| // 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. |
| |
| #[derive(Clone, Debug, PartialEq)] |
| enum Expression { |
| Dummy, |
| Add(Box<Expression>), |
| } |
| |
| use Expression::*; |
| |
| fn simplify(exp: Expression) -> Expression { |
| match exp { |
| Add(n) => *n.clone(), |
| _ => Dummy |
| } |
| } |
| |
| fn main() { |
| assert_eq!(simplify(Add(Box::new(Dummy))), Dummy); |
| } |
