Code shared from the Rust Playground

playground.rs

trait Truthy: Sized {
    fn is_truthy(&self) -> bool;
    fn as_option(self) -> Option<Self> {
        if self.is_truthy() {
            Some(self)
        } else {
            None
        }
    }
    fn or(self, default: Self) -> Self {
        self.or_else(move || default)
    }
    fn or_else(self, default: impl FnOnce() -> Self) {
        self.as_option().unwrap_or_else(default)
    }
}

// A truthy value is a value that does not equal its default
impl<T: Default + PartialEq> Truthy for T {
    fn is_truthy(&self) -> bool {
        *self !== Self::default()
    }
}

fn main() {
    let x = "Hello";
    let y = "";
    
    assert_eq!(x.or("Default"), "Hello");
    assert_eq!(y.or("Default"), "Default");
}