implemented containerType.count(predicate)

stdlib/ktSrc/JavaIterables.kt

@@ -22,6 +22,16 @@ inline fun <T> java.lang.Iterable<T>.all(predicate: (T)-> Boolean) : Boolean {
   return true
 }
 
+/** Returns the number of items which match the given predicate  */
+inline fun <T> java.lang.Iterable<T>.count(predicate: (T)-> Boolean) : Int {
+  var answer = 0
+  for (elem in this) {
+    if (predicate(elem))
+      answer += 1
+  }
+  return answer
+}
+
 /** Returns the first item in the collection which matches the given predicate or null if none matched */
 inline fun <T> java.lang.Iterable<T>.find(predicate: (T)-> Boolean) : T? {
   for (elem in this) {

testlib/test/CollectionTest.kt

@@ -29,6 +29,12 @@ class CollectionTest() : TestSupport() {
     }
   }
 
+  fun testCount() {
+    assertEquals(1, data.count{it.startsWith("b")})
+    // TODO size should implement size property to be polymorphic with collections
+    assertEquals(2, data.count{it.length == 3})
+  }
+
   fun testFilter() {
     val foo = data.filter{it.startsWith("f")}
 
@@ -153,5 +159,4 @@ class CollectionTest() : TestSupport() {
       }
     }
   }
-
 }