Control.Algebra

The Algebra class is the mechanism with which effects are interpreted.

An instance of the Algebra class defines an interpretation of an effect signature atop a given monad.

Since: 1.0.0.0

Documentation

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

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

Methods

alg :: sig m a -> m a

Construct a value in the carrier for an effect signature (typically a sum of a handled effect and any remaining effects).

Instances

Algebra Choose NonEmpty

Defined in Control.Algebra

Methods

alg :: Choose NonEmpty a -> NonEmpty a

Algebra Empty Maybe

Defined in Control.Algebra

Methods

alg :: Empty Maybe a -> Maybe a

Algebra NonDet []

Defined in Control.Algebra

Methods

alg :: NonDet [] a -> [a]

Algebra sig m => Algebra sig (Alt m)

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

Defined in Control.Algebra

Methods

alg :: sig (Alt m) a -> Alt m a

Algebra sig m => Algebra sig (Ap m)

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

Defined in Control.Algebra

Methods

alg :: sig (Ap m) a -> Ap m a

Algebra sig m => Algebra sig (IdentityT m)

Defined in Control.Algebra

Methods

alg :: sig (IdentityT m) a -> IdentityT m a

Algebra (Lift IO) IO

Defined in Control.Algebra

Methods

alg :: Lift IO IO a -> IO a

Algebra (Lift Identity) Identity

Defined in Control.Algebra

Methods

alg :: Lift Identity Identity a -> Identity a

Monad m => Algebra (Lift m) (LiftC m)

Defined in Control.Carrier.Lift

Methods

alg :: Lift m (LiftC m) a -> LiftC m a

Algebra (Error e) (Either e)

Defined in Control.Algebra

Methods

alg :: Error e (Either e) a -> Either e a

Monoid w => Algebra (Writer w) ((,) w)

Defined in Control.Algebra

Methods

alg :: Writer w ((,) w) a -> (w, a)

Algebra (Reader r) ((->) r :: Type -> Type)

Defined in Control.Algebra

Methods

alg :: Reader r ((->) r) a -> r -> a

(Algebra sig m, Effect sig) => Algebra (Choose :+: sig) (ChooseC m)

Defined in Control.Carrier.Choose.Church

Methods

alg :: (Choose :+: sig) (ChooseC m) a -> ChooseC m a

(Algebra sig m, Effect sig) => Algebra (Empty :+: sig) (EmptyC m)

Defined in Control.Carrier.Empty.Maybe

Methods

alg :: (Empty :+: sig) (EmptyC m) a -> EmptyC m a

(Algebra sig m, Effect sig) => Algebra (NonDet :+: sig) (NonDetC m)

Defined in Control.Carrier.NonDet.Church

Methods

alg :: (NonDet :+: sig) (NonDetC m) a -> NonDetC m a

(MonadIO m, Algebra sig m) => Algebra (Trace :+: sig) (TraceC m)

Defined in Control.Carrier.Trace.Printing

Methods

alg :: (Trace :+: sig) (TraceC m) a -> TraceC m a

Algebra sig m => Algebra (Trace :+: sig) (TraceC m)

Defined in Control.Carrier.Trace.Ignoring

Methods

alg :: (Trace :+: sig) (TraceC m) a -> TraceC m a

(Algebra sig m, Effect sig) => Algebra (Trace :+: sig) (TraceC m)

Defined in Control.Carrier.Trace.Returning

Methods

alg :: (Trace :+: sig) (TraceC m) a -> TraceC m a

(Algebra sig m, Effect sig) => Algebra (Fail :+: sig) (FailC m)

Defined in Control.Carrier.Fail.Either

Methods

alg :: (Fail :+: sig) (FailC m) a -> FailC m a

(Algebra sig m, Effect sig) => Algebra (Fresh :+: sig) (FreshC m)

Defined in Control.Carrier.Fresh.Strict

Methods

alg :: (Fresh :+: sig) (FreshC m) a -> FreshC m a

(Algebra sig m, Effect sig) => Algebra (Cut :+: (NonDet :+: sig)) (CutC m)

Defined in Control.Carrier.Cut.Church

Methods

alg :: (Cut :+: (NonDet :+: sig)) (CutC m) a -> CutC m a

(Algebra sig m, Effect sig) => Algebra (Cull :+: (NonDet :+: sig)) (CullC m)

Defined in Control.Carrier.Cull.Church

Methods

alg :: (Cull :+: (NonDet :+: sig)) (CullC m) a -> CullC m a

Algebra sig m => Algebra (Reader r :+: sig) (ReaderT r m)

