data-accessor-mtl-0.2.0.4: Use Accessor to access state in mtl State monad class

Safe HaskellSafe
LanguageHaskell98

Data.Accessor.Monad.MTL.State

Contents

Description

Access helper functions in the State monad class

Synopsis

accessors in the form of actions in the state monad

set :: MonadState r m => T r a -> a -> m () #

get :: MonadState r m => T r a -> m a #

modify :: MonadState r m => T r a -> (a -> a) -> m () #

getAndModify :: MonadState r m => T r a -> (a -> a) -> m a #

Modify a record element and return its old value.

modifyAndGet :: MonadState r m => T r a -> (a -> a) -> m a #

Modify a record element and return its new value.

(%=) :: MonadState r m => T r a -> a -> m () infix 1 #

Infix variant of set.

(%:) :: MonadState r m => T r a -> (a -> a) -> m () infix 1 #

Infix variant of modify.

lift a state monadic accessor to an accessor of a parent record

lift :: MonadState r mr => T r s -> State s a -> mr a #

liftT :: (Monad m, MonadTrans t, MonadState r (t m)) => T r s -> StateT s m a -> t m a #