Module Calendar_sig.S.Date


module Date: Date_sig.S 
Date implementation used by this calendar.
Since 2.0


Datatypes


type field = Period.date_field 
The different fields of a date.
Since 2.02
type -[< field ] date 
Type of a date, without specifying any precision level.
Since 2.02
type t = field date 
Type of a date.

type day =
| Sun
| Mon
| Tue
| Wed
| Thu
| Fri
| Sat
Days of the week.

type month =
| Jan
| Feb
| Mar
| Apr
| May
| Jun
| Jul
| Aug
| Sep
| Oct
| Nov
| Dec
Months of the year.
type year = int 
Year as an int.

Exceptions


exception Out_of_bounds
Raised when a date is outside the Julian period.
exception Undefined
Raised when a date belongs to [October 5th, 1582; October 14th, 1582].

Constructors


val make : year -> int -> int -> t
make year month day makes the date year-month-day. A BC year y corresponds to the year -(y+1).
Raises Example: years (5 BC) and (1 BC) respectively correspond to years (-4) and 0.
val lmake : year:year -> ?month:int -> ?day:int -> unit -> t
Labelled version of make. The default value of month and day is 1.
Since 1.05
Raises
val make_year : int -> [< `Year ] date
make_year y makes a date only represented by its year y. The month and the day of such a date are not relevant.
Since 2.02
val make_year_month : int -> int -> [< `Month | `Year ] date
make_year_month y m makes a date only represented by its year y and its month m. The day of such a date is not relevant.
Since 2.02
val today : unit -> t
Date of the current day (based on Time_Zone.current ()).
val from_jd : int -> t
Make a date from its Julian day.
Example: from_jd 0 returns the date 4713 BC-1-1.
val from_mjd : int -> t
Make a date from its modified Julian day (i.e. Julian day - 2 400 001). The Modified Julian day is more manageable than the Julian day.
Example: from_mjd 0 returns the date 1858-11-17.
val from_day_of_year : year -> int -> t
Make a date from a year and its day of the year.
Since 2.0
Example: from_day_of_year 2008 39 returns the date 2008-2-8.

Getters


val days_in_month : [< field > `Month `Year ] date -> int
Number of days in the month of a date.
Example: days_in_month (make 2003 6 26) returns 30.
val day_of_week : t -> day
Day of the week.
Example: day_of_week (make 2003 6 26) returns Thu.
val day_of_month : t -> int
Day of the month.
Example: day_of_month (make 2003 6 26) returns 26.
val day_of_year : t -> int
Day of the year.
Examples:
val week : t -> int
Week.
Examples:
val month : [< field > `Month ] date -> month
Month.
Example: month (make 2003 6 26) returns Jun.
val year : [< field > `Year ] date -> year
Year.
Example: year (make 2003 6 26) returns 2003.
val to_jd : t -> int
Julian day.
Example: to_jd (make (-4712) 1 1) returns 0.
val to_mjd : t -> int
Modified Julian day (i.e. Julian day - 2 400 001). The Modified Julian day is more manageable than the Julian day.
Example: to_mjd (make 1858 11 17) returns 0.

Dates are comparable


val equal : [< field ] date ->
[< field ] date -> bool
Equality function between two dates.
Since 1.09.0
See also Utils.Comparable.equal
val compare : [< field ] date ->
[< field ] date -> int
Comparison function between two dates.
See also Utils.Comparable.compare
val hash : [< field ] date -> int
Hash function for dates.
Since 2.0
See also Utils.Comparable.hash

Boolean operations on dates


val is_valid_date : year -> int -> int -> bool
Check if a date is valid, that is the date has not been coerced to look like a real date.
Since 2.0
Examples:
val is_leap_day : t -> bool
Return true if a date is a leap day (i.e. February, 24th of a leap year); false otherwise.
val is_gregorian : t -> bool
Return true if a date belongs to the Gregorian calendar; false otherwise.
val is_julian : t -> bool
Return true iff a date belongs to the Julian calendar; false otherwise.

Coercions


val to_unixtm : t -> Unix.tm
Convert a date into the Unix.tm type. The field is_isdst is always false. The fields Unix.tm_sec, Unix.tm_min and Unix.tm_hour are irrelevant.
Since 1.01
val from_unixtm : Unix.tm -> t
Inverse of to_unixtm. Assume the current time zone.
Since 1.01
val to_unixfloat : t -> float
Convert a date to a float such than to_unixfloat (make 1970 1 1) returns 0.0. So such a float is convertible with those of the Unix module. The fractional part of the result is always 0.
Since 1.01
val from_unixfloat : float -> t
Inverse of to_unixfloat. Ignore the fractional part of the argument. Assume the current time zone.
Since 1.01
val to_business : t -> year * int * day
Return the "business week" and the day in this week respecting ISO 8601. Notice that business weeks at the beginning and end of the year can sometimes have year numbers which don't match the real year.
Since 1.09.0
Examples:
val from_business : year -> int -> day -> t
Inverse of to_business respecting ISO-8601. Notice that business weeks at the beginning and end of the year can sometimes have year numbers which don't match the real year.
Since 1.09.0
Raises Invalid_argument if the date is bad.
val int_of_day : day -> int
Convert a day to an integer respecting ISO-8601. So, Monday is 1, Tuesday is 2, ..., and sunday is 7.
val day_of_int : int -> day
Inverse of int_of_day.
Raises Invalid_argument if the argument does not belong to 1; 7.
val int_of_month : month -> int
Convert a month to an integer respecting ISO-8601. So, January is 1, February is 2 and so on.
val month_of_int : int -> month
Inverse of int_of_month.
Raises Invalid_argument if the argument does not belong to 1; 12.

