# `Cldr.Number.System` [๐Ÿ”—](https://github.com/elixir-cldr/cldr_numbers/blob/v2.38.2/lib/cldr/number/system.ex#L1) Number systems information is used to define different representations for numeric values to an end user. Numbering systems are defined in CLDR as one of two different types: algorithmic and numeric. Numeric systems are simply a decimal based system that uses a predefined set of digits to represent numbers. Examples are Western digits (ASCII digits), Thai digits, Devanagari digits. Algorithmic systems are more complex in nature, since the proper formatting and presentation of a numeric quantity is based on some algorithm or set of rules. Examples are Chinese numerals, Hebrew numerals, or Roman numerals. In CLDR, the rules for presentation of numbers in an algorithmic system are defined using the rules based number formats (RBNF) which are implemented in `Cldr.Number.Rbnf`. ### Number system attributes Attributes for a number system map are as follows: * `:id` specifies the name of the number system that can be used to designate its use in formatting. * `:type` specifies whether the number system is algorithmic or numeric. * `:digits`For numeric systems, specifies the digits used to represent numbers, in order, starting from zero. * `:rules` specifies the RBNF ruleset to be used for formatting numbers from this number system. The rules specifier can contain simply a ruleset name, in which case the ruleset is assumed to be found in the rule set grouping "NumberingSystemRules". Alternatively, the specifier can denote a specific locale, ruleset grouping, and ruleset name, separated by slashes. An example of a number system map is: iex> Cldr.Number.System.number_systems()[:latn] %{type: :numeric, digits: "0123456789"} iex> Cldr.Number.System.number_systems()[:taml] %{type: :algorithmic, rules: "tamil"} ### Number system types Each number system also categories number systems into various types: * `:native` defines the number system used for the native digits, usually defined as a part of the script used to write the language. `:native` number system can only be a numeric positional decimal-digit number system, using digits with General_Category=Decimal_Number. Note that In locales where the native number system is the default, it is assumed that the number system "latn" (Western digits 0-9) is always acceptable, and can be selected using the `-nu` keyword as part of a Unicode locale name. * `:traditional` defines the traditional numerals for a locale. This numbering system may be numeric or algorithmic. If the traditional number system is not defined, the native number system is used as a fallback. * `:finance` defines the number system used for financial quantities. This number system may be numeric or algorithmic. This is often used for ideographic languages such as Chinese, where it would be easy to alter an amount represented in the default number system simply by adding additional strokes. If the financial number system is not specified, the default number system is used as a fallback. An example of a number system map for the `:zh` locale is: iex> Cldr.Number.System.number_systems_for(:zh, MyApp.Cldr) {:ok, %{default: :latn, native: :hanidec, traditional: :hans, finance: :hansfin}} This indicates that for the locale `:zh`, the number systems `:latn`, `:hanidec`, `:hans` and `:hansfin` are supported. These number systems are a mix of nuemeric systems and algorithmic systems. ### Specifying the number system in a locale name The types defined for other number systems can be used in a Unicode