Defined in Control.Algebra

Methods

alg :: (Reader r :+: sig) (ReaderT r m) a -> ReaderT r m a

Algebra sig m => Algebra (Reader r :+: sig) (ReaderC r m)

Defined in Control.Carrier.Reader

Methods

alg :: (Reader r :+: sig) (ReaderC r m) a -> ReaderC r m a

(Algebra sig m, Effect sig) => Algebra (State s :+: sig) (StateT s m)

Defined in Control.Algebra

Methods

alg :: (State s :+: sig) (StateT s m) a -> StateT s m a

(Algebra sig m, Effect sig) => Algebra (State s :+: sig) (StateT s m)

Defined in Control.Algebra

Methods

alg :: (State s :+: sig) (StateT s m) a -> StateT s m a

(Algebra sig m, Effect sig) => Algebra (State s :+: sig) (StateC s m)

Defined in Control.Carrier.State.Strict

Methods

alg :: (State s :+: sig) (StateC s m) a -> StateC s m a

(Algebra sig m, Effect sig) => Algebra (State s :+: sig) (StateC s m)

Defined in Control.Carrier.State.Lazy

Methods

alg :: (State s :+: sig) (StateC s m) a -> StateC s m a

(Algebra sig m, Effect sig) => Algebra (Throw e :+: sig) (ThrowC e m)

Defined in Control.Carrier.Throw.Either

Methods

alg :: (Throw e :+: sig) (ThrowC e m) a -> ThrowC e m a

(Algebra sig m, Effect sig) => Algebra (Error e :+: sig) (ExceptT e m)

Defined in Control.Algebra

Methods

alg :: (Error e :+: sig) (ExceptT e m) a -> ExceptT e m a

(Algebra sig m, Effect sig) => Algebra (Error e :+: sig) (ErrorC e m)

Defined in Control.Carrier.Error.Either

Methods

alg :: (Error e :+: sig) (ErrorC e m) a -> ErrorC e m a

(Algebra sig m, Effect sig, Monoid w) => Algebra (Writer w :+: sig) (WriterT w m)

Defined in Control.Algebra

Methods

alg :: (Writer w :+: sig) (WriterT w m) a -> WriterT w m a

(Algebra sig m, Effect sig, Monoid w) => Algebra (Writer w :+: sig) (WriterT w m)

Defined in Control.Algebra

Methods

alg :: (Writer w :+: sig) (WriterT w m) a -> WriterT w m a

(Monoid w, Algebra sig m, Effect sig) => Algebra (Writer w :+: sig) (WriterC w m)

Defined in Control.Carrier.Writer.Strict

Methods

alg :: (Writer w :+: sig) (WriterC w m) a -> WriterC w m a

(HFunctor eff, HFunctor sig, Reifies s (Handler eff m), Monad m, Algebra sig m) => Algebra (eff :+: sig) (InterpretC s eff m)

Defined in Control.Carrier.Interpret

Methods

alg :: (eff :+: sig) (InterpretC s eff m) a -> InterpretC s eff m a

(LabelledMember label sub sig, HFunctor sub, Algebra sig m) => Algebra (sub :+: sig) (UnderLabel label sub m)

Defined in Control.Effect.Labelled

Methods

alg :: (sub :+: sig) (UnderLabel label sub m) a -> UnderLabel label sub m a

(Algebra sig m, Effect sig, Monoid w) => Algebra (Reader r :+: (Writer w :+: (State s :+: sig))) (RWST r w s m)

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

(Algebra sig m, Effect sig, Monoid w) => Algebra (Reader r :+: (Writer w :+: (State s :+: sig))) (RWST r w s m)

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

(Algebra (eff :+: sig) (sub m), HFunctor eff, HFunctor sig) => Algebra (Labelled label eff :+: sig) (Labelled label sub m)

Defined in Control.Effect.Labelled

Methods

alg :: (Labelled label eff :+: sig) (Labelled label sub m) a -> Labelled label sub m a

run :: Identity a -> a

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

Since: 1.0.0.0

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

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:

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

send :: (Member eff sig, Algebra sig m) => eff m a -> m a

Construct a request for an effect to be interpreted by some handler later on.

Re-exports

data (f :+: g) (m :: * -> *) k infixr 4

Higher-order sums are used to combine multiple effects into a signature, typically by chaining on the right.

