@spec available_formats(
  Cldr.Locale.locale_reference(),
  Cldr.Calendar.calendar(),
  Cldr.backend()
) :: {:ok, map()} | {:error, {atom(), String.t()}}

Returns a map of the available datetime formats for a given locale and calendar.

Arguments

• locale is any locale returned by Cldr.known_locale_names/0 or a Cldr.LanguageTag.t/0. The default is Cldr.get_locale/0.

• calendar is any calendar returned by Cldr.DateTime.Format.calendars_for/1 The default is :gregorian.

• backend is any module that includes use Cldr and therefore is a Cldr backend module. The default is Cldr.default_backend/0.

Examples:

iex> Cldr.DateTime.available_formats(:en)
{:ok,
 %{
   yw: %{
     other: "'week' w 'of' Y",
     one: "'week' w 'of' Y",
     pluralize: :week_of_year
   },
   GyMMMEd: "E, MMM d, y G",
   Hms: "HH:mm:ss",
   MMMMW: %{
     other: "'week' W 'of' MMMM",
     one: "'week' W 'of' MMMM",
     pluralize: :week_of_month
   },
   E: "ccc",
   MMMd: "MMM d",
   yMEd: "E, M/d/y",
   yQQQ: "QQQ y",
   Ehm: %{unicode: "E h:mm a", ascii: "E h:mm a"},
   M: "L",
   hm: %{unicode: "h:mm a", ascii: "h:mm a"},
   yM: "M/y",
   GyMMMd: "MMM d, y G",
   GyMd: "M/d/y G",
   Gy: "y G",
   Hm: "HH:mm",
   EBhms: "E h:mm:ss B",
   d: "d",
   hms: %{unicode: "h:mm:ss a", ascii: "h:mm:ss a"},
   Ed: "d E",
   Ehms: %{unicode: "E h:mm:ss a", ascii: "E h:mm:ss a"},
   EHms: "E HH:mm:ss",
   Bh: "h B",
   h: %{unicode: "h a", ascii: "h a"},
   Bhms: "h:mm:ss B",
   Hmv: "HH:mm v",
   hmv: %{unicode: "h:mm a v", ascii: "h:mm a v"},
   yMd: "M/d/y",
   ms: "mm:ss",
   MMM: "LLL",
   y: "y",
   Bhm: "h:mm B",
   yMMM: "MMM y",
   yQQQQ: "QQQQ y",
   yMMMEd: "E, MMM d, y",
   yMMMM: "MMMM y",
   EBhm: "E h:mm B",
   Hmsv: "HH:mm:ss v",
   yMMMd: "MMM d, y",
   MEd: "E, M/d",
   EHm: "E HH:mm",
   GyMMM: "MMM y G",
   hmsv: %{unicode: "h:mm:ss a v", ascii: "h:mm:ss a v"},
   H: "HH",
   Md: "M/d",
   MMMEd: "E, MMM d",
   MMMMd: "MMMM d"
 }}

@spec formats(
  Cldr.Locale.locale_reference(),
  Cldr.Calendar.calendar(),
  Cldr.backend()
) :: {:ok, map()} | {:error, {atom(), String.t()}}

Returns a map of the standard datetime formats for a given locale and calendar.

Arguments

• locale is any locale returned by Cldr.known_locale_names/0 or a Cldr.LanguageTag.t/0. The default is Cldr.get_locale/0.

• calendar is any calendar returned by Cldr.DateTime.Format.calendars_for/1 The default is :gregorian.

• backend is any module that includes use Cldr and therefore is a Cldr backend module. The default is Cldr.default_backend/0.

Examples:

iex> Cldr.DateTime.Format.date_time_formats(:en)
{:ok, %Cldr.DateTime.Formats{
  full: "{1}, {0}",
  long: "{1}, {0}",
  medium: "{1}, {0}",
  short: "{1}, {0}"
}}

iex> Cldr.DateTime.Format.date_time_formats(:en, :buddhist, MyApp.Cldr)
{:ok, %Cldr.DateTime.Formats{
  full: "{1}, {0}",
  long: "{1}, {0}",
  medium: "{1}, {0}",
  short: "{1}, {0}"
}}

Guards whether the given datetime has components of a date.

Guard whether the given datetime has components of both a date and a time.

Guards whether the given datetime has components of a time.

Indicates if a given map fulfills the requirements for a naive date time or date time.

Indicates if a given map fulfills the requirements for a date time.

Indicates if a given map fulfills the requirements for a naive date time.

@spec to_string(Cldr.Calendar.any_date_time(), Cldr.backend(), options()) ::
  {:ok, String.t()} | {:error, {module(), String.t()}}

@spec to_string(Cldr.Calendar.any_date_time(), options(), []) ::
  {:ok, String.t()} | {:error, {module(), String.t()}}

Formats a DateTime according to a format string as defined in CLDR and described in TR35.

Arguments

• datetime is a DateTime.t/0 or NaiveDateTime.t/0 struct or any map that contains one or more of the keys :year, :month, :day, :hour, :minute and :second or :microsecond with optional :time_zone, :zone_abbr, :utc_offset, :std_offset and :calendar fields.

