE:FREQ=MONTHLY;BYDAY=2TU;COUNT=12""DTSTART;TZID=Europe/London:20260130T170000\nRRULE:FREQ=MONTHLY;BYDAY=-1FR;UNTIL=20261231T235959Z"

Details

Text form, storage, how it is shown, and operations

RecurrenceRule is in the group Time and calendar, and has been in Jadpo since 0.1.0.

Text form

text.from writes one standard text form, the same form text.parse reads back: DTSTART;TZID=Europe/London:20261026T093000\nRRULE:FREQ=WEEKLY;BYDAY=MO, DTSTART;TZID=America/New_York:20260310T090000\nRRULE:FREQ=MONTHLY;BYDAY=2TU;COUNT=12 and DTSTART;TZID=Europe/London:20260130T170000\nRRULE:FREQ=MONTHLY;BYDAY=-1FR;UNTIL=20261231T235959Z.

How it is stored

It is stored in one column named for the field, of type text. DTSTART;TZID=Europe/London:20260130T170000\nRRULE:FREQ=MONTHLY;BYDAY=-1FR;UNTIL=20261231T235959Z is stored as E'DTSTART;TZID=Europe/London:20260130T170000\nRRULE:FREQ=MONTHLY;BYDAY=-1FR;UNTIL=20261231T235959Z'.

How it is shown to people

text.format(value, locale:) shows it to people in their locale.

With locale: Locale.en_gb:

Value Shown
"DTSTART;TZID=Europe/London:20261026T093000\nRRULE:FREQ=WEEKLY;BYDAY=MO" "DTSTART;TZID=Europe/London:20261026T093000\nRRULE:FREQ=WEEKLY;BYDAY=MO"
"DTSTART;TZID=America/New_York:20260310T090000\nRRULE:FREQ=MONTHLY;BYDAY=2TU;COUNT=12" "DTSTART;TZID=America/New_York:20260310T090000\nRRULE:FREQ=MONTHLY;BYDAY=2TU;COUNT=12"
"DTSTART;TZID=Europe/London:20260130T170000\nRRULE:FREQ=MONTHLY;BYDAY=-1FR;UNTIL=20261231T235959Z" "DTSTART;TZID=Europe/London:20260130T170000\nRRULE:FREQ=MONTHLY;BYDAY=-1FR;UNTIL=20261231T235959Z"
"DTSTART;VALUE=DATE:20240229\nRRULE:FREQ=YEARLY" "DTSTART;VALUE=DATE:20240229\nRRULE:FREQ=YEARLY"

Operations

  • temporal.occurrences(rule: RecurrenceRule, from: T, count: Int) -> List<ZonedTime>: The next count occurrences of rule at or after from, in its zone (RFC 5545): fewer when the rule ends first; count is from 1 to 1000, so an unbounded rule is never expanded without a bound. From a date, the days they fall on, List<CalendarDate>, which a rule on dates gives; from an Instant, a timed rule's local times.

It also takes text.parse, text.from, text.format, json.read, json.write and ==. How every standard type behaves says how they work.

Related

Markdown for agents: /docs/types/type-recurrence-rule.md.Built from Jadpo main at aee2e8f.