// Copyright 2012 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 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. trait Positioned { fn SetX(&mut self, isize); fn X(&self) -> isize; } trait Movable: Positioned { fn translate(&mut self, dx: isize) { let x = self.X(); self.SetX(x + dx); } } struct Point { x: isize, y: isize } impl Positioned for Point { fn SetX(&mut self, x: isize) { self.x = x; } fn X(&self) -> isize { self.x } } impl Movable for Point {} pub fn main() { let mut p = Point{ x: 1, y: 2}; p.translate(3); assert_eq!(p.X(), 4); }