defmodule Cldr.Number.System do
@moduledoc """
Functions to manage number systems which describe the numbering characteristics for a locale.
A number system defines the digits (if they exist in this number system) or
or rules (if the number system does not have decimal digits).
The system name is also used as a key to define the separators that are used
when formatting a number is this number_system. See
`Cldr.Number.Symbol.number_symbols_for/2`.
"""
alias Cldr.Locale
alias Cldr.Number.{System, Symbol}
alias Cldr.LanguageTag
alias Cldr.Math
@default_number_system_type :default
@type system_name :: atom()
@type types :: :default | :native | :traditional | :finance
defdelegate known_number_systems, to: Cldr
defdelegate known_number_system_types(backend), to: Cldr
@doc """
Return the default number system type name.
Currently this is `:default`. Note that this is
not the number system itself but the type of the
number system. It can be used to find the
default number system for a given locale with
`number_systems_for(locale)[default_number_system()]`.
## Example
iex> Cldr.Number.System.default_number_system_type
:default
"""
def default_number_system_type do
@default_number_system_type
end
@doc """
Return a map of all CLDR number systems and definitions.
## Example
iex> Cldr.Number.System.number_systems |> Enum.count
86
"""
@spec number_systems :: map()
@number_systems Cldr.Config.number_systems()
def number_systems do
@number_systems
end
@systems_with_digits Enum.reject(@number_systems, fn {_name, system} ->
is_nil(system[:digits])
end)
|> Map.new()
@doc """
Number systems that have their own digit characters defined.
"""
def systems_with_digits do
@systems_with_digits
end
@doc """
Returns the default number system from a language tag
or locale name.
## Arguments
* `locale` is any language tag returned be `Cldr.Locale.new/2`
or a locale name in the list returned by `Cldr.known_locale_names/1`
* `backend` is any `Cldr` backend. That is, any module that
contains `use Cldr`
## Returns
* A number system name as an atom
## Examples
iex> Cldr.Number.System.number_system_from_locale "en-US-u-nu-thai", MyApp.Cldr
:thai
iex> Cldr.Number.System.number_system_from_locale :"en-US", MyApp.Cldr
:latn
"""
@spec number_system_from_locale(Locale.locale_reference(), Cldr.backend()) :: system_name
def number_system_from_locale(%LanguageTag{locale: %{numbers: nil}} = locale, backend) do
locale
|> number_systems_for!(backend)
|> Map.fetch!(default_number_system_type())
end
def number_system_from_locale(%LanguageTag{locale: %{numbers: number_system}}, _backend) do
number_system
end
def number_system_from_locale(%LanguageTag{} = locale, backend) do
locale
|> number_systems_for!(backend)
|> Map.fetch!(default_number_system_type())
end
def number_system_from_locale(locale_name, backend) do
with {:ok, locale} <- Cldr.validate_locale(locale_name, backend) do
number_system_from_locale(locale, backend)
end
end
@doc """
Returns the number system from a language tag
or locale name.
## Arguments
* `locale` is any language tag returned be `Cldr.Locale.new/2`
## Returns
* A number system name as an atom
## Examples
iex> {:ok, locale} = MyApp.Cldr.validate_locale("en-US-u-nu-thai")
iex> Cldr.Number.System.number_system_from_locale(locale)
:thai
iex> {:ok, locale} = MyApp.Cldr.validate_locale("en-US")
iex> Cldr.Number.System.number_system_from_locale locale
:latn
iex> Cldr.Number.System.number_system_from_locale("ar")
:arab
"""
@spec number_system_from_locale(Locale.locale_reference()) :: system_name
def number_system_from_locale(%LanguageTag{locale: %{numbers: nil}} = locale) do
number_system_from_locale(locale.cldr_locale_name, locale.backend)
end
def number_system_from_locale(%LanguageTag{locale: %{numbers: number_system}}) do
number_system
end
def number_system_from_locale(%LanguageTag{cldr_locale_name: locale, backend: backend}) do
number_system_from_locale(locale, backend)
end
def number_system_from_locale(locale_name) do
number_system_from_locale(locale_name, Cldr.default_backend!())
end
@doc """
Returns the number systems available for a locale
or `{:error, message}` if the locale is not known.
