| Copyright | (c) Fumiaki Kinoshita 2015 |
|---|---|
| License | BSD3 |
| Maintainer | Fumiaki Kinoshita <fumiexcel@gmail.com> |
| Stability | provisional |
| Portability | GADTs, Rank2Types |
| Safe Haskell | Safe |
| Language | Haskell2010 |
Control.Object.Object
Description
Synopsis
- newtype Object f g = Object {}
- echo :: Functor f => Object f f
- (@>>@) :: Functor h => Object f g -> Object g h -> Object f h
- (@<<@) :: Functor h => Object g h -> Object f g -> Object f h
- liftO :: Functor g => (forall x. f x -> g x) -> Object f g
- (^>>@) :: Functor h => (forall x. f x -> g x) -> Object g h -> Object f h
- (@>>^) :: Functor h => Object f g -> (forall x. g x -> h x) -> Object f h
- (@||@) :: Functor h => Object f h -> Object g h -> Object (f `Sum` g) h
- unfoldO :: Functor g => (forall a. r -> f a -> g (a, r)) -> r -> Object f g
- unfoldOM :: Monad m => (forall a. r -> f a -> m (a, r)) -> r -> Object f m
- stateful :: Monad m => (forall a. t a -> StateT s m a) -> s -> Object t m
- (@~) :: Monad m => s -> (forall a. t a -> StateT s m a) -> Object t m
- variable :: Monad m => s -> Object (StateT s m) m
- (@-) :: Object f g -> f x -> g (x, Object f g)
- cascadeObject :: Monad m => Object t m -> Skeleton t a -> m (a, Object t m)
- cascading :: Monad m => Object t m -> Object (Skeleton t) m
- data Fallible t a where
- filteredO :: Monad m => (forall x. t x -> Bool) -> Object t m -> Object (Fallible t) m
- filterO :: (forall x. t x -> Bool) -> Object (Fallible t) (Skeleton t)
- invokesOf :: Monad m => ((Object t m -> WriterT r m (Object t m)) -> s -> WriterT r m s) -> t a -> (a -> r) -> StateT s m r
- invokes :: (Traversable t, Monad m, Monoid r) => f a -> (a -> r) -> StateT (t (Object f m)) m r
- (@!=) :: Monad m => ((Object t m -> WriterT a m (Object t m)) -> s -> WriterT a m s) -> t a -> StateT s m a
- announce :: (Traversable t, Monad m) => f a -> StateT (t (Object f m)) m [a]
- withBuilder :: Functor f => ((a -> Endo [a]) -> f (Endo [a])) -> f [a]
Documentation
The type Object f g represents objects which can handle messages f, perform actions in the environment g.
It can be thought of as an automaton that transforms effects.
Objects can be composed just like functions using @>>@; the identity element is echo.
Objects are morphisms of the category of actions.
- Naturality
runObject obj . fmap f ≡ fmap f . runObject obj
(@>>@) :: Functor h => Object f g -> Object g h -> Object f h infixr 1 Source #
The categorical composition of objects.
liftO :: Functor g => (forall x. f x -> g x) -> Object f g Source #
Lift a natural transformation into an object.
(@||@) :: Functor h => Object f h -> Object g h -> Object (f `Sum` g) h Source #
Combine objects so as to handle a Sum of interfaces.
Stateful construction
unfoldO :: Functor g => (forall a. r -> f a -> g (a, r)) -> r -> Object f g Source #
An unwrapped analog of stateful
id = unfoldO runObject
iterative = unfoldO iterObjectcascading = unfoldO cascadeObject
stateful :: Monad m => (forall a. t a -> StateT s m a) -> s -> Object t m Source #
Build a stateful object.
stateful t s = t ^>>@ variable s
(@~) :: Monad m => s -> (forall a. t a -> StateT s m a) -> Object t m infix 1 Source #
Flipped stateful.
it is super convenient to use with the LambdaCase extension.
Method cascading
cascadeObject :: Monad m => Object t m -> Skeleton t a -> m (a, Object t m) Source #
Pass zero or more messages to an object.
cascading :: Monad m => Object t m -> Object (Skeleton t) m Source #
Add capability to handle multiple messages at once.
Filtering
Manipulation on StateT
invokesOf :: Monad m => ((Object t m -> WriterT r m (Object t m)) -> s -> WriterT r m s) -> t a -> (a -> r) -> StateT s m r Source #
Send a message to an object through a lens.
invokes :: (Traversable t, Monad m, Monoid r) => f a -> (a -> r) -> StateT (t (Object f m)) m r Source #
(@!=) :: Monad m => ((Object t m -> WriterT a m (Object t m)) -> s -> WriterT a m s) -> t a -> StateT s m a Source #
A method invocation operator on StateT.