foldr2'cps.hs

foldr2'cps _ z []     p k _ = k z
foldr2'cps f z (x:xs) p k k' 
    | p x       = k' x
    | otherwise = foldr2'cps f z xs p (\y -> k $ f x y) k'

main = do print $ foldr2'cps (++) [] [[1,2],[3,4],[5,6]] 
                    (== []) id id
          print $ foldr2'cps (++) [] [[1,2],[3,4],[],[5,6]] 
                    (== []) id id
          print $ foldr2'cps (+) 0 [1..10] (== 0) id id
          print $ foldr2'cps (+) 0 [1..10] (== 5) id id

foldr2cps.hs

foldr2_cps _ z []     p k _ = k z
foldr2_cps f z (x:xs) p k k' 
    | p x       = k' x
    | otherwise = foldr2_cps f z xs p (\y -> k $ f x y) k'

main = do print $ foldr2'cps (++) [] [[1,2],[3,4],[5,6]] 
                    (== []) id id
          print $ foldr2'cps (++) [] [[1,2],[3,4],[],[5,6]] 
                    (== []) id id
          print $ foldr2'cps (+) 0 [1..10] (== 0) id id
          print $ foldr2'cps (+) 0 [1..10] (== 5) id id