Szathmáry László honlapja @ DEIK | DLang / date and time

(1) simple examples

import std.stdio;
import std.datetime;

bool isLeapYear(const int year) pure {
return yearIsLeapYear(year);
}

void main()
{
auto today = Date(2025, 8, 19); // Aug 19, 2025
auto xmas = Date(2025, 12, 24); // Dec 24, 2025

assert(today < xmas); // true

writeln(today); // "2025-Aug-19"

today += dur!"days"(1); // add 1 day

writeln(today); // "2025-Aug-20"
writeln(today.dayOfWeek()); // wed
assert(today.dayOfWeek() == DayOfWeek.wed); // true

writeln(isLeapYear(2020)); // true
}

Notes:

Easy to create a date object from a date.
Dates are comparable with <, ≤, etc.
When you print a date, it uses a format that is completely clear to understand.
Easy to increment/decrement a date.
Easy to figure out the day of a date (Monday, Tuesday, etc.).