Data and Math

vcalendar

Leap years, month lengths and the weekday of a given date.

Released v1.0.0 · 2026-09-28

Import

use "stdlib/calendar.ven"

Gregorian calendar arithmetic: leap years, the length of a month, the name of a month or a weekday, and the weekday a given day falls on, worked out with Zeller's congruence. It covers the proleptic Gregorian calendar, with no month or year grid rendering.

vcalendar.ven

print isleap(2000)

Reference (5 functions)

isleap
leapdays
weekday
monthrange
monthcalendar

API reference

`isleap(year)`

Tests whether year is a Gregorian leap year.

isleap(2000)

`leapdays(y1, y2)`

Counts the leap years in the half-open range [y1, y2).

leapdays(2000, 2001)

`weekday(year, month, day)`

Gives back the day of the week for year-month-day.

weekday(2024, 1, 1)

`monthrange(year, month)`

monthrange(2024, 2)

`monthcalendar(year, month)`

monthcalendar(2024, 2)

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