[Haskell-cafe] How to understand such a newtype ?

newtype X a = X (ReaderT XConf (StateT XState IO) a) #ifndef __HADDOCK__ deriving (Functor, Monad, MonadIO, MonadState XState, MonadReader XConf, Typeable) #endif In `X (ReaderT XConf (StateT XState IO) a)`, X is a type constructor, how to understand `(ReaderT XConf (StateT XState IO) a)` ? And why use `#ifndef __HADDOCK__` ? Sincerely! ----- fac n = foldr (*) 1 [1..n] -- View this message in context: http://old.nabble.com/How-to-understand-such-a-newtype---tp26462332p26462332... Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com.