#[derive(Default, Debug)]
struct Options {
    a: i32,
    b: i32,
    c: i32,
    d: i32,
    e: f64,
}

impl Options {
    fn with_a(self, a: impl Into<i32>) -> Self {
        Self {
            a: a.into(),
            ..self
        }
    }

    fn with_e(self, e: impl Into<f64>) -> Self {
        Self {
            e: e.into(),
            ..self
        }
    }
}

fn main() {
    let opts = Options::default().with_a(1).with_e(2.0);
    println!("{:?}", opts);
}