Copyright	(c) Alexander Vieth 2019
License	Apache-2.0
Maintainer	aovieth@gmail.com
Safe Haskell	Safe-Inferred
Language	Haskell2010

Control.Tracer.Arrow

Description

Synopsis

data TracerA (m :: Type -> Type) a b where
- Emitting :: forall (m :: Type -> Type) a x b. Kleisli m a x -> Kleisli m x b -> TracerA m a b
- Squelching :: forall (m :: Type -> Type) a b. Kleisli m a b -> TracerA m a b
runTracerA :: forall (m :: Type -> Type) a. Monad m => TracerA m a () -> Kleisli m a ()
compute :: forall (m :: Type -> Type) a b. Applicative m => (a -> b) -> TracerA m a b
emit :: Applicative m => (a -> m ()) -> TracerA m a ()
effect :: (a -> m b) -> TracerA m a b
squelch :: forall (m :: Type -> Type) a. Applicative m => TracerA m a ()
nat :: (forall x. m x -> n x) -> TracerA m a b -> TracerA n a b

Documentation

data TracerA (m :: Type -> Type) a b where Source #

Formal representation of a tracer arrow as a Kleisli arrow over some monad, but tagged so that we know whether it has any effects which will emit a trace.

Constructors

Emitting :: forall (m :: Type -> Type) a x b. Kleisli m a x -> Kleisli m x b -> TracerA m a b	An emitting part, followed by a non-emitting part. The non-emitting part is there so that later emitting parts can be tacked-on later.
Squelching :: forall (m :: Type -> Type) a b. Kleisli m a b -> TracerA m a b	No emitting. There may be side-effects, but they are assumed to be benign and will be discarded by `runTracerA`.

Instances

Instances details

Monad m => Category (TracerA m :: Type -> Type -> Type) Source #
Instance details Defined in Control.Tracer.Arrow Methods id :: TracerA m a a # (.) :: TracerA m b c -> TracerA m a b -> TracerA m a c #
Monad m => Arrow (TracerA m) Source #
Instance details Defined in Control.Tracer.Arrow Methods arr :: (b -> c) -> TracerA m b c # first :: TracerA m b c -> TracerA m (b, d) (c, d) # second :: TracerA m b c -> TracerA m (d, b) (d, c) # (***) :: TracerA m b c -> TracerA m b' c' -> TracerA m (b, b') (c, c') # (&&&) :: TracerA m b c -> TracerA m b c' -> TracerA m b (c, c') #
Monad m => ArrowChoice (TracerA m) Source #
Instance details Defined in Control.Tracer.Arrow Methods left :: TracerA m b c -> TracerA m (Either b d) (Either c d) # right :: TracerA m b c -> TracerA m (Either d b) (Either d c) # (+++) :: TracerA m b c -> TracerA m b' c' -> TracerA m (Either b b') (Either c c') # (\|\|\|) :: TracerA m b d -> TracerA m c d -> TracerA m (Either b c) d #

runTracerA :: forall (m :: Type -> Type) a. Monad m => TracerA m a () -> Kleisli m a () Source #

The resulting Kleisli arrow includes all of the effects required to do the emitting part.

compute :: forall (m :: Type -> Type) a b. Applicative m => (a -> b) -> TracerA m a b Source #

Pure computation in a tracer: no side effects or emits.

emit :: Applicative m => (a -> m ()) -> TracerA m a () Source #

Do an emitting effect. Contrast with effect which does not make the tracer an emitting tracer.

effect :: (a -> m b) -> TracerA m a b Source #

Do a non-emitting effect. This effect will only be run if some part of the tracer downstream emits (see emit).

squelch :: forall (m :: Type -> Type) a. Applicative m => TracerA m a () Source #

Ignore the input and do not emit. The name is intended to lead to clear and suggestive arrow expressions.

nat :: (forall x. m x -> n x) -> TracerA m a b -> TracerA n a b Source #

Use a natural transformation to change the underlying monad.