Modulecontra-tracer-0.2.1.1Haskell2010

Control.Tracer.Arrow

Synopsis

data TracerA
value runTracerA
value compute
value emit
value effect
value squelch
value nat

Packagecontra-tracer-0.2.1.1
Exports7
LanguageHaskell2010
LicenceApache-2.0
SourceArrow.hs

datadata TracerA (m :: Type -> Type) a b where

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 :: 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 :: 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.

Instances3Category, Arrow, ArrowChoice

Monad m => Category (TracerA m)Defined in contra-tracer-0.2.1.1 · Control.Tracer.Arrow
Monad m => Arrow (TracerA m)Defined in contra-tracer-0.2.1.1 · Control.Tracer.Arrow
Monad m => ArrowChoice (TracerA m)Defined in contra-tracer-0.2.1.1 · Control.Tracer.Arrow

valuerunTracerA :: Monad m => TracerA m a () -> Kleisli m a ()

Source#

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

valuecompute :: Applicative m => (a -> b) -> TracerA m a b

Source#

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

valueemit :: Applicative m => (a -> m ()) -> TracerA m a ()

Source#

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

valueeffect :: (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).

valuesquelch :: 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.

valuenat :: (forall x. m x -> n x) -> TracerA m a b -> TracerA n a b

Source#

Use a natural transformation to change the underlying monad.