-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/


-- | External reference with reactivity support
--   
--   The package provides you with <a>IORef</a> that has attached reflex
--   <a>Event</a>. Each time the variable changes the event fires. It is
--   very useful for communication with external event sources or using it
--   as environment level state.
@package reflex-external-ref
@version 1.0.3.1


-- | External reference with reactivity support. The reference is needed in
--   glue code between reflex and external libs where you cannot sample
--   from dynamics with <a>MonadSample</a>.
module Reflex.ExternalRef

-- | Holds value of type <tt>a</tt> and provides ways for notifying FRP
--   network about changes of the variable.
--   
--   This abstraction is helpful for storing counters, lists of internal
--   resources and so on. It is designed to be updated from outputs of FRP
--   network, not from outer world.
data ExternalRef t a
ExternalRef :: !IORef a -> !Event t a -> !a -> IO () -> ExternalRef t a

-- | Storage of value (do not change this by yourself, use helpers)
[externalRef] :: ExternalRef t a -> !IORef a

-- | Event that fires when value is changed
[externalEvent] :: ExternalRef t a -> !Event t a

-- | Method of updating value of previous event
[externalFire] :: ExternalRef t a -> !a -> IO ()

-- | Creation of external ref in host monad
newExternalRef :: (MonadIO m, TriggerEvent t m) => a -> m (ExternalRef t a)

-- | Read current value of external reference
readExternalRef :: MonadIO m => ExternalRef t a -> m a

-- | Write new value to external reference and notify FRP network. The
--   function evaluates the value to WNF.
writeExternalRef :: MonadIO m => ExternalRef t a -> a -> m ()

-- | Atomically modify an external ref and notify FRP network. The function
--   evaluates the value to WNF.
modifyExternalRef :: MonadIO m => ExternalRef t a -> (a -> (a, b)) -> m b

-- | Atomically modify an external ref and notify FRP network. The function
--   evaluates the value to WNF. Returns nothing
modifyExternalRef_ :: MonadIO m => ExternalRef t a -> (a -> a) -> m ()

-- | If the function evaluates to Just then Atomically modify an external
--   ref and notify FRP network. The function evaluates the value to WNF.
--   Return the Maybe result of function's evaluation
modifyExternalRefMaybe :: MonadIO m => ExternalRef t a -> (a -> Maybe (a, b)) -> m (Maybe b)

-- | If the function evaluates to Just then Atomically modify an external
--   ref and notify FRP network. The function evaluates the value to WNF.
--   Returns nothing The function discards the result
modifyExternalRefMaybe_ :: MonadIO m => ExternalRef t a -> (a -> Maybe a) -> m ()

-- | Modify (not atomically) an external ref and notify FRP network. The
--   function evaluates the value to WNF.
modifyExternalRefM :: MonadIO m => ExternalRef t a -> (a -> m (a, b)) -> m b

-- | Modify (not atomically) an external ref and notify FRP network. The
--   function evaluates the value to WNF.
modifyExternalRefM_ :: MonadIO m => ExternalRef t a -> (a -> m a) -> m ()

-- | If the function evaluates to Just then Modify (not atomically) an
--   external ref and notify FRP network. The function evaluates the value
--   to WNF.
modifyExternalRefMaybeM :: MonadIO m => ExternalRef t a -> (a -> m (Maybe (a, b))) -> m (Maybe b)

-- | If the function evaluates to Just then Modify (not atomically) an
--   external ref and notify FRP network. The function evaluates the value
--   to WNF. The function discards the result
modifyExternalRefMaybeM_ :: MonadIO m => ExternalRef t a -> (a -> m (Maybe a)) -> m ()

-- | Construct a behavior from external reference
externalRefBehavior :: (MonadHold t m, MonadIO m) => ExternalRef t a -> m (Behavior t a)

-- | Get dynamic that tracks value of the internal ref
externalRefDynamic :: (MonadHold t m, MonadIO m) => ExternalRef t a -> m (Dynamic t a)

-- | Create external ref that tracks content of dynamic. Editing of the ref
--   has no effect on the original dynamic.
externalFromDynamic :: (MonadHold t m, TriggerEvent t m, PerformEvent t m, Reflex t, MonadIO m, MonadIO (Performable m)) => Dynamic t a -> m (ExternalRef t a)

-- | Creates external ref as a result of "fmapping" a function to the
--   original ref. ExternalRef t is not a true Functior, since it requres
--   monadic action to "fmap" Editing of the new ref has no effect on the
--   original dynamic.
fmapExternalRef :: (MonadIO m, TriggerEvent t m, PerformEvent t m, MonadIO (Performable m)) => (a -> b) -> ExternalRef t a -> m (ExternalRef t b)
instance GHC.Generics.Generic (Reflex.ExternalRef.ExternalRef t a)
instance Control.DeepSeq.NFData (Reflex.ExternalRef.ExternalRef t a)