The calendars that ship as lookup tables generated by mix dayoff.sync:
Hijri and Hebrew (from the reference parser's own tables), the Chinese,
Korean and Vietnamese lunisolar calendars with their solar terms, and the
equinox and solstice dates. Each file is decoded once into
:persistent_term.
Outside a table's range a lookup returns no dates and logs a warning once, where the reference implementation stays silent.
Summary
Functions
The local calendar date of an equinox or solstice in a timezone, as
"MM-DD". Fixed offsets ("+09:00") and the named zones the rules use
are precomputed by the sync.
The Gregorian date of a lunar date in the lunar year that starts in the
Gregorian year, as the reference date-chinese computes it: a leap month
request takes the month after the regular one, and day may run past the
month (day 0 is the eve of the month). The table also carries the days
where the reference's own round trip through its lunar labeling lands a
day off from "day 1 plus the offset" (a handful per year, 2033 among
them), so those match too.
The dates of day of month in a mapped calendar that fall in the
Gregorian year, the way the reference CalEventMap.inYear finds them:
scanning the month's first days in the neighbouring Gregorian years,
keeping the ones that land in year, and only the given calendar year
when one is asked for. A month can start twice in one Gregorian year.
The Gregorian date of day of solar term term (1 is Lichun at 315°,
5 is Qingming) as solarTerm(term, year) in date-chinese gives it.
Types
Functions
The local calendar date of an equinox or solstice in a timezone, as
"MM-DD". Fixed offsets ("+09:00") and the named zones the rules use
are precomputed by the sync.
iex> Dayoff.Calendar.Tables.equinox(:march, 2026, "+09:00")
~D[2026-03-20]
iex> Dayoff.Calendar.Tables.equinox(:september, 2026, "America/Santiago")
~D[2026-09-22]The Gregorian date of a lunar date in the lunar year that starts in the
Gregorian year, as the reference date-chinese computes it: a leap month
request takes the month after the regular one, and day may run past the
month (day 0 is the eve of the month). The table also carries the days
where the reference's own round trip through its lunar labeling lands a
day off from "day 1 plus the offset" (a handful per year, 2033 among
them), so those match too.
iex> Dayoff.Calendar.Tables.lunar_date(:chinese, 2026, 1, false, 1)
~D[2026-02-17]
iex> Dayoff.Calendar.Tables.lunar_date(:chinese, 2026, 1, false, 0)
~D[2026-02-16]The dates of day of month in a mapped calendar that fall in the
Gregorian year, the way the reference CalEventMap.inYear finds them:
scanning the month's first days in the neighbouring Gregorian years,
keeping the ones that land in year, and only the given calendar year
when one is asked for. A month can start twice in one Gregorian year.
iex> Dayoff.Calendar.Tables.mapped_dates(:hijri, 2026, 10, 1, nil)
[~D[2026-03-20]]
iex> Dayoff.Calendar.Tables.mapped_dates(:hebrew, 2026, 13, 14, nil)
[~D[2026-03-03]]The Gregorian date of day of solar term term (1 is Lichun at 315°,
5 is Qingming) as solarTerm(term, year) in date-chinese gives it.
iex> Dayoff.Calendar.Tables.solar_term(:chinese, 2026, 5, 1)
~D[2026-04-05]