Control.Monad.Trans.Free

Haskell 98 free monads

Documentation

data Free f a

Constructors

Pure a

Free (f (Free f a))

Instances

MonadTrans Free

Functor f => Monad (Free f)

Functor f => Functor (Free f)

(Functor v, MonadPlus v) => MonadPlus (Free v)

Functor f => Applicative (Free f)

Foldable f => Foldable (Free f)

Traversable f => Traversable (Free f)

Alternative v => Alternative (Free v)

Traversable1 f => Traversable1 (Free f)

Foldable1 f => Foldable1 (Free f)

Functor f => Apply (Free f)

Functor f => Bind (Free f)

(Eq (f (Free f a)), Eq a) => Eq (Free f a)

(Ord (f (Free f a)), Ord a) => Ord (Free f a)

(Read (f (Free f a)), Read a) => Read (Free f a)

(Show (f (Free f a)), Show a) => Show (Free f a)

retract :: Monad f => Free f a -> f a

retract . lift = id | retract . liftF = id

liftF :: Functor f => f a -> Free f a

iter :: Functor f => (f a -> a) -> Free f a -> a

wrap :: f (Free f a) -> Free f a