Constructors

L (f m k)

R (g m k)

Instances

Algebra NonDet []

Defined in Control.Algebra

Methods

alg :: NonDet [] a -> [a]

LabelledMember label l r => LabelledMember (label :: k) l (l' :+: r)

Right-recursion: if t is a member of r, we can inject it into r in O(n), followed by lifting that into l :+: r in O(1).

Defined in Control.Effect.Labelled

Methods

injLabelled :: forall (m :: Type -> Type) a. Labelled label l m a -> (l' :+: r) m a

LabelledMember (label :: k) l (Labelled label l :+: r)

Left-occurrence: if t is at the head of a signature, we can inject it in O(1).

Defined in Control.Effect.Labelled

Methods

injLabelled :: forall (m :: Type -> Type) a. Labelled label l m a -> (Labelled label l :+: r) m a

LabelledMember label t (l1 :+: (l2 :+: r)) => LabelledMember (label :: k) t ((l1 :+: l2) :+: r)

Left-recursion: if t is a member of l1 :+: l2 :+: r, then we can inject it into (l1 :+: l2) :+: r by injection into a right-recursive signature, followed by left-association.

Defined in Control.Effect.Labelled

Methods

injLabelled :: forall (m :: Type -> Type) a. Labelled label t m a -> ((l1 :+: l2) :+: r) m a

Member l r => Member l (l' :+: r)

Right-recursion: if t is a member of r, we can inject it into r in O(n), followed by lifting that into l :+: r in O(1).

Defined in Control.Effect.Sum

Methods

inj :: forall (m :: Type -> Type) a. l m a -> (l' :+: r) m a

Member l (l :+: r)

Left-occurrence: if t is at the head of a signature, we can inject it in O(1).

Defined in Control.Effect.Sum

Methods

inj :: forall (m :: Type -> Type) a. l m a -> (l :+: r) m a

Member t (l1 :+: (l2 :+: r)) => Member t ((l1 :+: l2) :+: r)

Left-recursion: if t is a member of l1 :+: l2 :+: r, then we can inject it into (l1 :+: l2) :+: r by injection into a right-recursive signature, followed by left-association.

Defined in Control.Effect.Sum

Methods

inj :: forall (m :: Type -> Type) a. t m a -> ((l1 :+: l2) :+: r) m a

Algebra (Error e) (Either e)

Defined in Control.Algebra

Methods

alg :: Error e (Either e) a -> Either e a

Generic1 ((f :+: g) m :: Type -> Type)

Defined in Control.Effect.Sum

Associated Types

type Rep1 ((f :+: g) m) :: k -> Type

Methods

from1 :: forall (a :: k). (f :+: g) m a -> Rep1 ((f :+: g) m) a

to1 :: forall (a :: k). Rep1 ((f :+: g) m) a -> (f :+: g) m a

(Effect f, Effect g) => Effect (f :+: g)

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)

(HFunctor f, HFunctor g) => HFunctor (f :+: g)

Defined in Control.Effect.Sum

Methods

hmap :: Functor m => (forall x. m x -> n x) -> (f :+: g) m a -> (f :+: g) n a

(Algebra sig m, Effect sig) => Algebra (Choose :+: sig) (ChooseC m)

Defined in Control.Carrier.Choose.Church

Methods

alg :: (Choose :+: sig) (ChooseC m) a -> ChooseC m a

(Algebra sig m, Effect sig) => Algebra (Empty :+: sig) (EmptyC m)

Defined in Control.Carrier.Empty.Maybe

Methods

alg :: (Empty :+: sig) (EmptyC m) a -> EmptyC m a

(Algebra sig m, Effect sig) => Algebra (NonDet :+: sig) (NonDetC m)

Defined in Control.Carrier.NonDet.Church

Methods

alg :: (NonDet :+: sig) (NonDetC m) a -> NonDetC m a

(MonadIO m, Algebra sig m) => Algebra (Trace :+: sig) (TraceC m)

Defined in Control.Carrier.Trace.Printing

Methods

alg :: (Trace :+: sig) (TraceC m) a -> TraceC m a

Algebra sig m => Algebra (Trace :+: sig) (TraceC m)

Defined in Control.Carrier.Trace.Ignoring

Methods

alg :: (Trace :+: sig) (TraceC m) a -> TraceC m a

(Algebra sig m, Effect sig) => Algebra (Trace :+: sig) (TraceC m)

Defined in Control.Carrier.Trace.Returning

Methods

alg :: (Trace :+: sig) (TraceC m) a -> TraceC m a

(Algebra sig m, Effect sig) => Algebra (Fail :+: sig) (FailC m)

