Add methods to Collection.

sdk/lib/core/set.dart

Index: sdk/lib/core/set.dart
diff --git a/sdk/lib/core/set.dart b/sdk/lib/core/set.dart
index 95a633a447ca6b9c5165e0475d6cb8e9145e5948..b4f34db50e769ef34495e9556fb08aef6dfd421a 100644
--- a/sdk/lib/core/set.dart
+++ b/sdk/lib/core/set.dart
@@ -32,7 +32,7 @@ abstract class Set<E> extends Collection<E> {
    * in the set. Returns false otherwise. The method has no effect
    * if [value] value was not in the set.
    */
-  bool remove(E value);
+  bool remove(Object value);

[floitsch, 2013/01/17 13:36:58]

make it "var" ?

[Lasse Reichstein Nielsen, 2013/01/18 11:41:48]

Object is correct here. We only use ==, possibly hashCode.

 
   /**
    * Adds all the elements of the given [iterable] to the set.
@@ -40,11 +40,6 @@ abstract class Set<E> extends Collection<E> {
   void addAll(Iterable<E> iterable);
 
   /**
-   * Removes all the elements of the given collection from the set.
-   */
-  void removeAll(Iterable<E> iterable);
-
-  /**
    * Returns true if [collection] contains all the elements of this
    * collection.
    */
@@ -66,9 +61,9 @@ abstract class Set<E> extends Collection<E> {
    * Removes all elements in the set.
    */
   void clear();
-
 }
 
+
 abstract class HashSet<E> extends Set<E> {
   factory HashSet() => new _HashSetImpl<E>();
 
@@ -105,12 +100,42 @@ class _HashSetImpl<E> extends Iterable<E> implements HashSet<E> {
     return _backingMap.containsKey(value);
   }
 
-  bool remove(E value) {
+  bool remove(Object value) {
     if (!_backingMap.containsKey(value)) return false;
     _backingMap.remove(value);
     return true;
   }
 
+  void removeAll(Iterable elements) {

[floitsch, 2013/01/17 13:36:58]

should not be necessary if Collection provides default implementations.
Same below.

[Lasse Reichstein Nielsen, 2013/01/18 11:41:48]

Done.

+    for (var element in elements) {
+      remove(element);
+    }
+  }
+
+  void retainAll(Iterable elements) {
+    Set other;
+    if (elements is Set) {
+      other = elements
+    } else {
+      other = new Set.from(elements);
+    }
+    removeMatching((E e) => !set.contains(e));
+  }
+
+  void removeMatching(bool test(E element)) {
+    List<E> toRemove = <E>[];
+    // TODO(lrn): Consider making HashSet able to handle remove
+    // during iteration.
+    for (E element in this) {
+      if (test(element)) {
+        toRemove.add(element);
+      }
+    }
+    for (E element in toRemove) {
+      remove(element);
+    }
+  }
+
   void addAll(Iterable<E> iterable) {
     for (E element in iterable) {
       add(element);
@@ -129,12 +154,6 @@ class _HashSetImpl<E> extends Iterable<E> implements HashSet<E> {
     return new Set<E>.from(other).containsAll(this);
   }
 
-  void removeAll(Iterable<E> iterable) {
-    for (E value in iterable) {
-      remove(value);
-    }
-  }
-
   bool containsAll(Collection<E> collection) {
     return collection.every((E value) {
       return contains(value);