Getting Started

Cldr is an Elixir library for the Unicode Consortium’s Common Locale Data Repository (CLDR). The intentions of CLDR, and this library, it to simplify the locale specific formatting of numbers, lists, currencies, calendars, units of measure and dates/times. As of April 2017 and Version 0.1.0, Cldr is based upon CLDR version 31.0.1.

Installation

Add ex_cldr as a dependency to your mix project:

defp deps do
  [
    {:ex_cldr, "~> 0.5.0"}
  ]
end

then retrieve ex_cldr from hex:

mix deps.get
mix deps.compile

Although Cldr is purely a library application, it should be added to your application list so that it gets bundled correctly for release. This applies for Elixir versions up to 1.3.x; version 1.4 will automatically do this for you.

def application do
  [applications: [:ex_cldr]]
end

Additional Cldr Packages: Units, Lists, Dates and Times

ex_cldr includes functions for the localisation and formatting of numbers and currencies. Additional functionality is available by adding additional packages:

List formatting: ex_cldr_lists
Unit formatting: ex_cldr_units
Date/Time/DateTime formatting: ex_cldr_dates_times

Each of these packages includes ex_cldr as a dependency so configuring any of these additional packages will automatically install ex_cldr.

Quick Configuration

Without any specific configuration Cldr will support the “en” locale only. To support additional locales update your config.exs file (or the relevant environment version).

config :ex_cldr,
  default_locale: "en",
  locales: ["fr-*", "pt-BR", "en", "pl", "ru", "th", "he"],
  gettext: MyApp.Gettext

Configures a default locale of “en” (which is itself the Cldr default). Additional locales are configured with the :locales key. In this example, all locales starting with “fr-“ will be configured along with Brazilian Portugues, English, Polish, Russian, Thai and Hebrew.

Recompiling after a configuration change

Note that Elixir can’t determine dependencies based upon configuration so when you make changes to your Cldr configuration a forced recompilation is required in order for the changes to take affect. To recompile:

iex> mix deps.compile ex_cldr --force

Cldr pre-computes a lot of the CLDR specification and compiles them into functions to provide better runtime performance. Needing to recompile the dependency after a configuration change comes as a result of that.

Downloading Configured Locales

Cldr can be installed from either github or from hex.

If installed from github then all 516 locales are installed when the repo is cloned into your application deps.
If installed from hex then only the locales “en” and “root” are installed. When you configure additional locales these will be downloaded during application compilation. Please note above the requirement for a force recompilation in this situation.

Localizing and Formatting Numbers

The Cldr.Number module provides number formatting. The public API for number formatting is Cldr.Number.to_string/2. Some examples:

iex> Cldr.Number.to_string 12345
"12,345"

iex> Cldr.Number.to_string 12345, locale: "fr"
"12 345"

iex> Cldr.Number.to_string 12345, locale: "fr", currency: "USD"
"12 345,00 $US"

iex(4)> Cldr.Number.to_string 12345, format: "#E0"
"1.2345E4"

iex(> Cldr.Number.to_string 1234, format: :roman
"MCCXXXIV"

iex> Cldr.Number.to_string 1234, format: :ordinal
"1,234th"

iex> Cldr.Number.to_string 1234, format: :spellout
"one thousand two hundred thirty-four"

See h Cldr.Number and h Cldr.Number.to_string in iex for further information.

Localizing Lists

The Cldr.List module provides list formatting. The public API for list formating is Cldr.List.to_string/2. Some examples:

iex> Cldr.List.to_string(["a", "b", "c"], locale: "en")
"a, b, and c"

iex> Cldr.List.to_string(["a", "b", "c"], locale: "en", format: :unit_narrow)
"a b c"

iex> Cldr.List.to_string(["a", "b", "c"], locale: "fr")
"a, b et c"

Seer h Cldr.List and h Cldr.List.to_string in iex for further information.

Localizing Units

The Cldr.Unit module provides unit formatting. The public API for unit formating is Cldr.Unit.to_string/3. Some examples:

iex> Cldr.Unit.to_string 123, :volume_gallon
  "123 gallons"

  iex> Cldr.Unit.to_string 1234, :volume_gallon, format: :long
  "1 thousand gallons"

  iex> Cldr.Unit.to_string 1234, :volume_gallon, format: :short
  "1K gallons"

  iex> Cldr.Unit.to_string 1234, :frequency_megahertz
  "1,234 megahertz"

  iex> Cldr.Unit.available_units
  [:volume_gallon, :pressure_pound_per_square_inch, :digital_terabyte,
   :digital_bit, :digital_gigabit, :digital_kilobit, :volume_pint,
   :speed_kilometer_per_hour, :concentr_part_per_million, :energy_calorie,
   :volume_milliliter, :length_fathom, :length_foot, :volume_cubic_yard,
   :mass_microgram, :length_nautical_mile, :volume_deciliter,
   :consumption_mile_per_gallon, :volume_bushel, :volume_cubic_centimeter,
   :length_light_year, :volume_gallon_imperial, :speed_meter_per_second,
   :power_kilowatt, :power_watt, :length_millimeter, :digital_gigabyte,
   :duration_nanosecond, :length_centimeter, :volume_cup_metric,
   :length_kilometer, :angle_degree, :acceleration_g_force, :electric_ampere,
   :volume_quart, :duration_century, :angle_revolution, :volume_hectoliter,
   :area_square_meter, :digital_megabyte, :light_lux, :duration_year,
   :energy_kilocalorie, :frequency_megahertz, :power_horsepower,
   :volume_cubic_meter, :area_hectare, :frequency_hertz, :length_furlong,
   :length_astronomical_unit, ...]

