Safe Haskell	Safe-Inferred
Language	Haskell2010

Effectful.Labeled.Writer

Contents

Effect
- Handlers
  - Local
  - Shared
Operations

Description

Convenience functions for the Labeled Writer effect.

Since: 2.4.0.0

Synopsis

data Writer w :: Effect where
- Tell :: w -> Writer w m ()
- Listen :: m a -> Writer w m (a, w)
runWriterLocal :: forall label w es a. (HasCallStack, Monoid w) => Eff (Labeled label (Writer w) : es) a -> Eff es (a, w)
execWriterLocal :: forall label w es a. (HasCallStack, Monoid w) => Eff (Labeled label (Writer w) : es) a -> Eff es w
runWriterShared :: forall label w es a. (HasCallStack, Monoid w) => Eff (Labeled label (Writer w) : es) a -> Eff es (a, w)
execWriterShared :: forall label w es a. (HasCallStack, Monoid w) => Eff (Labeled label (Writer w) : es) a -> Eff es w
tell :: forall label w es. (HasCallStack, Labeled label (Writer w) :> es) => w -> Eff es ()
listen :: forall label w es a. (HasCallStack, Labeled label (Writer w) :> es) => Eff es a -> Eff es (a, w)
listens :: forall label w es a b. (HasCallStack, Labeled label (Writer w) :> es) => (w -> b) -> Eff es a -> Eff es (a, b)

Effect

data Writer w :: Effect where Source #

Provide access to a write only value of type w.

Constructors

Tell :: w -> Writer w m ()
Listen :: m a -> Writer w m (a, 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 label w es a. (HasCallStack, Monoid w) => Eff (Labeled label (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 label w es a. (HasCallStack, Monoid w) => Eff (Labeled label (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 label w es a. (HasCallStack, Monoid w) => Eff (Labeled label (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 label w es a. (HasCallStack, Monoid w) => Eff (Labeled label (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 label w es. (HasCallStack, Labeled label (Writer w) :> es) => w -> Eff es () Source #

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

listen :: forall label w es a. (HasCallStack, Labeled label (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 label w es a b. (HasCallStack, Labeled label (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