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std.datetime.systime.SysTime.roll - multiple declarations

Function SysTime.roll

Adds the given number of years or months to this SysTime. A negative number will subtract.

ref SysTime roll(string units) (
  long value,
  AllowDayOverflow allowOverflow = AllowDayOverflow.yes
) nothrow scope @safe
if (units == "years");

The difference between rolling and adding is that rolling does not affect larger units. Rolling a SysTime 12 months gets the exact same SysTime. However, the days can still be affected due to the differing number of days in each month.

Because there are no units larger than years, there is no difference between adding and rolling years.

Parameters

NameDescription
units The type of units to add ("years" or "months").
value The number of months or years to add to this SysTime.
allowOverflow Whether the days should be allowed to overflow, causing the month to increment.

Example

import std.datetime.date : AllowDayOverflow, DateTime;

auto st1 = SysTime(DateTime(2010, 1, 1, 12, 33, 33));
st1.roll!"months"(1);
writeln(st1); // SysTime(DateTime(2010, 2, 1, 12, 33, 33))

auto st2 = SysTime(DateTime(2010, 1, 1, 12, 33, 33));
st2.roll!"months"(-1);
writeln(st2); // SysTime(DateTime(2010, 12, 1, 12, 33, 33))

auto st3 = SysTime(DateTime(1999, 1, 29, 12, 33, 33));
st3.roll!"months"(1);
writeln(st3); // SysTime(DateTime(1999, 3, 1, 12, 33, 33))

auto st4 = SysTime(DateTime(1999, 1, 29, 12, 33, 33));
st4.roll!"months"(1, AllowDayOverflow.no);
writeln(st4); // SysTime(DateTime(1999, 2, 28, 12, 33, 33))

auto st5 = SysTime(DateTime(2000, 2, 29, 12, 30, 33));
st5.roll!"years"(1);
writeln(st5); // SysTime(DateTime(2001, 3, 1, 12, 30, 33))

auto st6 = SysTime(DateTime(2000, 2, 29, 12, 30, 33));
st6.roll!"years"(1, AllowDayOverflow.no);
writeln(st6); // SysTime(DateTime(2001, 2, 28, 12, 30, 33))

Function SysTime.roll

Adds the given number of units to this SysTime. A negative number will subtract.

ref SysTime roll(string units) (
  long value
) nothrow scope @safe
if (units == "days");

The difference between rolling and adding is that rolling does not affect larger units. For instance, rolling a SysTime one year's worth of days gets the exact same SysTime.

Accepted units are "days", "minutes", "hours", "minutes", "seconds", "msecs", "usecs", and "hnsecs".

Note that when rolling msecs, usecs or hnsecs, they all add up to a second. So, for example, rolling 1000 msecs is exactly the same as rolling 100,000 usecs.

Parameters

NameDescription
units The units to add.
value The number of units to add to this SysTime.

Example

import core.time : msecs, hnsecs;
import std.datetime.date : DateTime;

auto st1 = SysTime(DateTime(2010, 1, 1, 11, 23, 12));
st1.roll!"days"(1);
writeln(st1); // SysTime(DateTime(2010, 1, 2, 11, 23, 12))
st1.roll!"days"(365);
writeln(st1); // SysTime(DateTime(2010, 1, 26, 11, 23, 12))
st1.roll!"days"(-32);
writeln(st1); // SysTime(DateTime(2010, 1, 25, 11, 23, 12))

auto st2 = SysTime(DateTime(2010, 7, 4, 12, 0, 0));
st2.roll!"hours"(1);
writeln(st2); // SysTime(DateTime(2010, 7, 4, 13, 0, 0))

auto st3 = SysTime(DateTime(2010, 2, 12, 12, 0, 0));
st3.roll!"hours"(-1);
writeln(st3); // SysTime(DateTime(2010, 2, 12, 11, 0, 0))

auto st4 = SysTime(DateTime(2009, 12, 31, 0, 0, 0));
st4.roll!"minutes"(1);
writeln(st4); // SysTime(DateTime(2009, 12, 31, 0, 1, 0))

auto st5 = SysTime(DateTime(2010, 1, 1, 0, 0, 0));
st5.roll!"minutes"(-1);
writeln(st5); // SysTime(DateTime(2010, 1, 1, 0, 59, 0))

auto st6 = SysTime(DateTime(2009, 12, 31, 0, 0, 0));
st6.roll!"seconds"(1);
writeln(st6); // SysTime(DateTime(2009, 12, 31, 0, 0, 1))

auto st7 = SysTime(DateTime(2010, 1, 1, 0, 0, 0));
st7.roll!"seconds"(-1);
writeln(st7); // SysTime(DateTime(2010, 1, 1, 0, 0, 59))

auto dt = DateTime(2010, 1, 1, 0, 0, 0);
auto st8 = SysTime(dt);
st8.roll!"msecs"(1);
writeln(st8); // SysTime(dt, msecs(1))

auto st9 = SysTime(dt);
st9.roll!"msecs"(-1);
writeln(st9); // SysTime(dt, msecs(999))

auto st10 = SysTime(dt);
st10.roll!"hnsecs"(1);
writeln(st10); // SysTime(dt, hnsecs(1))

auto st11 = SysTime(dt);
st11.roll!"hnsecs"(-1);
writeln(st11); // SysTime(dt, hnsecs(9_999_999))

Authors

Jonathan M Davis

License

Boost License 1.0.