Downloaded 29 times
Uploaded byĐặng Thái Sơn
Introduction to Functional Reactive Programming
This document discusses functional reactive programming (FRP). It begins by defining FRP as combining functional programming with reactive programming, where signals emit values over time in a declarative rather than imperative style. It provides examples of how FRP can be used to search APIs reactively based on user input and start/stop timers based on user gestures. The document notes advantages of FRP like conciseness, readability, ease of asynchronous programming, and maintainability. It outlines some FRP concepts like observables, transformations, composition, and filtering. It acknowledges criticisms of FRP's complexity but argues that FRP is actually simple and that simplicity should be the goal. It predicts FRP will become increasingly important.
Introduction to Functional Reactive Programming
- 1. Reactive Thinking fb.me/dangthaison.91 |@dangthaison91
- 2.
- 3. 1. What isFRP?
- 4.
- 5.
- 6. a = b+ c
- 7. FRP: Streams ofvalues over time
- 9. Core of FRPis Signal
- 10. Signal emits value overthe time
- 11.
- 12. Imperative Write correct sequenceof codes in the correct order. Step by step. (How) Declarative Write code to describes what you want to do.
- 13. 2. Why isFRP?
- 14. Example 1 Search APIas you type but: - Don't spam API server every seconds - Only make request if keyword changed - Cancel previous requests
- 15.
- 16.
- 20. Example 2 When theuser starts simultaneously panning and rotating an object, start a countdown from 3. Stop the timer either when the countdown ends or when the user stops the gestures.
- 21.
- 22.
- 23. Imperative - When theuser touches the screen - Check if a user is panning an object, store that information - Check if both gestures are running simultaneously - start a timer, from 3, counting down. - Check if the user is rotating an object, store that information - Check if both gestures are running simultaneously - start a timer, from 3, counting down. - Check if the user stopped panning - Stop the timer if needed - Check if the user stopped rotating - Stop the timer if needed - When the timer ticks, decrease the number of seconds left - If the number of seconds left is zero, stop the timer*
- 24. There is aBetter Way!
- 25.
- 26.
- 27.
- 30.
- 31.
- 32. Declarative Define condition “simultaneously`panning` and `rotating`” Define condition “start a countdown from `3`” Define condition “when the user stops the gestures” Define what a timer is When the user starts simultaneously `panning` and `rotating` an object, start a countdown from `3`. Stop the timer either when the countdown ends or when the user stops the gestures.”
- 33. Advantages • Code moreconcise & clear, easy to understand without context • Readability, highly express • Make Asynchronous easier • UI Binding • Maintainability, Extensibility ...
- 34.
- 35.
- 36. What we cando • Observables • Transformations • Composition • Combination • Filter • Buffer ...
- 38. Denial • FRP ishard, imperative is more easier • FRP just is trend! • Just another Framework • Unnecessarily complex
- 40. 3. Thinking inReactive
- 41. FRP is hard,but it is SIMPLE
- 42.
- 43.
- 44.
- 45. Simple made Easy —Rick Hickey
- 46. FRP is goodTrend
- 47.
- 48.
- 49.