O, great. I didn't know you can write it this way.

Tom Nielsen wrote:
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
<[email protected]> 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.
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