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1 // Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file | 1 // Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file |
2 // for details. All rights reserved. Use of this source code is governed by a | 2 // for details. All rights reserved. Use of this source code is governed by a |
3 // BSD-style license that can be found in the LICENSE file. | 3 // BSD-style license that can be found in the LICENSE file. |
4 | 4 |
5 part of "core.dart"; | 5 part of "dart:core"; |
6 | 6 |
7 /** | 7 /** |
8 * The reserved word [:null:] denotes an object that is the sole instance of | 8 * The reserved word [:null:] denotes an object that is the sole instance of |
9 * this class. | 9 * this class. |
10 * | 10 * |
11 * It is a compile-time error for a class to attempt to extend or implement | 11 * It is a compile-time error for a class to attempt to extend or implement |
12 * Null. | 12 * Null. |
13 */ | 13 */ |
14 class Null { | 14 class Null { |
15 factory Null._uninstantiable() { | 15 factory Null._uninstantiable() { |
16 throw new UnsupportedError('class Null cannot be instantiated'); | 16 throw new UnsupportedError('class Null cannot be instantiated'); |
17 } | 17 } |
18 | 18 |
19 external int get hashCode; | 19 external int get hashCode; |
20 | 20 |
21 /** Returns the string `"null"`. */ | 21 /** Returns the string `"null"`. */ |
22 String toString() => "null"; | 22 String toString() => "null"; |
23 } | 23 } |
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