// 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. use std::cell::Cell; struct shrinky_pointer<'a> { i: &'a Cell, } impl<'a> Drop for shrinky_pointer<'a> { fn drop(&mut self) { println!("Hello!"); self.i.set(self.i.get() - 1); } } impl<'a> shrinky_pointer<'a> { pub fn look_at(&self) -> isize { return self.i.get(); } } fn shrinky_pointer(i: &Cell) -> shrinky_pointer { shrinky_pointer { i: i } } pub fn main() { let my_total = &Cell::new(10); { let pt = shrinky_pointer(my_total); assert_eq!(pt.look_at(), 10); } println!("my_total = {}", my_total.get()); assert_eq!(my_total.get(), 9); }