Specs

add_days(fixed() | jd_date(), integer(), :fixed | :date) :: fixed() | jd_date()

Adds the number of days to a fixed day or JD date.

If days is negative, the days will be subtracted.

The type parameter determines the type of the returned value:

• :fixed returns a fixed day (default),
• :date returns a JD date.

Examples

  iex>Elixir.JD.add_days(730739, 100)
  730839
  iex>Elixir.JD.add_days(730739, -100)
  730639

  iex>Elixir.JD.add_days(730739, 100, :fixed)
  730839
  iex>Elixir.JD.add_days(730739, -100, :fixed)
  730639

  iex>Elixir.JD.add_days(730739, 100, :date)
  {2452263.5}
  iex>Elixir.JD.add_days(730739, -100, :date)
  {2452063.5}

  iex>Elixir.JD.add_days({2452163.5}, 100)
  730839
  iex>Elixir.JD.add_days({2452163.5}, -100)
  730639

  iex>Elixir.JD.add_days({2452163.5}, 100, :fixed)
  730839
  iex>Elixir.JD.add_days({2452163.5}, -100, :fixed)
  730639

  iex>Elixir.JD.add_days({2452163.5}, 100, :date)
  {2452263.5}
  iex>Elixir.JD.add_days({2452163.5}, -100, :date)
  {2452063.5}

Specs

as_date(fixed() | jd_date()) :: jd_date()

Returns a fixed day or JD date as a JD date.

This is a convenience function to simplify certain function calls.

Examples

  iex>Elixir.JD.as_date(730739)
  {2452163.5}
  iex>Elixir.JD.as_date({2452163.5})
  {2452163.5}

Specs

as_fixed(fixed() | jd_date()) :: fixed()

Returns a fixed day or JD date as a fixed day.

This is a convenience function to simplify certain function calls.

Examples

  iex>Elixir.JD.as_fixed(730739)
  730739
  iex>Elixir.JD.as_fixed({2452163.5})
  730739

Specs

as_type(fixed() | jd_date(), :fixed | :date) :: fixed() | jd_date()

Returns a fixed day or JD date either as a fixed day or a JD date.

The type parameter determines the type of the returned value:

• :fixed returns a fixed day (default),
• :date returns a JD date.

Examples

  iex>Elixir.JD.as_type(730739)
  730739
  iex>Elixir.JD.as_type(730739, :fixed)
  730739
  iex>Elixir.JD.as_type(730739, :date)
  {2452163.5}
  iex>Elixir.JD.as_type({2452163.5})
  730739
  iex>Elixir.JD.as_type({2452163.5}, :fixed)
  730739
  iex>Elixir.JD.as_type({2452163.5}, :date)
  {2452163.5}

Specs

compare(jd_date(), jd_date()) :: :lt | :eq | :gt

Compares two JD dates and returns...

• :lt if date1 is smaller (= earlier) than date2,
• :eq if date1 is equal date2,
• :gt if date1 is larger (= later) than date2.

Examples

  iex>Elixir.JD.compare({2452163.5}, {2452163.5})
  :eq
  iex>Elixir.JD.compare({2452163.5}, {2452263.5})
  :lt
  iex>Elixir.JD.compare({2452263.5}, {2452163.5})
  :gt

Specs

date(jd_day()) :: t()

Returns a JD date from its fields day.

Example

  iex>Elixir.JD.date(2452163.5)
  {2452163.5}

Specs

date_diff(fixed() | jd_date(), fixed() | jd_date()) :: integer()

Returns the difference (= number of days) between two JD dates.

The dates can be given as fixed days or JD dates in arbitrary combination. The difference is calculated by date2 - date1.

If cal_date2 is larger (= later) than cal_date1 the result is positive.

If cal_date2 is smaller (= earlier) than cal_date1 the result is negative.

