import Data.List (partition)

unpartition :: [Bool] -> [a] -> [a] -> [a]
unpartition [] _ _ = []
unpartition (True:ps) (a:as) bs = a:unpartition ps as bs
unpartition (False:ps) as (b:bs) = b:unpartition ps as bs

onPartitions :: (Monad m) =>
  (a -> Bool) -> ([a] -> m [b]) -> ([a] -> m [b]) -> [a] -> m [b]
onPartitions p t f xs = let
  partitions = map p xs
  (pt, pf) = partition snd (zip xs partitions)
  in do
      yt <- t (map fst pt)
      yf <- f (map fst pf)
      pure $ unpartition partitions yt yf

main :: IO ()
main = do
  onPartitions even (traverse print) (traverse print) [1..10]
  pure ()