Macro gazebo::cmp_chain

macro_rules! cmp_chain {
    ($e:expr) => { ... };
    ($e:expr, $($x:expr),+ $(,)?) => { ... };
}

Performs a chain of comparison operation expressions yielding std::cmp::Ordering, supporting early exit upon hitting the first expressions that doesn’t yield std::cmp::Ordering::Equal and returning the result of that. This is useful for easily writing a sequence of expressions necessary to yield a comparison result. The macro is expanded inplace, so any expressions dealing with Result types are allowed provided that the larger scope allows returning result.

use std::cmp::Ordering;
use gazebo::cmp_chain;

assert_eq!(
    cmp_chain! {
        1.cmp(&1),
        Ok::<_, ()>(2.cmp(&2))?,
        3.cmp(&4),
        panic!("won't reach this"),
    },
    Ordering::Less,
);