The essence of Reactive Programming
- 1. The Essence of Reactive Programming A Theoretical Approach Eddy Bertoluzzo
- 2. What does it mean to be Reactive?
- 3. ● Reactive Programming - Wikipedia Let’s ask Google
- 4. Reactive Programming - Wikipedia
- 5. ● Reactive Programming - Wikipedia ● ReactiveX - Rx* ● Functional Reactive Programming Let’s ask Google
- 6. Reactive Programming ??? Functional Reactive Programming
- 7. Reactive Programming != Functional Reactive Programming
- 8. ● Reactive Programming - Wikipedia ● ReactiveX - Rx* ● Functional Reactive Programming ● Reactive Manifesto - Reactive Streams Let’s ask Google
- 10. ● Reactive Programming - Wikipedia ● ReactiveX - Rx* ● Functional Reactive Programming ● Reactive Manifesto - Reactive Streams Let’s ask Google
- 12. Quoting Leslie Lamport “There’s something about the culture of software that has impeded the use of specification. We have a wonderful way of describing things precisely that’s been developed over the last couple of millennia, called mathematics. I think that’s what we should be using as a way of thinking about what we build.”
- 13. The Four Fundamental Effects One Many Sync a Iterable a Async Future a ???
- 14. The Four Fundamental Effects One Many Sync a Iterable a Async Future a Reactive Programming
- 15. Can you feel the Duality tonight? Interactive vs Reactive Sync vs Async Pull vs Push Iterable vs ???
- 16. Iterable data Iterator a = Iterator { moveNext :: () -> IO Bool , current :: () -> a } newtype Iterable a = Iterable { getIterator :: () -> IO (Iterator a) }
- 17. Optional Values data Maybe a = Nothing | Just a
- 18. Iterable data Iterator a = Iterator { moveNext :: () -> IO Bool , current :: () -> a } newtype Iterable a = Iterable { getIterator :: () -> IO (Iterator a) }
- 19. Iterable data Iterator a = Iterator { moveNext :: () -> IO (Maybe a) } newtype Iterable a = Iterable { getIterator :: () -> IO (Iterator a) }
- 20. Coproducts data Either a b = Left a | Right b
- 21. Iterable data Iterator a = Iterator { moveNext :: () -> IO (Maybe a) } newtype Iterable a = Iterable { getIterator :: () -> IO (Iterator a) }
- 22. Iterable data Iterator a = Iterator { moveNext :: () -> IO (Either SomeException (Maybe a)) } newtype Iterable a = Iterable { getIterator :: () -> IO (Iterator a) }
- 23. Iterable type Iterator a = () -> IO (Either SomeException (Maybe a)) type Iterable a = () -> IO (Iterator a)
- 24. Iterable type Iterator a = () -> IO a type Iterable a = () -> IO (Iterator a)
- 25. Iterable type Iterator a = () -> IO a type Iterable a = () -> IO (() -> IO a)
- 26. Iterator == Getter () -> IO a
- 27. Covariance a <: b Iterator a <: Iterator b
- 28. Covariance a <: b Iterator a <: Iterator b
- 29. Covariance Coke <: Drink VCoke <: VDrink
- 30. Functor fmap :: (a -> b) -> Iterator a -> Iterator b fmap f ia = () -> f (ia ()) fmap f ia = f . ia -- g (f (x)) = g . f fmap = (.)
- 31. Iterable == Getter of Getters () -> IO (() -> IO a)
- 32. Iterable == Getter of Getters () -> IO (() -> IO a)
- 33. Lifting Transform a function into a corresponding function within another - usually more general - setting. lift :: (Iterator a -> Iterator b) -> Iterable a -> Iterable b lift f iia = () -> f (iia ()) lift = (.)
