Rule

A rule engine written in rust. There's also a python fork.

The rule is a json string or rust object of a list expression. The expression is like [op, arg0, arg1, ..., argn], the op is the operator, and arg0..n is the arguments for the operator. Any argument can be another expression.

For writing convenience, the first argument will be tried to resolve as the context parameter. Or, you can just use the special var operator to indicate the context parameter.

Usage

use rule::{Rule, Result, json};

fn main() -> Result<()> {
    let context = json!({"a": 1, "world": "hello"});

    assert!(Rule::new(json!(["=", "a", 1]))?.matches(&context)?);
    assert!(Rule::new(json!(["=", ["var", "a"], 1]))?.matches(&context)?);
    assert!(Rule::from_str(r#"["=", ["var", "a"], 1]"#)?.matches(&context)?);
    assert!(Rule::from_value(["=", "world", "hello"])?.matches(&context)?);

    // TODO:
    // assert!(rule!(["=", "a", 1]).matches(&context)?);

    Ok(())
}

ToDos

• add more built-in Ops
• support register custom Ops
• support rule! macro

License

http://tclh123.mit-license.org/