KT-923 Collection.indices property

stdlib/ktSrc/JavaUtil.kt

@@ -19,6 +19,8 @@ inline fun linkedList<T>(vararg values: T) : LinkedList<T>  = values.to(LinkedLi
 /** Returns a new HashSet with a variable number of initial elements */
 inline fun hashSet<T>(vararg values: T) : HashSet<T> = values.to(HashSet<T>(values.size))
 
+val Collection<*>.indices : IntRange
+    get() = 0..size-1
 
 inline fun <T> java.util.Collection<T>.toArray() : Array<T> {
   val answer = Array<T>(this.size)

testlib/test/CollectionTest.kt

@@ -245,6 +245,14 @@ class CollectionTest() : TestSupport() {
     fails { hashSet<Char>().last() }
   }
 
+  fun testIndices() {
+    val indices = data.indices
+    assertEquals(0, indices.start)
+    assertEquals(1, indices.end)
+    assertEquals(2, indices.size)
+    assertFalse(indices.isReversed)
+  }
+
   fun testContains() {
     assertTrue(data.contains("foo"))
     assertTrue(data.contains("bar"))