Safe Haskell	Safe-Inferred
Language	Haskell2010

Control.Monad.Changeset.Class

Description

A type class generalising the API of ChangesetT.

Synopsis

class (Monad m, Monoid w, RightAction w s) => MonadChangeset s w m | m -> s, m -> w where
- changeset :: (s -> (a, w)) -> m a
- change :: w -> m ()
- current :: m s

Documentation

class (Monad m, Monoid w, RightAction w s) => MonadChangeset s w m | m -> s, m -> w where Source #

Monads containing changeset state.

This usually implies that the ChangesetT monad transformer is part of the monad transformer stack of m. See its documentation for details.

Methods

Arguments

:: (s -> (a, w))	Receives the current state and has to output a value and a change.
-> m a

Apply a changeset to the state.

change :: w -> m () Source #

Apply a change to the state. The Action instance is used to mutate the state.

Observe the current state.

Instances details

(Monad m, Monad (t m), MonadTrans t, MFunctor t, MonadChangeset s w m) => MonadChangeset s w (t m) Source #
Instance details Defined in Control.Monad.Changeset.Class Methods changeset :: (s -> (a, w)) -> t m a Source # change :: w -> t m () Source # current :: t m s Source #
(RightAction w s, Monoid w, Monad m) => MonadChangeset s w (ChangesetT s w m) Source #
Instance details Defined in Control.Monad.Trans.Changeset Methods changeset :: (s -> (a, w)) -> ChangesetT s w m a Source # change :: w -> ChangesetT s w m () Source # current :: ChangesetT s w m s Source #