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//! Fluent is a modern localization system designed to improve how software is translated. //! //! The Rust implementation provides the low level components for syntax operations, like parser //! and AST, and the core localization struct - [`FluentBundle`]. //! //! [`FluentBundle`] is the low level container for storing and formatting localization messages //! in a single locale. //! //! This crate provides also a number of structures needed for a localization API such as [`FluentResource`], //! [`FluentMessage`], [`FluentArgs`], and [`FluentValue`]. //! //! Together, they allow implementations to build higher-level APIs that use [`FluentBundle`] //! and add user friendly helpers, framework bindings, error fallbacking, //! language negotiation between user requested languages and available resources, //! and I/O for loading selected resources. //! //! # Example //! //! ``` //! use fluent_bundle::{FluentBundle, FluentValue, FluentResource, FluentArgs}; //! //! // Used to provide a locale for the bundle. //! use unic_langid::langid; //! //! let ftl_string = String::from(" //! hello-world = Hello, world! //! intro = Welcome, { $name }. //! "); //! let res = FluentResource::try_new(ftl_string) //! .expect("Failed to parse an FTL string."); //! //! let langid_en = langid!("en-US"); //! let mut bundle = FluentBundle::new(&[langid_en]); //! //! bundle //! .add_resource(res) //! .expect("Failed to add FTL resources to the bundle."); //! //! let msg = bundle.get_message("hello-world") //! .expect("Message doesn't exist."); //! let mut errors = vec![]; //! let pattern = msg.value //! .expect("Message has no value."); //! let value = bundle.format_pattern(&pattern, None, &mut errors); //! //! assert_eq!(&value, "Hello, world!"); //! //! let mut args = FluentArgs::new(); //! args.add("name", FluentValue::from("John")); //! //! let msg = bundle.get_message("intro") //! .expect("Message doesn't exist."); //! let mut errors = vec![]; //! let pattern = msg.value.expect("Message has no value."); //! let value = bundle.format_pattern(&pattern, Some(&args), &mut errors); //! //! // The FSI/PDI isolation marks ensure that the direction of //! // the text from the variable is not affected by the translation. //! assert_eq!(value, "Welcome, \u{2068}John\u{2069}."); //! ``` //! //! # Ergonomics & Higher Level APIs //! //! Reading the example, you may notice how verbose it feels. //! Many core methods are fallible, others accumulate errors, and there //! are intermediate structures used in operations. //! //! This is intentional as it serves as building blocks for variety of different //! scenarios allowing implementations to handle errors, cache and //! optimize results. //! //! At the moment it is expected that users will use //! the `fluent-bundle` crate directly, while the ecosystem //! matures and higher level APIs are being developed. //! //! [`FluentBundle`]: ./type.FluentBundle.html //! [`FluentResource`]: ./struct.FluentResource.html //! [`FluentMessage`]: ./struct.FluentMessage.html //! [`FluentValue`]: ./types/enum.FluentValue.html //! [`FluentArgs`]: ./struct.FluentArgs.html #[macro_use] extern crate rental; use intl_memoizer::{IntlLangMemoizer, Memoizable}; use unic_langid::LanguageIdentifier; mod args; pub mod bundle; pub mod concurrent; mod entry; mod errors; pub mod memoizer; mod message; pub mod resolver; mod resource; pub mod types; pub use args::FluentArgs; pub use errors::FluentError; pub use message::{FluentAttribute, FluentMessage}; pub use resource::FluentResource; pub use types::FluentValue; /// A collection of localization messages for a single locale, which are meant /// to be used together in a single view, widget or any other UI abstraction. /// /// # Examples /// /// ``` /// use fluent_bundle::{FluentBundle, FluentResource, FluentValue, FluentArgs}; /// use unic_langid::langid; /// /// let ftl_string = String::from("intro = Welcome, { $name }."); /// let resource = FluentResource::try_new(ftl_string) /// .expect("Could not parse an FTL string."); /// /// let langid_en = langid!