data Flag = Flag {
    _flagName :: String
  , _flagDep :: [Int]
  }


-- If a flag with name 'fname' already exists in the input list,
-- add 'fdep' to it. Otherwise append a new Flag to the list with 'fdep'
-- being the only item.
addFlag :: [Flag] -> String -> Int -> [Flag]
addFlag flags fname fdep = undefined