Snap.Snaplet.AcidState

Documentation

data Acid st

Data type holding acid-state snaplet data.

Instances

HasAcid (Acid st) st

class HasAcid myState acidState where

Type class standardizing a context that holds an AcidState.

You can minimize boilerplate in your application by adding an instance like the following:

 data App = App { ... _acid :: Snaplet (Acid MyState) ... }
 instance HasAcid App MyState where
     getAcidStore = getL (snapletValue . acid)

Methods

getAcidStore :: myState -> Acid acidState

Instances

HasAcid (Acid st) st

acidInit

Arguments

:: (IsAcidic st, Typeable st)

=> st

Initial state to be used if

-> SnapletInit b (Acid st)

acidInit'

Arguments

:: IsAcidic st

=> FilePath

Location of the acid-state store on disk

-> st

Initial state to be used if

-> SnapletInit b (Acid st)

Initializer allowing you to specify the location of the acid-state store.

update :: (MonadState s m, HasAcid s (MethodState event), UpdateEvent event, MonadIO m) => event -> m (EventResult event)

Wrapper for acid-state's update function that works for arbitrary instances of HasAcid.

query :: (HasAcid s (MethodState event), MonadIO m, QueryEvent event, MonadState s m) => event -> m (EventResult event)

Wrapper for acid-state's query function that works for arbitrary instances of HasAcid.

createCheckpoint :: (MonadIO m, MonadState s m, HasAcid s st) => m ()

closeAcidState :: (MonadIO m, MonadState s m, HasAcid s st) => m ()

module Data.Acid