month() -- 수신자
- Date
- 최소 인자 수
- 0
- 최대 인자 수
- 0
Declaration and parameters
링크사용 조건
기본 포함 · 미정
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.
수신자
Date
매개변수 제약
Date is an immutable proleptic Gregorian calendar date from 0001-01-01 through 9999-12-31. It contains no time of day, time zone, or locale. The same calendar rules apply before and after 1582.
Date.fromYmd accepts years from 1 through 9999 and months from 1 through 12. The day must be a real day of the selected month and year. All range endpoints are included.
A year divisible by 4 is a leap year except a century year that is not divisible by 400. February has 29 days in a leap year and 28 otherwise. April, June, September, and November have 30 days. The other months have 31.
Valid components return Ok containing that date. Year zero, a year outside the supported range, an invalid month, and an invalid day return Err containing a descriptive nonempty string. Components are not normalized into another date.
The error string describes the failed construction and has no stable machine readable format. Callers branch on Ok or Err.
Date.year, Date.month, and Date.day are calls with no arguments. They return the validated components of the receiver. A valid Date makes these observations total and leaves the receiver unchanged.
Arguments are evaluated once in source order before validation. An earlier fault prevents later evaluation. Constructors and observations do not read a host clock or perform external effects.
관련 규칙 · Construct valid Gregorian civil dates →결과
The declared result type is int.
효과
실패
Result and effects
링크This call returns the receiver month and leaves the date unchanged.
Resolved contracts
링크Related entries
링크Construct valid Gregorian civil dates
링크Construct valid Gregorian civil dates
Date is an immutable proleptic Gregorian calendar date from 0001-01-01 through 9999-12-31. It contains no time of day, time zone, or locale. The same calendar rules apply before and after 1582.
Date.fromYmd accepts years from 1 through 9999 and months from 1 through 12. The day must be a real day of the selected month and year. All range endpoints are included.
A year divisible by 4 is a leap year except a century year that is not divisible by 400. February has 29 days in a leap year and 28 otherwise. April, June, September, and November have 30 days. The other months have 31.
Valid components return Ok containing that date. Year zero, a year outside the supported range, an invalid month, and an invalid day return Err containing a descriptive nonempty string. Components are not normalized into another date.
The error string describes the failed construction and has no stable machine readable format. Callers branch on Ok or Err.
Date.year, Date.month, and Date.day are calls with no arguments. They return the validated components of the receiver. A valid Date makes these observations total and leaves the receiver unchanged.
Arguments are evaluated once in source order before validation. An earlier fault prevents later evaluation. Constructors and observations do not read a host clock or perform external effects.
이유
Validating civil dates at construction gives every date observation a definite value. A shared Gregorian calendar and year range make dates independent of locale, time zones, and historical calendar cutovers.
Read leap day and both supported endpoints
링크import std.date { Date }import std.testimport std.iolet leap = test.assertOk(Date.fromYmd(2000, 2, 29))io.writeLine("{leap.year()} {leap.month()} {leap.day()}")io.writeLine(leap.toIso())io.writeLine(test.assertOk(Date.fromYmd(1, 1, 1)).toIso())io.writeLine(test.assertOk(Date.fromYmd(9999, 12, 31)).toIso())
2000 2 29
2000-02-29
0001-01-01
9999-12-31
기대 결과
기대 결과
실행을 마칩니다. 종료 코드 0.
2000 2 292000-02-290001-01-019999-12-31
Reject invalid years, months, and days without normalization
링크import std.date { Date }import std.iofunction reject(year: int, month: int, day: int) -> () {match (Date.fromYmd(year, month, day)) {case Err(_) => io.writeLine("rejected")case Ok(_) => io.writeLine("accepted")}}reject(1900, 2, 29)reject(2023, 2, 29)reject(2024, 0, 1)reject(2024, 13, 1)reject(2024, 4, 31)reject(2024, 1, 0)reject(2024, 1, 32)reject(-1, 1, 1)reject(10000, 1, 1)reject(9223372036854775807, 1, 1)
rejected
rejected
rejected
rejected
rejected
rejected
rejected
rejected
rejected
rejected
기대 결과
기대 결과
실행을 마칩니다. 종료 코드 0.
rejectedrejectedrejectedrejectedrejectedrejectedrejectedrejectedrejectedrejected
Reject year zero during component construction
링크import std.date { Date }import std.iomatch (Date.fromYmd(0, 1, 1)) {case Err(_) => io.writeLine("year zero rejected")case Ok(_) => io.writeLine("accepted")}
year zero rejected
기대 결과
기대 결과
실행을 마칩니다. 종료 코드 0.
year zero rejected
Evaluate all components before date validation
링크import std.date { Date }import std.iofunction observed(label: string, value: int) -> int {io.writeLine(label)return value}match (Date.fromYmd(observed("year", 2024), observed("month", 13), observed("day", 1))) {case Err(_) => io.writeLine("rejected")case Ok(_) => io.writeLine("accepted")}
year
month
day
rejected
기대 결과
기대 결과
실행을 마칩니다. 종료 코드 0.
yearmonthdayrejected