AnyLang - Static Localization for Rust

A Rust proc-macro crate for embedding localization files directly into your binary at compile time. Supports JSON format with TOML support planned for future releases.

Features

• Zero-runtime overhead - All translations are compiled into your binary
• Type-safe - Full Rust type checking for all localized strings
• Hierarchical organization - Nested JSON objects become nested Rust modules
• Multi-format support - JSON with TOML coming soon
• Flexible data types - Supports strings, numbers, booleans, arrays, and null values

Installation

Add to your Cargo.toml:

[dependencies]
anylang = { version = "0.1", features = ["json"] }

Usage

Basic JSON Localization

You can do the arrangement differently, but for convenience I will do it like this:

main.rs
lang/
├── en_US.json
├── ru_RU.json
└── de_DE.json

en_US.json:

{
    "ping": "pong",
    "dummy": {
        "foo": "buzz",
        "some": ["none", "or", 0]
    },
    "rust": {
        "rust": "rust",
        "is": null,
        "good": {
            "true": [1, true]
        }
    }
}

ru_RU.json:

{
    "ping": "понг",
    "dummy": {
        "foo": "базз",
        "some": ["ничего", "или", 0]
    },
    "rust": {
        "rust": "раст",
        "is": null,
        "good": {
            "true": [1, true]
        }
    }
}

Support for non-string types

There is also support for all standard JSON types. Examples below

de_DE.json:

228.01

These examples work in different variations of the main.rs file:

use anylang::include_json_dir;

// Include English translations
include_json_dir!("./lang", "en_US");

fn main() {
    assert_eq!(lang::PING, "pong");
    assert_eq!(lang::dummy::FOO, "buzz");
    assert_eq!(lang::dummy::SOME, ["none", "or", "0"]);
    assert_eq!(lang::rust::RUST, "rust");
    assert!(lang::rust::IS.is_empty());
    assert_eq!(lang::rust::good::TRUE, ["1", "true"]);
}

use anylang::include_json_dir;

// Include Russian translations
include_json_dir!("./lang", "ru_RU");

fn main() {
    assert_eq!(lang::PING, "понг");
    assert_eq!(lang::dummy::FOO, "базз");
    assert_eq!(lang::dummy::SOME, ["ничего", "или", "0"]);
    assert_eq!(lang::rust::RUST, "раст");
    assert!(lang::rust::IS.is_empty());
    assert_eq!(lang::rust::good::TRUE, ["1", "true"]);
}

use anylang::include_json_dir;

// Include German translations (simple value)
include_json_dir!("./lang", "de_DE");

fn main() {
    assert_eq!(lang::DE_DE, "228.01");
}

JSON Array Support

AnyLang also supports JSON arrays as root elements:

en_US.json:

[
    {
        "ping": "pong"
    },
    {
        "dummy": {
            "some": ["none", "or", 0]
        },
        "foo": "buzz",
        "rust": {
            "rust": "rust",
            "is": null,
            "good": {
                "true": [1, true]
            }
        }
    }
]

Type Conversion

All JSON types are automatically converted to Rust string types:

• String → &'static str
• Number → &'static str (string representation)
• Boolean → &'static str ("true" or "false")
• Null → &'static str (empty string)
• Array → [&'static str; N]
• Object → Rust module with constants

Naming Convention

JSON keys are converted to SCREAMING_SNAKE_CASE for Rust constants:

• "foo_bar" becomes FOO_BAR
• "some_key" becomes SOME_KEY

Roadmap

• JSON support
• TOML support
• YAML support