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.
16 // methods we want to export as methods as well as operators
19 fn vmul(self, other: f64) -> Vec2 {
20 Vec2 { x: self.x * other, y: self.y * other }
24 // Right-hand-side operator visitor pattern
25 trait RhsOfVec2Mul<Result> { fn mul_vec2_by(&self, lhs: &Vec2) -> Result; }
27 // Vec2's implementation of Mul "from the other side" using the above trait
28 impl<Res, Rhs: RhsOfVec2Mul<Res>> Mul<Rhs,Res> for Vec2 {
29 fn mul(&self, rhs: &Rhs) -> Res { rhs.mul_vec2_by(self) }
32 // Implementation of 'f64 as right-hand-side of Vec2::Mul'
33 impl RhsOfVec2Mul<Vec2> for f64 {
34 fn mul_vec2_by(&self, lhs: &Vec2) -> Vec2 { lhs.vmul(*self) }
37 // Usage with failing inference
39 let a = Vec2 { x: 3.0f64, y: 4.0f64 };
41 // the following compiles and works properly
42 let v1: Vec2 = a * 3.0f64;
43 println!("{} {}", v1.x, v1.y);
45 // the following compiles but v2 will not be Vec2 yet and
46 // using it later will cause an error that the type of v2
49 println!("{} {}", v2.x, v2.y); // error regarding v2's type