Use foldr in place of explicit recursion and toList (#162)

CHANGELOG.md

@@ -18,6 +18,8 @@ The changelog is available [on GitHub][2].
  Made `die` be polymorphic in its return type.
 * [#164](https://github.com/kowainik/relude/issues/164):
  Reexport `ShortByteString`, `toShort`/`fromShort` functions.
+* [#162](https://github.com/kowainik/relude/pull/162):
+ Use `foldr` instead of explicit recursion and `toList`.
 
 ## 0.5.0 — Mar 18, 2019
 

src/Relude/Foldable/Fold.hs

@@ -177,12 +177,11 @@ Nothing
 False
 -}
 andM :: (Foldable f, Monad m) => f (m Bool) -> m Bool
-andM = go . toList
+andM = foldr go (pure True)
  where
- go [] = pure True
- go (p:ps) = do
+ go p acc = do
  q <- p
- if q then go ps else pure False
+ if q then acc else pure False
 {-# INLINEABLE andM #-}
 {-# SPECIALIZE andM :: [IO Bool] -> IO Bool #-}
 
@@ -196,12 +195,11 @@ Just True
 Nothing
 -}
 orM :: (Foldable f, Monad m) => f (m Bool) -> m Bool
-orM = go . toList
+orM = foldr go (pure False)
  where
- go [] = pure False
- go (p:ps) = do
+ go p acc = do
  q <- p
- if q then pure True else go ps
+ if q then pure True else acc
 {-# INLINEABLE orM #-}
 {-# SPECIALIZE orM :: [IO Bool] -> IO Bool #-}
 
@@ -215,12 +213,11 @@ Just False
 Nothing
 -}
 allM :: (Foldable f, Monad m) => (a -> m Bool) -> f a -> m Bool
-allM p = go . toList
+allM p = foldr go (pure True)
  where
- go [] = pure True
- go (x:xs) = do
+ go x acc = do
  q <- p x
- if q then go xs else pure False
+ if q then acc else pure False
 {-# INLINEABLE allM #-}
 {-# SPECIALIZE allM :: (a -> IO Bool) -> [a] -> IO Bool #-}
 
@@ -234,12 +231,11 @@ Just True
 Nothing
 -}
 anyM :: (Foldable f, Monad m) => (a -> m Bool) -> f a -> m Bool
-anyM p = go . toList
+anyM p = foldr go (pure False)
  where
- go [] = pure False
- go (x:xs) = do
+ go x acc = do
  q <- p x
- if q then pure True else go xs
+ if q then pure True else acc
 {-# INLINEABLE anyM #-}
 {-# SPECIALIZE anyM :: (a -> IO Bool) -> [a] -> IO Bool #-}