See h Cldr.Unit and h Cldr.Unit.to_string in iex for further information.

Localizing Dates, Times and DateTimes

As of version 0.2.0, formatting of relative dates and date times is supported with the Cldr.Date.Relative module. The public API is Cldr.Date.Relative.to_string/2. Some examples:

iex> Cldr.Date.Relative.to_string(-1)
  "1 second ago"

  iex> Cldr.Date.Relative.to_string(1)
  "in 1 second"

  iex> Cldr.Date.Relative.to_string(1, unit: :day)
  "tomorrow"

  iex> Cldr.Date.Relative.to_string(1, unit: :day, locale: "fr")
  "demain"

  iex> Cldr.Date.Relative.to_string(1, unit: :day, format: :narrow)
  "tomorrow"

  iex> Cldr.Date.Relative.to_string(1234, unit: :year)
  "in 1,234 years"

  iex> Cldr.Date.Relative.to_string(1234, unit: :year, locale: "fr")
  "dans 1 234 ans"

  iex> Cldr.Date.Relative.to_string(31)
  "in 31 seconds"

  iex> Cldr.Date.Relative.to_string(~D[2017-04-29], relative_to: ~D[2017-04-26])
  "in 3 days"

  iex> Cldr.Date.Relative.to_string(310, format: :short, locale: "fr")
  "dans 5 min"

  iex> Cldr.Date.Relative.to_string(310, format: :narrow, locale: "fr")
  "+5 min"

  iex> Cldr.Date.Relative.to_string 2, unit: :wed, format: :short
  "in 2 Wed."

  iex> Cldr.Date.Relative.to_string 1, unit: :wed, format: :short
  "next Wed."

  iex> Cldr.Date.Relative.to_string -1, unit: :wed, format: :short
  "last Wed."

  iex> Cldr.Date.Relative.to_string -1, unit: :wed
  "last Wednesday"

  iex> Cldr.Date.Relative.to_string -1, unit: :quarter
  "last quarter"

  iex> Cldr.Date.Relative.to_string -1, unit: :mon, locale: "fr"
  "lundi dernier"

  iex> Cldr.Date.Relative.to_string(~D[2017-04-29], unit: :ziggeraut)
  {:error,
   "Unknown time unit :ziggeraut.  Valid time units are [:day, :hour, :minute, :month, :second, :week, :year, :mon, :tue, :wed, :thu, :fri, :sat, :sun, :quarter]"}

Gettext Integration

There is an experimental plurals module for Gettext called Cldr.Gettext.Plural. Its not yet fully tested. It is configured in Gettext by:

defmodule MyApp.Gettext do
  use Gettext, plural_forms: Cldr.Gettext.Plural
end

Cldr.Gettext.Plural will fall back to Gettext pluralisation if the locale is not known to Cldr. This module is only compiled if Gettext is configured as a dependency in your project.

Phoenix Integration

There is an imcomplete (ie development not finished) implemenation of a Plug intended to parse the HTTP accept-language header into Cldr compatible locale and number system. Since it’s not development complete it definitely won’t work yet. Comments and ideas (and pull requests) are, however, welcome.

About Locale strings

Note that Cldr defines locale string according to the Unicode standard:

Language codes are two lowercase letters (ie “en”, not “EN”)
Potentially one or more modifiers separated by “-“ (dash), not a “_“. (underscore). If you configure a Gettext module then Cldr will transliterate Gettext’s “_“ into “-“ for compatibility.
Typically the modifier is a territory code. This is commonly a two-letter uppercase combination. For example “pt-BR” is the locale referring to Brazilian Portugese.
In Cldr a locale is always a binary and never an atom. Locale strings are often passed around in HTTP headers and converting to atoms creates an attack vector we can do without.
The locales known to Cldr can be retrieved by Cldr.known_locales to get the locales known to this configuration of Cldr and Cldr.all_locales to get the locales available in the CLDR data repository.

Testing

Tests cover the full 516 locales defined in CLDR. Since Cldr attempts to maximumize the work done at compile time in order to minimize runtime execution, the compilation phase for tests is several minutes.

Tests are run on Elixir 1.5.x. Elixir below 1.5 is not supported.

Cldr

v0.5.0