rhai/tests/native.rs

use rhai::{Dynamic, Engine, EvalAltResult, ImmutableString, NativeCallContext, INT};
use std::any::TypeId;

#[cfg(not(feature = "no_module"))]
#[cfg(not(feature = "unchecked"))]
#[test]
fn test_native_context() -> Result<(), Box<EvalAltResult>> {
    let mut engine = Engine::new();

    engine.set_max_modules(40);
    engine.register_fn("test", |context: NativeCallContext, x: INT| {
        context.engine().max_modules() as INT + x
    });

    assert_eq!(engine.eval::<INT>("test(2)")?, 42);

    Ok(())
}

#[test]
fn test_native_context_fn_name() -> Result<(), Box<EvalAltResult>> {
    fn add_double(
        context: NativeCallContext,
        args: &mut [&mut Dynamic],
    ) -> Result<Dynamic, Box<EvalAltResult>> {
        let x = args[0].as_int().unwrap();
        let y = args[1].as_int().unwrap();
        Ok(format!("{}_{}", context.fn_name(), x + 2 * y).into())
    }

    let mut engine = Engine::new();

    engine
        .register_raw_fn(
            "add_double",
            &[TypeId::of::<INT>(), TypeId::of::<INT>()],
            add_double,
        )
        .register_raw_fn(
            "append_x2",
            &[TypeId::of::<INT>(), TypeId::of::<INT>()],
            add_double,
        );

    assert_eq!(engine.eval::<String>("add_double(40, 1)")?, "add_double_42");

    assert_eq!(engine.eval::<String>("append_x2(40, 1)")?, "append_x2_42");

    Ok(())
}

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

    assert_eq!(
        engine.eval::<String>(r#"let x = "hello, "; let y = "world"; x + y"#)?,
        "hello, world"
    );
    assert_eq!(
        engine.eval::<String>(r#"let x = "hello"; let y = (); x + y"#)?,
        "hello"
    );

    // Overload the `+` operator for strings

    engine
        .register_fn(
            "+",
            |s1: ImmutableString, s2: ImmutableString| -> ImmutableString {
                format!("{}***{}", s1, s2).into()
            },
        )
        .register_fn("+", |s1: ImmutableString, _: ()| -> ImmutableString {
            format!("{} Foo!", s1).into()
        });

    assert_eq!(
        engine.eval::<String>(r#"let x = "hello"; let y = "world"; x + y"#)?,
        "hello***world"
    );
    assert_eq!(
        engine.eval::<String>(r#"let x = "hello"; let y = (); x + y"#)?,
        "hello Foo!"
    );

    Ok(())
}