Defined in Control.Carrier.Fail.Either

Methods

alg :: (Fail :+: sig) (FailC m) a -> FailC m a

(Algebra sig m, Effect sig) => Algebra (Fresh :+: sig) (FreshC m)

Defined in Control.Carrier.Fresh.Strict

Methods

alg :: (Fresh :+: sig) (FreshC m) a -> FreshC m a

(Algebra sig m, Effect sig) => Algebra (Cut :+: (NonDet :+: sig)) (CutC m)

Defined in Control.Carrier.Cut.Church

Methods

alg :: (Cut :+: (NonDet :+: sig)) (CutC m) a -> CutC m a

(Algebra sig m, Effect sig) => Algebra (Cull :+: (NonDet :+: sig)) (CullC m)

Defined in Control.Carrier.Cull.Church

Methods

alg :: (Cull :+: (NonDet :+: sig)) (CullC m) a -> CullC m a

Algebra sig m => Algebra (Reader r :+: sig) (ReaderT r m)

Defined in Control.Algebra

Methods

alg :: (Reader r :+: sig) (ReaderT r m) a -> ReaderT r m a

Algebra sig m => Algebra (Reader r :+: sig) (ReaderC r m)

Defined in Control.Carrier.Reader

Methods

alg :: (Reader r :+: sig) (ReaderC r m) a -> ReaderC r m a

(Algebra sig m, Effect sig) => Algebra (State s :+: sig) (StateT s m)

Defined in Control.Algebra

Methods

alg :: (State s :+: sig) (StateT s m) a -> StateT s m a

(Algebra sig m, Effect sig) => Algebra (State s :+: sig) (StateT s m)

Defined in Control.Algebra

Methods

alg :: (State s :+: sig) (StateT s m) a -> StateT s m a

(Algebra sig m, Effect sig) => Algebra (State s :+: sig) (StateC s m)

Defined in Control.Carrier.State.Strict

Methods

alg :: (State s :+: sig) (StateC s m) a -> StateC s m a

(Algebra sig m, Effect sig) => Algebra (State s :+: sig) (StateC s m)

Defined in Control.Carrier.State.Lazy

Methods

alg :: (State s :+: sig) (StateC s m) a -> StateC s m a

(Algebra sig m, Effect sig) => Algebra (Throw e :+: sig) (ThrowC e m)

Defined in Control.Carrier.Throw.Either

Methods

alg :: (Throw e :+: sig) (ThrowC e m) a -> ThrowC e m a

(Algebra sig m, Effect sig) => Algebra (Error e :+: sig) (ExceptT e m)

Defined in Control.Algebra

Methods

alg :: (Error e :+: sig) (ExceptT e m) a -> ExceptT e m a

(Algebra sig m, Effect sig) => Algebra (Error e :+: sig) (ErrorC e m)

Defined in Control.Carrier.Error.Either

Methods

alg :: (Error e :+: sig) (ErrorC e m) a -> ErrorC e m a

(Algebra sig m, Effect sig, Monoid w) => Algebra (Writer w :+: sig) (WriterT w m)

Defined in Control.Algebra

Methods

alg :: (Writer w :+: sig) (WriterT w m) a -> WriterT w m a

(Algebra sig m, Effect sig, Monoid w) => Algebra (Writer w :+: sig) (WriterT w m)

Defined in Control.Algebra

Methods

alg :: (Writer w :+: sig) (WriterT w m) a -> WriterT w m a

(Monoid w, Algebra sig m, Effect sig) => Algebra (Writer w :+: sig) (WriterC w m)

Defined in Control.Carrier.Writer.Strict

Methods

alg :: (Writer w :+: sig) (WriterC w m) a -> WriterC w m a

(HFunctor eff, HFunctor sig, Reifies s (Handler eff m), Monad m, Algebra sig m) => Algebra (eff :+: sig) (InterpretC s eff m)

Defined in Control.Carrier.Interpret

Methods

alg :: (eff :+: sig) (InterpretC s eff m) a -> InterpretC s eff m a

(LabelledMember label sub sig, HFunctor sub, Algebra sig m) => Algebra (sub :+: sig) (UnderLabel label sub m)

Defined in Control.Effect.Labelled

Methods

alg :: (sub :+: sig) (UnderLabel label sub m) a -> UnderLabel label sub m a

(Algebra sig m, Effect sig, Monoid w) => Algebra (Reader r :+: (Writer w :+: (State s :+: sig))) (RWST r w s m)

