Struct LocaleFallbacker 

pub struct LocaleFallbacker { /* private fields */ }

Implements the algorithm defined in UTS #35: Locale Inheritance and Matching.

Note that this implementation performs some additional steps compared to the UTS #35 algorithm. See the design doc for a detailed description and #2243 to track alignment with UTS #35.

If running fallback in a loop, use DataLocale::is_und() to break from the loop.

Examples

use icu::locid::locale;
use icu::locid_transform::fallback::LocaleFallbacker;

// Set up a LocaleFallbacker with data.
let fallbacker = LocaleFallbacker::new();

// Create a LocaleFallbackerIterator with a default configuration.
// By default, uses language priority with no additional extension keywords.
let mut fallback_iterator = fallbacker
    .for_config(Default::default())
    .fallback_for(locale!("hi-Latn-IN").into());

// Run the algorithm and check the results.
assert_eq!(fallback_iterator.get(), &locale!("hi-Latn-IN").into());
fallback_iterator.step();
assert_eq!(fallback_iterator.get(), &locale!("hi-Latn").into());
fallback_iterator.step();
assert_eq!(fallback_iterator.get(), &locale!("en-IN").into());
fallback_iterator.step();
assert_eq!(fallback_iterator.get(), &locale!("en-001").into());
fallback_iterator.step();
assert_eq!(fallback_iterator.get(), &locale!("en").into());
fallback_iterator.step();
assert_eq!(fallback_iterator.get(), &locale!("und").into());

Implementations

impl LocaleFallbacker

pub const fn new<'a>() -> LocaleFallbackerBorrowed<'a>

Creates a LocaleFallbacker with compiled fallback data (likely subtags and parent locales).

✨ Enabled with the compiled_data Cargo feature.

📚 Help choosing a constructor

pub fn try_new_with_any_provider( provider: &(impl AnyProvider + ?Sized), ) -> Result<Self, DataError>

A version of [Self :: new] that uses custom data provided by an AnyProvider.

📚 Help choosing a constructor

pub fn try_new_unstable<P>(provider: &P) -> Result<Self, DataError>

where P: DataProvider<LocaleFallbackLikelySubtagsV1Marker> + DataProvider<LocaleFallbackParentsV1Marker> + DataProvider<CollationFallbackSupplementV1Marker> + ?Sized,

A version of Self::new that uses custom data provided by a DataProvider.

📚 Help choosing a constructor

⚠️ The bounds on provider may change over time, including in SemVer minor releases.

pub fn new_without_data() -> Self

Creates a LocaleFallbacker without fallback data. Using this constructor may result in surprising behavior, especially in multi-script languages.

pub fn for_config( &self, config: LocaleFallbackConfig, ) -> LocaleFallbackerWithConfig<'_>

Associates a configuration with this fallbacker.

pub fn as_borrowed(&self) -> LocaleFallbackerBorrowed<'_>

Creates a borrowed version of this fallbacker for performance.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 512 bytes