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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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