49 lines
1.1 KiB
Rust
49 lines
1.1 KiB
Rust
//@ run-pass
|
|
// Test overloading of the `[]` operator. In particular test that it
|
|
// takes its argument *by reference*.
|
|
|
|
use std::ops::Index;
|
|
|
|
struct AssociationList<K,V> {
|
|
pairs: Vec<AssociationPair<K,V>> }
|
|
|
|
#[derive(Clone)]
|
|
struct AssociationPair<K,V> {
|
|
key: K,
|
|
value: V
|
|
}
|
|
|
|
impl<K,V> AssociationList<K,V> {
|
|
fn push(&mut self, key: K, value: V) {
|
|
self.pairs.push(AssociationPair {key: key, value: value});
|
|
}
|
|
}
|
|
|
|
impl<'a, K: PartialEq + std::fmt::Debug, V:Clone> Index<&'a K> for AssociationList<K,V> {
|
|
type Output = V;
|
|
|
|
fn index(&self, index: &K) -> &V {
|
|
for pair in &self.pairs {
|
|
if pair.key == *index {
|
|
return &pair.value
|
|
}
|
|
}
|
|
panic!("No value found for key: {:?}", index);
|
|
}
|
|
}
|
|
|
|
pub fn main() {
|
|
let foo = "foo".to_string();
|
|
let bar = "bar".to_string();
|
|
|
|
let mut list = AssociationList {pairs: Vec::new()};
|
|
list.push(foo.clone(), 22);
|
|
list.push(bar.clone(), 44);
|
|
|
|
assert_eq!(list[&foo], 22);
|
|
assert_eq!(list[&bar], 44);
|
|
|
|
assert_eq!(list[&foo], 22);
|
|
assert_eq!(list[&bar], 44);
|
|
}
|