Core Date Operations

Everything you do with plain dates and datetimes in GMT.

• Getting the Current Date and Time — read “now” as ISO strings in plain, zoned, UTC, and Unix shapes.
• Plain Arithmetic — add, subtract, and diff dates and datetimes with overflow control and rounding.
• Durations — parse, validate, combine, rebalance, and format ISO 8601 duration strings.
• Comparisons — order, equality, weekends, business days, and now-relative predicates.
• Formatting — locale-aware display, relative labels, calendar-day labels, and fixed machine formats.
• Parsing — extract components from ISO strings and decode interchange grammars.
• Validation — validate date/time strings, timezone identifiers, intervals, and ranges.
• Calendar Systems — express dates in non-Gregorian calendars with native arithmetic.