Control.Monad.Skeleton

Documentation

data MonadView t m x where

A deconstructed action

Constructors

Return :: a -> MonadView t m a

(:>>=) :: !(t a) -> (a -> m b) -> MonadView t m b infixl 1

Instances

Functor m => Functor (MonadView t m)

Defined in Control.Monad.Skeleton

Methods

fmap :: (a -> b) -> MonadView t m a -> MonadView t m b

(<$) :: a -> MonadView t m b -> MonadView t m a

hoistMV :: (forall x. s x -> t x) -> (m a -> n a) -> MonadView s m a -> MonadView t n a

Transform the instruction as well as the continuation.

iterMV :: Monad m => (t a -> MonadView m t a) -> t a -> m a

Join MonadView recursively.

data Skeleton t a where

Skeleton t is a monadic skeleton (operational monad) made out of t. Skeletons can be fleshed out by interpreting the instructions. It provides O(1) (>>=) and debone.

Constructors

ReturnS :: a -> Skeleton t a

BindS :: t a -> Cat (Kleisli (Skeleton t)) a b -> Skeleton t b

Instances

Applicative (Skeleton t)

Defined in Control.Monad.Skeleton

Methods

pure :: a -> Skeleton t a

(<*>) :: Skeleton t (a -> b) -> Skeleton t a -> Skeleton t b

liftA2 :: (a -> b -> c) -> Skeleton t a -> Skeleton t b -> Skeleton t c

(*>) :: Skeleton t a -> Skeleton t b -> Skeleton t b

(<*) :: Skeleton t a -> Skeleton t b -> Skeleton t a

Functor (Skeleton t)

Defined in Control.Monad.Skeleton

Methods

fmap :: (a -> b) -> Skeleton t a -> Skeleton t b

(<$) :: a -> Skeleton t b -> Skeleton t a

Monad (Skeleton t)

Defined in Control.Monad.Skeleton

Methods

(>>=) :: Skeleton t a -> (a -> Skeleton t b) -> Skeleton t b

(>>) :: Skeleton t a -> Skeleton t b -> Skeleton t b

return :: a -> Skeleton t a

bone :: t a -> Skeleton t a

A skeleton that has only one bone.

debone :: Skeleton t a -> MonadView t (Skeleton t) a

Extract the first instruction in Skeleton.

deboneBy :: (MonadView t (Skeleton t) a -> r) -> Skeleton t a -> r

Continuation-passing variant of debone which allows nicer expression using LambdaCase.

Usecase:

 interpretM :: Monad m => Skeleton m a -> m a
 interpretM = deboneBy $ \case
   Return a -> return a
   x :>>= f -> x >>= interpretM . f

boned :: MonadView t (Skeleton t) a -> Skeleton t a

Re-add a bone. Inverse of debone

hoistSkeleton :: forall s t a. (forall x. s x -> t x) -> Skeleton s a -> Skeleton t a

Lift a transformation between bones into transformation between skeletons.