use crate::List;
use std::cmp::Ordering;
use std::cmp::Ordering::*;
impl<A: PartialEq> PartialEq for List<A> {
fn eq(&self, other: &List<A>) -> bool {
self.len() == other.len() && {
for (a, b) in self.iter().zip(other.iter()) {
if a != b {
return false;
}
}
true
}
}
}
impl<A: Eq> Eq for List<A> {}
impl<A: PartialOrd> PartialOrd for List<A> {
fn partial_cmp(&self, other: &List<A>) -> Option<Ordering> {
let (mut a, mut b) = (self.iter(), other.iter());
loop {
match (a.next(), b.next()) {
(None, None) => return Some(Equal),
(None, _) => return Some(Less),
(_, None) => return Some(Greater),
(Some(x), Some(y)) => match x.partial_cmp(&y) {
Some(Equal) => (),
non_eq => return non_eq,
},
}
}
}
}
impl<A: Ord> Ord for List<A> {
fn cmp(&self, other: &List<A>) -> Ordering {
let (mut a, mut b) = (self.iter(), other.iter());
loop {
match (a.next(), b.next()) {
(None, None) => return Equal,
(None, _) => return Less,
(_, None) => return Greater,
(Some(x), Some(y)) => match x.cmp(&y) {
Equal => (),
non_eq => return non_eq,
},
}
}
}
}