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use indexmap::indexmap;
use indexmap::Equivalent;
use std::hash::Hash;
#[derive(Debug, Hash)]
pub struct Pair<A, B>(pub A, pub B);
impl<A, B, C, D> PartialEq<(A, B)> for Pair<C, D>
where
C: PartialEq<A>,
D: PartialEq<B>,
{
fn eq(&self, rhs: &(A, B)) -> bool {
self.0 == rhs.0 && self.1 == rhs.1
}
}
impl<A, B, X> Equivalent<X> for Pair<A, B>
where
Pair<A, B>: PartialEq<X>,
A: Hash + Eq,
B: Hash + Eq,
{
fn equivalent(&self, other: &X) -> bool {
*self == *other
}
}
#[test]
fn test_lookup() {
let s = String::from;
let map = indexmap! {
(s("a"), s("b")) => 1,
(s("a"), s("x")) => 2,
};
assert!(map.contains_key(&Pair("a", "b")));
assert!(!map.contains_key(&Pair("b", "a")));
}
#[test]
fn test_string_str() {
let s = String::from;
let mut map = indexmap! {
s("a") => 1, s("b") => 2,
s("x") => 3, s("y") => 4,
};
assert!(map.contains_key("a"));
assert!(!map.contains_key("z"));
assert_eq!(map.swap_remove("b"), Some(2));
}