## Arguments
* `locale` is any valid locale name returned by `Cldr.known_locale_names/0`
or a `Cldr.LanguageTag` struct returned by ``Cldr.Locale.new!/2``
* `backend` is any `Cldr` backend. That is, any module that
contains `use Cldr`
## Examples
iex> Cldr.Number.System.number_systems_for :en
{:ok, %{default: :latn, native: :latn}}
iex> Cldr.Number.System.number_systems_for :th
{:ok, %{default: :latn, native: :thai}}
iex> Cldr.Number.System.number_systems_for "zz", TestBackend.Cldr
{:error, {Cldr.InvalidLanguageError, "The language \\"zz\\" is invalid"}}
"""
@spec number_systems_for(Locale.locale_reference(), Cldr.backend()) ::
{:ok, map()} | {:error, {module(), String.t()}}
def number_systems_for(locale, backend) do
Module.concat(backend, Number.System).number_systems_for(locale)
end
@doc false
def number_systems_for(locale) do
number_systems_for(locale, Cldr.default_backend!())
end
@doc """
Returns the number systems available for a locale
or raises if the locale is not known.
## Arguments
* `locale` is any valid locale name returned by `Cldr.known_locale_names/0`
or a `Cldr.LanguageTag` struct returned by ``Cldr.Locale.new!/2``
* `backend` is any `Cldr` backend. That is, any module that
contains `use Cldr`. The default is `Cldr.default_backend!/0`.
## Examples
iex> Cldr.Number.System.number_systems_for! "en"
%{default: :latn, native: :latn}
iex> Cldr.Number.System.number_systems_for! "th", TestBackend.Cldr
%{default: :latn, native: :thai}
"""
@spec number_systems_for!(Locale.locale_reference(), Cldr.backend()) :: map() | no_return()
def number_systems_for!(locale, backend) do
case number_systems_for(locale, backend) do
{:error, {exception, message}} ->
raise exception, message
{:ok, systems} ->
systems
end
end
@doc false
def number_systems_for!(locale) do
number_systems_for!(locale, Cldr.default_backend!())
end
@doc """
Returns the actual number system from a number system type.
## Arguments
* `locale` is any valid locale name returned by `Cldr.known_locale_names/0`
or a `Cldr.LanguageTag` struct returned by ``Cldr.Locale.new!/2``
* `system_name` is any number system name returned by
`Cldr.known_number_systems/0` or a number system type
returned by `Cldr.known_number_system_types/0`
* `backend` is any `Cldr` backend. That is, any module that
contains `use Cldr`
## Returns
* `{:ok, number_system_map}` or
* `{:error, {exception, reason}}`
## Notes
This function will decode a number system type into the actual
number system. If the number system provided can't be decoded
it is returned as is.
## Examples
iex> Cldr.Number.System.number_system_for "th", :latn, TestBackend.Cldr
{:ok, %{digits: "0123456789", type: :numeric}}
iex> Cldr.Number.System.number_system_for "en", :default, TestBackend.Cldr
{:ok, %{digits: "0123456789", type: :numeric}}
iex> Cldr.Number.System.number_system_for "he", :traditional, TestBackend.Cldr
{:ok, %{rules: "hebrew", type: :algorithmic}}
iex> Cldr.Number.System.number_system_for "en", :finance, TestBackend.Cldr
{
:error,
{
Cldr.UnknownNumberSystemError,
"The number system :finance is unknown for the locale named :en. Valid number systems are %{default: :latn, native: :latn}"
}
}
iex> Cldr.Number.System.number_system_for "en", :native, TestBackend.Cldr
{:ok, %{digits: "0123456789", type: :numeric}}
"""
@spec number_system_for(Locale.locale_reference, System.system_name(), Cldr.backend()) ::
{:ok, map()} | {:error, {module(), String.t()}}
def number_system_for(locale, system_name, backend) do
with {:ok, locale} <- Cldr.validate_locale(locale, backend),
{:ok, system_name} <- system_name_from(system_name, locale, backend) do
{:ok, Map.get(number_systems(), system_name)}
else
{:error, reason} -> {:error, reason}
end
end
@doc """
Returns the names of the number systems available for
a locale or an `{:error, message}` tuple if the locale
is not known.
