Generics.Putlenses.Putlens

General framework for put-based lenses.

A well-behaved putlens is expected to satisfy two properties: GetPut: |Just v = get l s => s = runPutM (put (Just s) v) e st| PutGet: |s' = runPutM (put s v') e st => Just v' = get s'|

Documentation

evalSt :: State s a -> s -> a

readSt :: MonadState s m => m s

writeSt :: MonadState s m => s -> m ()

runSt :: State s a -> s -> (a, s)

data Lens s v

Interface for normal lenses

Constructors

Lens

Fields

get :: s -> v

put :: s -> v -> s

type PutM e st a = ReaderT (e, Bool) (State (st, Bool)) a

Monad for put-based lenses includes an environment, state, and boolean tags that our system will use to ensure GetPut and PutGet

type Get s v = s -> Maybe v

type Put st e s v = Maybe s -> v -> PutM e st s

type Create st e s v = v -> PutM e st s

data Putlens st e s v

Framework for put-based lenses

Constructors

Putlens

Fields

getputM :: s -> (Maybe v, Create st e s v)

createM :: Create st e s v

type Putlens' s v = Putlens () s s v

getM :: Putlens st e s v -> Get s v

Forward |get| function

putM :: Putlens st e s v -> Put st e s v

Backward |put| function

evalPutM :: PutM e st s -> (e, Bool) -> (st, Bool) -> s

Runs a putlens for a particular environment and state

runPutM :: PutM e st s -> (e, Bool) -> (st, Bool) -> (s, Bool)

withPutM :: (st -> e -> a) -> PutM e st a

Computes a value of type |a| using the current state and environment

simplelens2put :: Lens' s v -> Putlens st e s v

put2lens :: Eq v => Putlens' s v -> Lens s v

Converts a putlens to a normal lens. Initializes the environment as the original source, the state as empty, the GetPut tag as True and the PutGet tag as False

get' :: Eq v => Putlens' s v -> s -> v

put' :: Eq v => Putlens' s v -> s -> v -> s

getput' :: Eq v => Putlens' s v -> s -> (v, v -> s)