| Safe Haskell | None |
|---|
Algebra.Monad.Writer
- class (Monad m, Monoid w) => MonadWriter w m | m -> w where
- mute :: (MonadWriter w m, Monoid w) => m a -> m a
- intercept :: (MonadWriter w m, Monoid w) => m a -> m (w, a)
- data WriterT w m a
- type Writer w a = WriterT w Id a
- _writerT :: (Functor m, Functor m') => Iso (WriterT w m a) (WriterT w' m' b) (m (w, a)) (m' (w', b))
- _writer :: Iso (Writer w a) (Writer w' b) (w, a) (w', b)
The Writer monad
class (Monad m, Monoid w) => MonadWriter w m | m -> w whereSource
Instances
| Monoid w => MonadWriter w ((,) w) | |
| MonadWriter w m => MonadWriter w (ListT m) | |
| MonadWriter w m => MonadWriter w (StateT s m) | |
| MonadWriter w m => MonadWriter w (ReaderT r m) | |
| (Monoid w, Monad m) => MonadWriter w (WriterT w m) | |
| (Monoid w, Monad m) => MonadWriter w (ParserT w s m) | |
| (Monad m, Monoid w) => MonadWriter w (RWST r w s m) |
mute :: (MonadWriter w m, Monoid w) => m a -> m aSource
intercept :: (MonadWriter w m, Monoid w) => m a -> m (w, a)Source
The Writer transformer
A simple Writer monad
Instances
| (Monoid w, Monad m) => MonadWriter w (WriterT w m) | |
| (Monoid w, MonadReader r m) => MonadReader r (WriterT w m) | |
| (Monoid w, MonadState r m) => MonadState r (WriterT w m) | |
| Monoid w => MonadTrans (WriterT w) | |
| Monoid w => MonadInternal (WriterT w) | |
| (Unit m, Monoid w) => Unit (WriterT w m) | |
| (Monoid w, MonadCont m) => MonadCont (WriterT w m) | |
| (Monoid w, MonadList m) => MonadList (WriterT w m) | |
| (Monoid w, MonadFix m) => MonadFix (WriterT w m) | |
| (Monoid w, Monad m) => Monad (WriterT w m) | |
| (Monoid w, Monad m) => Applicative (WriterT w m) | |
| Functor m => Functor (WriterT w m) | |
| Foldable m => Foldable (WriterT w m) | |
| Traversable m => Traversable (WriterT w m) | |
| Ring (m (a, Void, w)) => Ring (WriterT w m a) | |
| Monoid (m (a, Void, w)) => Monoid (WriterT w m a) | |
| Semigroup (m (a, Void, w)) => Semigroup (WriterT w m a) |