Index: tool/input_sdk/lib/collection/hash_map.dart |
diff --git a/tool/input_sdk/lib/collection/hash_map.dart b/tool/input_sdk/lib/collection/hash_map.dart |
index 003cd4f18c8b642fe3df060d72093d26a57fb77c..dacf929e0ac2e9687b3e8e60f0961e6b7e24faad 100644 |
--- a/tool/input_sdk/lib/collection/hash_map.dart |
+++ b/tool/input_sdk/lib/collection/hash_map.dart |
@@ -5,9 +5,9 @@ |
part of dart.collection; |
/** Default function for equality comparison in customized HashMaps */ |
-bool _defaultEquals(Object a, Object b) => a == b; |
+bool _defaultEquals(a, b) => a == b; |
/** Default function for hash-code computation in customized HashMaps */ |
-int _defaultHashCode(Object a) => a.hashCode; |
+int _defaultHashCode(a) => a.hashCode; |
/** Type of custom equality function */ |
typedef bool _Equality<K>(K a, K b); |
@@ -27,7 +27,7 @@ typedef int _Hasher<K>(K object); |
* |
* Iterating the map's keys, values or entries (through [forEach]) |
* may happen in any order. |
- * The itearation order only changes when the map is modified. |
+ * The iteration order only changes when the map is modified. |
* Values are iterated in the same order as their associated keys, |
* so iterating the [keys] and [values] in parallel |
* will give matching key and value pairs. |
@@ -56,15 +56,32 @@ abstract class HashMap<K, V> implements Map<K, V> { |
* The [isValidKey] function defaults to just testing if the object is a |
* [K] instance. |
* |
+ * Example: |
+ * |
+ * new HashMap<int,int>(equals: (int a, int b) => (b - a) % 5 == 0, |
+ * hashCode: (int e) => e % 5) |
+ * |
+ * This example map does not need an `isValidKey` function to be passed. |
+ * The default function accepts only `int` values, which can safely be |
+ * passed to both the `equals` and `hashCode` functions. |
+ * |
+ * If neither `equals`, `hashCode`, nor `isValidKey` is provided, |
+ * the default `isValidKey` instead accepts all keys. |
+ * The default equality and hashcode operations are assumed to work on all |
+ * objects. |
+ * |
+ * Likewise, if `equals` is [identical], `hashCode` is [identityHashCode] |
+ * and `isValidKey` is omitted, the resulting map is identity based, |
+ * and the `isValidKey` defaults to accepting all keys. |
+ * Such a map can be created directly using [HashMap.identity]. |
+ * |
* The used `equals` and `hashCode` method should always be consistent, |
* so that if `equals(a, b)` then `hashCode(a) == hashCode(b)`. The hash |
* of an object, or what it compares equal to, should not change while the |
- * object is in the table. If it does change, the result is unpredictable. |
+ * object is a key in the map. If it does change, the result is unpredictable. |
* |
* If you supply one of [equals] and [hashCode], |
* you should generally also to supply the other. |
- * An example would be using [identical] and [identityHashCode], |
- * which is equivalent to using the shorthand [HashMap.identity]). |
*/ |
external factory HashMap({bool equals(K key1, K key2), |
int hashCode(K key), |
@@ -75,7 +92,8 @@ abstract class HashMap<K, V> implements Map<K, V> { |
* |
* Effectively a shorthand for: |
* |
- * new HashMap(equals: identical, hashCode: identityHashCodeOf) |
+ * new HashMap(equals: identical, |
+ * hashCode: identityHashCode) |
*/ |
external factory HashMap.identity(); |
@@ -84,7 +102,7 @@ abstract class HashMap<K, V> implements Map<K, V> { |
*/ |
factory HashMap.from(Map other) { |
HashMap<K, V> result = new HashMap<K, V>(); |
- other.forEach((k, v) { result[k] = v; }); |
+ other.forEach((k, v) { result[k as K] = v as V; }); |
return result; |
} |