locale identifier to select the proper number system without having to know the specific number system by name. For example: * To select the Hindi language using the native digits for numeric formatting, use locale ID: "hi-IN-u-nu-native". * To select the Chinese language using the appropriate financial numerals, use locale ID: "zh-u-nu-finance". * To select the Tamil language using the traditional Tamil numerals, use locale ID: "ta-u-nu-traditio". * To select the Arabic language using western digits 0-9, use locale ID: "ar-u-nu-latn". # `system_name` ```elixir @type system_name() :: atom() ``` # `types` ```elixir @type types() :: :default | :native | :traditional | :finance ``` # `algorithmic_systems` *since 2.32.0* Returns a map of the number systems that are algorithmic. Algorithmic number systems don't have decimal digits. Numbers are formed by algorithm using rules based number formats. The `:rules` field contains the name of the RBNF rule that will be used with formatting a number with `format: :standard` (which is also the default when no `:format` is specified). See also `Cldr.Number.System.numeric_systems/0`. ### Example ==> Cldr.Number.System.algorithmic_systems() %{ roman: %{type: :algorithmic, rules: "roman-upper"}, armn: %{type: :algorithmic, rules: "armenian-upper"}, armnlow: %{type: :algorithmic, rules: "armenian-lower"}, cyrl: %{type: :algorithmic, rules: "cyrillic-lower"}, ethi: %{type: :algorithmic, rules: "ethiopic"}, geor: %{type: :algorithmic, rules: "georgian"}, grek: %{type: :algorithmic, rules: "greek-upper"}, greklow: %{type: :algorithmic, rules: "greek-lower"}, hanidays: %{ type: :algorithmic, rules: "zh/SpelloutRules/spellout-numbering-days" }, hans: %{type: :algorithmic, rules: "zh/SpelloutRules/spellout-cardinal"}, hansfin: %{ type: :algorithmic, rules: "zh/SpelloutRules/spellout-cardinal-financial" }, ... } # `default_number_system_type` Return the default number system type name. The default number system type is `:default`. Note that this is not the number system itself but the type of the number system. ## Example iex> Cldr.Number.System.default_number_system_type() :default # `default_rbnf_rule` Returns the default RBNF rule name for an algorithmic number system. ### 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`. * `backend` is any `Cldr` backend. That is, any module that contains `use Cldr`. ### Returns * `{:ok, {module, rule_function, locale}}` or * `{:error, {module(), reason}}` ### Example iex> Cldr.Number.System.default_rbnf_rule(:taml, MyApp.Cldr) {:ok, {MyApp.Cldr.Rbnf.NumberSystem, :tamil, :und}} iex> Cldr.Number.System.default_rbnf_rule(:hebr, MyApp.Cldr) {:ok, {MyApp.Cldr.Rbnf.NumberSystem, :hebrew, :und}} iex> Cldr.Number.System.default_rbnf_rule(:jpanfin, MyApp.Cldr) {:ok, {MyApp.Cldr.Rbnf.Spellout, :spellout_cardinal_financial, :ja}} iex> Cldr.Number.System.default_rbnf_rule(:latn, MyApp.Cldr) {:error, {Cldr.UnknownNumberSystemError, "The number system :latn is not algorithmic"}} # `generate_transliteration_map` 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"}} # `known_number_system_types` # `known_number_systems` # `number_system_digits` ```elixir @spec number_system_digits(system_name()) :: {:ok, String.t()} | {:error, {module(), String.t()}} ``` Returns the digits for a number system as a string. ### 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"}} # `number_system_digits!` ```elixir @spec number_system_digits!