Safe Haskell	None
Language	Haskell2010

Control.Effect.Fresh

Contents

Fresh effect
Re-exports

Description

This effect provides source to an infinite source of Int values, suitable for generating "fresh" values to uniquely identify data without needing to invoke random numbers or impure IO.

Predefined carriers:

Control.Carrier.Fresh.Strict.

Synopsis

data Fresh m k = Fresh (Int -> m k)
fresh :: Has Fresh sig m => m Int
class (HFunctor sig, Monad m) => Algebra sig m | m -> sig
class HFunctor sig => Effect sig
type Has eff sig m = (Members eff sig, Algebra sig m)
run :: Identity a -> a

Fresh effect

data Fresh m k Source #

Since: 0.1.0.0

Constructors

Fresh (Int -> m k)

Instances

Instances details

Effect Fresh Source #
Instance details Defined in Control.Effect.Fresh Methods thread :: (Functor ctx, Monad m) => ctx () -> (forall x. ctx (m x) -> n (ctx x)) -> Fresh m a -> Fresh n (ctx a) Source #
HFunctor Fresh Source #
Instance details Defined in Control.Effect.Fresh Methods hmap :: Functor m => (forall x. m x -> n x) -> Fresh m a -> Fresh n a Source #
Functor m => Functor (Fresh m) Source #
Instance details Defined in Control.Effect.Fresh Methods fmap :: (a -> b) -> Fresh m a -> Fresh m b # (<$) :: a -> Fresh m b -> Fresh m a #
Generic1 (Fresh m :: Type -> Type) Source #
Instance details Defined in Control.Effect.Fresh Associated Types type Rep1 (Fresh m) :: k -> Type # Methods from1 :: forall (a :: k). Fresh m a -> Rep1 (Fresh m) a # to1 :: forall (a :: k). Rep1 (Fresh m) a -> Fresh m a #
(Algebra sig m, Effect sig) => Algebra (Fresh :+: sig) (FreshC m) Source #
Instance details Defined in Control.Carrier.Fresh.Strict Methods alg :: (Fresh :+: sig) (FreshC m) a -> FreshC m a Source #
type Rep1 (Fresh m :: Type -> Type) Source #
Instance details Defined in Control.Effect.Fresh type Rep1 (Fresh m :: Type -> Type) = D1 ('MetaData "Fresh" "Control.Effect.Fresh" "fused-effects-1.0.0.1-inplace" 'False) (C1 ('MetaCons "Fresh" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (((->) Int :: Type -> Type) :.: Rec1 m)))

fresh :: Has Fresh sig m => m Int Source #

Produce a fresh (i.e. unique) Int.

m >> fresh ≠ m >> fresh >> fresh

Since: 0.1.0.0

Re-exports

class (HFunctor sig, Monad m) => Algebra sig m | m -> sig Source #

The class of carriers (results) for algebras (effect handlers) over signatures (effects), whose actions are given by the alg method.