Period


module Period: sig .. end
A period is the number of days between two dates.

Arithmetic operations on dates and periods


val add : ([< field ] as 'a) date ->
'a Period.period -> 'a date
add d p returns d + p.
Raises Examples:
val sub : ([< field ] as 'a) date ->
'a date ->
[< field > `Day `Week ] Period.period
sub d1 d2 returns the period between d1 and d2.
val precise_sub : ([< field ] as 'a) date ->
'a date -> Period.t
precise_sub d1 d2 returns the period between d1 and d2. It is equivalent to sub, but:
Since 2.03
val rem : ([< field ] as 'a) date ->
'a Period.period -> 'a date
rem d p is equivalent to add d (Period.opp p).
Raises
val next : ([< field ] as 'a) date -> 'a -> 'a date
next d f returns the date corresponding to the next specified field.
Raises Example: next (make 2003 12 31) `Month returns the date 2004-1-31 (i.e. one month later).
val prev : ([< field ] as 'a) date -> 'a -> 'a date
prev d f returns the date corresponding to the previous specified field.
Raises Example: prev (make 2003 12 31) `Year returns the date 2002-12-31 (i.e. one year ago).

Operations on years


val is_leap_year : year -> bool
Return true if a year is a leap year; false otherwise.
val same_calendar : year -> year -> bool
Return true if two years have the same calendar; false otherwise.
val days_in_year : ?month:month -> year -> int
Number of days in a year.

days_in_year ~month y returns the number of days in the year y up to the end of the given month. Thus days_in_year ~month:Dec y is the same as days_in_year y.

val weeks_in_year : year -> int
Number of weeks in a year.
val week_first_last : int -> year -> t * t
Return the first and last days of a week in a year.
Since 1.08
val nth_weekday_of_month : year -> month -> day -> int -> t
nth_weekday_of_month y m d n returns the n-th day d in the month m of the year y (for instance the 3rd Thursday of the month).
Since 1.09.0
val century : year -> int
Century of a year.
Examples:
val millenium : year -> int
Millenium of a year.
Examples:
val solar_number : year -> int
Solar number.

In the Julian calendar there is a one-to-one relationship between the Solar number and the day on which a particular date falls.

val indiction : year -> int
Indiction.

The Indiction was used in the middle ages to specify the position of a year in a 15 year taxation cycle. It was introduced by emperor Constantine the Great on 1 September 312 and ceased to be used in 1806.

The Indiction has no astronomical significance.

val golden_number : year -> int
Golden number.

Considering that the relationship between the moon's phases and the days of the year repeats itself every 19 years, it is natural to associate a number between 1 and 19 with each year. This number is the so-called Golden number.

val epact : year -> int
Epact.

The Epact is a measure of the age of the moon (i.e. the number of days that have passed since an "official" new moon) on a particular date.

val easter : year -> t
Easter Sunday.

In the Christian world, Easter (and the days immediately preceding it) is the celebration of the death and resurrection of Jesus in (approximately) AD 30.

val carnaval : year -> t
Carnaval Monday. carnaval y is easter y - 48.
Since 1.09.0
val mardi_gras : year -> t
Mardi Gras. mardi_gras y is easter y - 47.
Since 1.09.0
val ash : year -> t
Ash Wednesday. ash y is easter y - 46.
Since 1.09.0
val palm : year -> t
Palm Sunday. palm y is easter y - 7.
Since 1.09.0
val easter_friday : year -> t
Easter Friday. easter_friday y is easter y - 2.
Since 1.09.0
val easter_saturday : year -> t
Easter Saturday. easter_saturday y is easter y - 1.
Since 1.09.0
val easter_monday : year -> t
Easter Monday. easter_monday y is easter y + 1.
Since 1.09.0
val ascension : year -> t
Ascension. ascension y is easter y + 39.
Since 1.09.0
val withsunday : year -> t
Withsunday. withsunday y is easter y + 49.
Since 1.09.0
val withmonday : year -> t
Withmonday. withmonday y is easter y + 50.
Since 1.09.0
val corpus_christi : year -> t
Feast of Corpus Christi. corpus_christi y is easter + 60.
Since 1.09.0