Language/12_Expressions/28_Postfix_Expressions_A06_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
 * @reviewer iefremov
 */
import "../../Utils/expect.dart";

bool opInvoked = false;

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

main() {
  var foo = new A("foo");
  Expect.isFalse(opInvoked);
  
  Expect.equals("foo", (foo--).value);
  Expect.isTrue(opInvoked);
  Expect.equals("foo-1", foo.value);
}