crowbook-localize

A library to localize strings, translating them according to runtime options.

Basically, this library allows your project to generate a lformat! macro, that behaves similarly to format!, except the message string (the first argument) might get translated (if you can find the appropriate string for the language).

Usage

First, you'll need to add the following to your Cargo.toml file:

build = "build.rs"

[build-dependencies]
crowbook-localize = "0.0.3"

[dependencies]
lazy_static = "0.2" # the generated file needs `lazy_static!`

You'll then need to create the build.rs file, which can look like this:

extern crate crowbook_localize;
use crowbook_localize::{Localizer, Extractor};

fn main() {
    // Generate the `localize_macros.rs` file
    let mut localizer = Localizer::new();
    localizer.write_macro_file(concat!(env!("CARGO_MANIFEST_DIR"), "/src/lib/localize_macros.rs")).unwrap();

    // Generate a `lang/default.pot` containing strings used to call `lformat!`
    let mut extractor = Extractor::new();
    extractor.add_messages_from_dir(concat!(env!("CARGO_MANIFEST_DIR"), "/src")).unwrap();
    extractor.write_pot_file(concat!(env!("CARGO_MANIFEST_DIR"), "/lang/default.pot")).unwrap();
}

This way, a localize_macros.rs file will be created at build time in src/lib. To use it, the last step is to modify your src/lib/lib.rs file:

#[macro_use] extern crate lazy_static;
#[macro_use] mod localize_macros;

Once this is done, you can start replacing your calls to format! with calls to lformat!.

In order to get translation, you'll need to actually translate the strings in separate files, and set your build.rs to load them.

E.g., if you have the following code:

println!("{}", lformat!("Hello, world!"));

and you want it translated in french, you'll have to create a lang/fr.mo file from the lang/default.pot file containing:

msgid "Hello, world!";
msgstr "Bonjour le monde !";

And load it in your build.rs file:

let mut localizer = Localizer::new();
localizer.add_lang("fr", include_str!(concat!(env!("CARGO_MANIFEST_DIR"), "/lang/fr.mo"))).unwrap();
localizer.write_macro_file("...");

Once this is done, you can use the localize_macros::set_lang function to switch the language at runtime:

use localize_macros::set_lang;
set_lang("en");
println!("{}", lformat!("Hello, world!")); // prints "Hello, world!"
set_lang("fr");
println!("{}", lformat!("Hello, world!")); // prints "Bonjour le monde !"

Warning

In case the complexity of the operation didn't discourage you, I should warn you that this library is highly experimental at this time.

Documentation

See the documentation on docs.rs.

ChangeLog

See the ChangeLog file.

Author

Élisabeth Henry liz.henry@ouvaton.org.

License

This is free software, published under the Mozilla Public License, version 2.0.