[!NOTE] If you are looking for the Python Readme, please see zmanim-core-bindings.
If you are looking for the Javascript Readme, please see zmanim-core-bindings.

Zmanim Core

A high-performance, no_std Rust library for calculating Jewish religious times (zmanim) and astronomical events. This library provides accurate calculations for sunrise, sunset, prayer times, and Jewish calendar dates based on astronomical algorithms.

🌟 Features

• Astronomical Calculations: Precise sunrise, sunset, and astronomical event calculations
• Jewish Religious Times: Complete zmanim calculations including:
  • Alos Hashachar (dawn)
  • Tzais (nightfall)
  • Chatzos (midday)
  • Prayer times (Shacharis, Mincha, Maariv)
  • Candle lighting times
• Hebrew Calendar: Full Jewish calendar support with:
  • Date conversions
  • Holiday calculations
  • Parsha (weekly Torah portion) information
  • Daf Yomi calculations
• Geolocation Support: Location-based calculations using coordinates
• Cross-Platform: Supports multiple targets including:
  • Windows, Linux, macOS
  • WebAssembly (WASM)
  • Embedded systems (thumbv7em-none-eabihf)
• High Performance: Optimized Rust implementation with LTO and stripping
• No Standard Library: no_std compatible for embedded and WASM use cases

Documentation

This fork closely follows the original KosherJava api where possible. See the JavaDoc for documentation: https://kosherjava.com/zmanim/docs/api/index.html?overview-summary.html

🚀 Quick Start

Installation

Run the following

cargo add zmanim-core

Basic Usage

use zmanim_core::prelude::*;
use chrono::{DateTime, Utc};

// Create a location (Jerusalem coordinates)
let location = GeoLocation::new(
    31.78,   // latitude
    35.22,   // longitude
    754.0,   // elevation in meters
);

// Create a calendar for a specific date
let timestamp = chrono::Utc::now().timestamp_millis();
let calendar = ZmanimCalendar::new(
    timestamp, 
    location, 
    false,  // Use astronomical chatzos for zmanim
    false,  // Use astronomical chatzos for other zmanim
    18 * 60 * 1000, // Candle lighting offset in milliseconds
);

// Get sunrise and sunset times
if let Some(alos72) = calendar.get_alos72() {
    println!("Alos72: {}", DateTime::from_timestamp_millis(alos72).unwrap());
}

if let Some(sunset) = calendar.get_astronomical_calendar().get_sunset() {
    println!("Sunset: {}", DateTime::from_timestamp_millis(sunset).unwrap());
}

// Get Jewish date information
let jewish_date = JewishDate::from_gregorian(
    timestamp, 
    4 * 60 * 60 * 1000, // Timezone offset in milliseconds (4 Hours)
);
println!("Jewish Date: {} {}, {}", 
    jewish_date.get_day_of_month(),
    jewish_date.get_jewish_month_name(),
    jewish_date.get_jewish_year()
);

🧪 Testing

This library includes comprehensive testing against the original KosherJava implementation to ensure accuracy and correctness.

Run Tests

# Run all tests
cargo test

# Run tests with output
cargo test -- --nocapture

# Run specific test module
cargo test zmanim_calendar_tests

Test Coverage

The test suite includes:

• Unit tests for all modules

• Integration tests against Java reference implementation

• Astronomical calculation accuracy tests

• Jewish calendar correctness tests

• Cross-platform compatibility tests

Features

The library supports multiple build targets:

• Native: Windows, Linux, macOS
• WebAssembly: Browser and Node.js compatibility
• Embedded: ARM Cortex-M7 and similar microcontrollers

📖 Documentation

• API Reference: docs.rs/zmanim-core
• Tests: Comprehensive test suite in tests/

🤝 Contributing

We welcome contributions! Please see our contributing guidelines:

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests for new functionality
5. Ensure all tests pass
6. Submit a pull request

Development Setup

# Clone the repository
git clone https://github.com/dickermoshe/zmanim-core.git
cd zmanim-core

# Install dependencies
cargo build

# Run tests
cargo test

# Check formatting
cargo fmt --check

# Run clippy
cargo clippy

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

🙏 Acknowledgments

This library is a Rust port of the KosherJava library, which provides the reference implementation and testing framework. Special thanks to the KosherJava contributors for their excellent work.

📞 Support

• Issues: GitHub Issues
• Discussions: GitHub Discussions
• Documentation: docs.rs/zmanim-core

Made with ❤️ for the Jewish community and Rust enthusiasts