1 // Copyright 2012-2014 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.
15 fn bind<B>(&self, f: |&A| -> Vec<B> ) -> Vec<B> ;
18 impl<A> vec_monad<A> for Vec<A> {
19 fn bind<B>(&self, f: |&A| -> Vec<B> ) -> Vec<B> {
20 let mut r = Vec::new();
21 for elt in self.iter() {
22 r.push_all_move(f(elt));
28 trait option_monad<A> {
29 fn bind<B>(&self, f: |&A| -> Option<B>) -> Option<B>;
32 impl<A> option_monad<A> for Option<A> {
33 fn bind<B>(&self, f: |&A| -> Option<B>) -> Option<B> {
35 Some(ref a) => { f(a) }
41 fn transform(x: Option<int>) -> Option<~str> {
42 x.bind(|n| Some(*n + 1) ).bind(|n| Some(n.to_str()) )
46 assert_eq!(transform(Some(10)), Some(~"11"));
47 assert_eq!(transform(None), None);
49 .bind(|x| vec!(x.clone(), *x + "!") )
50 .bind(|x| vec!(x.clone(), *x + "?") ) ==
51 vec!(~"hi", ~"hi?", ~"hi!", ~"hi!?"));