rust-rule-engine 1.20.1

A blazing-fast Rust rule engine with RETE algorithm, backward chaining inference, and GRL (Grule Rule Language) syntax. Features: forward/backward chaining, pattern matching, unification, O(1) rule indexing, TMS, expression evaluation, method calls, streaming with Redis state backend, watermarking, and custom functions. Production-ready for business rules, expert systems, real-time stream processing, and decision automation.
Documentation 
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// Expression Evaluation Demo - CLIPS-style arithmetic
// This demonstrates runtime expression evaluation in GRL

rule "CalculateOrderTotal" salience 100 no-loop {
    when
        Order.quantity > 0 && Order.price > 0
    then
        Log("Calculating order total...");
        Order.total = Order.quantity * Order.price;
        Order.discount = Order.total * 0.1;
        Order.final = Order.total - Order.discount;
}

rule "CalculateTax" salience 90 no-loop {
    when
        Order.final > 0
    then
        Log("Calculating tax...");
        Order.tax = Order.final * 0.08;
        Order.grandTotal = Order.final + Order.tax;
}

rule "BulkDiscount" salience 80 no-loop {
    when
        Order.quantity >= 10
    then
        Log("Applying bulk discount!");
        Order.bulkSavings = Order.total * 0.15;
}