Language/Mixins/Mixin_Composition/order_t01.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 mixin application of the form S with M1,...,Mk; defines a
 * class C whose superclass is the application of the mixin composition
 * Mk−1 ∗ ... ∗ M1 to S.
 * ...
 * The composition of two mixins, M1< T1...TkM1 > and M2< U1...UkM2 >,
 * written M1< T1...TkM1 > ∗ M2< U1...UkM2 > defines an anonymous mixin
 * such that for any class S< V1...VkS >, the application of
 * M1< T1...TkM1 > ∗ M2< U1...UkM2 >
 * to S< V1...VkS > is equivalent to
 * abstract class Id1< T1...TkM1, U1...UkM2, V1...VkS > =
 * Id2< U1...UkM2, V1...VkS > with M1< T1...TkM1 >;
 * where Id2 denotes
 * abstract class Id2< U1...UkM2, V1...VkS > =
 * S< V1...VkS > with M2< U1...UkM2 >;
 * @description Checks that mixin composition applies mixins in the right
 * order
 * @author sgrekhov@unipro.ru
 */
import "../../../Utils/expect.dart";

class A {
  int m = 0;
}

class M1 {
  int m = 1;
}

class M2 {
  int m = 2;
}

class M3 {
  int m = 3;
}

class B1 = A with M1, M2;
class B2 = A with M1, M2, M3;
class B3 = B1 with M3, M2, M1;

main() {
  B1 b1 = new B1();
  B2 b2 = new B2();
  B3 b3 = new B3();

  Expect.equals(2, b1.m);
  Expect.equals(3, b2.m);
  Expect.equals(1, b3.m);
}