Safe Haskell	None
Language	Haskell2010

Effectful.Writer.Dynamic

Contents

Effect
- Handlers
  - Local
  - Shared
Operations

Description

The dynamically dispatched variant of the Writer effect.

Note: unless you plan to change interpretations at runtime, it's recommended to use one of the statically dispatched variants, i.e. Effectful.Writer.Static.Local or Effectful.Writer.Static.Shared.

Synopsis

data Writer w (a :: Type -> Type) b where
- Tell :: forall w (a :: Type -> Type). w -> Writer w a ()
- Listen :: forall (a :: Type -> Type) a1 w. a a1 -> Writer w a (a1, w)
runWriterLocal :: forall w (es :: [(Type -> Type) -> Type -> Type]) a. (HasCallStack, Monoid w) => Eff (Writer w ': es) a -> Eff es (a, w)
execWriterLocal :: forall w (es :: [(Type -> Type) -> Type -> Type]) a. (HasCallStack, Monoid w) => Eff (Writer w ': es) a -> Eff es w
runWriterShared :: forall w (es :: [(Type -> Type) -> Type -> Type]) a. (HasCallStack, Monoid w) => Eff (Writer w ': es) a -> Eff es (a, w)
execWriterShared :: forall w (es :: [(Type -> Type) -> Type -> Type]) a. (HasCallStack, Monoid w) => Eff (Writer w ': es) a -> Eff es w
tell :: forall w (es :: [Effect]). (HasCallStack, Writer w :> es) => w -> Eff es ()
listen :: forall w (es :: [Effect]) a. (HasCallStack, Writer w :> es) => Eff es a -> Eff es (a, w)
listens :: forall w (es :: [Effect]) b a. (HasCallStack, Writer w :> es) => (w -> b) -> Eff es a -> Eff es (a, b)

Effect

data Writer w (a :: Type -> Type) b where Source #

Provide access to a write only value of type w.

Constructors

Tell :: forall w (a :: Type -> Type). w -> Writer w a ()
Listen :: forall (a :: Type -> Type) a1 w. a a1 -> Writer w a (a1, w)

Instances

Instances details

type DispatchOf (Writer w) Source #
Instance details Defined in Effectful.Writer.Dynamic type DispatchOf (Writer w) = 'Dynamic

Handlers

Local

runWriterLocal :: forall w (es :: [(Type -> Type) -> Type -> Type]) a. (HasCallStack, Monoid w) => Eff (Writer w ': es) a -> Eff es (a, w) Source #

Run the Writer effect and return the final value along with the final output (via Effectful.Writer.Static.Local).

execWriterLocal :: forall w (es :: [(Type -> Type) -> Type -> Type]) a. (HasCallStack, Monoid w) => Eff (Writer w ': es) a -> Eff es w Source #

Run a Writer effect and return the final output, discarding the final value (via Effectful.Writer.Static.Local).

Shared

runWriterShared :: forall w (es :: [(Type -> Type) -> Type -> Type]) a. (HasCallStack, Monoid w) => Eff (Writer w ': es) a -> Eff es (a, w) Source #

Run the Writer effect and return the final value along with the final output (via Effectful.Writer.Static.Shared).

execWriterShared :: forall w (es :: [(Type -> Type) -> Type -> Type]) a. (HasCallStack, Monoid w) => Eff (Writer w ': es) a -> Eff es w Source #

Run the Writer effect and return the final output, discarding the final value (via Effectful.Writer.Static.Shared).

Operations

tell :: forall w (es :: [Effect]). (HasCallStack, Writer w :> es) => w -> Eff es () Source #

Append the given output to the overall output of the Writer.

listen :: forall w (es :: [Effect]) a. (HasCallStack, Writer w :> es) => Eff es a -> Eff es (a, w) Source #

Execute an action and append its output to the overall output of the Writer.

listens :: forall w (es :: [Effect]) b a. (HasCallStack, Writer w :> es) => (w -> b) -> Eff es a -> Eff es (a, b) Source #

Execute an action and append its output to the overall output of the Writer, then return the final value along with a function of the recorded output.

listens f m ≡ second f <$> listen m