## Arguments
* `locale` is any locale returned by ``Cldr.Locale.new!/2`` or
a `Cldr.LanguageTag` struct
* `backend` is any `Cldr` backend. That is, any module that
contains `use Cldr`
## Examples
iex> Cldr.Number.System.number_system_names_for("en", TestBackend.Cldr)
{:ok, [:latn]}
iex> Cldr.Number.System.number_system_names_for("th", TestBackend.Cldr)
{:ok, [:latn, :thai]}
iex> Cldr.Number.System.number_system_names_for("he", TestBackend.Cldr)
{:ok, [:latn, :hebr]}
iex> Cldr.Number.System.number_system_names_for("zz", TestBackend.Cldr)
{:error, {Cldr.InvalidLanguageError, "The language \\"zz\\" is invalid"}}
"""
@spec number_system_names_for(Locale.locale_reference(), Cldr.backend()) ::
{:ok, list(atom())} | {:error, {module(), String.t()}}
def number_system_names_for(locale, backend) do
with {:ok, locale} <- Cldr.validate_locale(locale, backend),
{:ok, systems} <- number_systems_for(locale, backend) do
{:ok, systems |> Map.values() |> Enum.uniq()}
else
{:error, reason} -> {:error, reason}
end
end
@doc """
Returns the names of the number systems available for
a locale or an `{:error, message}` tuple if the locale
is not known.
## Arguments
* `locale` is any valid locale name returned by `Cldr.known_locale_names/0`
or a `Cldr.LanguageTag` struct returned by ``Cldr.Locale.new!/2``
* `backend` is any `Cldr` backend. That is, any module that
contains `use Cldr`
## Examples
iex> Cldr.Number.System.number_system_names_for!("en", TestBackend.Cldr)
[:latn]
iex> Cldr.Number.System.number_system_names_for!("th", TestBackend.Cldr)
[:latn, :thai]
iex> Cldr.Number.System.number_system_names_for!("he", TestBackend.Cldr)
[:latn, :hebr]
"""
@spec number_system_names_for!(Locale.locale_reference(), Cldr.backend()) ::
[system_name()] | no_return()
def number_system_names_for!(locale, backend) do
case number_system_names_for(locale, backend) do
{:error, {exception, message}} ->
raise exception, message
{:ok, names} ->
names
end
end
@doc """
Returns a number system name for a given locale and number system reference.
## Arguments
* `system_name` is any number system name returned by
`Cldr.known_number_systems/0` or a number system type
returned by `Cldr.known_number_system_types/0`
* `locale` is any valid locale name returned by `Cldr.known_locale_names/0`
or a `Cldr.LanguageTag` struct returned by ``Cldr.Locale.new!/2``
* `backend` is any `Cldr` backend. That is, any module that
contains `use Cldr`
## Notes
Number systems can be references in one of two ways:
* As a number system type such as :default, :native, :traditional and
:finance. This allows references to a number system for a locale in a
consistent fashion for a given use
* WIth the number system name directly, such as :latn, :arab or any of the
other 70 or so
This function dereferences the supplied `system_name` and returns the
actual system name.
## Examples
ex> Cldr.Number.System.system_name_from(:default, "en", TestBackend.Cldr)
{:ok, :latn}
iex> Cldr.Number.System.system_name_from("latn", "en", TestBackend.Cldr)
{:ok, :latn}
iex> Cldr.Number.System.system_name_from(:native, "en", TestBackend.Cldr)
{:ok, :latn}
iex> Cldr.Number.System.system_name_from(:nope, "en", TestBackend.Cldr)
{
:error,
{Cldr.UnknownNumberSystemError, "The number system :nope is unknown"}
}
Note that return value is not guaranteed to be a valid
number system for the given locale as demonstrated in the third example.
