rust/src/test/run-pass/overloaded-index-autoderef.rs
Niko Matsakis 0b5bc3314f Implement new operator dispatch semantics.
Key points are:
1. `a + b` maps directly to `Add<A,B>`, where `A` and `B` are the types of `a` and `b`.
2. Indexing and slicing autoderefs consistently.
2014-11-05 11:29:15 -05:00

80 lines
1.7 KiB
Rust

// Copyright 2014 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 overloaded indexing combined with autoderef.
struct Foo {
x: int,
y: int,
}
impl Index<int,int> for Foo {
fn index(&self, z: &int) -> &int {
if *z == 0 {
&self.x
} else {
&self.y
}
}
}
impl IndexMut<int,int> for Foo {
fn index_mut(&mut self, z: &int) -> &mut int {
if *z == 0 {
&mut self.x
} else {
&mut self.y
}
}
}
trait Int {
fn get(self) -> int;
fn get_from_ref(&self) -> int;
fn inc(&mut self);
}
impl Int for int {
fn get(self) -> int { self }
fn get_from_ref(&self) -> int { *self }
fn inc(&mut self) { *self += 1; }
}
fn main() {
let mut f = box Foo {
x: 1,
y: 2,
};
assert_eq!(f[1], 2);
f[0] = 3;
assert_eq!(f[0], 3);
// Test explicit IndexMut where `f` must be autoderef:
{
let p = &mut f[1];
*p = 4;
}
// Test explicit Index where `f` must be autoderef:
{
let p = &f[1];
assert_eq!(*p, 4);
}
// Test calling methods with `&mut self`, `self, and `&self` receivers:
f[1].inc();
assert_eq!(f[1].get(), 5);
assert_eq!(f[1].get_from_ref(), 5);
}