| // Copyright 2012 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| // Test overloading of the `[]` operator. In particular test that it |
| // takes its argument *by reference*. |
| |
| |
| #![feature(core)] |
| |
| 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); |
| } |