Examples

  iex>Elixir.JD.date_diff(730739, 730839)
  100
  iex>Elixir.JD.date_diff(730839, 730739)
  -100
  iex>Elixir.JD.date_diff({2452163.5}, {2452263.5})
  100
  iex>Elixir.JD.date_diff({2452263.5}, {2452163.5})
  -100
  iex>Elixir.JD.date_diff(730739, {2452263.5})
  100
  iex>Elixir.JD.date_diff({2452163.5}, 730839)
  100

Specs

day(fixed() | jd_date(), :atom | :index | :name | :value) ::
  :atom | integer() | String.t() | number()

Returns the day field of a JD date.

The type parameter determines the type of the returned day:

• :atom returns the internal name of day,
• :index returns the position of the day field within the date,
• :name returns the common name of the day,
• :value returns the value of the day (default).

Examples

  iex>Elixir.JD.day(730739)
  2452163.5
  iex>Elixir.JD.day(730739, :atom)
  :day
  iex>Elixir.JD.day(730739, :index)
  0
  iex>Elixir.JD.day(730739, :name)
  "Day"
  iex>Elixir.JD.day(730739, :value)
  2452163.5

  iex>Elixir.JD.day({2452163.5})
  2452163.5
  iex>Elixir.JD.day({2452163.5}, :atom)
  :day
  iex>Elixir.JD.day({2452163.5}, :index)
  0
  iex>Elixir.JD.day({2452163.5}, :name)
  "Day"
  iex>Elixir.JD.day({2452163.5}, :value)
  2452163.5

Specs

epoch() :: number()

Returns the epoch of the JD calendar.

Example

  iex>Elixir.JD.epoch()
  -1721424.5

Specs

eq(jd_date(), jd_date()) :: boolean()

Returns true if JD date1 is equal JD date2, otherwise false.

Examples

  iex>Elixir.JD.eq({2452163.5}, {2452163.5})
  true
  iex>Elixir.JD.eq({2452163.5}, {2452263.5})
  false
  iex>Elixir.JD.eq({2452263.5}, {2452163.5})
  false

Specs

field_atom(integer()) :: atom()

Returns the name of the field atom in a JD date at field_index.

Example

  iex>Elixir.JD.field_atom(0)
  :day

Specs

field_atoms() :: [atom()]

Returns a list of the field atoms (names) of a JD date.

Example

  iex>Elixir.JD.field_atoms()
  [:day]

Specs

field_count() :: integer()

Returns the number of fields in a JD date

Example

  iex>Elixir.JD.field_count()
  1

Specs

field_index(atom()) :: integer()

Returns the index (= position) of the field_atom in a JD date.

Example

  iex>Elixir.JD.field_index(:day)
  0

Specs

from_date(tuple(), module()) :: jd_date()

from_date(tuple(), module()) :: {:error, String.t()}

Converts the other_date of the other_calendar into the equivalent date of the JD calendar.

Example

  iex>Elixir.JD.from_date({2001, 9, 11}, Gregorian)
  {2452163.5}

Specs

from_fixed(fixed()) :: jd_date()

Converts a fixed day to a JD date.

Example

  iex>Elixir.JD.from_fixed(730739)
  {2452163.5}

Specs

from_rata_die(tuple() | integer()) :: jd_date()

Converts a RataDie date into the equivalent JD date.

The RataDie date can be given as a tuple or by a RataDie rd.

Examples

  iex>Elixir.JD.from_rata_die({730739})
  {2452163.5}
  iex>Elixir.JD.from_rata_die(730739)
  {2452163.5}

Specs

from_unix(tuple() | integer()) :: jd_date()

Converts a Unix date into the equivalent JD date.

The Unix date can be given as a tuple or by Unix seconds.

Examples

  iex>Elixir.JD.from_unix({1000166400})
  {2452163.5}
  iex>Elixir.JD.from_unix(1000166400)
  {2452163.5}

Specs

ge(jd_date(), jd_date()) :: boolean()

Returns true if JD date1 is greater (= later) than or equal JD date2, otherwise false.

