Language/Expressions/Postfix_Expressions/variable_increment_t02.dart

/*
 * Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 * for details. All rights reserved. Use of this source code is governed by a
 * BSD-style license that can be found in the LICENSE file.
 */
/**
 * @assertion A postfix expression of the form v++, where v is an identifier, is
 * equivalent to (){var r = v; v = r + 1; return r}().
 * @description Checks that evaluation of an expression of the form v++
 * is equivalent to (){var r = v; v = r + 1; return r;}() in implementation
 * (basically, that postfix ++ works via operator+ in the described manner).
 * @author rodionov
 */
import '../../../Utils/expect.dart';

bool plusInvoked = false;

class A {
  final String value;
  
  A(this.value);
  
  operator +(var other) {
    plusInvoked = true;
    return new A("${value}${other}");
  }
}

main() {
  var foo = new A("foo");
  Expect.isFalse(plusInvoked);
  
  Expect.equals("foo", (foo++).value);
  Expect.isTrue(plusInvoked);
  Expect.equals("foo1", foo.value);
}