Elixir v1.8.0-rc.1 Calendar behaviour View Source
This module defines the responsibilities for working with calendars, dates, times and datetimes in Elixir.
Currently it defines types and the minimal implementation for a calendar behaviour in Elixir. The goal of the Calendar features in Elixir is to provide a base for interoperability instead of full-featured datetime API.
For the actual date, time and datetime structures, see Date,
Time, NaiveDateTime and DateTime.
Note the year, month, day, etc. designations are overspecified
(i.e. an integer instead of 1..12 for months) because different
calendars may have a different number of days per month, months per year and so on.
Link to this section Summary
Types
A calendar implementation
Any map/struct that contains the date fields
Any map/struct that contains the datetime fields
The internal time format is used when converting between calendars.
The internal date format that is used when converting between calendars.
Microseconds with stored precision.
Any map/struct that contains the naive_datetime fields
The time zone standard offset in seconds (not zero in summer times)
Any map/struct that contains the time fields
The time zone ID according to the IANA tz database (e.g. Europe/Zurich)
Specifies the time zone database for calendar operations.
The time zone UTC offset in seconds
The time zone abbreviation (e.g. CET or CEST or BST etc.)
Functions
Returns true if two calendars have the same moment of starting a new day,
false otherwise.
Gets the current time zone database.
Sets the current time zone database.
Returns a microsecond tuple truncated to a given precision (:microsecond,
:millisecond or :second).
Callbacks
Converts the date into a string according to the calendar.
Converts the datetime (with time zone) into a string according to the calendar.
Calculates the day and era from the given year, month, and day.
Calculates the day of the week from the given year, month, and day.
Calculates the day of the year from the given year, month, and day.
Define the rollover moment for the given calendar.
Returns how many days there are in the given year-month.
Returns true if the given year is a leap year.
Returns how many months there are in the given year.
Converts iso_days/0 to the Calendar's datetime format.
Converts the given datetime (without time zone) into the iso_days/0 format.
Converts the datetime (without time zone) into a string according to the calendar.
Calculates the quarter of the year from the given year, month, and day.
Converts day_fraction/0 to the Calendar's time format.
Converts the given time to the day_fraction/0 format.
Converts the time into a string according to the calendar.
Should return true if the given date describes a proper date in the calendar.
Should return true if the given time describes a proper time in the calendar.
Calculates the year and era from the given year.
Link to this section Types
Specs
calendar() :: module()
A calendar implementation
Specs
date() :: %{
optional(any()) => any(),
:calendar => calendar(),
:year => year(),
:month => month(),
:day => day()
}
Any map/struct that contains the date fields
Specs
datetime() :: %{
optional(any()) => any(),
:calendar => calendar(),
:year => year(),
:month => month(),
:day => day(),
:hour => hour(),
:minute => minute(),
:second => second(),
:microsecond => microsecond(),
:time_zone => time_zone(),
:zone_abbr => zone_abbr(),
:utc_offset => utc_offset(),
:std_offset => std_offset()
}
Any map/struct that contains the datetime fields
Specs
day() :: pos_integer()
Specs
day_fraction() ::
{parts_in_day :: non_neg_integer(), parts_per_day :: pos_integer()}
The internal time format is used when converting between calendars.
It represents time as a fraction of a day (starting from midnight).
parts_in_day specifies how much of the day is already passed,
while parts_per_day signifies how many parts there fit in a day.
Specs
day_of_week() :: non_neg_integer()
Specs
era() :: non_neg_integer()
Specs
hour() :: non_neg_integer()
Specs
iso_days() :: {days :: integer(), day_fraction()}
The internal date format that is used when converting between calendars.
This is the number of days including the fractional part that has passed of the last day since 0000-01-01+00:00T00:00.000000 in ISO 8601 notation (also known as midnight 1 January BC 1 of the proleptic Gregorian calendar).
Specs
microsecond() :: {0..999_999, 0..6}
Microseconds with stored precision.
The precision represents the number of digits that must be used when representing the microseconds to external format. If the precision is 0, it means microseconds must be skipped.
Specs
minute() :: non_neg_integer()
Specs
month() :: pos_integer()
Specs
naive_datetime() :: %{
optional(any()) => any(),
:calendar => calendar(),
:year => year(),
:month => month(),
:day => day(),
:hour => hour(),
:minute => minute(),
:second => second(),
:microsecond => microsecond()
}
Any map/struct that contains the naive_datetime fields
Specs
second() :: non_neg_integer()
Specs
std_offset() :: integer()
The time zone standard offset in seconds (not zero in summer times)
Specs
time() :: %{
optional(any()) => any(),
:hour => hour(),
:minute => minute(),
:second => second(),
:microsecond => microsecond()
}
Any map/struct that contains the time fields
Specs
time_zone() :: String.t()
The time zone ID according to the IANA tz database (e.g. Europe/Zurich)
Specs
time_zone_database() :: module()
Specifies the time zone database for calendar operations.
Many functions in the DateTime module require a time zone database.