- 34. Functor fmap' :: (a -> b) -> Iterable a -> Iterable b fmap' f iia = lift (fmap f) iia
- 35. Applying Duality == Reverse all the ->
- 36. Observer type Iterator a = () -> IO a = () IO <- a type Observer a = a -> IO ()
- 37. Observer type Iterator a = () -> IO a = () IO <- a type Observer a = a -> IO ()
- 38. Observer type Iterator a = () -> IO a = () IO <- a type Observer a = a -> IO ()
- 39. Observable type Iterable a = () -> IO (() -> IO a) = () IO <- (() IO <- a) type Observable a = (a -> IO ()) -> IO ()
- 40. Observable type Iterable a = () -> IO (() -> IO a) = () IO <- (() IO <- a) type Observable a = (a -> IO ()) -> IO ()
- 41. Observable type Iterable a = () -> IO (() -> IO a) = () IO <- (() IO <- a) type Observable a = (a -> IO ()) -> IO ()
- 42. Observable type Observer a = a -> IO () type Observable a = (a -> IO ()) -> IO ()
- 43. Observer == Setter a -> IO ()
- 44. Contravariance a <: b Observer b <: Observer a
- 45. Contravariance a <: b Observer b <: Observer a
- 46. Contravariance Coke <: Drink RDrink <: RCoke
- 47. Contravariant Functor contramap :: (a -> b) -> Observer b -> Observer a contramap f ob = a -> ob (f a) contramap f ob = ob . f contramap = flip (.)
- 48. Observable == Setter of Setters (a -> IO ()) -> IO ()
- 49. Observable == Setter of Setters (a -> IO ()) -> IO ()
- 50. Lifting lift :: (Observer b -> Observer a) -> Observable a -> Observable b lift f ooa = ob -> ooa (f ob) lift f ooa = ooa . f lift = flip (.)
- 51. Functor fmap :: (a -> b) -> Observable a -> Observable b fmap f ooa = lift (contramap f) ooa
- 52. Continuation Passing Style (CPS) Suspended computation taking a continuation as argument. Instead of returning a result, they will push it to the continuation. cps :: (a -> r) -> r add :: Int -> Int -> Int add x y = x + y add_cps :: Int -> Int -> ((Int -> r) -> r) add_cps x y = k -> k (x + y)
- 53. Observable == CPS function cps :: (a -> r ) -> r observable :: (a -> IO ()) -> IO ()
- 54. Observable type Observer a = a -> IO () type Observable a = (a -> IO ()) -> IO ()
- 55. Observable type Observer a = Either SomeException (Maybe a) -> IO () type Observable a = (Observer a) -> IO ()
- 56. Observable newtype Observer a = Observer { onNext :: Either SomeException (Maybe a) -> IO () } newtype Observable a = { subscribe :: (Observer a) -> IO () }
- 57. Observable data Observer a = Observer { onNext :: a -> IO () , onError :: SomeException -> IO () , onCompleted :: IO () } newtype Observable a = { subscribe :: (Observer a) -> IO () }
- 58. The Four Fundamental Effects One Many Sync a Iterable a Async Future a Observable a
- 60. Quoting Gérard Berry Interactive programs interact at their own speed with users or with other programs… Reactive programs also maintain a continuous interaction with their environment, but at a speed which is determined by the environment, not by the program itself.
- 62. Reactive Streams public interface Publisher<T> { public void subscribe(Subscriber<? super T> s); } public interface Subscriber<T> { public void onSubscribe(Subscription s); public void onNext(T t); public void onError(Throwable t); public void onComplete(); }
- 63. Reactive Streams public interface Subscription { public void request(long n); public void cancel(); }
- 64. AsyncIterable data AsyncIterator a = AsyncIterator { moveNext :: () -> IO (Future Bool) , current :: () -> a } newtype AsyncIterable a = AsyncIterable { getAsyncIterable :: () -> AsyncIterable a }
- 65. The Four Fundamental Effects One Many Sync a Iterable a Async Future a Observable a AsyncIterable a
- 66. Use the Right Tool for the Right Job