1 files changed, 4 insertions, 0 deletions

diff --git a/src/Data/Word64Map.hs b/src/Data/Word64Map.hs
index 9e93c8c8..adc9c27e 100644
--- a/src/Data/Word64Map.hs
+++ b/src/Data/Word64Map.hs
@@ -6,6 +6,7 @@ module Data.Word64Map where
 import Data.Bits
 import qualified Data.IntMap as IntMap
          ;import Data.IntMap (IntMap)
+import Data.Monoid
 import Data.Typeable
 import Data.Word
 
@@ -23,6 +24,9 @@ fitsInInt proxy = (original == casted)
 
 newtype Word64Map a = Word64Map (IntMap (IntMap a))
 
+size :: Word64Map a -> Int
+size (Word64Map m) = getSum $ foldMap (\n -> Sum (IntMap.size n)) m
+
 empty :: Word64Map a
 empty = Word64Map IntMap.empty