Struct icu_provider_adapters::fallback::LocaleFallbackProvider

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pub struct LocaleFallbackProvider<P> { /* private fields */ }

Expand description

A data provider wrapper that performs locale fallback. This enables arbitrary locales to be handled at runtime.

§Examples

use icu_locid::langid;
use icu_provider::prelude::*;
use icu_provider::hello_world::*;
use icu_provider_adapters::fallback::LocaleFallbackProvider;


let req = DataRequest {
    locale: &langid!("ja-JP").into(),
    metadata: Default::default(),
};

// The provider does not have data for "ja-JP":
DataProvider::<HelloWorldV1Marker>::load(&provider, req).expect_err("No fallback");

// But if we wrap the provider in a fallback provider...
let provider = LocaleFallbackProvider::try_new_unstable(provider)
    .expect("Fallback data present");

// ...then we can load "ja-JP" based on "ja" data
let response =
  DataProvider::<HelloWorldV1Marker>::load(&provider, req).expect("successful with vertical fallback");

assert_eq!(
    response.metadata.locale.unwrap(),
    langid!("ja").into(),
);
assert_eq!(
    response.payload.unwrap().get().message,
    "こんにちは世界",
);

Implementations§

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impl LocaleFallbackProvider
where P: DataProvider<LocaleFallbackLikelySubtagsV1Marker> + DataProvider<LocaleFallbackParentsV1Marker> + DataProvider<CollationFallbackSupplementV1Marker>,

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

Create a LocaleFallbackProvider by wrapping another data provider and then loading fallback data from it.

If the data provider being wrapped does not contain fallback data, use LocaleFallbackProvider::new_with_fallbacker.

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impl LocaleFallbackProvider
where P: AnyProvider,

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

Create a LocaleFallbackProvider by wrapping another data provider and then loading fallback data from it.

If the data provider being wrapped does not contain fallback data, use LocaleFallbackProvider::new_with_fallbacker.

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impl LocaleFallbackProvider

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pub fn new_with_fallbacker(provider: P, fallbacker: LocaleFallbacker) -> Self

Wrap a provider with an arbitrary fallback engine.

This relaxes the requirement that the wrapped provider contains its own fallback data.

§Examples

use icu_locid::langid;
use icu_locid_transform::LocaleFallbacker;
use icu_provider::hello_world::*;
use icu_provider::prelude::*;
use icu_provider_adapters::fallback::LocaleFallbackProvider;

let provider = HelloWorldProvider;

let req = DataRequest {
    locale: &langid!("de-CH").into(),
    metadata: Default::default(),
};

// There is no "de-CH" data in the `HelloWorldProvider`
DataProvider::<HelloWorldV1Marker>::load(&provider, req)
    .expect_err("No data for de-CH");

// `HelloWorldProvider` does not contain fallback data,
// but we can construct a fallbacker with `icu_locid_transform`'s
// compiled data.
let provider = LocaleFallbackProvider::new_with_fallbacker(
    provider,
    LocaleFallbacker::new().static_to_owned(),
);

// Now we can load the "de-CH" data via fallback to "de".
let german_hello_world: DataPayload<HelloWorldV1Marker> = provider
    .load(req)
    .expect("Loading should succeed")
    .take_payload()
    .expect("Data should be present");

assert_eq!("Hallo Welt", german_hello_world.get().message);