"""
@spec system_name_from(system_name, Locale.locale_reference(), Cldr.backend()) ::
{:ok, atom()} | {:error, {module(), String.t()}}
def system_name_from(system_name, locale, backend) do
with {:ok, locale} <- Cldr.validate_locale(locale, backend),
{:ok, number_system} <- validate_number_system_or_type(system_name, backend),
{:ok, number_systems} <- number_systems_for(locale, backend) do
cond do
Map.has_key?(number_systems, number_system) ->
{:ok, Map.get(number_systems, number_system)}
number_system in Map.values(number_systems) ->
{:ok, number_system}
true ->
{:error, unknown_number_system_for_locale_error(system_name, locale, number_systems)}
end
else
{:error, reason} -> {:error, reason}
end
end
@doc """
Returns a number system name for a given locale and number system reference
and raises if the number system is not available for the given locale.
## Arguments
* `system_name` is any number system name returned by
`Cldr.known_number_systems/0` or a number system type
returned by `Cldr.known_number_system_types/0`
* `locale` is any valid locale name returned by `Cldr.known_locale_names/0`
or a `Cldr.LanguageTag` struct returned by ``Cldr.Locale.new!/2``
* `backend` is any `Cldr` backend. That is, any module that
contains `use Cldr`
## Examples
iex> Cldr.Number.System.system_name_from!(:default, "en", TestBackend.Cldr)
:latn
iex> Cldr.Number.System.system_name_from!("latn", "en", TestBackend.Cldr)
:latn
iex> Cldr.Number.System.system_name_from!(:traditional, "he", TestBackend.Cldr)
:hebr
"""
@spec system_name_from!(system_name, Locale.locale_reference(), Cldr.backend()) ::
atom() | no_return()
def system_name_from!(system_name, locale, backend) do
case system_name_from(system_name, locale, backend) do
{:error, {exception, message}} ->
raise exception, message
{:ok, name} ->
name
end
end
@doc """
Returns locale and number systems that have the same digits and
separators as the supplied one.
## Arguments
* `locale` is any valid locale name returned by `Cldr.known_locale_names/0`
or a `Cldr.LanguageTag` struct returned by ``Cldr.Locale.new!/2``
* `system_name` is any number system name returned by
`Cldr.known_number_systems/0` or a number system type
returned by `Cldr.known_number_system_types/0`
* `backend` is any `Cldr` backend. That is, any module that
contains `use Cldr`
## Returns
## Notes
Transliterating between locale & number systems is expensive. To avoid
unnecessary transliteration we look for locale and number systems that have
the same digits and separators. Typically we are comparing to locale "en"
and number system "latn" since this is what the number formatting routines use
as placeholders.
## Examples
"""
@spec number_systems_like(Locale.locale_reference(), system_name, Cldr.backend()) ::
{:ok, list()} | {:error, {module(), String.t()}}
def number_systems_like(locale, number_system, backend) do
with {:ok, _} <- Cldr.validate_locale(locale, backend),
{:ok, %{digits: digits}} <- number_system_for(locale, number_system, backend),
{:ok, symbols} <- Symbol.number_symbols_for(locale, number_system, backend),
{:ok, names} <- number_system_names_for(locale, backend) do
likes = do_number_systems_like(digits, symbols, names, backend)
{:ok, likes}
end
end
defp do_number_systems_like(digits, symbols, names, backend) do
Enum.map(Cldr.known_locale_names(backend), fn this_locale ->
Enum.reduce(names, [], fn this_system, acc ->
locale = Locale.new!(this_locale, backend)
case number_system_for(locale, this_system, backend) do
{:error, _} ->
acc
{:ok, %{digits: these_digits}} ->
{:ok, these_symbols} = Symbol.number_symbols_for(locale, this_system, backend)
if digits == these_digits && symbols == these_symbols do
acc ++ {locale, this_system}
end
end
end)
end)
|> Enum.reject(&(is_nil(&1) || &1 == []))
end
@doc """
Returns `{:ok, digits}` for a number system, or an `{:error, message}` if the
number system is not known.