Since: 1.0.0.0

Minimal complete definition

alg

Instances

Instances details

Algebra Choose NonEmpty Source #
Instance details Defined in Control.Algebra Methods alg :: Choose NonEmpty a -> NonEmpty a Source #
Algebra Empty Maybe Source #
Instance details Defined in Control.Algebra Methods alg :: Empty Maybe a -> Maybe a Source #
Algebra NonDet [] Source #
Instance details Defined in Control.Algebra Methods alg :: NonDet [] a -> [a] Source #
Algebra sig m => Algebra sig (Alt m) Source #	This instance permits effectful actions to be lifted into the `Alt` monad, which eases the invocation of repeated alternation with `<\|>`: a <\|> b <\|> c <\|> d is equivalent to getAlt (mconcat [a, b, c, d]) Since: 1.0.1.0
Instance details Defined in Control.Algebra Methods alg :: sig (Alt m) a -> Alt m a Source #
Algebra sig m => Algebra sig (Ap m) Source #	This instance permits effectful actions to be lifted into the `Ap` monad given a monoidal return type, which can provide clarity when chaining calls to `mappend`. mappend <$> act1 <> (mappend <$> act2 <> act3) is equivalent to getAp (act1 <> act2 <> act3) Since: 1.0.1.0
Instance details Defined in Control.Algebra Methods alg :: sig (Ap m) a -> Ap m a Source #
Algebra sig m => Algebra sig (IdentityT m) Source #
Instance details Defined in Control.Algebra Methods alg :: sig (IdentityT m) a -> IdentityT m a Source #
Algebra (Lift IO) IO Source #
Instance details Defined in Control.Algebra Methods alg :: Lift IO IO a -> IO a Source #
Algebra (Lift Identity) Identity Source #
Instance details Defined in Control.Algebra Methods alg :: Lift Identity Identity a -> Identity a Source #
Monad m => Algebra (Lift m) (LiftC m) Source #
Instance details Defined in Control.Carrier.Lift Methods alg :: Lift m (LiftC m) a -> LiftC m a Source #
Algebra (Error e) (Either e) Source #
Instance details Defined in Control.Algebra Methods alg :: Error e (Either e) a -> Either e a Source #
Monoid w => Algebra (Writer w) ((,) w) Source #
Instance details Defined in Control.Algebra Methods alg :: Writer w ((,) w) a -> (w, a) Source #
Algebra (Reader r) ((->) r :: Type -> Type) Source #
Instance details Defined in Control.Algebra Methods alg :: Reader r ((->) r) a -> r -> a Source #
(Algebra sig m, Effect sig) => Algebra (Choose :+: sig) (ChooseC m) Source #
Instance details Defined in Control.Carrier.Choose.Church Methods alg :: (Choose :+: sig) (ChooseC m) a -> ChooseC m a Source #
(Algebra sig m, Effect sig) => Algebra (Empty :+: sig) (EmptyC m) Source #
Instance details Defined in Control.Carrier.Empty.Maybe Methods alg :: (Empty :+: sig) (EmptyC m) a -> EmptyC m a Source #
(Algebra sig m, Effect sig) => Algebra (NonDet :+: sig) (NonDetC m) Source #
Instance details Defined in Control.Carrier.NonDet.Church Methods alg :: (NonDet :+: sig) (NonDetC m) a -> NonDetC m a Source #
(MonadIO m, Algebra sig m) => Algebra (Trace :+: sig) (TraceC m) Source #
Instance details Defined in Control.Carrier.Trace.Printing Methods alg :: (Trace :+: sig) (TraceC m) a -> TraceC m a Source #
Algebra sig m => Algebra (Trace :+: sig) (TraceC m) Source #
Instance details Defined in Control.Carrier.Trace.Ignoring Methods alg :: (Trace :+: sig) (TraceC m) a -> TraceC m a Source #
(Algebra sig m, Effect sig) => Algebra (Trace :+: sig) (TraceC m) Source #
Instance details Defined in Control.Carrier.Trace.Returning Methods alg :: (Trace :+: sig) (TraceC m) a -> TraceC m a Source #
(Algebra sig m, Effect sig) => Algebra (Fail :+: sig) (FailC m) Source #
Instance details Defined in Control.Carrier.Fail.Either Methods alg :: (Fail :+: sig) (FailC m) a -> FailC m a Source #
(Algebra sig m, Effect sig) => Algebra (Fresh :+: sig) (FreshC m) Source #
Instance details Defined in Control.Carrier.Fresh.Strict Methods alg :: (Fresh :+: sig) (FreshC m) a -> FreshC m a Source #
