newtype VMT m a = VMT {runVMT :: StateT VMState m a} deriving (Monad, MonadIO, MonadTrans, TransM, MonadState VMState)
works here (ghc-6.10.3) On Wed, Sep 16, 2009 at 11:42 AM, Miguel Mitrofanov <miguelim...@yandex.ru> wrote: > newtype VMT m a = > VMT {runVMT :: StateT VMState m a} > deriving (Monad, MonadIO, MonadTrans, TransM) > > Unfortunately, you can't automatically derive MonadState, since it's a > multi-paremeter type class. You'll have to write down the derivation > yourself. _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe