test.rs

fn example() -> Result<()> {
    let mut state = State::new();

    fn add(stack: FunctionStack) -> Result<i32> {
        let sz = stack.check_size(1..)?;

        let mut sum = 0f64;
        for i in 1..(sz + 1) {
            sum += stack.arg::<f64>(i)?;
        }
        stack.push(sum);

        Ok(1)
    }

    state.set("test", Table::new(|cxt| {
        cxt.set("add", add);
    }));

    state.eval(r#"
print(test.add(5))               -- 5
print(test.add(5, 10))           -- 15
print(test.add(5, 10, 100, 200)) -- 315
    "#)?;

    Ok(())
}