Control.Comonad.Store.MemoTrie

The trie-memoizing store (state-in-context/costate) comonad transformer is subject to the laws:

 x = seek (pos x) x
 y = pos (seek y x)
 seek y x = seek y (seek z x)

Thanks go to Russell O'Connor and Daniel Peebles for their help formulating and proving the laws for this comonad transformer.

The Store comonad

type Store s = StoreT s Identity

store :: HasTrie s => (s -> a) -> s -> Store s a

runStore :: HasTrie s => Store s a -> (s -> a, s)

The Store comonad transformer

data StoreT s w a

Constructors

StoreT (w (s :->: a)) s

Instances

(ComonadEnv m w, HasTrie s) => ComonadEnv m (StoreT s w)

(Comonad w, HasTrie s) => ComonadStore s (StoreT s w)

(ComonadTraced m w, HasTrie s) => ComonadTraced m (StoreT s w)

ComonadHoist (StoreT s)

HasTrie s => ComonadTrans (StoreT s)

(Functor w, HasTrie s) => Functor (StoreT s w)

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

(Comonad w, HasTrie s) => Comonad (StoreT s w)

(Extend w, HasTrie s) => Extend (StoreT s w)

(Typeable s, Typeable1 w, Typeable a) => Typeable (StoreT s w a)

storeT :: (Functor w, HasTrie s) => w (s -> a) -> s -> StoreT s w a

runStoreT :: (Functor w, HasTrie s) => StoreT s w a -> (w (s -> a), s)

Operations

module Control.Comonad.Store.Class