Files
sdk/tests/language/patterns/version_2_29_changes_test.dart
Robert Nystrom dbaf041ae4 Format tests/language/p*.
Change-Id: Ia3238c1781422ec5eb7a219a5cf8af645a4c5876
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/409000
Commit-Queue: Bob Nystrom <rnystrom@google.com>
Reviewed-by: Lasse Nielsen <lrn@google.com>
Auto-Submit: Bob Nystrom <rnystrom@google.com>
2025-02-11 15:31:25 -08:00

51 lines
1.2 KiB
Dart

// Copyright (c) 2023, 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.
// This test captures the changes introduced in 2.29 of the patterns proposal.
import 'dart:collection';
import "package:expect/expect.dart";
main() {
var map = {'a': 1, 'b': 2};
// Map patterns don't access length.
Expect.isTrue(switch (NoLengthMap(map)) {
{'a': _} => true,
_ => false,
});
// Map patterns match even if there are extra keys.
Expect.equals('a b', switch (map) {
{'a': _, 'b': _} => 'a b',
{'a': _} => 'a',
{'b': _} => 'b',
_ => '???',
});
}
class NoLengthMap extends MapBase<String, int> {
final Map<String, int> _inner;
NoLengthMap(this._inner);
@override
int get length => throw UnsupportedError('No length!');
@override
int? operator [](Object? key) => _inner[key];
@override
void operator []=(String key, int value) => _inner[key] = value;
@override
void clear() => _inner.clear();
@override
Iterable<String> get keys => _inner.keys;
@override
int? remove(Object? key) => _inner.remove(key);
}