Language/Expressions/If_null_Expressions/syntax_t01.dart

// Copyright (c) 2015, 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
///  ifNullExpression:
///   logicalOrExpression (‘??’ logicalOrExpression)*
///
/// @description Verify several kinds of if-null expressions, logicalOrExpression
/// is a constant value.
/// @static-warning
/// @author a.semenov@unipro.ru

import '../../../Utils/expect.dart';

main() {
  Expect.equals(1, 1 ?? 2);
  Expect.equals(1, 1 ?? 2 ?? 3);
  Expect.equals(1, 1 ?? 2 ?? 3 ?? 4);
  Expect.equals(2, null ?? 2);
  Expect.equals(1, null ?? 1 ?? 2);
  Expect.equals(1, null ?? 1 ?? 2 ?? 3);
  Expect.equals(1, null ?? null ?? 1 ?? 2 ?? 3);
  Expect.equals(true, null ?? true ?? 2 ?? 3);
  Expect.equals(false, null ?? false ?? 2 ?? 3);
  Expect.equals('a', 'a' ?? 'bcd');
  Expect.equals('abc', 'abc' ?? 'cde' ?? 'fgh');
  Expect.equals('abc', null ?? 'abc' ?? 'cde' ?? 'fgh');
}