Repeatedly.hs

repeatedly :: (a -> b -> b) -> ([a] -> b -> b)
repeatedly = flip . foldl' . flip

repeatedlyM :: Monad m => (a -> b -> m b) -> ([a] -> b -> m b)
repeatedlyM = flip . foldlM' . flip

foldlM' :: forall m a b. Monad m => (b -> a -> m b) -> b -> [a] -> m b
foldlM' f e = go e
  where
    go :: b -> [a] -> m b
    go acc []     = pure acc
    go acc (a:as) = f acc a >>= \acc' -> go acc' as