Some library functions implemented in terms of foldr

stdFolds.hs

module StdFolds where

myOr :: [Bool] -> Bool
myOr = foldr (||) False

myAny :: (a -> Bool) -> [a] -> Bool
myAny = flip foldr False . ((||) .)

myElem :: Eq a => a -> [a] -> Bool
myElem = myAny.(==)

myMap :: (a -> b) -> [a] -> [b]
myMap = flip foldr [] . ((:) .)