effect-handlers-0.1.0.4: A library for writing extensible algebraic effects and handlers. Similar to extensible-effects but with deep handlers.
Control.Effects.Writer
Synopsis
data Writer m a Source
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 () Source
Send a value into the writer
writerHandler :: Monoid m => Handler (Writer m) r a (a, m) Source
Handles writes by mappending them together.
mappend