ZEN Expression Language

The expression language of ZEN Engine, the open-source Business Rules Engine (BRE) from GoRules.

ZEN expressions are readable by business users and fast enough for hot paths: a complete language for conditions, calculations and data transformation, with lexer, parser, compiler, VM, type checking and natural-language rendering included in this crate.

use serde_json::json;
use zen_expression::evaluate_expression;

fn main() {
    let result = evaluate_expression(
        "sum(items) * multiplier",
        json!({ "items": [10, 20, 30], "multiplier": 2 }).into(),
    )
    .unwrap();
    // => 120
}

Reusable expressions compile once via compile_expression and evaluate repeatedly against different contexts.

Resources

• ZEN Expression Language reference - syntax, operators, built-in functions and date operations
• ZEN Engine - the rules engine built on this language
• GoRules - the platform around the open-source engine
• Online Editor - try expressions in the free editor with a built-in simulator

License

MIT License