(Algebra sig m, Effect sig) => Algebra (Cut :+: (NonDet :+: sig)) (CutC m) Source #
Instance details Defined in Control.Carrier.Cut.Church Methods alg :: (Cut :+: (NonDet :+: sig)) (CutC m) a -> CutC m a Source #
(Algebra sig m, Effect sig) => Algebra (Cull :+: (NonDet :+: sig)) (CullC m) Source #
Instance details Defined in Control.Carrier.Cull.Church Methods alg :: (Cull :+: (NonDet :+: sig)) (CullC m) a -> CullC m a Source #
Algebra sig m => Algebra (Reader r :+: sig) (ReaderT r m) Source #
Instance details Defined in Control.Algebra Methods alg :: (Reader r :+: sig) (ReaderT r m) a -> ReaderT r m a Source #
Algebra sig m => Algebra (Reader r :+: sig) (ReaderC r m) Source #
Instance details Defined in Control.Carrier.Reader Methods alg :: (Reader r :+: sig) (ReaderC r m) a -> ReaderC r m a Source #
(Algebra sig m, Effect sig) => Algebra (State s :+: sig) (StateT s m) Source #
Instance details Defined in Control.Algebra Methods alg :: (State s :+: sig) (StateT s m) a -> StateT s m a Source #
(Algebra sig m, Effect sig) => Algebra (State s :+: sig) (StateT s m) Source #
Instance details Defined in Control.Algebra Methods alg :: (State s :+: sig) (StateT s m) a -> StateT s m a Source #
(Algebra sig m, Effect sig) => Algebra (State s :+: sig) (StateC s m) Source #
Instance details Defined in Control.Carrier.State.Strict Methods alg :: (State s :+: sig) (StateC s m) a -> StateC s m a Source #
(Algebra sig m, Effect sig) => Algebra (State s :+: sig) (StateC s m) Source #
Instance details Defined in Control.Carrier.State.Lazy Methods alg :: (State s :+: sig) (StateC s m) a -> StateC s m a Source #
(Algebra sig m, Effect sig) => Algebra (Throw e :+: sig) (ThrowC e m) Source #
Instance details Defined in Control.Carrier.Throw.Either Methods alg :: (Throw e :+: sig) (ThrowC e m) a -> ThrowC e m a Source #
(Algebra sig m, Effect sig) => Algebra (Error e :+: sig) (ExceptT e m) Source #
Instance details Defined in Control.Algebra Methods alg :: (Error e :+: sig) (ExceptT e m) a -> ExceptT e m a Source #
(Algebra sig m, Effect sig) => Algebra (Error e :+: sig) (ErrorC e m) Source #
Instance details Defined in Control.Carrier.Error.Either Methods alg :: (Error e :+: sig) (ErrorC e m) a -> ErrorC e m a Source #
(Algebra sig m, Effect sig, Monoid w) => Algebra (Writer w :+: sig) (WriterT w m) Source #
Instance details Defined in Control.Algebra Methods alg :: (Writer w :+: sig) (WriterT w m) a -> WriterT w m a Source #
(Algebra sig m, Effect sig, Monoid w) => Algebra (Writer w :+: sig) (WriterT w m) Source #
Instance details Defined in Control.Algebra Methods alg :: (Writer w :+: sig) (WriterT w m) a -> WriterT w m a Source #
(Monoid w, Algebra sig m, Effect sig) => Algebra (Writer w :+: sig) (WriterC w m) Source #
Instance details Defined in Control.Carrier.Writer.Strict Methods alg :: (Writer w :+: sig) (WriterC w m) a -> WriterC w m a Source #
(HFunctor eff, HFunctor sig, Reifies s (Handler eff m), Monad m, Algebra sig m) => Algebra (eff :+: sig) (InterpretC s eff m) Source #
Instance details Defined in Control.Carrier.Interpret Methods alg :: (eff :+: sig) (InterpretC s eff m) a -> InterpretC s eff m a Source #
(Algebra sig m, Effect sig, Monoid w) => Algebra (Reader r :+: (Writer w :+: (State s :+: sig))) (RWST r w s m) Source #
Instance details Defined in Control.Algebra Methods alg :: (Reader r :+: (Writer w :+: (State s :+: sig))) (RWST r w s m) a -> RWST r w s m a Source #
(Algebra sig m, Effect sig, Monoid w) => Algebra (Reader r :+: (Writer w :+: (State s :+: sig))) (RWST r w s m) Source #
Instance details Defined in Control.Algebra Methods alg :: (Reader r :+: (Writer w :+: (State s :+: sig))) (RWST r w s m) a -> RWST r w s m a Source #

