i18n-runtime** 🎉

🌍 i18n-runtime

Effortless, fast, and type-safe internationalization (i18n) for Rust apps.
Supports both runtime JSON loading and compile-time PHF maps (when used with i18n-codegen).

✨ Features

• ✅ Runtime JSON mode — load translations directly from locales/*.json
• ⚡ Compile-time PHF mode — use generated Rust maps for O(1) lookups
• 🔄 Fallback logic — handles tags like en-IN-BR → en-IN → en
• 🔐 Type-safe keys — auto-generated MessageKey enum
• 🚀 Zero-cost lookups — powered by phf

📦 Installation

Add to your Cargo.toml:

[dependencies]
i18n-runtime = "0.1"

# Only required if you use generated PHF mode
phf = "0.11"

🚀 Quick Start

Runtime JSON mode

1. Define messages.schema.json:

{
  "keys": ["welcome", "login_success", "login_failed"]
}

2. Add a locale file locales/en.json:

{
  "welcome": "Welcome!",
  "login_success": "You have logged in successfully.",
  "login_failed": "Login failed. Please try again."
}

3. Use it in code:

use i18n_runtime::{I18n, Locale};

fn main() -> anyhow::Result<()> {
    let i18n = I18n::from_json_dir("./locales", "en")?;

    let tags = ["en", "hi-IN", "fr"];
    for tag in &tags {
        let loc = Locale::new(tag);
        let msg = i18n.get_owned(&loc, "welcome").unwrap_or("<missing>".into());
        println!("{:<6} => {}", tag, msg);
    }

    Ok(())
}

Output:

en     => Welcome!
hi-IN  => स्वागत है!
fr     => Welcome!

Generated PHF mode

1. Install i18n-codegen:

cargo install i18n-codegen

2. Run the generator:

i18n-codegen ./ ./src/generated_i18n

This creates:

src/generated_i18n/generated_keys.rs   # MessageKey enum
src/generated_i18n/locales/EN.rs       # en.json → phf::Map
src/generated_i18n/locales/HI_IN.rs    # hi-IN.json → phf::Map
src/generated_i18n/mod.rs              # registry

3. Use in code:

// include generated files
include!("generated_i18n/generated_keys.rs");
mod generated_i18n { include!("generated_i18n/mod.rs"); }

use i18n_runtime::{I18n, Locale};

fn main() {
    let registry = generated_i18n::get_generated_registry();
    let i18n = I18n::from_generated_registry(registry, "en");

    let msg = i18n
        .get_by_str_key(&Locale::new("hi-IN"), MessageKey::Welcome.as_str())
        .unwrap();
    println!("{}", msg); // स्वागत है!
}

🔄 Fallback Logic

en-IN-BR → en-IN → en → fallback locale.

🧩 Ecosystem

• i18n-runtime — runtime API (this crate)
• i18n-codegen — generator CLI for compile-time PHF maps

📜 License

MIT