[Haskell-cafe] Deriving

[Daryoush Mehrtash]

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:Functor>,
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
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