Shaum

A production-grade Rust library for Islamic fasting (Shaum) jurisprudence with high-precision astronomical calculations for Hilal visibility.

Features

Fiqh Engine

• Hijri Conversion: Umm al-Qura algorithm with moon-sighting adjustment support.
• Rule Priority: Haram > Wajib > Sunnah > Makruh > Mubah.
• Status Classification:
  • Wajib: Ramadan
  • Haram: Eid al-Fitr, Eid al-Adha, Days of Tashriq
  • Sunnah: Arafah, Ashura, Tasu'a, Ayyamul Bidh, Mondays, Thursdays, Shawwal
  • Makruh: Singling out Friday or Saturday

Astronomy Engine

Native high-precision ephemeris calculations for Hilal visibility determination:

• Sun Position: VSOP87 theory (~1 arcsec precision)
• Moon Position: ELP2000-82 theory (~1 arcsec precision)
• Coordinate Systems: Ecliptic, Equatorial, Horizontal
• Corrections: Topocentric parallax, atmospheric refraction (Bennett)
• Visibility: MABIMS criteria (altitude ≥ 3°, elongation ≥ 6.4°)

Validated against 87 years of historical Indonesian Ramadan dates (1938-2024).

Installation

Rust

[dependencies]
shaum = "0.8"

JavaScript/TypeScript (NPM)

npm install shaum-wasm

Deno (JSR)

import { analyze } from "jsr:@islam/shaum";

Usage

Rust

use shaum::prelude::*;
use chrono::NaiveDate;

let date = NaiveDate::from_ymd_opt(2025, 6, 5).unwrap();
let analysis = shaum::analyze_date(date)?;

println!("Status: {:?}", analysis.primary_status);

JavaScript

import init, { analyze } from 'shaum-wasm';

await init();

const result = analyze("2025-06-05");
console.log(result.primaryStatus);

Workspace Structure

shaum/
├── crates/
│   ├── shaum-types/       # Zero-dependency types
│   ├── shaum-calendar/    # Hijri conversion
│   ├── shaum-astronomy/   # VSOP87/ELP2000
│   ├── shaum-rules/       # Fasting jurisprudence
│   ├── shaum-network/     # Async geolocation
│   └── shaum-core/        # Facade crate
├── bindings/
│   ├── shaum_wasm/        # WebAssembly
│   └── shaum_py/          # Python (pyo3)
└── xtask/                 # Build automation

Validation

| Component | Method | Precision | |-----------|--------|-----------| | Sun (VSOP87) | Meeus Example 25.a | ~0.27 arcsec | | Moon (ELP2000) | Meeus Example 47.a | ~0.02 arcsec | | Historical | Indonesian Ramadan 1938-2024 | 87/87 passed |

References

• Jean Meeus, Astronomical Algorithms (2nd ed.)
• MABIMS visibility criteria (Indonesia/Malaysia/Brunei/Singapore)
• VSOP87 (Bretagnon & Francou, 1988)
• ELP2000-82 (Chapront-Touzé & Chapront, 1983)

License

MIT License. Copyright (c) 2026 Mohammad Farid Hendianto.