• backend is any module that includes use Cldr and therefore is a Cldr backend module. The default is Cldr.default_backend!/0.

• options is a keyword list of options for formatting.

Options

• :format is one of :short, :medium, :long, :full, or a format ID or a format string. The default is :medium for full datetimes (that is, dates having :year, :month, :day, :hour, :minutes, :second and :calendar fields). The default for partial datetimes is to derive a candidate format ID from the date and find the best match from the formats returned by Cldr.DateTime.available_formats/3. See here for more information about specifying formats.

• :date_format is any one of :short, :medium, :long, :full. If defined, this option is used to format the date part of the date time. This option is only acceptable if the :format option is not specified, or is specified as either :short, :medium, :long, :full. If :date_format is not specified then the date format is defined by the :format option.

• :time_format is any one of :short, :medium, :long, :full. If defined, this option is used to format the time part of the date time. This option is only acceptable if the :format option is not specified, or is specified as either :short, :medium, :long, :full. If :time_format is not specified then the time format is defined by the :format option.

• :style is either :at or :default. When set to :at the datetime may be formatted with a localised string representing <date> at <time> if such a format exists. See Cldr.DateTime.Format.date_time_at_formats/2.

• :prefer is either :unicode (the default) or :ascii. A small number of formats have two variants - one using Unicode spaces (typically non-breaking space) and another using only ASCII whitespace. The :ascii format is primarily to support legacy use cases and is not recommended. See Cldr.DateTime.Format.date_time_available_formats/3 to see which formats have these variants.

• :locale is any valid locale name returned by Cldr.known_locale_names/0 or a Cldr.LanguageTag.t/0 struct. The default is Cldr.get_locale/0.

• :number_system a number system into which the formatted datetime digits should be transliterated. See Cldr.known_number_systems/0. The default is the number system associated with the :locale.

• :separators selects which of the available symbol sets should be used when formatting fractional seconds (format character S). The default is :standard. Some limited locales have an alternative :us variant that can be used. See Cldr.Number.Symbol.number_symbols_for/3 for the symbols supported for a given locale and number system.

• :era which, if set to :variant, will use a variant for the era if one is available in the requested locale. In the :en locale, for example, era: :variant will return CE instead of AD and BCE instead of BC.

• period: :variant will use a variant for the time period and flexible time period if one is available in the locale. For example, in the :en locale period: :variant will return "pm" instead of "PM".

Variant Preference

• A small number of formats have one of two different alternatives, each with their own preference specifier. The preferences are specified with the :prefer option to Cldr.Date.to_string/3. The preference is expressed as an atom, or a list of one or two atoms with one atom being either :unicode or :ascii and one atom being either :default or :variant.

  • Some formats (at the time of publishng only time formats but that may change in the future) have :unicode and :ascii versions of the format. The difference is the use of ascii space (0x20) as a separateor in the :ascii verison whereas the :unicode version may use non-breaking or other space characters. The default is :unicode and this is the strongly preferred option. The :ascii format is primarily to support legacy use cases and is not recommended. See Cldr.Time.available_formats/3 to see which formats have these variants.

  • Some formats (at the time of publishing, only date and datetime formats) have :default and :variant versions of the format. These variant formats are only included in a small number of locales. For example, the :"en-CA" locale, which has a :default format respecting typical Canadian formatting and a :variant that is more closely aligned to US formatting. The default is :default.

Notes

• If the provided datetime contains only date fields, the call is delegated to Cldr.Date.to_string/2.

• If the provided datetime contains only time fields, the call is delegated to Cldr.Time.to_string/2.

Returns

• {:ok, formatted_datetime} or

• {:error, reason}

Examples

iex> {:ok, date_time} = DateTime.from_naive(~N[2000-01-01 23:59:59.0], "Etc/UTC")
iex> Cldr.DateTime.to_string(date_time)
{:ok, "Jan 1, 2000, 11:59:59 PM"}
iex> Cldr.DateTime.to_string(date_time, MyApp.Cldr, locale: :en)
{:ok, "Jan 1, 2000, 11:59:59 PM"}
iex> Cldr.DateTime.to_string(date_time, MyApp.Cldr, format: :long, locale: :en)
{:ok, "January 1, 2000, 11:59:59 PM UTC"}
iex> Cldr.DateTime.to_string(date_time, MyApp.Cldr, format: :hms, locale: :en)
{:ok, "11:59:59 PM"}
iex> Cldr.DateTime.to_string(date_time, MyApp.Cldr, format: :full, locale: :en)
{:ok, "Saturday, January 1, 2000, 11:59:59 PM GMT"}
iex> Cldr.DateTime.to_string(date_time, MyApp.Cldr, format: :full, locale: :fr)
{:ok, "samedi 1 janvier 2000, 23:59:59 UTC"}
iex> Cldr.DateTime.to_string(date_time, MyApp.Cldr, format: :full, style: :at, locale: :en)
{:ok, "Saturday, January 1, 2000 at 11:59:59 PM GMT"}
iex> Cldr.DateTime.to_string(date_time, MyApp.Cldr, format: :full, style: :at, locale: :fr)
{:ok, "samedi 1 janvier 2000 à 23:59:59 UTC"}
iex> Cldr.DateTime.to_string(date_time, MyApp.Cldr, format: :MMMMW, locale: :fr)
{:ok, "semaine 1 (janvier)"}
iex> Cldr.DateTime.to_string(date_time, MyApp.Cldr, format: :yw, locale: :fr)
{:ok, "semaine 1 de 2000"}

