Functional reactive programming
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This document provides an overview of functional reactive programming (FRP). It begins by discussing programming paradigms like imperative and declarative programming. FRP is then introduced as a programming paradigm that combines functional programming and reactive programming. Functional programming treats computation as mathematical functions while reactive programming involves asynchronous data streams. The document explains core FRP concepts like streams and signals. It also introduces RxSwift, a library that brings FRP to iOS. Finally, examples are provided to demonstrate the advantages of using an FRP approach.
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Imperative vs Declarative
Imperative programming Declarative programming
let numbers = [1, 2, 3, 4, 5, 6]
let sum = reduce(numbers, 0, +)
let odds = filter(numbers, { $0 % 2 == 1})
let array = [1, 2, 3, 4, 5, 6]
var sum = 0
var odds = []
for element in array {
sum += element
if element % 2 == 1 {
odds
.append(element)
}
}](https://image.slidesharecdn.com/functionalreactiveprogramming-170404151445/85/Functional-reactive-programming-6-320.jpg)
![Functional programming
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let numbers = [1, 2, 3, 4, 5, 6]
let doubled = numbers.map($0 * $0)
let sum = doubled.reduce(0, combine: +))](https://image.slidesharecdn.com/functionalreactiveprogramming-170404151445/85/Functional-reactive-programming-18-320.jpg)
Functional reactive programming
- 1. Functional reactive programming Hoang Hai Hung 1 September, 2016
- 2. Outline 1.Programming paradigms 2. Functional reactive programming 3. RxSwift 4. Demo 2
- 3. What is Programming language ? A programming language is a notation for writing programs, which are specifications of a computation or algorithm. 3
- 4. Programming paradigms Pascal, C Java, C++ Haskell, Lisp Prolog Swift 4
- 5. Imperative vs Declarative Telling the “machine” how to do something, and as a result what you want to happen will happen. Imperative programming Telling the “machine” what you would like to happen, and let the computer figure out how to do it. Declarative programming BUT, HOW ? 5
- 6. 6 Imperative vs Declarative Imperative programming Declarative programming let numbers = [1, 2, 3, 4, 5, 6] let sum = reduce(numbers, 0, +) let odds = filter(numbers, { $0 % 2 == 1}) let array = [1, 2, 3, 4, 5, 6] var sum = 0 var odds = [] for element in array { sum += element if element % 2 == 1 { odds .append(element) } }
- 7. Imperative vs Declarative 7 Imperative programming Declarative programming
- 11. Imperative way (cont.) Pyramid of Doom 11
- 13. Imperative vs Declarative Stand up, walk 10 steps by your foot to the fridge, use your hand to open the door, get me the water, walk back 10 steps ... Imperative programming Honey, i wish i had a glass of cold water now. Declarative programming 13 Thanks, honeyYou don’t say ?
- 14. Advantages of Declarative Programming Minimizes mutability Reduces state side-effects More understandable code More scalable 14
- 15. Outline 1. Programming paradigm 2. Functional reactive programming 3. RxSwift 4. Demo 15
- 16. Functional reactive programming (FRP) Functional reactive programming (FRP) is a programming paradigm for reactive programming using the building blocks of functional programming 16
- 17. Functional programming 17 Functional programming is a programming paradigm that treats computation as the evaluation of mathematical functions and avoids changing-state and mutable data
- 18. Functional programming 18 let numbers = [1, 2, 3, 4, 5, 6] let doubled = numbers.map($0 * $0) let sum = doubled.reduce(0, combine: +))
- 19. Reactive programming Reactive programming is programming with asynchronous data streams. 19
- 20. Reactive programming C = A + B 20
- 21. Functional reactive programming Closure/Lambdas Pure Function First-Class Functions High-Order Functions Functional Events/Data – Driven Push Asynchronous Reactive 21 https://medium.com/@jugoncalves/functional-programming-should-be-your-1-priority-for-2015-47dd4641d6b9 https://medium.com/reactive-programming/what-is-reactive-programming-bc9fa7f4a7fc
- 22. Outline 1. Programming paradigm 2. Functional reactive programming 3. RxSwift 4. Demo 22
- 23. Stream 23 A stream is a sequence of ongoing events ordered in time.
- 24. Stream 24
- 25. Signal 25 Signal is a value that changes over time.
- 26. Example Khi người dùng thực hiện đồng thời `di chuyển` (pan) và `xoay` vật thể (rotate), thực hiện đếm ngược từ `3`. Dừng đếm ngược khi người dùng bỏ tay ra hoặc đếm ngược đến 0. 26
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- 31. 31
- 35. Advantages of FRP Code more concise & clear, easy to understand without context Readability, highly express Make Asynchronous easier 35
- 36. 36 Conclusion
- 37. 37 Conclusion
- 38. 38
- 39. Outline 1. Programming paradigm 2. Functional reactive programming 3. RxSwift 4. Demo 39
- 40. THANK YOU ! 40