Safe Haskell	None
Language	Haskell2010

Control.Monad.State.Persistent

Synopsis

Documentation

A State monad that can store earlier versions of the state.

Instances

Monad m => MonadState s (PersistentStateT s m) Source #
Methods get :: PersistentStateT s m s # put :: s -> PersistentStateT s m () # state :: (s -> (a, s)) -> PersistentStateT s m a #
Monad m => Monad (PersistentStateT s m) Source #
Methods (>>=) :: PersistentStateT s m a -> (a -> PersistentStateT s m b) -> PersistentStateT s m b # (>>) :: PersistentStateT s m a -> PersistentStateT s m b -> PersistentStateT s m b # return :: a -> PersistentStateT s m a # fail :: String -> PersistentStateT s m a #
Functor m => Functor (PersistentStateT s m) Source #
Methods fmap :: (a -> b) -> PersistentStateT s m a -> PersistentStateT s m b # (<$) :: a -> PersistentStateT s m b -> PersistentStateT s m a #
Monad m => Applicative (PersistentStateT s m) Source #
Methods pure :: a -> PersistentStateT s m a # (<>) :: PersistentStateT s m (a -> b) -> PersistentStateT s m a -> PersistentStateT s m b # (>) :: PersistentStateT s m a -> PersistentStateT s m b -> PersistentStateT s m b # (<*) :: PersistentStateT s m a -> PersistentStateT s m b -> PersistentStateT s m a #

Create a snapshot of the current state and add it to the list of states that we store.

run a persistentStateT, returns a triplet with the value, the last state and a list of all states (including the last one) in chronological order