Struct intl_memoizer::IntlMemoizer

pub struct IntlMemoizer { /* private fields */ }

IntlMemoizer is designed to handle lazily-initialized references to internationalization formatters.

Constructing a new formatter is often expensive in terms of memory and performance, and the instance is often read-only during its lifetime. The format operations in comparison are relatively cheap.

Because of this relationship, it can be helpful to memoize the constructors, and re-use them across multiple format operations. This strategy is used where all instances of intl APIs such as PluralRules, DateTimeFormat etc. are memoized between all FluentBundle instances.

Example

For a more complete example of the memoization, see the IntlLangMemoizer documentation. This example provides a higher-level overview.

let mut memoizer = IntlMemoizer::default();

// The memoziation happens per-locale.
let en_us = "en-US".parse().expect("Failed to parse.");
let en_us_memoizer: Rc<IntlLangMemoizer> = memoizer.get_for_lang(en_us);

// These arguments are passed into the constructor for `ExampleFormatter`. The
// construct_args will be used for determining the memoization, but the message
// can be different and re-use the constructed instance.
let construct_args = (String::from("prefix:"),);
let message = "The format operation will run";

// Use the `ExampleFormatter` from the `IntlLangMemoizer` example. It returns a
// string that demonstrates the configuration of the formatter. This step will
// construct a new formatter if needed, and run the format operation.
//
// See `IntlLangMemoizer` for more details on this step.
let en_us_result = en_us_memoizer
    .with_try_get::<ExampleFormatter, _, _>(construct_args.clone(), |intl_example| {
        intl_example.format(message)
    });

// The example formatter constructs a string with diagnostic information about
// the configuration.
assert_eq!(
    en_us_result.unwrap(),
    "prefix: lang(en-US) string(The format operation will run)"
);

// The process can be repeated for a new locale.

let de_de = "de-DE".parse().expect("Failed to parse.");
let de_de_memoizer: Rc<IntlLangMemoizer> = memoizer.get_for_lang(de_de);

let de_de_result = de_de_memoizer
    .with_try_get::<ExampleFormatter, _, _>(construct_args.clone(), |intl_example| {
        intl_example.format(message)
    });

assert_eq!(
    de_de_result.unwrap(),
    "prefix: lang(de-DE) string(The format operation will run)"
);

Implementations

impl IntlMemoizer

pub fn get_for_lang(&mut self, lang: LanguageIdentifier) -> Rc<IntlLangMemoizer>

Get a IntlLangMemoizer for a given language. If one does not exist for a locale, it will be constructed and weakly retained. See IntlLangMemoizer for more detailed documentation how to use it.

Trait Implementations

impl Default for IntlMemoizer

fn default() -> IntlMemoizer

Returns the “default value” for a type.