localize_it – Simple and fast library for localization

A tiny, zero-allocation localization system for Rust designed with #![no_std] support.

This crate provides a macro-based API for defining compile-time locales and localized string expressions without using dynamic memory, hash maps, or runtime lookups. All localized strings are stored in fixed-size arrays, and the active locale is stored in an atomic variable, making access extremely fast and thread-safe.

Features

O(1) localization lookup
Zero allocations
no_std compatible
Thread-safe global locale (AtomicUsize)
Macro-based API
No external dependencies

Usage

Add the following to your Cargo.toml:

[dependencies]

localize_it = "1.0.0"

Example

The recommended usage pattern is to create a dedicated locale module that contains locale initialization and grouped expression modules. For example:

src/
├─ main.rs
└─ locale/
   ├─ mod.rs     # Locale initialization
   ├─ error.rs   # Expression package for error messages
   └─ ui.rs      # Expression package for UI elements

// mod.rs

pub mod error;
pub mod ui;

use localize_it::init_locale;

// Initialize locale with two languages
init_locale!(EN, RU);

// error.rs

use crate::locale::Expression;

// Expressions can be created manually without the macro
pub const COOKIE_BUTTON: Expression = [
    "Sorry, the button doesn't work",
    "Извините, кнопка не работает",
];

// ui.rs

use crate::locale::Locale;
use localize_it::expression;

// Recommended way to create expressions using the macro
expression!(COOKIE_BUTTON => {EN: "Click to get a cookie", RU: "Нажмите, чтобы получить печенье"});

// main.rs (or wherever you want to use the localized strings)

use crate::locale::error;
use crate::locale::ui;
use crate::locale::{get_locale, set_locale};
use localize_it::localize;

fn main() {
    let current_locale = get_locale(); // Get current locale

    set_locale(Locale::RU); // Set locale

    localize!(error::COOKIE_BUTTON); // Get one expression
    localize!(ui::COOKIE_BUTTON); // Get another expression
}

How It Works

Locales are defined as an enum with #[repr(usize)]
Each localized string is compiled into a fixed-size &'static str array
The active locale is stored as an atomic integer
Localization resolves to a simple array index operation
Invalid locale values safely fall back to the first locale variant

License

This project is licensed under either of