Recursive operator for parsing values from deeply nested Objects in Aeson

deepvalue.hs

(.:/) :: (FromJSON a) => Object
                         -> [Text]
                         -> Parser a
obj .:/ (k:ks) = maybe (fail msg) parseJSON parsed
 where parsed = deepValue ks =<< M.lookup k obj
       msg    = "Failed to find " ++ (intercalate "/" $ map unpack (k:ks))
obj .:/ []     = parseJSON $ Object obj

deepValue :: [Text]
             -> Value
             -> Maybe Value
deepValue (k:[]) (Object obj) = M.lookup k obj
deepValue (k:[]) _            = Nothing
deepValue (k:ks) (Object obj) = deepValue ks =<< M.lookup k obj
deepValue (k:ks) _            = Nothing
deepValue [] v                = Just v