Control.Effect.Update

Documentation

data Eff w 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

type Unit (Maybe *) Update = Nothing *

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

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

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