rhai/tests/var_scope.rs

use rhai::{Engine, EvalAltResult, Scope};

#[test]
fn test_var_scope() -> Result<(), EvalAltResult> {
    let mut engine = Engine::new();
    let mut scope = Scope::new();

    engine.eval_with_scope::<()>(&mut scope, "let x = 4 + 5")?;
    assert_eq!(engine.eval_with_scope::<i64>(&mut scope, "x")?, 9);
    engine.eval_with_scope::<()>(&mut scope, "x = x + 1; x = x + 2;")?;
    assert_eq!(engine.eval_with_scope::<i64>(&mut scope, "x")?, 12);
    assert_eq!(engine.eval_with_scope::<()>(&mut scope, "{let x = 3}")?, ());
    assert_eq!(engine.eval_with_scope::<i64>(&mut scope, "x")?, 12);

    Ok(())
}

#[test]
fn test_scope_eval() -> Result<(), EvalAltResult> {
    let mut engine = Engine::new();

    // First create the state
    let mut scope = Scope::new();

    // Then push some initialized variables into the state
    // NOTE: Remember the default numbers used by Rhai are i64 and f64.
    //       Better stick to them or it gets hard to work with other variables in the script.
    scope.push("y".into(), 42_i64);
    scope.push("z".into(), 999_i64);

    // First invocation
    engine
        .eval_with_scope::<()>(
            &mut scope,
            r"
                let x = 4 + 5 - y + z;
                y = 1;
            ",
        )
        .expect("y and z not found?");

    // Second invocation using the same state
    if let Ok(result) = engine.eval_with_scope::<i64>(&mut scope, "x") {
        println!("result: {}", result); // should print 966
    }

    // Variable y is changed in the script
    assert_eq!(scope.get_value::<i64>("y").unwrap(), 1);

    Ok(())
}