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Elixir module for parsing bcp 47 ( spec'd language tags.
defmodule BCP47 do
@moduledoc ~S"""
Main BCP47 module.
The `BCP47` module provides a parser for
[bcp 47]( spec'd language tags.
@type tag :: String.t
@doc """
Gets the locale for the current process and the given backend.
This function returns the value of the locale for the current process and the
given `backend`. If there is no locale for the current process and the given
backend, the default locale is set as the locale for the current process and
the given backend and then returned. For more information on the default
locale and how it can be set, refer to the documentation of the `Gettext`
## Examples
#=> %{
langtag: %{
language: %{ language: "hy", extlang: [] },
script: "Latn",
region: "IT",
variant: ["arevela"],
extension: [],
privateuse: []
privateuse: [],
grandfathered: %{ irregular: nil, regular: nil }
@spec parse(tag) :: %{}
def parse(tag) do
cond do
# Return :error for nil values and non-matches
tag == nil -> {:error, "Param 'tag' cannot be nil."}
!valid?(tag) -> {:error, "Param 'tag' with value is invaild."}
# Parse otherwise
true ->
captures = Regex.named_captures(expression, tag)
{:ok, %{
langtag: %{
language: extract_language(captures["language"]),
script: captures["script"],
region: captures["region"],
variant: extract_variants(captures["variant"]),
extension: extract_extensions(captures["extension"]),
privateuse: extract_private(captures["lang_private"])
privateuse: extract_private(captures["private"]),
grandfathered: %{
irregular: captures["gf_irregular"],
regular: captures["gf_regular"]
@spec valid?(tag, Keywort.t) :: boolean
def valid?(tag, opts \\ []) do
if opts[:ietf_only] do
valid_ietf? tag
Blank.present?(tag) && Regex.match?(expression, tag)
defp valid_ietf?(tag) do
Blank.present?(tag) && String.downcase(tag) in ietf_codes
defp expression() do
defp extract_language(string) do
[language|extlang] = string |> String.split("-")
%{ language: language, extlang: extlang }
defp extract_variants(string) do
[_|variants] = string |> String.split("-")
defp extract_extensions(string) do
|> Regex.scan(string, capture: :all_but_first)
|> List.flatten
|> match ->
[singleton|values] = String.split(match, "-")
%{ singleton: singleton, values: values }
defp extract_private(string) do
|> Regex.scan(string, capture: :all_but_first)
|> List.flatten
|> Enum.flat_map(fn match ->
[_|values] = String.split(match, "-")
defp ietf_codes do
~w(af af-na af-za agq agq-cm ak ak-gh am am-et ar ar-001 ar-ae ar-bh ar-dj ar-dz ar-eg ar-eh ar-er ar-il ar-iq ar-jo ar-km ar-kw ar-lb ar-ly ar-ma ar-mr ar-om ar-ps ar-qa ar-sa ar-sd ar-so ar-ss ar-sy ar-td ar-tn ar-ye as as-in asa asa-tz ast ast-es az az-cyrl az-cyrl-az az-latn az-latn-az bas bas-cm be be-by bem bem-zm bez bez-tz bg bg-bg bm bm-latn bm-latn-ml bn bn-bd bn-in bo bo-cn bo-in br br-fr brx brx-in bs bs-cyrl bs-cyrl-ba bs-latn bs-latn-ba ca ca-ad ca-es ca-es-valencia ca-fr ca-it cgg cgg-ug chr chr-us cs cs-cz cy cy-gb da da-dk da-gl dav dav-ke de de-at de-be de-ch de-de de-li de-lu dje dje-ne dsb dsb-de dua dua-cm dyo dyo-sn dz dz-bt ebu ebu-ke ee ee-gh ee-tg el el-cy el-gr en en-001 en-150 en-ag en-ai en-as en-au en-bb en-be en-bm en-bs en-bw en-bz en-ca