## Arguments
* `system_name` is any number system name returned by
`Cldr.known_number_systems/0` or a number system type
returned by `Cldr.known_number_system_types/0`
## Returns
* `{:ok, string_of_digits}` or
* `{:error, {exception, reason}}`
## Examples
iex> Cldr.Number.System.number_system_digits(:latn)
{:ok, "0123456789"}
iex> Cldr.Number.System.number_system_digits(:nope)
{:error, {Cldr.UnknownNumberSystemError, "The number system :nope is not known or does not have digits"}}
"""
@spec number_system_digits(system_name()) ::
{:ok, String.t()} | {:error, {module(), String.t()}}
def number_system_digits(system_name) do
if system = Map.get(systems_with_digits(), system_name) do
{:ok, Map.get(system, :digits)}
else
{:error, number_system_digits_error(system_name)}
end
end
@doc """
Returns `digits` for a number system, or raises an exception if the
number system is not know.
## Arguments
* `system_name` is any number system name returned by
`Cldr.known_number_systems/0` or a number system type
returned by `Cldr.known_number_system_types/0`
## Returns
* A string of the number systems digits or
* raises an exception
## Examples
iex> Cldr.Number.System.number_system_digits! :latn
"0123456789"
Cldr.Number.System.number_system_digits! :nope
** (Cldr.UnknownNumberSystemError) The number system :nope is not known or does not have digits
"""
@spec number_system_digits!(system_name) :: String.t() | no_return()
def number_system_digits!(system_name) do
case number_system_digits(system_name) do
{:ok, digits} ->
digits
{:error, {exception, message}} ->
raise exception, message
end
end
@doc """
Converts a number into the representation of
a non-latin number system.
This function converts numbers to a known
number system only, it does not provide number
formatting.
## Arguments
* `number` is a `float`, `integer` or `Decimal`
* `system_name` is any number system name returned by
`Cldr.known_number_systems/0` or a number system type
returned by `Cldr.known_number_system_types/0`
* `backend` is any `Cldr` backend. That is, any module that
contains `use Cldr`
## Returns
* `{:ok, string_of_digits}` or
* `{:error, {exception, reason}}`
## Notes
There are two types of number systems in CLDR:
* `:numeric` in which the number system defines
a direct mapping between the latin digits `0..9`
into a the number system equivalent. In this case,
` to_system/3` invokes `Cldr.Number.Transliterate.transliterate_digits/3`
for the given number.
* `:algorithmic` in which the number system
does not have the same structure as the `:latn`
number system and therefore the conversion is
done algorithmically. For CLDR the algorithm
is implemented through `Cldr.Rbnf` rulesets.
These rulesets are considered by CLDR to be
less rigorous than the `:numeric` number systems
and caution and testing for a specific use case
is recommended.
## Examples
iex> Cldr.Number.System.to_system 123456, :hebr, TestBackend.Cldr
{:ok, "קכ״ג׳תנ״ו"}
iex> Cldr.Number.System.to_system 123, :hans, TestBackend.Cldr
{:ok, "一百二十三"}
iex> Cldr.Number.System.to_system 123, :hant, TestBackend.Cldr
{:ok, "一百二十三"}
iex> Cldr.Number.System.to_system 123, :hansfin, TestBackend.Cldr
{:ok, "壹佰贰拾叁"}
"""
@spec to_system(Math.number_or_decimal(), atom, Cldr.backend()) ::
{:ok, binary()} | {:error, {module(), String.t()}}
def to_system(number, system_name, backend) do
Module.concat(backend, Number.System).to_system(number, system_name)
end
@doc """
Converts a number into the representation of
a non-latin number system. Returns a converted
string or raises on error.
