Control.Comonad.Trans.Discont.Memo

Discont is the density comonad of a constant functor, just as Cont is a Codensity monad of a constant functor. (For the definition of Density and Codensity, see the non-Haskell 98 adjunctions package)

Note that while Discont and Store are isomorphic, DiscontT and StoreT are not.

Like the memoizing store comonad, version memoizes the result of applying the continuation to the current context.

The discontinuation comonad

type Discont s = DiscontT s Identity

discont :: (s -> a) -> s -> Discont s a

The discontinuation comonad transformer

runDiscont :: Discont s a -> (s -> a, s)

data DiscontT s w a

Instances

ComonadTrans (DiscontT s)

Functor (DiscontT s w)

(Typeable s, Typeable1 w) => Typeable1 (DiscontT s w)

Comonad (DiscontT s w)

Extend (DiscontT s w)

discontT :: (w s -> a) -> w s -> DiscontT s w a

runDiscontT :: DiscontT s w a -> (w s -> a, w s)