en-cc en-ck en-cm en-cx en-dg en-dm en-er en-fj en-fk en-fm en-gb en-gd en-gg en-gh en-gi en-gm en-gu en-gy en-hk en-ie en-im en-in en-io en-je en-jm en-ke en-ki en-kn en-ky en-lc en-lr en-ls en-mg en-mh en-mo en-mp en-ms en-mt en-mu en-mw en-my en-na en-nf en-ng en-nr en-nu en-nz en-pg en-ph en-pk en-pn en-pr en-pw en-rw en-sb en-sc en-sd en-sg en-sh en-sl en-ss en-sx en-sz en-tc en-tk en-to en-tt en-tv en-tz en-ug en-um en-us en-us-posix en-vc en-vg en-vi en-vu en-ws en-za en-zm en-zw eo eo-001 es es-419 es-ar es-bo es-cl es-co es-cr es-cu es-do es-ea es-ec es-es es-gq es-gt es-hn es-ic es-mx es-ni es-pa es-pe es-ph es-pr es-py es-sv es-us es-uy es-ve et et-ee eu eu-es ewo ewo-cm fa fa-af fa-ir ff ff-cm ff-gn ff-mr ff-sn fi fi-fi fil fil-ph fo fo-fo fr fr-be fr-bf fr-bi fr-bj fr-bl fr-ca fr-cd fr-cf fr-cg fr-ch fr-ci fr-cm fr-dj fr-dz fr-fr fr-ga fr-gf fr-gn fr-gp fr-gq fr-ht fr-km fr-lu fr-ma fr-mc fr-mf fr-mg fr-ml fr-mq fr-mr fr-mu fr-nc fr-ne fr-pf fr-pm fr-re fr-rw fr-sc fr-sn fr-sy fr-td fr-tg fr-tn fr-vu fr-wf fr-yt fur fur-it fy fy-nl ga ga-ie gd gd-gb gl gl-es gsw gsw-ch gsw-fr gsw-li gu gu-in guz guz-ke gv gv-im ha ha-latn ha-latn-gh ha-latn-ne ha-latn-ng haw haw-us he he-il hi hi-in hr hr-ba hr-hr hsb hsb-de hu hu-hu hy hy-am id id-id ig ig-ng ii ii-cn is is-is it it-ch it-it it-sm ja ja-jp jgo jgo-cm jmc jmc-tz ka ka-ge kab kab-dz kam kam-ke kde kde-tz kea kea-cv khq khq-ml ki ki-ke kk kk-cyrl kk-cyrl-kz kkj kkj-cm kl kl-gl kln kln-ke km km-kh kn kn-in ko ko-kp ko-kr kok kok-in ks ks-arab ks-arab-in ksb ksb-tz ksf ksf-cm ksh ksh-de kw kw-gb ky ky-cyrl ky-cyrl-kg lag lag-tz lb lb-lu lg lg-ug lkt lkt-us ln ln-ao ln-cd ln-cf ln-cg lo lo-la lt lt-lt lu lu-cd luo luo-ke luy luy-ke lv lv-lv mas mas-ke mas-tz mer mer-ke mfe mfe-mu mg mg-mg mgh mgh-mz mgo mgo-cm mk mk-mk ml ml-in mn mn-cyrl mn-cyrl-mn mr mr-in ms ms-latn ms-latn-bn ms-latn-my ms-latn-sg mt mt-mt mua mua-cm my my-mm naq naq-na nb nb-no nb-sj nd nd-zw ne ne-in ne-np nl nl-aw nl-be nl-bq nl-cw nl-nl nl-sr nl-sx nmg nmg-cm nn nn-no nnh nnh-cm nus nus-sd nyn nyn-ug om om-et om-ke or or-in os os-ge os-ru pa pa-arab pa-arab-pk pa-guru pa-guru-in pl pl-pl ps ps-af pt pt-ao pt-br pt-cv pt-gw pt-mo pt-mz pt-pt pt-st pt-tl qu qu-bo qu-ec qu-pe rm rm-ch rn rn-bi ro ro-md ro-ro rof rof-tz root ru ru-by ru-kg ru-kz ru-md ru-ru ru-ua rw rw-rw rwk rwk-tz sah sah-ru saq saq-ke sbp sbp-tz se se-fi se-no se-se seh seh-mz ses ses-ml sg sg-cf shi shi-latn shi-latn-ma shi-tfng shi-tfng-ma si si-lk sk sk-sk sl sl-si smn smn-fi sn sn-zw so so-dj so-et so-ke so-so sq sq-al sq-mk sq-xk sr sr-cyrl sr-cyrl-ba sr-cyrl-me sr-cyrl-rs sr-cyrl-xk sr-latn sr-latn-ba sr-latn-me sr-latn-rs sr-latn-xk sv sv-ax sv-fi sv-se sw sw-cd sw-ke sw-tz sw-ug ta ta-in ta-lk ta-my ta-sg te te-in teo teo-ke teo-ug th th-th ti ti-er ti-et to to-to tr tr-cy tr-tr twq twq-ne tzm tzm-latn tzm-latn-ma ug ug-arab ug-arab-cn uk uk-ua ur ur-in ur-pk uz uz-arab uz-arab-af uz-cyrl uz-cyrl-uz uz-latn uz-latn-uz vai vai-latn vai-latn-lr vai-vaii vai-vaii-lr vi vi-vn vun vun-tz wae wae-ch xog xog-ug yav yav-cm yi yi-001 yo yo-bj yo-ng zgh zgh-ma zh zh-hans zh-hans-cn zh-hans-hk zh-hans-mo zh-hans-sg zh-hant zh-hant-hk zh-hant-mo zh-hant-tw zu zu-za)
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