Date-time classes

date-time

The class of a date-time object. date-time instances are created with the function date-time. The function merge-date-times also can create date-time objects. The values in the slots of a date-time object are immutable. The slot readers for the date-time class are:

date-time-ymd-yd-before-year-0: a boolean, true if the Calendar date is before the year 0. (See also date-time-ywd-before-year-0. Note that these functions may return different values for some days around January 1, year 0.)
date-time-ymd-yd-century
date-time-ymd-yd-year-in-century
date-time-ymd-month
date-time-ymd-day
date-time-yd-day
date-time-ywd-before-year-0: a boolean, true if the Week date is before the year 0. (See also date-time-ymd-yd-before-year-0. Note that these functions may return different values for some days around January 1, year 0.)
date-time-ywd-century: an integer specifying the Week date century.
date-time-ywd-decade-in-century: an integer specifying the Week date decade in the century.
date-time-ywd-year-in-decade: the Week date year in the decade.
date-time-ywd-week: an integer between 1 and 53, inclusive.
date-time-ywd-day: an integer from 1 (Monday) to 7 (Sunday).
date-time-hour: an integer specifying the hour.
date-time-hourf: a rational specfying the hour and fraction of an hour.
date-time-minute: an integer specifying the minute.
date-time-minutef: a rational specfying the minute and fraction of a minute.
date-time-second: an integer specifying the second.
date-time-secondf: a rational specfying the second and fraction of a second.
date-time-zone-hour: an integer.
date-time-zone-minute: an integer.

See also the functions decode-date-time, date-time-year, and date-time-zone and the classes duration and time-interval.

See date-time.html for information on support in Allegro CL for parsing and generating time expressions using the ISO 8601 standard.

duration

The class of a duration object. The function duration creates duration objects.

A duration is a length of time, without a specified beginning or end. The time-interval class has a duration object as one of its slot values, and also a start and an end.

The readers for duration are:

See also the functions time-interval, add-duration, and subtract-duration.

See date-time.html for information on support in Allegro CL for parsing and generating time expressions using the ISO 8601 standard. See particularly the section Adding/Subtracting Durations.

time-interval

This is the class of time-interval objects, which (when fully specified) have a start, an end, a duration, and a number of recurrences. time-intervals are created with the time-interval function.

Time intervals have four slots:

start, with reader time-interval-start.
end, with reader time-interval-end.
duration, with reader time-interval-duration.
recurrences, with reader time-interval-recurrences.

See date-time.html for information on support in Allegro CL for parsing and generating time expressions using the ISO 8601 standard.

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Allegro CL version 11.0