Data.Accessor.MonadLib

Access helper functions in State and Reader monads

accessors in the form of actions in the state monad

set :: StateM m r => T r a -> a -> m ()

get :: StateM m r => T r a -> m a

modify :: StateM m r => T r a -> (a -> a) -> m ()

getAndModify :: StateM m r => T r a -> (a -> a) -> m a

Modify a record element and return its old value.

modifyAndGet :: StateM m r => T r a -> (a -> a) -> m a

Modify a record element and return its new value.

(%=) :: StateM m r => T r a -> a -> m ()

Infix variant of set.

(%:) :: StateM m r => T r a -> (a -> a) -> m ()

Infix variant of modify.

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

lift :: StateM m r => T r s -> State s a -> m a

liftT :: Monad m => T r s -> StateT s m a -> StateT r m a

accessors in the form of actions in the reader monad

ask :: ReaderM m r => T r a -> m a

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

focusingOn :: ReaderM m r => T r s -> Reader s a -> m a

focusingOnT :: Monad m => T r s -> ReaderT s m a -> ReaderT r m a