Dynarule 🚀

A flexible, JSON-based rule engine for Rust, designed for dynamic condition evaluation. Supports nested conditions, custom functions, rule priorities, dynamic updates, and templated outcomes using Tera.

✨ Features

• ⚡️ Define rules in JSON
• 🔍 Evaluate conditions with operators (>, <, >=, <=, =)
• 🌳 Nested conditions with AND/OR
• 🛠 Custom functions (e.g., length(name))
• ⚖️ Rule prioritization and stop-on-first-match
• 🔄 Dynamic rule reloading from files
• 📝 Templated outcomes (e.g., "Hello, {{name}}!")

📦 Installation

Add this to your Cargo.toml:

[dependencies]
dynarule = "0.1.0"

📚 Usage

Simple Rule Evaluation

This example shows a basic rule that checks if an age is over 18:

use dynarule::{RuleEngine, Rule, Condition, Outcome};
use std::collections::HashMap;
use serde_json;

fn main() {
    let rule = Rule {
        condition: Condition::Simple("age > 18".to_string()),
        outcome: Outcome {
            key: "eligible".to_string(),
            value: serde_json::json!(true)
        },
        ..Default::default()
    };
    let engine = RuleEngine::new(vec![rule]);

    let mut input = HashMap::new();
    input.insert("age".to_string(), serde_json::json!(25));
    let context = HashMap::new();
    let outcomes = engine.evaluate(&input, &context).unwrap();
    println!("Outcomes: {:?}", outcomes);  // Prints: [Outcome { key: "eligible", value: true }]
}

Advanced Example

This example demonstrates nested conditions, templating, and contextual data:

use dynarule::{RuleEngine, Rule, Condition, Outcome};
use std::collections::HashMap;
use serde_json;

fn main() {
    let rule = Rule {
        condition: Condition::And(vec![
            Condition::Simple("age > 18".to_string()),
            Condition::Simple("time > 12".to_string()),
        ]),
        outcome: Outcome {
            key: "access".to_string(),
            value: serde_json::json!("Hello, {{name}} at {{time}}!")
        },
        priority: 10,
    };
    let engine = RuleEngine::new(vec![rule]);

    let mut input = HashMap::new();
    input.insert("age".to_string(), serde_json::json!(25));
    input.insert("name".to_string(), serde_json::json!("Haile"));
    let mut context = HashMap::new();
    context.insert("time".to_string(), serde_json::json!(14));
    let outcomes = engine.evaluate(&input, &context).unwrap();
    println!("Outcomes: {:?}", outcomes);  // Prints: [Outcome { key: "access", value: "Hello, Haile at 14!" }]
}

🗺 Roadmap

• Rule Chaining
• Type Safety for Inputs and Outputs
• Performance Optimization
• Debugging and Logging
• Extensibility via Plugins
• Multi-Format Rule Support

📄 License

Licensed under either of:

• MIT License (LICENSE-MIT or http://opensource.org/licenses/MIT)
• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0) at your option.