## Arguments
* `number` is a `float`, `integer` or `Decimal`
* `system_name` is any number system name returned by
`Cldr.known_number_systems/0` or a number system type
returned by `Cldr.known_number_system_types/0`
* `backend` is any `Cldr` backend. That is, any module that
contains `use Cldr`
## Returns
* `string_of_digits` or
* raises an exception
See `Cldr.Number.System.to_system/3` for further
information.
## Examples
iex> Cldr.Number.System.to_system! 123, :hans, TestBackend.Cldr
"一百二十三"
iex> Cldr.Number.System.to_system! 123, :hant, TestBackend.Cldr
"一百二十三"
iex> Cldr.Number.System.to_system! 123, :hansfin, TestBackend.Cldr
"壹佰贰拾叁"
"""
@spec to_system!(Math.number_or_decimal(), atom, Cldr.backend()) ::
binary() | no_return()
def to_system!(number, system_name, backend) do
case to_system(number, system_name, backend) do
{:ok, string} -> string
{:error, {exception, reason}} -> raise exception, reason
end
end
@doc """
Generate a transliteration map between two character classes
## Arguments
* `from` is any `String.t()` intended to represent the
digits of a number system but that's not a requirement.
* `to` is any `String.t()` that is the same length as `from`
intended to represent the digits of a number system.
## Returns
* A map where the keys are the graphemes in `from` and the
values are the graphemes in `to` or
* `{:error, {exception, reason}}`
## Examples
iex> Cldr.Number.System.generate_transliteration_map "0123456789", "9876543210"
%{
"0" => "9",
"1" => "8",
"2" => "7",
"3" => "6",
"4" => "5",
"5" => "4",
"6" => "3",
"7" => "2",
"8" => "1",
"9" => "0"
}
iex> Cldr.Number.System.generate_transliteration_map "0123456789", "987654321"
{:error,
{ArgumentError, "\\"0123456789\\" and \\"987654321\\" aren't the same length"}}
"""
def generate_transliteration_map(from, to) when is_binary(from) and is_binary(to) do
do_generate_transliteration_map(from, to, String.length(from), String.length(to))
end
defp do_generate_transliteration_map(from, to, from_length, to_length)
when from_length == to_length do
from
|> String.graphemes()
|> Enum.zip(String.graphemes(to))
|> Enum.into(%{})
end
defp do_generate_transliteration_map(from, to, _from_length, _to_length) do
{:error, {ArgumentError, "#{inspect(from)} and #{inspect(to)} aren't the same length"}}
end
defp validate_number_system_or_type(number_system, backend) do
with {:ok, number_system} <- Cldr.validate_number_system(number_system) do
{:ok, number_system}
else
{:error, _} ->
with {:ok, number_system} <- Cldr.validate_number_system_type(number_system, backend) do
{:ok, number_system}
else
{:error, _reason} -> {:error, Cldr.unknown_number_system_error(number_system)}
end
end
end
@doc """
Returns an error tuple for an number system unknown to a given locale.
## Arguments
* `number_system` is any number system name **not** returned by `Cldr.known_number_systems/0`
* `locale` is any valid locale name returned by `Cldr.known_locale_names/0`
or a `Cldr.LanguageTag` struct returned by ``Cldr.Locale.new!/2``
* `valid_number_systems` is a map returned by `Cldr.Number.System.number_systems_for/2`
"""
def unknown_number_system_for_locale_error(number_system, locale, valid_number_systems) do
{
Cldr.UnknownNumberSystemError,
"The number system #{inspect(number_system)} is unknown " <>
"for the locale named #{Cldr.locale_name(locale)}. " <>
"Valid number systems are #{inspect(valid_number_systems)}"
}
end
@doc false
def number_system_digits_error(system_name) do
{
Cldr.UnknownNumberSystemError,
"The number system #{inspect(system_name)} is not known or does not have digits"
}
end
end
