PETR SIMASenior iOS Developer, Ackee

Functional reactive programming

It's functional.

It's reactive.

You want to start using it today.

Functional reactive programming

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1.5 years of experience with FRP

both iOS and Android

more to come at future mDevTalks

FRP at Ackee

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for-loops

mutable state

"Push-based"

Imperative programming

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map, reduce, filter, flatMap

If a pure function is called with the same arguments, the same result will be returned.

declarative, "Pull-based", eliminates side effects, avoids

changing-state and mutable data

Functional programming

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= reactive programming (asynchronous dataflow programming)

using the building blocks of functional programming (e.g. map, reduce, filter)

If a pure function is called with the same arguments, the same

result will be returned.

implicit parameter - time

FRP

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Demo

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composable, reusable

unidirectional dataflow

easy to reason about code

More buzzwords

ab

ab

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composable, reusable

unidirectional dataflow

easy to reason about code

More buzzwords

Input --->

---> Output

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composable, reusable

unidirectional dataflow

easy to reason about code

More buzzwords

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composable, reusable

unidirectional dataflow

easy to reason about code

More buzzwords

Input --->

---> Output

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composable, reusable

unidirectional dataflow

easy to reason about code

More buzzwords

Input --->

---> Output

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Railway oriented programming

Error handling

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Reactive code consists of elementary operations.

Don't be "too dry".

DRY principle?

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Android

RxJava

Where to start?

iOS

RxSwift

Reactive Cocoa

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Android

RxJava

Where to start?

iOS

RxSwift

Reactive Cocoa

Windows Phone

Rx.NET

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Android

RxJava

Where to start?

iOS

RxSwift

Reactive Cocoa

Windows Phone

Rx.NET (RxExtensions)

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Architecture of a reactive application

...

...ab

ab

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Architecture of a reactive application

Massive View Controller

MVP MVVM

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Architecture of a reactive application

MVC Model View Presenter

MVVM

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Architecture of a reactive application

MVC MVP Model View ViewModel

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Demo

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RxSwift, RxJava, ...

Observable

Hot and cold signals

Reactive Cocoa

Signal

SignalProducer

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A hot signal is active regardless of observers. "Signals are streams that are already in progress, e.g. notifications, user input, etc."

A cold signal starts work when subscribed to. "Cold signals represent operations or tasks, e.g. network requests."

Cold signals are lazy.

Hot and cold signals

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Signals are hot.

SignalProducers are cold.

SignalProducer.start() creates a Signal.

Hot and cold signals

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a mechanism for memory management and cancellation

disposable.dispose() interrupts a signal

usually don't have to be used directly in Reactive Cocoa

Disposables

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Actions, Schedulers, ...

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https://github.com/ReactiveCocoa/ReactiveCocoa/tree/master/

Documentation

https://github.com/ReactiveX

http://neilpa.me/rac-marbles/

Documentation

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