class HFunctor sig => Effect sig Source #

The class of effect types, which must:

Be functorial in their last two arguments, and
Support threading effects in higher-order positions through using the carrier’s suspended context.

All first-order effects (those without existential occurrences of m) admit a default definition of thread provided a Generic1 instance is available for the effect.

Since: 1.0.0.0

Instances

Instances details

Effect Choose Source #
Instance details Defined in Control.Effect.Choose.Internal Methods thread :: (Functor ctx, Monad m) => ctx () -> (forall x. ctx (m x) -> n (ctx x)) -> Choose m a -> Choose n (ctx a) Source #
Effect Empty Source #
Instance details Defined in Control.Effect.Empty.Internal Methods thread :: (Functor ctx, Monad m) => ctx () -> (forall x. ctx (m x) -> n (ctx x)) -> Empty m a -> Empty n (ctx a) Source #
Effect Trace Source #
Instance details Defined in Control.Effect.Trace Methods thread :: (Functor ctx, Monad m) => ctx () -> (forall x. ctx (m x) -> n (ctx x)) -> Trace m a -> Trace n (ctx a) Source #
Effect Fresh Source #
Instance details Defined in Control.Effect.Fresh Methods thread :: (Functor ctx, Monad m) => ctx () -> (forall x. ctx (m x) -> n (ctx x)) -> Fresh m a -> Fresh n (ctx a) Source #
Effect Cut Source #
Instance details Defined in Control.Effect.Cut Methods thread :: (Functor ctx, Monad m) => ctx () -> (forall x. ctx (m x) -> n (ctx x)) -> Cut m a -> Cut n (ctx a) Source #
Effect Cull Source #
Instance details Defined in Control.Effect.Cull Methods thread :: (Functor ctx, Monad m) => ctx () -> (forall x. ctx (m x) -> n (ctx x)) -> Cull m a -> Cull n (ctx a) Source #
Effect (Catch e) Source #
Instance details Defined in Control.Effect.Catch.Internal Methods thread :: (Functor ctx, Monad m) => ctx () -> (forall x. ctx (m x) -> n (ctx x)) -> Catch e m a -> Catch e n (ctx a) Source #
Functor sig => Effect (Lift sig) Source #
Instance details Defined in Control.Effect.Lift.Internal Methods thread :: (Functor ctx, Monad m) => ctx () -> (forall x. ctx (m x) -> n (ctx x)) -> Lift sig m a -> Lift sig n (ctx a) Source #
Effect (Reader r) Source #
Instance details Defined in Control.Effect.Reader.Internal Methods thread :: (Functor ctx, Monad m) => ctx () -> (forall x. ctx (m x) -> n (ctx x)) -> Reader r m a -> Reader r n (ctx a) Source #
Effect (State s) Source #
Instance details Defined in Control.Effect.State.Internal Methods thread :: (Functor ctx, Monad m) => ctx () -> (forall x. ctx (m x) -> n (ctx x)) -> State s m a -> State s n (ctx a) Source #
Effect (Throw e) Source #
Instance details Defined in Control.Effect.Throw.Internal Methods thread :: (Functor ctx, Monad m) => ctx () -> (forall x. ctx (m x) -> n (ctx x)) -> Throw e m a -> Throw e n (ctx a) Source #
Effect (Writer w) Source #
Instance details Defined in Control.Effect.Writer.Internal Methods thread :: (Functor ctx, Monad m) => ctx () -> (forall x. ctx (m x) -> n (ctx x)) -> Writer w m a -> Writer w n (ctx a) Source #
(Effect f, Effect g) => Effect (f :+: g) Source #
Instance details Defined in Control.Effect.Sum Methods thread :: (Functor ctx, Monad m) => ctx () -> (forall x. ctx (m x) -> n (ctx x)) -> (f :+: g) m a -> (f :+: g) n (ctx a) Source #

type Has eff sig m = (Members eff sig, Algebra sig m) Source #

m is a carrier for sig containing eff.

Note that if eff is a sum, it will be decomposed into multiple Member constraints. While this technically allows one to combine multiple unrelated effects into a single Has constraint, doing so has two significant drawbacks:

Due to a problem with recursive type families, this can lead to significantly slower compiles.
It defeats ghc’s warnings for redundant constraints, and thus can lead to a proliferation of redundant constraints as code is changed.

run :: Identity a -> a Source #

Run an action exhausted of effects to produce its final result value.

Since: 1.0.0.0