#cldr #icu #unicode #localization #locale #i18n


API for managing Unicode Language and Locale Identifiers

7 releases (breaking)

new 1.0.0-beta1 Aug 5, 2022
0.6.0 May 10, 2022
0.5.0 Jan 31, 2022
0.4.0 Nov 2, 2021
0.1.0 Oct 15, 2020

#13 in Internationalization (i18n)

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Used in 32 crates (23 directly)


7.5K SLoC

icu_locid crates.io

Parsing, manipulating, and serializing Unicode Language and Locale Identifiers.

This module is published as its own crate (icu_locid) and as part of the icu crate. See the latter for more details on the ICU4X project.

The module provides algorithms for parsing a string into a well-formed language or locale identifier as defined by UTS #35: Unicode LDML 3. Unicode Language and Locale Identifiers.

[Locale] is the most common structure to use for storing information about a language, script, region, variants and extensions. In almost all cases, this struct should be used as the base unit for all locale management operations.

[LanguageIdentifier] is a strict subset of [Locale] which can be useful in a narrow range of cases where Unicode Extensions are not relevant.

If in doubt, use [Locale].


use icu::locid::subtags::{Language, Region};
use icu::locid::Locale;

let mut loc: Locale = "en-US".parse().expect("Parsing failed.");

let lang: Language = "en".parse().expect("Parsing failed.");
let region: Region = "US".parse().expect("Parsing failed.");

assert_eq!(loc.id.language, lang);
assert_eq!(loc.id.script, None);
assert_eq!(loc.id.region, Some(region));
assert_eq!(loc.id.variants.len(), 0);

let region: Region = "GB".parse().expect("Parsing failed.");
loc.id.region = Some(region);

assert_eq!(loc.to_string(), "en-GB");


use icu::locid::{langid, subtags_language as language, subtags_region as region};

let lid = langid!("EN_US");

assert_eq!(lid.language, language!("en"));
assert_eq!(lid.region, Some(region!("US")));

For more details, see [Locale] and [LanguageIdentifier].

More Information

For more information on development, authorship, contributing etc. please visit ICU4X home page.