Hi Krasimir, > insert :: k -> v -> Chart k v -> Maybe (Chart k v) > > where the result is (Just _) if the (k,v) is actually added to the > chart or Nothing if it was already there and nothing have to be done.
insertLookupWithKey :: Ord k => (k -> a -> a -> a) -> k -> a -> Map k a -> (Maybe a, Map k a) This should provide the information you need, without the double traversal of the data structure. Thanks Neil _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
