Date

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A proleptic Gregorian calendar date: year, month, day.

Year range: - Default: 1970..=9999 (matches default tzdata coverage). - With -D HISTORICAL_TZ: 1..=9999 (matches widened tzdata coverage back through pre-1900 LMT-era zones).

Calendar math (leap years, day-of-week, days-in-month, day-of-year, arithmetic) uses the proleptic Gregorian rule for all years in range, even those preceding regional Gregorian adoption (1582 onward).

class val Date

Constructors

create

[Source]

Construct a date. Errors if year is outside the supported range, or if (month, day) is not a real calendar date (e.g. Feb 30, Apr 31, Feb 29 of a non-leap year).

new val create(
  year': I16 val,
  month': U8 val,
  day': U8 val)
: Date val^ ?

Parameters

• year': I16 val
• month': U8 val
• day': U8 val

Returns

• Date val^ ?

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epoch

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1970-01-01 — non-partial because the epoch date is always valid in every supported configuration. Used for stubs and as a safe default.

new val epoch()
: Date val^

Returns

• Date val^

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Public Functions

year

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fun val year()
: I16 val

Returns

• I16 val

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month

[Source]

fun val month()
: U8 val

Returns

• U8 val

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day

[Source]

fun val day()
: U8 val

Returns

• U8 val

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is_leap_year

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True if this date's year is leap under the proleptic Gregorian rule.

fun val is_leap_year()
: Bool val

Returns

• Bool val

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days_in_month

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Number of days in this date's month (28..=31), accounting for leap year.

fun val days_in_month()
: U8 val

Returns

• U8 val

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day_of_week

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Day-of-week via Zeller's congruence (proleptic Gregorian).

fun val day_of_week()
: DayOfWeek

Returns

• DayOfWeek

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day_of_year

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Ordinal day within the year: 1 for Jan 1, up to 365 or 366.

fun val day_of_year()
: U16 val

Returns

• U16 val

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days_since_epoch

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Days from 1970-01-01. Negative for pre-epoch dates.

fun val days_since_epoch()
: I32 val

Returns

• I32 val

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compare

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fun val compare(
  other: Date val)
: Compare

Parameters

• other: Date val

Returns

• Compare

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eq

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fun val eq(
  other: Date val)
: Bool val

Parameters

• other: Date val

Returns

• Bool val

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ne

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fun val ne(
  other: Date val)
: Bool val

Parameters

• other: Date val

Returns

• Bool val

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lt

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fun val lt(
  other: Date val)
: Bool val

Parameters

• other: Date val

Returns

• Bool val

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le

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fun val le(
  other: Date val)
: Bool val

Parameters

• other: Date val

Returns

• Bool val

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gt

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fun val gt(
  other: Date val)
: Bool val

Parameters

• other: Date val

Returns

• Bool val

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ge

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fun val ge(
  other: Date val)
: Bool val

Parameters

• other: Date val

Returns

• Bool val

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add_days

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Return a new Date n days after this one (negative for past). Errors if the result is outside the supported year range.

fun val add_days(
  n: I32 val)
: (Date val | ArithmeticError)

Parameters

• n: I32 val

Returns

• (Date val | ArithmeticError)

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add_months

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Return a new Date n months after this one (negative for past). On month-shift overflow (e.g. Jan 31 + 1 month), policy decides between clamping (Feb 28/29) and rejecting (ArithmeticPolicyReject).

fun val add_months(
  n: I32 val,
  policy: OverflowPolicy)
: (Date val | ArithmeticError)

Parameters

• n: I32 val
• policy: OverflowPolicy

Returns

• (Date val | ArithmeticError)

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add_period

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Apply months and days from p. The nanos component is ignored because Date has no time-of-day to apply it to (pair with TimeOfDay or use ZonedDateTime for sub-day arithmetic).

fun val add_period(
  p: Period val,
  policy: OverflowPolicy)
: (Date val | ArithmeticError)

Parameters

• p: Period val
• policy: OverflowPolicy

Returns

• (Date val | ArithmeticError)

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string

[Source]

ISO 8601 date format: YYYY-MM-DD. Negative years prefixed with '-'.

fun val string()
: String iso^

Returns

• String iso^

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