effect-handlers-0.1.0.0

Safe HaskellNone
LanguageHaskell2010

Control.Effects.Free.Writer

Synopsis

Documentation

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

Constructors

Writer m a 

Instances

Functor (Writer m) 
Typeable (* -> * -> *) Writer 

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.