("en-US"); /// let mut bundle = FluentBundle::new(&[langid_en]); /// /// bundle.add_resource(&resource) /// .expect("Failed to add FTL resources to the bundle."); /// /// let mut args = FluentArgs::new(); /// args.add("name", FluentValue::from("Rustacean")); /// /// let msg = bundle.get_message("intro").expect("Message doesn't exist."); /// let mut errors = vec![]; /// let pattern = msg.value.expect("Message has no value."); /// let value = bundle.format_pattern(&pattern, Some(&args), &mut errors); /// assert_eq!(&value, "Welcome, \u{2068}Rustacean\u{2069}."); /// /// ``` /// /// # `FluentBundle` Life Cycle /// /// ## Create a bundle /// /// To create a bundle, call [`FluentBundle::new`] with a locale list that represents the best /// possible fallback chain for a given locale. The simplest case is a one-locale list. /// /// Fluent uses [`LanguageIdentifier`] which can be created using `langid!` macro. /// /// ## Add Resources /// /// Next, call [`add_resource`] one or more times, supplying translations in the FTL syntax. /// /// Since [`FluentBundle`] is generic over anything that can borrow a [`FluentResource`], /// one can use [`FluentBundle`] to own its resources, store references to them, /// or even [`Rc<FluentResource>`] or [`Arc<FluentResource>`]. /// /// The [`FluentBundle`] instance is now ready to be used for localization. /// /// ## Format /// /// To format a translation, call [`get_message`] to retrieve a [`FluentMessage`], /// and then call [`format_pattern`] on the message value or attribute in order to /// retrieve the translated string. /// /// The result of [`format_pattern`] is an [`Cow<str>`]. It is /// recommended to treat the result as opaque from the perspective of the program and use it only /// to display localized messages. Do not examine it or alter in any way before displaying. This /// is a general good practice as far as all internationalization operations are concerned. /// /// If errors were encountered during formatting, they will be /// accumulated in the [`Vec<FluentError>`] passed as the third argument. /// /// While they are not fatal, they usually indicate problems with the translation, /// and should be logged or reported in a way that allows the developer to notice /// and fix them. /// /// /// # Locale Fallback Chain /// /// [`FluentBundle`] stores messages in a single locale, but keeps a locale fallback chain for the /// purpose of language negotiation with i18n formatters. For instance, if date and time formatting /// are not available in the first locale, [`FluentBundle`] will use its `locales` fallback chain /// to negotiate a sensible fallback for date and time formatting. /// /// # Concurrency /// /// As you may have noticed, `FluentBundle` is a specialization of [`FluentBundleBase`] /// which works with an [`IntlMemoizer`][] over `RefCell`. /// In scenarios where the memoizer must work concurrently, there's an implementation of /// `IntlMemoizer` that uses `Mutex` and there's [`concurrent::FluentBundle`] which works with that. /// /// [`add_resource`]: ./bundle/struct.FluentBundleBase.html#method.add_resource /// [`FluentBundle::new`]: ./bundle/struct.FluentBundleBase.html#method.new /// [`FluentMessage`]: ./struct.FluentMessage.html /// [`FluentBundle`]: ./type.FluentBundle.html /// [`FluentResource`]: ./struct.FluentResource.html /// [`get_message`]: ./bundle/struct.FluentBundleBase.html#method.get_message /// [`format_pattern`]: ./bundle/struct.FluentBundleBase.html#method.format_pattern /// [`Cow<str>`]: http://doc.rust-lang.org/std/borrow/enum.Cow.html /// [`Rc<FluentResource>`]: https://doc.rust-lang.org/std/rc/struct.Rc.html /// [`Arc<FluentResource>`]: https://doc.rust-lang.org/std/sync/struct.Arc.html /// [`LanguageIdentifier`]: https://crates.io/crates/unic-langid /// [`IntlMemoizer`]: https://github.com/projectfluent/fluent-rs/tree/master/intl-memoizer /// [`Vec<FluentError>`]: ./enum.FluentError.html /// [`concurrent::FluentBundle`]: ./concurrent/type.FluentBundle.html pub type FluentBundle<R> = bundle::FluentBundleBase<R, IntlLangMemoizer>; impl memoizer::MemoizerKind for IntlLangMemoizer { fn new(lang: LanguageIdentifier) -> Self where Self: Sized, { Self::new(lang) } fn with_try_get_threadsafe<I, R, U>(&self, args: I::Args, cb: U) -> Result<R, I::Error> where Self: Sized, I: Memoizable + Send + Sync + 'static, I::Args: Send + Sync + 'static, U: FnOnce(&I) -> R, { self.with_try_get(args, cb) } fn stringify_value(&self, value: &dyn types::FluentType) -> std::borrow::Cow<'static, str> { value.as_string(self) } }