Safe Haskell	None
Language	Haskell2010

Control.Effect.Select

Contents

Effect
Actions
Interpretations
Carriers

Synopsis

newtype Select s m a where
- Select :: (forall r. (a -> m (s, r)) -> m r) -> Select s m a
select :: Eff (Select s) m => (forall r. (a -> m (s, r)) -> m r) -> m a
runSelect :: forall s a m p. (Carrier m, Threaders '[ContThreads] m p) => (a -> m s) -> SelectC s a m a -> m a
data SelectC s r m a

Effect

newtype Select s m a where Source #

An effect for backtracking search.

Constructors

Select :: (forall r. (a -> m (s, r)) -> m r) -> Select s m a

Instances

Instances details

Eff (Shift (s, r)) m => Handler (SelectH r) (Select s) m Source #
Instance details Defined in Control.Effect.Internal.Select Methods effHandler :: EffHandler (Select s) m Source #

Actions

select :: Eff (Select s) m => (forall r. (a -> m (s, r)) -> m r) -> m a Source #

Perform a search: capture the continuation of the program, so that you may test values of a and observe what corresponding s each value would result in at the end of the program (which may be seen as the evaluation of a). When you find a satisfactory a, you may return the associated r.

The way higher-order actions interact with the continuation depends on the interpretation of Select. In general, you cannot expect to interact with the continuation in any meaningful way: for example, you should not assume that you will be able to catch an exception thrown at some point in the future of the computation by using catch on the continuation.

Interpretations

runSelect :: forall s a m p. (Carrier m, Threaders '[ContThreads] m p) => (a -> m s) -> SelectC s a m a -> m a Source #

Run a Select s effect by providing an evaluator for the final result of type a.

Derivs (SelectC s r m) = Select s ': Derivs m

Prims  (SelectC s r m) = Prims m

Carriers

data SelectC s r m a Source #

Instances

Instances details

MonadBase b m => MonadBase b (SelectC s r m) Source #
Instance details Defined in Control.Effect.Internal.Select Methods liftBase :: b α -> SelectC s r m α #
MonadTrans (SelectC s r) Source #
Instance details Defined in Control.Effect.Internal.Select Methods lift :: Monad m => m a -> SelectC s r m a #
Monad (SelectC s r m) Source #
Instance details Defined in Control.Effect.Internal.Select Methods (>>=) :: SelectC s r m a -> (a -> SelectC s r m b) -> SelectC s r m b # (>>) :: SelectC s r m a -> SelectC s r m b -> SelectC s r m b # return :: a -> SelectC s r m a #
Functor (SelectC s r m) Source #
Instance details Defined in Control.Effect.Internal.Select Methods fmap :: (a -> b) -> SelectC s r m a -> SelectC s r m b # (<$) :: a -> SelectC s r m b -> SelectC s r m a #
MonadFail m => MonadFail (SelectC s r m) Source #
Instance details Defined in Control.Effect.Internal.Select Methods fail :: String -> SelectC s r m a #
Applicative (SelectC s r m) Source #
Instance details Defined in Control.Effect.Internal.Select Methods pure :: a -> SelectC s r m a # (<>) :: SelectC s r m (a -> b) -> SelectC s r m a -> SelectC s r m b # liftA2 :: (a -> b -> c) -> SelectC s r m a -> SelectC s r m b -> SelectC s r m c # (>) :: SelectC s r m a -> SelectC s r m b -> SelectC s r m b # (<*) :: SelectC s r m a -> SelectC s r m b -> SelectC s r m a #
MonadIO m => MonadIO (SelectC s r m) Source #
Instance details Defined in Control.Effect.Internal.Select Methods liftIO :: IO a -> SelectC s r m a #
MonadThrow m => MonadThrow (SelectC s r m) Source #
Instance details Defined in Control.Effect.Internal.Select Methods throwM :: Exception e => e -> SelectC s r m a #
MonadCatch m => MonadCatch (SelectC s r m) Source #
Instance details Defined in Control.Effect.Internal.Select Methods catch :: Exception e => SelectC s r m a -> (e -> SelectC s r m a) -> SelectC s r m a #
(Carrier m, Threads (FreeT (ContBase (m (s, r)) (s, r))) (Prims m)) => Carrier (SelectC s r m) Source #
Instance details Defined in Control.Effect.Internal.Select Associated Types type Derivs (SelectC s r m) :: [Effect] Source # type Prims (SelectC s r m) :: [Effect] Source # Methods algPrims :: Algebra' (Prims (SelectC s r m)) (SelectC s r m) a Source # reformulate :: Monad z => Reformulation' (Derivs (SelectC s r m)) (Prims (SelectC s r m)) (SelectC s r m) z a Source # algDerivs :: Algebra' (Derivs (SelectC s r m)) (SelectC s r m) a Source #
type Derivs (SelectC s r m) Source #
Instance details Defined in Control.Effect.Internal.Select type Derivs (SelectC s r m) = Derivs (ReinterpretC (SelectH r) (Select s) '[Shift (s, r)] (ShiftC (s, r) m))
type Prims (SelectC s r m) Source #
Instance details Defined in Control.Effect.Internal.Select type Prims (SelectC s r m) = Prims (ReinterpretC (SelectH r) (Select s) '[Shift (s, r)] (ShiftC (s, r) m))