witherable 0.0 → 0.1

raw patch · 2 files changed

+5/−7 lines, 2 files

Files

• src/Data/Witherable.hs +4/−3
• witherable.cabal +1/−4

@@ -10,6 +10,7 @@ import qualified Data.Foldable as F
 import Data.Hashable
 import Data.Functor.Identity
+import Control.Monad.Trans.Maybe
 
 -- | Like `traverse`, but you can remove elements instead of updating them.
 -- @traverse f = wither (fmap Just . f)@
@@ -22,11 +23,11 @@   catMaybes :: Witherable t => t (Maybe a) -> t a
   catMaybes = runIdentity . wither pure
 
-  witherM :: Monad m => (a -> m (Maybe b)) -> t a -> m (t b)
-  witherM f = unwrapMonad . wither (WrapMonad . f)
+  witherM :: Monad m => (a -> MaybeT m b) -> t a -> m (t b)
+  witherM f = unwrapMonad . wither (WrapMonad . runMaybeT . f)
 
 -- | 'blightM' is 'witherM' with its arguments flipped.
-blightM :: (Monad m, Witherable t) => t a -> (a -> m (Maybe b)) -> m (t b)
+blightM :: (Monad m, Witherable t) => t a -> (a -> MaybeT m b) -> m (t b)
 blightM = flip witherM
 {-# INLINE blightM #-}
 

@@ -1,8 +1,5 @@--- Initial witherable.cabal generated by cabal init.  For further 
--- documentation, see http://haskell.org/cabal/users-guide/
-
 name:                witherable
-version:             0.0
+version:             0.1
 synopsis:            Generalization of catMaybes
 -- description:         
 homepage:            https://github.com/fumieval/witherable