definition module rwst

from Data.Functor import class Functor
from Data.Monoid import class Monoid, class Semigroup
from Control.Applicative import class Applicative
from Control.Monad import class Monad

:: RWST r w s m a

instance Functor (RWST r w s m) | Monad m & Monoid w
instance Applicative (RWST r w s m) | Monad m & Monoid w
instance Monad (RWST r w s m) | Monad m & Monoid w