[Haskell-cafe] Hopefully simple monad question

[Tom Nielsen]

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
<miguelimo38 at 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.