(system_name()) :: String.t() | no_return() ``` Returns `digits` for a number system, or raises an exception. ### 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 # `number_system_for` ```elixir @spec number_system_for(Cldr.Locale.locale_reference(), system_name(), Cldr.backend()) :: {:ok, map()} | {:error, {module(), String.t()}} ``` 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}} # `number_system_from_locale` ```elixir @spec number_system_from_locale(Cldr.Locale.locale_reference()) :: system_name() | {:error, {module(), String.t()}} ``` 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-EG") :arab # `number_system_from_locale` ```elixir @spec number_system_from_locale(Cldr.Locale.locale_reference(), Cldr.backend()) :: system_name() | {:error, {module(), String.t()}} ``` 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 # `number_system_names_for` ```elixir @spec number_system_names_for(Cldr.Locale.locale_reference(), Cldr.backend()) :: {:ok, [atom()]} | {:error, {module(), String.t()}} ``` Returns the names of the number systems available for a locale. ### Arguments * `locale` is any locale returned by `Cldr.Locale.new!/2`. * `backend` is any `Cldr` backend. That is, any module that contains `use Cldr`. ### Returns * `{:ok, list_of_number_system_names}` or * `{:error, {exception, reason}}`. ### 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"}} # `number_system_names_for!` ```elixir @spec number_system_names_for!(Cldr.Locale.locale_reference(), Cldr.backend()) :: [system_name()] | no_return() ``` Returns the names of the number systems available for a locale or raises an exception. ## 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`. ### Returns * `list_of_number_system_names` or * raises and exception. ## 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] # `number_systems` ```elixir @spec number_systems() :: %{ ahom: %{digits: String.t(), type: :numeric}, tirh: %{digits: String.t(), type: :numeric}, tols: %{digits: String.t(), type: :numeric}, arabext: %{digits: String.t(), type: :numeric}, arab: %{digits: String.t(), type: :numeric}, orya: %{digits: String.t(), type: :numeric}, armnlow: %{rules: String.t(), type: :algorithmic}, romanlow: %{rules: String.t(), type: :algorithmic}, beng: %{digits: String.t(), type: :numeric}, onao: %{digits: String.t(), type: :numeric}, mtei: %{digits: String.t(), type: :numeric}, mymrtlng: %{digits: String.t(), type: :numeric}, knda: %{digits: String.t(), type: :numeric}, cakm: %{digits: String.t(), type: :numeric}, telu: %{digits: String.t(), type: :numeric}, rohg: %{digits: String.t(), type: :numeric}, ethi: %{rules: String.t(), type: :algorithmic}, hant: %{rules: String.t(), type: :algorithmic}, gonm: %{digits: String.t(), type: :numeric}, hanidec: %{digits: String.t(), type: :numeric}, sunu: %{digits: String.t(), type: :numeric}, cyrl: %{rules: String.t(), type: :algorithmic}, tnsa: %{digits: String.t(), type: :numeric}, latn: %{digits: String.t(), type: :numeric}, tibt: %{digits: String.t(), type: :numeric}, laoo: %{digits: String.t(), type: :numeric}, grek: %{rules: String.t(), type: :algorithmic}, fullwide: %{digits: String.t(), type: :numeric}, gukh: %{digits: String.t(), type: :numeric}, mroo: %{digits: String.t(), type: :numeric}, hanidays: %{rules: String.t(), type: :algorithmic}, sora: %{digits: String.t(), type: :numeric}, hebr: %{rules: String.t(), type: :algorithmic}, olck: %{digits: String.t(), type: :numeric}, mathmono: %{digits: String.t(), type: :numeric}, outlined: %{digits: String.t(), type: :numeric}, tamldec: %{digits: String.t(), type: :numeric}, mathdbl: %{digits: String.t(), type: :numeric}, roman: %{rules: String.t(), type: :algorithmic}, mymr: %{digits: String.t(), type: :numeric}, mathsans: %{digits: String.t(), type: :numeric}, hmng: %{digits: String.t(), type: :numeric}, hansfin: %{rules: String.t(), type: :algorithmic}, taml: %{rules: String.t(), type: :algorithmic}, lepc: %{digits: String.t(), type: :numeric}, osma: %{digits: String.t(), type: :numeric}, kawi: %{digits: String.t(), type: :numeric}, nkoo: %{digits: String.t(), type: :numeric}, gara: %{digits: String.t(), type: :numeric}, wcho: %{digits: String.t(), type: :numeric}, takr: %{digits: String.t(), type: :numeric}, talu: %{digits: String.t(), type: :numeric}, gong: %{digits: String.t(), type: :numeric}, deva: %{digits: String.t(), type: :numeric}, bhks: %{digits: String.t(), type: :numeric}, saur: %{digits: String.t(), type: :numeric}, mymrshan: %{digits: String.t(), type: :numeric}, cham: %{digits: String.t(), type: :numeric}, modi: %{digits: String.t(), type: :numeric}, mlym: %{digits: String.t(), type: :numeric}, vaii: %{digits: String.t(), type: :numeric}, wara: %{digits: String.t(), type: :numeric}, sind: %{digits: String.t(), type: :numeric}, guru: %{digits: String.t(), type: :numeric}, armn: %{rules: String.t(), type: :algorithmic}, diak: %{digits: String.t(), type: :numeric}, shrd: %{digits: String.t(), type: :numeric}, mong: %{digits: String.t(), type: :numeric}, jpan: %{rules: String.t(), type: :algorithmic}, lana: %{digits: String.t(), type: :numeric}, jpanyear: %{rules: String.t(), type: :algorithmic}, mymrepka: %{digits: String.t(), type: :numeric}, kali: %{digits: String.t(), type: :numeric}, hans: %{rules: String.t(), type: :algorithmic}, lanatham: %{digits: String.t(), type: :numeric}, sinh: %{digits: String.t(), type: :numeric}, thai: %{digits: String.t(), type: :numeric}, geor: %{rules: String.t(), type: :algorithmic}, limb: %{digits: String.t(), type: :numeric}, jpanfin: %{rules: String.t(), type: :algorithmic}, khmr: %{digits: String.t(), type: :numeric}, nagm: %{digits: String.t(), type: :numeric}, sund: %{digits: String.t(), type: :numeric}, hantfin: %{rules: String.t(), type: :algorithmic}, bali: %{digits: String.t(), type: :numeric}, greklow: %{rules: String.t(), type: :algorithmic}, krai: %{digits: String.t(), type: :numeric}, brah: %{digits: String.t(), type: :numeric}, newa: %{digits: String.t(), type: :numeric}, segment: %{digits: String.t(), type: :numeric}, java: %{digits: String.t(), type: :numeric}, mathsanb: %{digits: String.t(), type: :numeric}, mathbold: %{digits: String.t(), type: :numeric}, hmnp: %{digits: String.t(), type: :numeric}, adlm: %{digits: String.t(), type: :numeric}, mymrpao: %{digits: String.t(), type: :numeric}, gujr: %{digits: String.t(), type: :numeric} } ``` Return a map of all CLDR number systems and their definitions. ## Example iex> Cldr.Number.System.number_systems() |> Enum.count 97 # `number_systems_for` ```elixir @spec number_systems_for(Cldr.Locale.locale_reference(), Cldr.backend()) :: {:ok, map()} | {:error, {module(), String.t()}} ``` Returns the number system types mapped to a number system name for a locale. When formatting a nummber it is acceptable to refer to either the nuumber system type or the number system name. ### 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`. ### Returns * `{:ok, number_system_map}` or * `{:error, {exception, reason}}`. ### 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"}} # `number_systems_for!` ```elixir @spec number_systems_for!(Cldr.Locale.locale_reference(), Cldr.backend()) :: map() | no_return() ``` Returns the number system types mapped to a number system name for a locale or raises an exception. ### 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`. ### Returns * `number_system_map` or * raises an exception. ### 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} # `number_systems_like` ```elixir @spec number_systems_like( Cldr.Locale.locale_reference(), system_name(), Cldr.backend() ) :: {:ok, list()} | {:error, {module(), String.t()}} ``` 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 ==> import Cldr.LanguageTag.Sigil ==> Cldr.Number.System.number_systems_like(:en, :latn, MyApp.Cldr) {:ok, [ {~l[en], :latn}, {~l[en-IN], :latn}, {~l[ta], :latn}, {~l[th], :latn}, {~l[zh], :latn} ] } # `numeric_systems` Returns a map of the number systems that have their own digit character representations. See also `Cldr.Number.System.algorithmic_systems/0`. ### Example ==> Cldr.Number.System.numeric_systems() %{ gonm: %{type: :numeric, digits: "๐‘ต๐‘ต‘๐‘ต’๐‘ต“๐‘ต”๐‘ต•๐‘ต–๐‘ต—๐‘ต˜๐‘ต™"}, mathdbl: %{type: :numeric, digits: "๐Ÿ˜๐Ÿ™๐Ÿš๐Ÿ›๐Ÿœ๐Ÿ๐Ÿž๐ŸŸ๐Ÿ ๐Ÿก"}, bhks: %{type: :numeric, digits: "๐‘ฑ๐‘ฑ‘๐‘ฑ’๐‘ฑ“๐‘ฑ”๐‘ฑ•๐‘ฑ–๐‘ฑ—๐‘ฑ˜๐‘ฑ™"}, deva: %{type: :numeric, digits: "เฅฆเฅงเฅจเฅฉเฅชเฅซเฅฌเฅญเฅฎเฅฏ"}, adlm: %{type: :numeric, digits: "๐žฅ๐žฅ‘๐žฅ’๐žฅ“๐žฅ”๐žฅ•๐žฅ–๐žฅ—๐žฅ˜๐žฅ™"}, telu: %{type: :numeric, digits: "เฑฆเฑงเฑจเฑฉเฑชเฑซเฑฌเฑญเฑฎเฑฏ"}, cakm: %{type: :numeric, digits: "๐‘„ถ๐‘„ท๐‘„ธ๐‘„น๐‘„บ๐‘„ป๐‘„ผ๐‘„ฝ๐‘„พ๐‘„ฟ"}, mathsans: %{ type: :numeric, digits: "๐Ÿข๐Ÿฃ๐Ÿค๐Ÿฅ๐Ÿฆ๐Ÿง๐Ÿจ๐Ÿฉ๐Ÿช๐Ÿซ" }, nkoo: %{type: :numeric, digits: "฿€฿฿‚฿ƒ฿„฿…฿†฿‡฿ˆ฿‰"}, ... } # `system_name_from` ```elixir @spec system_name_from(system_name(), Cldr.Locale.locale_reference(), Cldr.backend()) :: {:ok, atom()} | {:error, {module(), String.t()}} ``` 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`. ### Returns * `{:ok, number_system_name}` or * `{:error, {exception, reason}}`. ### 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. # `system_name_from!` ```elixir @spec system_name_from!(system_name(), Cldr.Locale.locale_reference(), Cldr.backend()) :: atom() | no_return() ``` Returns a number system name for a given locale and number system reference or raises an exception. ### 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`. ### Returns * `number_system_name` or * raises an exception. ### 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 # `systems_with_digits` > This function is deprecated. Use numeric_systems/0 instead. # `to_system` ```elixir @spec to_system(Cldr.Math.number_or_decimal(), atom(), Cldr.backend()) :: {:ok, binary()} | {:error, {module(), String.t()}} ``` 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, "ืงื›ืดื’ืณืชื ืดื•"} iex> Cldr.Number.System.to_system(123, :hans, TestBackend.Cldr) {:ok, "ไธ€็™พไบŒๅไธ‰"} iex> Cldr.Number.System.to_system(123, :hant, TestBackend.Cldr) {:ok, "ไธ€็™พไบŒๅไธ‰"} iex> Cldr.Number.System.to_system(123, :hansfin, TestBackend.Cldr) {:ok, "ๅฃนไฝฐ่ดฐๆ‹พๅ"} # `to_system!` ```elixir @spec to_system!(Cldr.Math.number_or_decimal(), atom(), Cldr.backend()) :: binary() | no_return() ``` Converts a number into the representation of a non-latin number system or raises an exception. ### 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) "ไธ€็™พไบŒๅไธ‰" iex> Cldr.Number.System.to_system!(123, :hant, TestBackend.Cldr) "ไธ€็™พไบŒๅไธ‰" iex> Cldr.Number.System.to_system!(123, :hansfin, TestBackend.Cldr) "ๅฃนไฝฐ่ดฐๆ‹พๅ" # `unknown_number_system_for_locale_error` 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`. ### Returns * `{Cldr.UnknownNumberSystemError, reason}` --- *Consult [api-reference.md](api-reference.md) for complete listing*