Moduleeffectful-core-2.3.0.1Haskell2010

Effectful.Writer.Dynamic

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.

1 type
7 values

Packageeffectful-core-2.3.0.1
Exports8
LanguageHaskell2010
LicenceBSD-3-Clause
SourceDynamic.hs

Effect

1 declaration

datadata Writer w (a :: Type -> Type) b where

Provide access to a write only value of type w.

Constructors

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

Instances1DispatchOf

type DispatchOf (Writer w) = 'DynamicDefined in effectful-core-2.3.0.1 · Effectful.Writer.Dynamic

Handlers

Local

valuerunWriterLocal :: Monoid w => Eff (Writer w ': es) a -> Eff es (a, w)

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

valueexecWriterLocal :: Monoid w => Eff (Writer w ': es) a -> Eff es w

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

Shared

valuerunWriterShared :: Monoid w => Eff (Writer w ': es) a -> Eff es (a, w)

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

valueexecWriterShared :: Monoid w => Eff (Writer w ': es) a -> Eff es w

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

Operations

3 declarations

valuetell :: (HasCallStack, Writer w :> es) => w -> Eff es ()

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

valuelisten :: (HasCallStack, Writer w :> es) => Eff es a -> Eff es (a, w)

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

valuelistens

:: (HasCallStack, Writer w :> es)
=> w -> b
-> Eff es a
-> Eff es (a, b)

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