# localize_it – Simple and fast localization library

[](https://crates.io/crates/localize_it)
[](https://docs.rs/localize_it)

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.
---
## Quick Example
```rust
use localize_it::{init_locale, expression, localize};
init_locale!(EN, RU);
expression!(HELLO => {
EN: "Hello",
RU: "Привет",
});
fn main() {
println!("{}", localize!(HELLO));
}
```
---
## Features
* O(1) localization lookup
* Zero allocations
* `no_std` compatible
* Thread-safe global locale (`AtomicUsize`)
* Macro-based API
* No external dependencies
---
## Design Constraints
- Locales are defined at compile time
- Expressions must be `&'static str`
---
## Example With Recommended Project Structure
The recommended usage pattern is to create a dedicated locale module that contains locale initialization and grouped expression modules.
For example:
```text
src/
├─ main.rs
└─ locale/
├─ mod.rs # Locale initialization
├─ error.rs # Expression module for error messages
└─ ui.rs # Expression module for UI elements
```
```rust
// mod.rs
pub mod error;
pub mod ui;
use localize_it::init_locale;
// Initialize locale with two languages
init_locale!(EN, RU);
```
```rust
// 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",
];
```
```rust
// 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",
});
```
```rust
// main.rs (or wherever you want to use the localized strings)
use crate::locale::{error, get_locale, set_locale, ui, Locale};
use localize_it::localize;
fn main() {
let current_locale = get_locale(); // Get current locale
println!("{:?}", current_locale);
set_locale(Locale::RU); // Set locale
// Get one expression
let button_error = localize!(error::COOKIE_BUTTON);
println!("{}", button_error);
// Get another expression
let button_label = localize!(ui::COOKIE_BUTTON);
println!("{}", button_label);
}
```
---
## Usage
Add the following to your `Cargo.toml`:
```toml
[dependencies]
localize_it = "1.1.0"
```
---
## 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
---
## License
This project is licensed under either of
* [Apache License, Version 2.0](https://www.apache.org/licenses/LICENSE-2.0)
([LICENSE-APACHE](https://github.com/ZenKerr/localize_it/blob/HEAD/LICENSE-APACHE))
* [MIT License](https://opensource.org/licenses/MIT)
([LICENSE-MIT](https://github.com/ZenKerr/localize_it/blob/HEAD/LICENSE-MIT))
at your option.