| // Copyright (c) 2019, 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 an extension declaration is a top-level declaration with a grammar |
| /// similar to: |
| /// <extension> ::= |
| /// `extension' <identifier>? <typeParameters>? `on' <type> `?'? `{' |
| /// memberDeclaration* |
| /// `}' |
| /// Such a declaration introduces its name (the identifier) into the surrounding |
| /// scope |
| /// |
| /// @description Check that identifier may be omitted |
| /// @author sgrekhov@unipro.ru |
| |
| |
| |
| import "../../Utils/expect.dart"; |
| |
| extension<T> on List<T> { |
| int get doubleLength => this.length * 2; |
| List<T> operator-() => this.reversed.toList(); |
| List<List<T>> split(int at) => <List<T>>[this.sublist(0, at), this.sublist(at)]; |
| String someMethod() => className; |
| static String get className => "List"; |
| } |
| |
| main() { |
| List<String> list = ["Lily", "was", "here"]; |
| Expect.equals(6, list.doubleLength); |
| Expect.listEquals([["Lily"], ["was", "here"]], list.split(1)); |
| Expect.listEquals(["here", "was", "Lily"], -list); |
| Expect.listEquals([["was", "here"], ["Lily"]], -list.split(1)); |
| Expect.equals("List", list.someMethod()); |
| } |