lens-action-0.2.0.2: Monadic Getters and Folds

Copyright(C) 2012-2014 Edward Kmett
LicenseBSD-style (see the file LICENSE)
MaintainerEdward Kmett <ekmett@gmail.com>
Stabilityprovisional
Portabilitynon-portable
Safe HaskellSafe
LanguageHaskell98

Control.Lens.Action.Internal

Contents

Description

 

Synopsis

Actions

class (Monad m, Functor f, Contravariant f) => Effective m r f | f -> m r where Source

An Effective Functor ignores its argument and is isomorphic to a Monad wrapped around a value.

That said, the Monad is possibly rather unrelated to any Applicative structure.

Methods

effective :: m r -> f a Source

ineffective :: f a -> m r Source

Instances

newtype Effect m r a Source

Wrap a monadic effect with a phantom type argument.

Constructors

Effect 

Fields

getEffect :: m r
 

Instances