date.pl -- Process dates and times

 date_time_value(?Field:atom, +Struct:datime, -Value) is nondet

Extract values from a date-time structure. Provided fields are

year	integer
month	1..12
day	1..31
hour	0..23
minute	0..59
second	0.0..60.0
utc_offset	integer	Offset to UTC in seconds (positive is west)
daylight_saving	bool	Name of timezone; fails if unknown
date	date(Y,M,D)
time	time(H,M,S)

 parse_time(+Text, -Stamp) is semidet

 parse_time(+Text, ?Format, -Stamp) is semidet

Stamp is a timestamp created from parsing Text using the representation Format. Currently supported formats are:

rfc_1123

Preferred for the HTTP protocol to represent time-stamps, e.g.

Fri, 08 Dec 2006 15:29:44 GMT

All components except for the time zone are obligatory. If the time zone is omitted, the time is interpreted as local time.

rfc_1036

(Outdated) alternative for HTTP Protocol, e.g.

Sunday, 06-Nov-94 08:49:37 GMT

iso_8601

Commonly used in XML documents. Actually the XML RFC3339 is a profile of ISO8601. For example

2006-12-08T15:29:44Z

The ISO8601 format allows removing components from the right, returning the lowest time stamp in the specified internal. If a time is specified but no time zone, the time stamp is computed for the local time. If only the date components are specified, the stamp uses UTC. To compute the start of a day in local time, use e.g. 2006-12-08T00.

asctime

ANSI C's asctime() format, e.g.

Sun Nov  6 08:49:37 1994

This format has no time zone and is interpreted as local time.

Arguments:

Text	- is an atom, string or list of character codes.

See also

- xsd_time_string/3 from library(sgml) implements RFC3339 strictly.

 day_of_the_week(+Date, -DayOfTheWeek) is det

Computes the day of the week for a given date. Days of the week are numbered from one to seven: monday = 1, tuesday = 2, ..., sunday = 7.

Arguments:

Date	- is a term of the form date(+Year, +Month, +Day)

 day_of_the_year(+Date, -DayOfTheYear) is det

Computes the day of the year for a given date. Days of the year are numbered from 1 to 365 (366 for a leap year).

Arguments:

Date	- is a term of the form date(+Year, +Month, +Day)

Re-exported predicates

The following predicates are exported from this file while their implementation is defined in imported modules or non-module files loaded by this module.

 parse_time(+Text, -Stamp) is semidet

 parse_time(+Text, ?Format, -Stamp) is semidet

Stamp is a timestamp created from parsing Text using the representation Format. Currently supported formats are:

rfc_1123

Preferred for the HTTP protocol to represent time-stamps, e.g.

Fri, 08 Dec 2006 15:29:44 GMT

All components except for the time zone are obligatory. If the time zone is omitted, the time is interpreted as local time.

rfc_1036

(Outdated) alternative for HTTP Protocol, e.g.

Sunday, 06-Nov-94 08:49:37 GMT

iso_8601

Commonly used in XML documents. Actually the XML RFC3339 is a profile of ISO8601. For example

2006-12-08T15:29:44Z

The ISO8601 format allows removing components from the right, returning the lowest time stamp in the specified internal. If a time is specified but no time zone, the time stamp is computed for the local time. If only the date components are specified, the stamp uses UTC. To compute the start of a day in local time, use e.g. 2006-12-08T00.

asctime

ANSI C's asctime() format, e.g.

Sun Nov  6 08:49:37 1994

This format has no time zone and is interpreted as local time.

Arguments:

Text	- is an atom, string or list of character codes.

See also

- xsd_time_string/3 from library(sgml) implements RFC3339 strictly.