By default, it uses the default time zone database returned by
Calendar.get_time_zone_database/0, which defaults to
Calendar.UTCOnlyTimeZoneDatabase which only handles "Etc/UTC"
datetimes and returns {:error, :utc_only_time_zone_database}
for any other time zone.
Other time zone databases (including ones provided by packages) can be configure as default either via configuration:
config :elixir, :time_zone_database, CustomTimeZoneDatabaseor by calling Calendar.put_time_zone_database/1.
See Calendar.TimeZoneDatabase for more information on custom
time zone databases.
Specs
utc_offset() :: integer()
The time zone UTC offset in seconds
Specs
week() :: pos_integer()
Specs
year() :: integer()
Specs
zone_abbr() :: String.t()
The time zone abbreviation (e.g. CET or CEST or BST etc.)
Link to this section Functions
Specs
compatible_calendars?(Calendar.calendar(), Calendar.calendar()) :: boolean()
Returns true if two calendars have the same moment of starting a new day,
false otherwise.
If two calendars are not compatible, we can only convert datetimes and times between them. If they are compatible, this means that we can also convert dates as well as naive datetimes between them.
Specs
get_time_zone_database() :: time_zone_database()
Gets the current time zone database.
Specs
put_time_zone_database(time_zone_database()) :: :ok
Sets the current time zone database.
Specs
truncate(Calendar.microsecond(), :microsecond | :millisecond | :second) :: Calendar.microsecond()
Returns a microsecond tuple truncated to a given precision (:microsecond,
:millisecond or :second).
Link to this section Callbacks
Specs
Converts the date into a string according to the calendar.
datetime_to_string(year, month, day, hour, minute, second, microsecond, time_zone, zone_abbr, utc_offset, std_offset)
View SourceSpecs
datetime_to_string( year(), month(), day(), hour(), minute(), second(), microsecond(), time_zone(), zone_abbr(), utc_offset(), std_offset() ) :: String.t()
Converts the datetime (with time zone) into a string according to the calendar.
Specs
day_of_era(year(), month(), day()) :: {non_neg_integer(), era()}
Calculates the day and era from the given year, month, and day.
Specs
day_of_week(year(), month(), day()) :: day_of_week()
Calculates the day of the week from the given year, month, and day.
Specs
day_of_year(year(), month(), day()) :: non_neg_integer()
Calculates the day of the year from the given year, month, and day.
Specs
day_rollover_relative_to_midnight_utc() :: day_fraction()
Define the rollover moment for the given calendar.
This is the moment, in your calendar, when the current day ends and the next day starts.
The result of this function is used to check if two calendars rollover at the same time of day. If they do not, we can only convert datetimes and times between them. If they do, this means that we can also convert dates as well as naive datetimes between them.
This day fraction should be in its most simplified form possible, to make comparisons fast.
Examples
- If, in your Calendar, a new day starts at midnight, return {0, 1}.
- If, in your Calendar, a new day starts at sunrise, return {1, 4}.
- If, in your Calendar, a new day starts at noon, return {1, 2}.
- If, in your Calendar, a new day starts at sunset, return {3, 4}.
Specs
Returns how many days there are in the given year-month.
Specs
Returns true if the given year is a leap year.
A leap year is a year of a longer length than normal. The exact meaning
is up to the calendar. A calendar must return false if it does not support
the concept of leap years.
Specs
Returns how many months there are in the given year.
Specs
naive_datetime_from_iso_days(iso_days()) :: {year(), month(), day(), hour(), minute(), second(), microsecond()}
Converts iso_days/0 to the Calendar's datetime format.
naive_datetime_to_iso_days(year, month, day, hour, minute, second, microsecond)
View SourceSpecs
naive_datetime_to_iso_days( year(), month(), day(), hour(), minute(), second(), microsecond() ) :: iso_days()
Converts the given datetime (without time zone) into the iso_days/0 format.
naive_datetime_to_string(year, month, day, hour, minute, second, microsecond)
View SourceSpecs
naive_datetime_to_string( year(), month(), day(), hour(), minute(), second(), microsecond() ) :: String.t()
Converts the datetime (without time zone) into a string according to the calendar.
Specs
quarter_of_year(year(), month(), day()) :: non_neg_integer()
Calculates the quarter of the year from the given year, month, and day.
Specs
time_from_day_fraction(day_fraction()) :: {hour(), minute(), second(), microsecond()}
Converts day_fraction/0 to the Calendar's time format.
Specs
time_to_day_fraction(hour(), minute(), second(), microsecond()) :: day_fraction()
Converts the given time to the day_fraction/0 format.
Specs
time_to_string(hour(), minute(), second(), microsecond()) :: String.t()
Converts the time into a string according to the calendar.
Specs
Should return true if the given date describes a proper date in the calendar.
Specs
valid_time?(hour(), minute(), second(), microsecond()) :: boolean()
Should return true if the given time describes a proper time in the calendar.
Specs
Calculates the year and era from the given year.