diff --git a/monadplus.cabal b/monadplus.cabal
--- a/monadplus.cabal
+++ b/monadplus.cabal
@@ -1,6 +1,6 @@
 
 name:               monadplus
-version:            1.4.1
+version:            1.4.2
 cabal-version:      >= 1.10
 author:             Hans Hoglund
 maintainer:         Hans Hoglund <hans@hanshoglund.se>
diff --git a/src/Control/Monad/Plus.hs b/src/Control/Monad/Plus.hs
--- a/src/Control/Monad/Plus.hs
+++ b/src/Control/Monad/Plus.hs
@@ -33,6 +33,7 @@
         mfold,
         mfromList,
         mfromMaybe,
+        mreturn,
 
         -- * Filtering
         -- mfilter,
@@ -49,6 +50,7 @@
         -- * Special maps
         mmapMaybe,
         mconcatMap,
+        mconcatMap',
         
         -- * Utility
         Partial(..),
@@ -99,6 +101,13 @@
 mfromMaybe = maybe mzero return
 
 -- | 
+-- Convert a partial function to a function returning an arbitrary
+-- 'MonadPlus' type.
+-- 
+mreturn :: MonadPlus m => (a -> Maybe b) -> a -> m b
+mreturn f = mfromMaybe . f
+
+-- | 
 -- The 'partition' function takes a predicate a list and returns
 -- the pair of lists of elements which do and do not satisfy the
 -- predicate, respectively; i.e.,
@@ -181,14 +190,15 @@
 mconcatMap :: MonadPlus m => (a -> [b]) -> m a -> m b
 mconcatMap f = mscatter . liftM f
 
-{-
-mmapLefts :: MonadPlus m => (a -> Either b c) -> m a -> m b
-mmapLefts f = mlefts . liftM f
+-- | 
+-- Modify, discard or spawn values.
+-- 
+-- This function generalizes the 'concatMap' function.
+-- 
+mconcatMap' :: (MonadPlus m, Foldable t) => (a -> t b) -> m a -> m b
+mconcatMap' f = mscatter' . liftM f
 
-mmapRights :: MonadPlus m => (a -> Either c b) -> m a -> m b
-mmapRights f = mrights . liftM f
 
--}
 
 -- |
 -- Convert a predicate to a partial function.
@@ -246,4 +256,5 @@
 instance Monoid (Partial a b) where
     mempty  = mzero
     mappend = mplus
-    
+
+