1 files changed, 10 insertions, 1 deletions
diff --git a/compiler/utils/Stream.hs b/compiler/utils/Stream.hs
index ad01fad40c..2ad2b8cc7a 100644
--- a/compiler/utils/Stream.hs
+++ b/compiler/utils/Stream.hs
@@ -7,7 +7,7 @@
 -- -----------------------------------------------------------------------------
 module Stream (
     Stream(..), yield, liftIO,
-    collect, fromList,
+    collect, consume, fromList,
     Stream.map, Stream.mapM, Stream.mapAccumL
   ) where
 
@@ -71,6 +71,15 @@ collect str = go str []
       Left () -> return (reverse acc)
       Right (a, str') -> go str' (a:acc)
 
+consume :: Monad m => Stream m a b -> (a -> m ()) -> m b
+consume str f = do
+    r <- runStream str
+    case r of
+      Left ret -> return ret
+      Right (a, str') -> do
+        f a
+        consume str' f
+
 -- | Turn a list into a 'Stream', by yielding each element in turn.
 fromList :: Monad m => [a] -> Stream m a ()
 fromList = mapM_ yield