From 8dc526a5e1468b4ba2959e8dec78bd09f63a870a Mon Sep 17 00:00:00 2001
From: Andrey Breslav <andrey.breslav@jetbrains.com>
Date: Wed, 23 Oct 2013 13:51:04 +0400
Subject: [PATCH] isEmpty() and flatten() added

---
 .../src/org/jetbrains/jet/utils/collections.kt             | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/core/util.runtime/src/org/jetbrains/jet/utils/collections.kt b/core/util.runtime/src/org/jetbrains/jet/utils/collections.kt
index fa20409d6f1..0e546c7c4e4 100644
--- a/core/util.runtime/src/org/jetbrains/jet/utils/collections.kt
+++ b/core/util.runtime/src/org/jetbrains/jet/utils/collections.kt
@@ -17,6 +17,7 @@
 package org.jetbrains.jet.utils
 
 import java.util.LinkedHashMap
+import java.util.ArrayList
 
 public fun <K, V> Iterable<V>.valuesToMap(key: (V) -> K): Map<K, V> {
     return iterator().valuesToMap(key)
@@ -57,4 +58,8 @@ public fun <K, V: Any> Iterator<K>.keysToMapExceptNulls(value: (K) -> V?): Map<K
     return map
 }
 
-public fun <T, C: Collection<T>> C.ifEmpty(body: () -> C): C = if (isEmpty()) body() else this
\ No newline at end of file
+public fun <T, C: Collection<T>> C.ifEmpty(body: () -> C): C = if (isEmpty()) body() else this
+
+public fun <T> Iterable<Iterable<T>>.flatten(): List<T> {
+    return flatMapTo(ArrayList<T>(), {it})
+}
\ No newline at end of file