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

(Algebra sig m, Effect sig, Monoid w) => Algebra (Reader r :+: (Writer w :+: (State s :+: sig))) (RWST r w s m)

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

(Algebra (eff :+: sig) (sub m), HFunctor eff, HFunctor sig) => Algebra (Labelled label eff :+: sig) (Labelled label sub m)

Defined in Control.Effect.Labelled

Methods

alg :: (Labelled label eff :+: sig) (Labelled label sub m) a -> Labelled label sub m a

(Functor (f m), Functor (g m)) => Functor ((f :+: g) m)

Defined in Control.Effect.Sum

Methods

fmap :: (a -> b) -> (f :+: g) m a -> (f :+: g) m b

(<$) :: a -> (f :+: g) m b -> (f :+: g) m a

(Foldable (f m), Foldable (g m)) => Foldable ((f :+: g) m)

Defined in Control.Effect.Sum

Methods

fold :: Monoid m0 => (f :+: g) m m0 -> m0

foldMap :: Monoid m0 => (a -> m0) -> (f :+: g) m a -> m0

foldMap' :: Monoid m0 => (a -> m0) -> (f :+: g) m a -> m0

foldr :: (a -> b -> b) -> b -> (f :+: g) m a -> b

foldr' :: (a -> b -> b) -> b -> (f :+: g) m a -> b

foldl :: (b -> a -> b) -> b -> (f :+: g) m a -> b

foldl' :: (b -> a -> b) -> b -> (f :+: g) m a -> b

foldr1 :: (a -> a -> a) -> (f :+: g) m a -> a

foldl1 :: (a -> a -> a) -> (f :+: g) m a -> a

toList :: (f :+: g) m a -> [a]

null :: (f :+: g) m a -> Bool

length :: (f :+: g) m a -> Int

elem :: Eq a => a -> (f :+: g) m a -> Bool

maximum :: Ord a => (f :+: g) m a -> a

minimum :: Ord a => (f :+: g) m a -> a

sum :: Num a => (f :+: g) m a -> a

product :: Num a => (f :+: g) m a -> a

(Traversable (f m), Traversable (g m)) => Traversable ((f :+: g) m)

Defined in Control.Effect.Sum

Methods

traverse :: Applicative f0 => (a -> f0 b) -> (f :+: g) m a -> f0 ((f :+: g) m b)

sequenceA :: Applicative f0 => (f :+: g) m (f0 a) -> f0 ((f :+: g) m a)

mapM :: Monad m0 => (a -> m0 b) -> (f :+: g) m a -> m0 ((f :+: g) m b)

sequence :: Monad m0 => (f :+: g) m (m0 a) -> m0 ((f :+: g) m a)

(Eq (f m k), Eq (g m k)) => Eq ((f :+: g) m k)

Defined in Control.Effect.Sum

Methods

(==) :: (f :+: g) m k -> (f :+: g) m k -> Bool

(/=) :: (f :+: g) m k -> (f :+: g) m k -> Bool

(Ord (f m k), Ord (g m k)) => Ord ((f :+: g) m k)

Defined in Control.Effect.Sum

Methods

compare :: (f :+: g) m k -> (f :+: g) m k -> Ordering

(<) :: (f :+: g) m k -> (f :+: g) m k -> Bool

(<=) :: (f :+: g) m k -> (f :+: g) m k -> Bool

(>) :: (f :+: g) m k -> (f :+: g) m k -> Bool

(>=) :: (f :+: g) m k -> (f :+: g) m k -> Bool

max :: (f :+: g) m k -> (f :+: g) m k -> (f :+: g) m k

min :: (f :+: g) m k -> (f :+: g) m k -> (f :+: g) m k

(Show (f m k), Show (g m k)) => Show ((f :+: g) m k)

Defined in Control.Effect.Sum

Methods

showsPrec :: Int -> (f :+: g) m k -> ShowS

show :: (f :+: g) m k -> String

showList :: [(f :+: g) m k] -> ShowS

type Rep1 ((f :+: g) m :: Type -> Type)

Defined in Control.Effect.Sum

type Rep1 ((f :+: g) m :: Type -> Type) = D1 ('MetaData ":+:" "Control.Effect.Sum" "fused-effects-1.0.2.2-inplace" 'False) (C1 ('MetaCons "L" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec1 (f m))) :+: C1 ('MetaCons "R" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec1 (g m))))

module Control.Effect.Class