| // Copyright 2014 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. |
| |
| // A model for how the `Fn` traits could work. You can implement at |
| // most one of `Go`, `GoMut`, or `GoOnce`, and then the others follow |
| // automatically. |
| |
| // aux-build:go_trait.rs |
| |
| |
| extern crate go_trait; |
| |
| use go_trait::{Go, GoMut, GoOnce, go, go_mut, go_once}; |
| |
| use std::rc::Rc; |
| use std::cell::Cell; |
| |
| /////////////////////////////////////////////////////////////////////////// |
| |
| struct SomeGoableThing { |
| counter: Rc<Cell<isize>> |
| } |
| |
| impl Go for SomeGoableThing { |
| fn go(&self, arg: isize) { |
| self.counter.set(self.counter.get() + arg); |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////// |
| |
| struct SomeGoOnceableThing { |
| counter: Rc<Cell<isize>> |
| } |
| |
| impl GoOnce for SomeGoOnceableThing { |
| fn go_once(self, arg: isize) { |
| self.counter.set(self.counter.get() + arg); |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////// |
| |
| fn main() { |
| let counter = Rc::new(Cell::new(0)); |
| let mut x = SomeGoableThing { counter: counter.clone() }; |
| |
| go(&x, 10); |
| assert_eq!(counter.get(), 10); |
| |
| go_mut(&mut x, 100); |
| assert_eq!(counter.get(), 110); |
| |
| go_once(x, 1_000); |
| assert_eq!(counter.get(), 1_110); |
| |
| let x = SomeGoOnceableThing { counter: counter.clone() }; |
| |
| go_once(x, 10_000); |
| assert_eq!(counter.get(), 11_110); |
| } |