[Haskell-cafe] Deriving

What happens when a type adds driving such as: newtype SupplyT s m a = SupplyT (StateT [s] m a) deriving (Functor http://haskell.org/ghc/docs/latest/html/libraries/base/Prelude.html#t:Functo..., Monad http://haskell.org/ghc/docs/latest/html/libraries/base/Prelude.html#t:Monad, MonadTrans, MonadIO) Two questions: How does the deriving implement the instance? Is there a way for me to add my own classes in the deriving? for example newtype ..... deriving( xyz) Thanks