[Haskell-cafe] I really donot know how to use `newtype` ?

import Control.Monad.State import Control.Monad.Reader data XConf = XConf {} data XState = XState {} newtype X a = X (ReaderT XConf (StateT XState IO) a)

:t StateT StateT :: (s -> m (a, s)) -> StateT s m a

:t ReaderT ReaderT :: (r -> m a) -> ReaderT r m a

then how to use `X` ? Would you mind explaining the newtype X in detail ? Sinerely! ----- fac n = foldr (*) 1 [1..n] -- View this message in context: http://old.nabble.com/I-really-donot-know-how-to-use-%60newtype%60---tp26541... Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com.