-- | The multi-valued version of mtl's MonadWriter
module Control.Monad.Trans.MultiWriter.Class
  (
  -- * MonadMultiWriter class
    MonadMultiWriter(..)
  )
where



import Control.Monad.Trans.Class  ( MonadTrans
                                  , lift )

import Data.Monoid



-- TODO: some haddock
class (Monad m, Monoid a) => MonadMultiWriter a m where
  mTell :: a -> m ()  

instance (MonadTrans t, Monad (t m), MonadMultiWriter a m)
      => MonadMultiWriter a (t m) where
  mTell :: a -> t m ()
mTell = m () -> t m ()
forall (t :: (* -> *) -> * -> *) (m :: * -> *) a.
(MonadTrans t, Monad m) =>
m a -> t m a
lift (m () -> t m ()) -> (a -> m ()) -> a -> t m ()
forall b c a. (b -> c) -> (a -> b) -> a -> c
. a -> m ()
forall a (m :: * -> *). MonadMultiWriter a m => a -> m ()
mTell