, mplus -- :: (MonadPlus m) => m a -> m a -> m a
)
, join -- :: (Monad m) => m (m a) -> m a
- , guard -- :: (Monad m) => Bool -> m ()
+ , guard -- :: (MonadPlus m) => Bool -> m ()
, when -- :: (Monad m) => Bool -> m () -> m ()
, unless -- :: (Monad m) => Bool -> m () -> m ()
, ap -- :: (Monad m) => (m (a -> b)) -> (m a) -> m b