1 // Copyright 2013 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 // If `Mul` used an associated type for its output, this test would
12 // work more smoothly.
16 #[derive(Copy, Clone)]
22 // methods we want to export as methods as well as operators
25 fn vmul(self, other: f64) -> Vec2 {
26 Vec2 { x: self.x * other, y: self.y * other }
30 // Right-hand-side operator visitor pattern
34 fn mul_vec2_by(&self, lhs: &Vec2) -> Self::Result;
37 // Vec2's implementation of Mul "from the other side" using the above trait
38 impl<Res, Rhs: RhsOfVec2Mul<Result=Res>> Mul<Rhs> for Vec2 {
41 fn mul(self, rhs: Rhs) -> Res { rhs.mul_vec2_by(&self) }
44 // Implementation of 'f64 as right-hand-side of Vec2::Mul'
45 impl RhsOfVec2Mul for f64 {
48 fn mul_vec2_by(&self, lhs: &Vec2) -> Vec2 { lhs.vmul(*self) }
51 // Usage with failing inference
53 let a = Vec2 { x: 3.0f64, y: 4.0f64 };
55 // the following compiles and works properly
56 let v1: Vec2 = a * 3.0f64;
57 println!("{} {}", v1.x, v1.y);
59 // the following compiles but v2 will not be Vec2 yet and
60 // using it later will cause an error that the type of v2
63 println!("{} {}", v2.x, v2.y); // error regarding v2's type