Add EqualityMap and EqualitySet. (#35)
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 74710a3..fa10220 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,8 @@
+## 1.11.0
+
+* Add `EqualityMap` and `EqualitySet` classes which use `Equality` objects for
+ key and element equality, respectively.
+
## 1.10.1
* `Set.difference` now takes a `Set<Object>` as argument.
diff --git a/lib/collection.dart b/lib/collection.dart
index 58d98f7..612508b 100644
--- a/lib/collection.dart
+++ b/lib/collection.dart
@@ -6,6 +6,8 @@
export "src/canonicalized_map.dart";
export "src/comparators.dart";
export "src/equality.dart";
+export "src/equality_map.dart";
+export "src/equality_set.dart";
export "src/functions.dart";
export "src/iterable_zip.dart";
export "src/priority_queue.dart";
diff --git a/lib/src/equality_map.dart b/lib/src/equality_map.dart
new file mode 100644
index 0000000..686e5bd
--- /dev/null
+++ b/lib/src/equality_map.dart
@@ -0,0 +1,32 @@
+// Copyright (c) 2016, 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.
+
+import 'dart:collection';
+
+import 'equality.dart';
+import 'wrappers.dart';
+
+/// A [Map] whose key equality is determined by an [Equality] object.
+class EqualityMap<K, V> extends DelegatingMap<K, V> {
+ /// Creates a map with equality based on [equality].
+ EqualityMap(Equality<K> equality)
+ : super(new LinkedHashMap(
+ equals: equality.equals,
+ hashCode: equality.hash,
+ isValidKey: equality.isValidKey));
+
+ /// Creates a map with equality based on [equality] that contains all
+ /// key-value pairs of [other].
+ ///
+ /// If [other] has multiple keys that are equivalent according to [equality],
+ /// the last one reached during iteration takes precedence.
+ EqualityMap.from(Equality<K> equality, Map<K, V> other)
+ : super(new LinkedHashMap(
+ equals: equality.equals,
+ hashCode: equality.hash,
+ isValidKey: equality.isValidKey)) {
+ addAll(other);
+ }
+}
+
diff --git a/lib/src/equality_set.dart b/lib/src/equality_set.dart
new file mode 100644
index 0000000..b0582ce
--- /dev/null
+++ b/lib/src/equality_set.dart
@@ -0,0 +1,32 @@
+// Copyright (c) 2016, 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.
+
+import 'dart:collection';
+
+import 'equality.dart';
+import 'wrappers.dart';
+
+/// A [Map] whose key equality is determined by an [Equality] object.
+class EqualitySet<E> extends DelegatingSet<E> {
+ /// Creates a set with equality based on [equality].
+ EqualitySet(Equality<E> equality)
+ : super(new LinkedHashSet(
+ equals: equality.equals,
+ hashCode: equality.hash,
+ isValidKey: equality.isValidKey));
+
+ /// Creates a set with equality based on [equality] that contains all
+ /// elements in [other].
+ ///
+ /// If [other] has multiple values that are equivalent according to
+ /// [equality], the first one reached during iteration takes precedence.
+ EqualitySet.from(Equality<E> equality, Iterable<E> other)
+ : super(new LinkedHashSet(
+ equals: equality.equals,
+ hashCode: equality.hash,
+ isValidKey: equality.isValidKey)) {
+ addAll(other);
+ }
+}
+
diff --git a/pubspec.yaml b/pubspec.yaml
index f92b73d..13b81f2 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
name: collection
-version: 1.10.1
+version: 1.11.0
author: Dart Team <misc@dartlang.org>
description: Collections and utilities functions and classes related to collections.
homepage: https://www.github.com/dart-lang/collection
diff --git a/test/equality_map_test.dart b/test/equality_map_test.dart
new file mode 100644
index 0000000..8225efd
--- /dev/null
+++ b/test/equality_map_test.dart
@@ -0,0 +1,37 @@
+// Copyright (c) 2016, 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.
+
+import 'package:collection/collection.dart';
+import 'package:test/test.dart';
+
+void main() {
+ test("uses the given equality", () {
+ var map = new EqualityMap(const IterableEquality());
+ expect(map, isEmpty);
+
+ map[[1, 2, 3]] = 1;
+ expect(map, containsPair([1, 2, 3], 1));
+
+ map[[1, 2, 3]] = 2;
+ expect(map, containsPair([1, 2, 3], 2));
+
+ map[[2, 3, 4]] = 3;
+ expect(map, containsPair([1, 2, 3], 2));
+ expect(map, containsPair([2, 3, 4], 3));
+ });
+
+ test("EqualityMap.from() prefers the lattermost equivalent key", () {
+ var map = new EqualityMap.from(const IterableEquality(), {
+ [1, 2, 3]: 1,
+ [2, 3, 4]: 2,
+ [1, 2, 3]: 3,
+ [2, 3, 4]: 4,
+ [1, 2, 3]: 5,
+ [1, 2, 3]: 6,
+ });
+
+ expect(map, containsPair([1, 2, 3], 6));
+ expect(map, containsPair([2, 3, 4], 4));
+ });
+}
diff --git a/test/equality_set_test.dart b/test/equality_set_test.dart
new file mode 100644
index 0000000..1b20684
--- /dev/null
+++ b/test/equality_set_test.dart
@@ -0,0 +1,48 @@
+// Copyright (c) 2016, 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.
+
+import 'package:collection/collection.dart';
+import 'package:test/test.dart';
+
+void main() {
+ test("uses the given equality", () {
+ var set = new EqualitySet(const IterableEquality());
+ expect(set, isEmpty);
+
+ var list1 = [1, 2, 3];
+ expect(set.add(list1), isTrue);
+ expect(set, contains([1, 2, 3]));
+ expect(set, contains(same(list1)));
+
+ var list2 = [1, 2, 3];
+ expect(set.add(list2), isFalse);
+ expect(set, contains([1, 2, 3]));
+ expect(set, contains(same(list1)));
+ expect(set, isNot(contains(same(list2))));
+
+ var list3 = [2, 3, 4];
+ expect(set.add(list3), isTrue);
+ expect(set, contains(same(list1)));
+ expect(set, contains(same(list3)));
+ });
+
+ test("EqualitySet.from() prefers the lattermost equivalent value", () {
+ var list1 = [1, 2, 3];
+ var list2 = [2, 3, 4];
+ var list3 = [1, 2, 3];
+ var list4 = [2, 3, 4];
+ var list5 = [1, 2, 3];
+ var list6 = [1, 2, 3];
+
+ var set = new EqualitySet.from(const IterableEquality(),
+ [list1, list2, list3, list4, list5, list6]);
+
+ expect(set, contains(same(list1)));
+ expect(set, contains(same(list2)));
+ expect(set, isNot(contains(same(list3))));
+ expect(set, isNot(contains(same(list4))));
+ expect(set, isNot(contains(same(list5))));
+ expect(set, isNot(contains(same(list6))));
+ });
+}
