Calendar

Apply years, then months, then civil days to a Gregorian date. Choose Reject, Clamp or Carry for nonexistent intermediate destinations. Return InvalidDestination or OutOfRange rather than silently choosing a policy. Clamping is not invertible and must not be used to step RFC recurrence rules.

Preserve an already validated date and its calendar without revalidation.

Retain a validated Julian date with its calendar identity, without conversion.

Access a stored Gregorian date without converting another calendar. Use in_calendar when conversion, rather than access, is intended.

Validate { year, month, day } in the explicitly selected calendar. Year is astronomical (zero means 1 BCE); month and day are one-based. Invalid month/day combinations and unsupported provider years return structured errors.

Describe a shared civil-day coordinate in the selected calendar. Return OutOfRange when the date is outside that calendar's supported years.

Read the shared civil-day coordinate, allowing equal-day comparison across calendars without introducing a timezone.

Read the calendar retained by this date description.

Read year, month and day in the retained calendar. Use in_calendar to convert before reading fields in a different calendar.

Convert to a description of the same civil day in the requested calendar. Return OutOfRange if that day is unsupported by the destination provider.

Equal day extent on the shared civil axis, independent of description.

Description equality retains calendar identity; use same_day for extents.

Hash date description identity, including the calendar, consistently with is_eq. Equal civil-day extent alone does not imply equal description hashes.

Describe the retained Gregorian or Julian date for diagnostics. No timezone or resolved position is inferred.

Construct an ordered calendar displacement from signed years, months and days. Components remain as supplied: twelve months is not normalized to one year.

Read the signed components as described, without applying them to a date or converting them to elapsed time.

Compare component definitions without an anchor; one year is not twelve months.

Hash component definitions consistently with equality. One year and twelve months remain distinct descriptions even when an application gives the same result.

Bounded component description; no anchor, normalization or elapsed claim.

Construct a displacement with the supplied signed year count and zero months/days.

Construct a displacement with the supplied signed month count and zero years/days.

Construct a displacement with the supplied signed civil-day count and zero years/months.

Select the whole provider year; year zero is 1 BCE.

Select a whole calendar month; invalid month numbers return InvalidMonth.

Select one validated civil date; no fixed elapsed duration is implied.

Describe the entire local hour beginning at the supplied date and hour. Reject an invalid hour; zone interpretation may later yield disconnected coverage.

Describe the entire local minute on the supplied date. Validate hour/minute fields; omitted seconds locate its start but do not narrow its resolution.

Describe the entire local second on the supplied date. Invalid clock fields and unsupported leap seconds return structured errors.

fraction is the supplied decimal integer: {value: 12, digits: 2} is .12. Zero digits and values requiring more digits are malformed. More than six digits are unsupported, even when trailing zeroes could be discarded.

Supplied field precision, preserved even when lower fields are zero.