| // Copyright 2013 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 Speak : Sized { |
| fn say(&self, s:&str) -> String; |
| fn hi(&self) -> String { hello(self) } |
| } |
| |
| fn hello<S:Speak>(s:&S) -> String{ |
| s.say("hello") |
| } |
| |
| impl Speak for isize { |
| fn say(&self, s:&str) -> String { |
| format!("{}: {}", s, *self) |
| } |
| } |
| |
| impl<T: Speak> Speak for Option<T> { |
| fn say(&self, s:&str) -> String { |
| match *self { |
| None => format!("{} - none", s), |
| Some(ref x) => { format!("something!{}", x.say(s)) } |
| } |
| } |
| } |
| |
| |
| pub fn main() { |
| assert_eq!(3.hi(), "hello: 3".to_string()); |
| assert_eq!(Some(Some(3)).hi(), |
| "something!something!hello: 3".to_string()); |
| assert_eq!(None::<isize>.hi(), "hello - none".to_string()); |
| |
| assert_eq!(Some(None::<isize>).hi(), "something!hello - none".to_string()); |
| assert_eq!(Some(3).hi(), "something!hello: 3".to_string()); |
| } |