rustformat

Is there a more concise way to format .expect() message?

I currently have to use this to format a .expect() message:

fn main() {
    let x: Option<&str> = None;
    x.expect(&format!("the world is ending: {}", "foo")[..]);
}

Is there a less verbose way?

Solution

  • First you don't need to write [..]

    If you really want to panic but also want to format the error message, I think I would use assert!():

    fn main() {
    let x: Option<&str> = None;
    assert!(x.is_some(), "the world is ending: {}", "foo");
    let _x = x.unwrap();
}

    If you want you could also use the unwrap crate:

    use unwrap::unwrap;

fn main() {
    let x: Option<&str> = None;
    let _x = unwrap!(x, "the world is ending: {}", "foo");
}

    Also, both these methods avoid the construction of the error String every time, unlike calling expect() with format!().