Control.Effect.Update

Documentation

data Eff (w :: Maybe *) where

Parametric effect update monad. A bit like a writer monad specialised to the Maybe monoid, providing a single memory cell that can be updated, but with heterogeneous behaviour. Provides an effect system that explains whether a single memory cell has been updated or not

Constructors

Put :: a -> Eff (Just a)

NoPut :: Eff Nothing

data Update w a

Constructors

Update

Fields

• runUpdate :: (a, Eff w)

Instances

Effect (Maybe *) Update

Associated Types

type Unit Update (m :: Update -> * -> *) :: k

type Plus Update (m :: Update -> * -> *) (f :: Update) (g :: Update) :: k

type Inv Update (m :: Update -> * -> *) (f :: Update) (g :: Update) :: Constraint

Methods

return :: a -> m (Unit Update m) a

(>>=) :: Inv Update m f g => m f a -> (a -> m g b) -> m (Plus Update m f g) b

(>>) :: Inv Update m f g => m f a -> m g b -> m (Plus Update m f g) b

type Unit (Maybe *) Update

type Unit (Maybe *) Update = Nothing *

type Inv (Maybe *) Update s t

type Inv (Maybe *) Update s t = ()

type Plus (Maybe *) Update s (Nothing *)

type Plus (Maybe *) Update s (Nothing *) = s

type Plus (Maybe *) Update s (Just * t)

type Plus (Maybe *) Update s (Just * t) = Just * t

put :: a -> Update (Just a) ()

Update the memory cell with a new value of type a