Function variants

tests/all/component_model/dynamic.rs:580–711

()

#[test]
fn variants() -> Result<()> {
    let engine = super::engine();
    let mut store = Store::new(&engine, ());

    let fragment = r#"
                (type $c' (record (field "D" bool) (field "E" u32)))
                (export $c "c" (type $c'))
                (type $Foo' (variant
                    (case "A" u32)
                    (case "B" float64)
                    (case "C" $c)
                ))
            "#;

    let component = Component::new(
        &engine,
        make_echo_component_with_params(
            fragment,
            &[
                Param(Type::U8, Some(0)),
                Param(Type::I64, Some(8)),
                Param(Type::I32, None),
            ],
        ),
    )?;
    let instance = Linker::new(&engine).instantiate(&mut store, &component)?;
    let func = instance.get_func(&mut store, "echo").unwrap();
    let input = Val::Variant("B".into(), Some(Box::new(Val::Float64(3.14159265))));
    let mut output = [Val::Bool(false)];
    func.call(&mut store, &[input.clone()], &mut output)?;

    assert_eq!(input, output[0]);

    // Do it again, this time using case "C"

    let component = Component::new(
        &engine,
        make_echo_component_with_params(
            fragment,
            &[
                Param(Type::U8, Some(0)),
                Param(Type::I64, Some(8)),
                Param(Type::I32, Some(12)),
            ],
        ),
    )?;
    let instance = Linker::new(&engine).instantiate(&mut store, &component)?;
    let func = instance.get_func(&mut store, "echo").unwrap();
    let input = Val::Variant(
        "C".into(),
        Some(Box::new(Val::Record(vec![
            ("D".into(), Val::Bool(true)),
            ("E".into(), Val::U32(314159265)),
        ]))),
    );
    func.call(&mut store, &[input.clone()], &mut output)?;

    assert_eq!(input, output[0]);