Examples

  iex>Elixir.JD.ge({2452163.5}, {2452163.5})
  true
  iex>Elixir.JD.ge({2452163.5}, {2452263.5})
  false
  iex>Elixir.JD.ge({2452263.5}, {2452163.5})
  true

Specs

gt(jd_date(), jd_date()) :: boolean()

Returns true if JD date1 is greater (= later) than JD date2, otherwise false.

Examples

  iex>Elixir.JD.gt({2452163.5}, {2452163.5})
  false
  iex>Elixir.JD.gt({2452163.5}, {2452263.5})
  false
  iex>Elixir.JD.gt({2452263.5}, {2452163.5})
  true

Specs

keyword() :: atom()

Returns the internal keyword of the JD calendar.

Example

  iex>Elixir.JD.keyword()
  :jd

Specs

le(jd_date(), jd_date()) :: boolean()

Returns true if JD date1 is smaller (= earlier) than or equal JD date2, otherwise false.

Examples

  iex>Elixir.JD.le({2452163.5}, {2452163.5})
  true
  iex>Elixir.JD.le({2452163.5}, {2452263.5})
  true
  iex>Elixir.JD.le({2452263.5}, {2452163.5})
  false

Specs

lt(jd_date(), jd_date()) :: boolean()

Returns true if JD date1 is smaller (= earlier) than JD date2, otherwise false.

Examples

  iex>Elixir.JD.lt({2452163.5}, {2452163.5})
  false
  iex>Elixir.JD.lt({2452163.5}, {2452263.5})
  true
  iex>Elixir.JD.lt({2452263.5}, {2452163.5})
  false

Specs

module() :: module()

Returns the module of the JD calendar.

Example

  iex>Elixir.JD.module()
  JD

Specs

name() :: atom()

Returns the internal name of the JD calendar.

Example

  iex>Elixir.JD.name()
  "JD"

Specs

range(jd_date(), jd_date()) :: integer()

Returns the distance between two JD dates as a range of fixed days.

Example

  iex>Elixir.JD.range({2452163.5}, {2452263.5})
  730739..730839

Specs

start_of_day() :: :midnight | :sunset | :sunrise | :noon

Returns the start of the day in the JD calendar.

Possible return values are:

• :midnight,
• :noon,
• :sunrise,
• :sunset,

Example

  iex>Elixir.JD.start_of_day()
  :noon

Specs

to_date(jd_date(), module()) :: tuple()

Converts a JD date into the equivalent date of the other_calendar.

For the following example to work the Gregorian calendar must be available.

Example

  iex>Elixir.JD.to_date({2452163.5}, Gregorian)
  {2001, 9, 11}

Specs

to_fixed(jd_date()) :: fixed()

to_fixed(jd_day()) :: fixed()

Converts a JD date given by day into a fixed day.

Example

  iex>Elixir.JD.to_fixed(2452163.5)
  730739

Specs

to_rata_die(jd_date()) :: {integer()}

to_rata_die(jd_day()) :: {integer()}

Converts a JD date given by day into the equivalent RataDie date.

Example

  iex>Elixir.JD.to_rata_die(2452163.5)
  {730739}

Specs

to_unix(jd_date()) :: {integer()}

to_unix(jd_day()) :: {integer()}

Converts a JD date given by day into the equivalent Unix date.

Example

  iex>Elixir.JD.to_unix(2452163.5)
  {1000166400}

Specs

today(:fixed | :date) :: fixed() | jd_date()

Returns the current date either as a fixed day or a JD date.

(This cannot be doctested, because today is a moving target.)

The type parameter determines the type of the returned value:

• :fixed returns a fixed day (default),
• :date returns a JD date.

Examples

  Elixir.JD.today()
  730739
  Elixir.JD.today(:fixed)
  730739
  Elixir.JD.today(:date)
  {2452163.5}