add- Модуль
- std.
date → - Получатель
- Date
- Минимальное число аргументов
- 1
- Максимальное число аргументов
- 1
Declaration and parameters
СсылкаДоступность
Включено по умолчанию · Не определено
Import std.date in language mode 5.21.
The current compiler selects std/date.tpz for this language mode. Availability in other released editions and inclusion in each installed distribution are Pending.
Получатель
Date
Ограничения параметров
Date.addDays accepts a signed int count of whole calendar days. Positive values move forward, negative values move backward, and zero returns the same date value.
The result follows the same proleptic Gregorian calendar as Date.fromYmd. Month boundaries, leap days, and year boundaries are crossed by counting calendar days. Historical calendar cutovers and daylight saving changes do not alter the result.
The result must remain from 0001-01-01 through 9999-12-31. A count whose mathematical result is outside that range raises TPZ4004 during execution. An intermediate integer overflow also raises TPZ4004.
An invalid result does not wrap, saturate, return a partial date, or change the receiver. Evaluation stops at the fault before later statements run.
The receiver is evaluated before the day count and each is evaluated once. An earlier fault prevents later evaluation. The operation has no external effects.
Adding a count and then its negative recovers the starting date when both results lie in range. Date.toIso and the component accessors observe the resulting date without changing it.
Связанное правило · Add whole calendar days within the civil date range →Результат
The declared result type is Date.
Эффекты
Ошибки
Result and effects
СсылкаCalendar arithmetic preserves the receiver. A result outside years 1 through 9999 raises TPZ4004.
Resolved contracts
СсылкаRelated entries
СсылкаAdd whole calendar days within the civil date range
СсылкаAdd whole calendar days within the civil date range
Date.addDays accepts a signed int count of whole calendar days. Positive values move forward, negative values move backward, and zero returns the same date value.
The result follows the same proleptic Gregorian calendar as Date.fromYmd. Month boundaries, leap days, and year boundaries are crossed by counting calendar days. Historical calendar cutovers and daylight saving changes do not alter the result.
The result must remain from 0001-01-01 through 9999-12-31. A count whose mathematical result is outside that range raises TPZ4004 during execution. An intermediate integer overflow also raises TPZ4004.
An invalid result does not wrap, saturate, return a partial date, or change the receiver. Evaluation stops at the fault before later statements run.
The receiver is evaluated before the day count and each is evaluated once. An earlier fault prevents later evaluation. The operation has no external effects.
Adding a count and then its negative recovers the starting date when both results lie in range. Date.toIso and the component accessors observe the resulting date without changing it.
Причина
Calendar arithmetic should depend on a date and a day count. A bounded result with an explicit overflow fault prevents wraparound from silently producing a different civil date.
Cross leap days, years, and the full supported interval
Ссылкаimport std.date { Date }import std.testimport std.iolet leap = test.assertOk(Date.fromYmd(2000, 2, 28))io.writeLine(leap.addDays(1).toIso())io.writeLine(leap.addDays(2).toIso())io.writeLine(leap.toIso())io.writeLine(test.assertOk(Date.fromYmd(1900, 2, 28)).addDays(1).toIso())io.writeLine(test.assertOk(Date.fromYmd(1582, 10, 4)).addDays(1).toIso())io.writeLine(test.assertOk(Date.fromYmd(2000, 1, 1)).addDays(-1).toIso())io.writeLine(leap.addDays(0).toIso())io.writeLine(test.assertOk(Date.fromYmd(1, 1, 1)).addDays(3652058).toIso())io.writeLine(test.assertOk(Date.fromYmd(9999, 12, 31)).addDays(-3652058).toIso())
2000-02-29
2000-03-01
2000-02-28
1900-03-01
1582-10-05
1999-12-31
2000-02-28
9999-12-31
0001-01-01
Ожидаемый результат
Ожидаемый результат
Выполнение завершается. Код завершения 0.
2000-02-292000-03-012000-02-281900-03-011582-10-051999-12-312000-02-289999-12-310001-01-01
Reject the day after the final supported date
Ссылкаimport std.date { Date }import std.testimport std.iolet date = test.assertOk(Date.fromYmd(9999, 12, 31))date.addDays(1)io.writeLine("after")
Нет стандартного вывода.Ожидаемый результат
Ожидаемый результат
Этап отклонения run. Ненулевой код завершения.
stdlib-date-range-overflow at
main.tpz:6:1
Reject the day before the first supported date
Ссылкаimport std.date { Date }import std.testimport std.iolet date = test.assertOk(Date.fromYmd(1, 1, 1))date.addDays(-1)io.writeLine("after")
Нет стандартного вывода.Ожидаемый результат
Ожидаемый результат
Этап отклонения run. Ненулевой код завершения.
stdlib-date-range-overflow at
main.tpz:6:1
Reject a day count that overflows signed arithmetic
Ссылкаimport std.date { Date }import std.testimport std.iolet date = test.assertOk(Date.fromYmd(1, 1, 1))date.addDays(-9223372036854775808)io.writeLine("after")
Нет стандартного вывода.Ожидаемый результат
Ожидаемый результат
Этап отклонения run. Ненулевой код завершения.
stdlib-date-range-overflow at
main.tpz:6:1
Evaluate a date receiver before its day count
Ссылкаimport std.date { Date }import std.testimport std.iofunction receiver() -> Date {io.writeLine("date")return test.assertOk(Date.fromYmd(2024, 2, 28))}function days() -> int {io.writeLine("days")return 1}let next = receiver().addDays(days())io.writeLine(next.toIso())
date
days
2024-02-29
Ожидаемый результат
Ожидаемый результат
Выполнение завершается. Код завершения 0.
datedays2024-02-29