| // Copyright 2015 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. |
| |
| trait Factory { |
| type Product; |
| fn create(&self) -> <Self as Factory>::Product; |
| } |
| |
| impl Factory for f64 { |
| type Product = f64; |
| fn create(&self) -> f64 { *self * *self } |
| } |
| |
| impl<A: Factory, B: Factory> Factory for (A, B) { |
| type Product = (<A as Factory>::Product, <B as Factory>::Product); |
| fn create(&self) -> (<A as Factory>::Product, <B as Factory>::Product) { |
| let (ref a, ref b) = *self; |
| (a.create(), b.create()) |
| } |
| } |
| |
| fn main() { |
| assert_eq!((16., 25.), (4., 5.).create()); |
| } |