effect-handlers-0.1.0.0
Control.Effects.Free.Writer
Synopsis
This module provides the familiar writer effect.
data Writer m a
The functor representing the effect. You shouldn't need to create this manually, just use tell
tell
Constructors
Instances
tell :: (Member (Writer m) r, Typeable m) => m -> Eff r ()
Send a value into the writer
writerHandler :: Monoid m => Handler (Writer m) r a (a, m)
Handles writes by mappending them together.
mappend