@spec to_string!(Cldr.Calendar.any_date_time(), Cldr.backend(), options()) ::
  String.t() | no_return()

@spec to_string!(Cldr.Calendar.any_date_time(), options(), []) ::
  String.t() | no_return()

Formats a DateTime according to a format string as defined in CLDR and described in TR35 returning a formatted string or raising on error.

Arguments

• datetime is a DateTime.t/0 or NaiveDateTime.t/0 struct or any map that contains one or more of the keys :year, :month, :day, :hour, :minute and :second or :microsecond with optional :time_zone, :zone_abbr, :utc_offset, :std_offset and :calendar fields.

• backend is any module that includes use Cldr and therefore is a Cldr backend module. The default is Cldr.default_backend!/0.

• options is a keyword list of options for formatting.

Options

• :format is one of :short, :medium, :long, :full, or a format ID or a format string. The default is :medium for full datetimes (that is, dates having :year, :month, :day, :hour, :minutes, :second and :calendar fields). The default for partial datetimes is to derive a candidate format ID from the date and find the best match from the formats returned by Cldr.DateTime.available_formats/3. See here for more information about specifying formats.

• :style is either :at or :default. When set to :at the datetime may be formatted with a localised string representing <date> at <time> if such a format exists. See Cldr.DateTime.Format.date_time_at_formats/2.

• :prefer is either :unicode (the default) or :ascii. A small number of datetime formats have two variants - one using Unicode spaces (typically non-breaking space) and another using only ASCII whitespace. The :ascii format is primarily to support legacy use cases and is not recommended. See Cldr.DateTime.Format.date_time_available_formats/2 to see which formats have these variants.

• :locale is any valid locale name returned by Cldr.known_locale_names/0 or a Cldr.LanguageTag.t/0 struct. The default is Cldr.get_locale/0.

• :number_system a number system into which the formatted datetime digits should be transliterated.

• :era which, if set to :variant, will use a variant for the era if one is available in the requested locale. In the :en locale, for example, era: :variant will return CE instead of AD and BCE instead of BC.

• period: :variant will use a variant for the time period and flexible time period if one is available in the locale. For example, in the :en locale period: :variant will return "pm" instead of "PM".

Variant Preference

• A small number of formats have one of two different alternatives, each with their own preference specifier. The preferences are specified with the :prefer option to Cldr.Date.to_string/3. The preference is expressed as an atom, or a list of one or two atoms with one atom being either :unicode or :ascii and one atom being either :default or :variant.

  • Some formats (at the time of publishng only time formats but that may change in the future) have :unicode and :ascii versions of the format. The difference is the use of ascii space (0x20) as a separateor in the :ascii verison whereas the :unicode version may use non-breaking or other space characters. The default is :unicode and this is the strongly preferred option. The :ascii format is primarily to support legacy use cases and is not recommended. See Cldr.Time.available_formats/3 to see which formats have these variants.

  • Some formats (at the time of publishing, only date and datetime formats) have :default and :variant versions of the format. These variant formats are only included in a small number of locales. For example, the :"en-CA" locale, which has a :default format respecting typical Canadian formatting and a :variant that is more closely aligned to US formatting. The default is :default.

Notes

• If the provided datetime contains only date fields, the call is delegated to Cldr.Date.to_string/2.

• If the provided datetime contains only time fields, the call is delegated to Cldr.Time.to_string/2.

Returns

• formatted_datetime or

• raises an exception

Examples

iex> {:ok, date_time} = DateTime.from_naive(~N[2000-01-01 23:59:59.0], "Etc/UTC")
iex> Cldr.DateTime.to_string!(date_time, MyApp.Cldr, locale: :en)
"Jan 1, 2000, 11:59:59 PM"
iex> Cldr.DateTime.to_string!(date_time, MyApp.Cldr, format: :long, locale: :en)
"January 1, 2000, 11:59:59 PM UTC"
iex> Cldr.DateTime.to_string!(date_time, MyApp.Cldr, format: :full, locale: :en)
"Saturday, January 1, 2000, 11:59:59 PM GMT"
iex> Cldr.DateTime.to_string!(date_time, MyApp.Cldr, format: :full, locale: :fr)
"samedi 1 janvier 2000, 23:59:59 UTC"
iex> Cldr.DateTime.to_string!(date_time, MyApp.Cldr, format: :MMMMW, locale: :fr)
"semaine 1 (janvier)"
iex> Cldr.DateTime.to_string!(date_time, MyApp.Cldr, format: :yw, locale: :fr)
"semaine 1 de 2000"