Function Reactive Programming in iOS

A brief overview into functional reactive programming, with some specific use cases in ReactiveCocoa.

Transcript

1. Functional Reactive iOS
2. Functional Reactive iOS
3. Functional Reactive OSX
4. Functional Reactive .NET
5. Functional Reactive JS
6. Functional Reactive
7. Functional Reactive Why you should consider programming
8. @iwantmyrealname
9. iwantmyreal.name
10. leanpub.com/ios7daybyday
11. @shinobicontrols
12. shinobicontrols.com
13. what is functional reactive programming?
14. what is functional reactive programming?
15. programming
16. computer programming is a process that leads from an original formulation of a computing problem to executable programs programming
17. what is functional reactive programming?
18. functional
19. functional stateless immutable 1st class functions
20. what is functional reactive programming?
21. reactive
22. reactive dataflow spreadsheets
23. what is functional reactive programming?
24. frp obvious
25. frp immutable events functional pipeline reactive signals
26. frp a standard interface for events
27. signals
28. signals what are
29. represent a stream of immutable events signals
30. events are signals next completed error
31. signals what can model?
32. delegation observer/databinding target-action blocks/lambdas/closures modelling
33. async tasks network events user interaction flow control modelling
34. signals what can be used for?
35. signals most useful when a functional pipeline is formed uses
36. map filter combine buffer signal operations zip concat takeUntil …
37. real world example
38. demo
39. example username password s sa sam p pa pas pass submit
40. example username password s sa sam p pa pas pass submit username password 1 2 3 1 2 3 4 string.length map
41. example username password s sa sam p pa pas pass submit username password 3 3 4 greater than 2 filter
42. example let usernameSignal = tf.rac_textSignal() .mapAs({ (value: NSString) -> NSNumber in return value.length }) .filterAs({ (value: NSNumber) -> Bool in return value.intValue > 2 })
43. example let usernameSignal = tf.rac_textSignal() .mapAs({ (value: NSString) -> NSNumber in return value.length }) .filterAs({ (value: NSNumber) -> Bool in return value.intValue > 2 })
44. example let usernameSignal = tf.rac_textSignal() .mapAs({ (value: NSString) -> NSNumber in return value.length }) .filterAs({ (value: NSNumber) -> Bool in return value.intValue > 2 })
45. example RACSignal.combineLatest([usernameSignal, passwordSignal]) .subscribeNext({ (value: AnyObject!) in button.enabled = true })
46. example RACSignal.combineLatest([usernameSignal, passwordSignal]) .subscribeNext({ (value: AnyObject!) in button.enabled = true })
47. more interesting example
48. example connect to a websocket which streams live edits from wikipedia
49. example RESPONSE: { "type":"unspecified", "content":"Wikipedia talk:Articles for creation/Bonnie ZoBell", “time":"2014-05-15T14:45:59.175Z" } RESPONSE: { "type":"unspecified", "content":"Wikipedia:WikiProject Spam/LinkReports/blog.wifirst.fr", “time":"2014-05-15T14:45:59.247Z" } RESPONSE: { "type":"special", "content":"", “time":"2014-05-15T14:46:00.262Z" } RESPONSE: { "type":"unspecified", "content":"Manhattan Film Academy", “time":"2014-05-15T14:46:00.828Z" }
50. example show the names of the edited pages
51. filter to get “unspecified” map to extract “content” subscribe and update label example
52. example wsConnector.messages .filterAs({ (dict: NSDictionary) in return (dict["type"] as NSString).isEqualToString("unspecified") }) .mapAs({ (dict: NSDictionary) -> NSString in return dict["content"] as NSString }) .deliverOn(RACScheduler.mainThreadScheduler()) .subscribeNextAs({(value: NSString) in self.tickerLabel.text = value })
53. example wsConnector.messages .filterAs({ (dict: NSDictionary) in return (dict["type"] as NSString).isEqualToString("unspecified") }) .mapAs({ (dict: NSDictionary) -> NSString in return dict["content"] as NSString }) .deliverOn(RACScheduler.mainThreadScheduler()) .subscribeNextAs({(value: NSString) in self.tickerLabel.text = value })
54. example wsConnector.messages .filterAs({ (dict: NSDictionary) in return (dict["type"] as NSString).isEqualToString("unspecified") }) .mapAs({ (dict: NSDictionary) -> NSString in return dict["content"] as NSString }) .deliverOn(RACScheduler.mainThreadScheduler()) .subscribeNextAs({(value: NSString) in self.tickerLabel.text = value })
55. example plot the live edit rate on a chart
56. buffer to collect sample map to count samples subscribe to add to chart example
57. example wsConnector.messages .bufferWithTime(5, onScheduler: scheduler) .mapAs({ (value: RACTuple) -> NSNumber in return NSNumber(double: Double(value.count) / 5.0) }) .deliverOn(RACScheduler.mainThreadScheduler()) .logNext() .subscribeNext({(x: AnyObject!) in self.datasource!.appendValue(x as NSNumber) })
58. example wsConnector.messages .bufferWithTime(5, onScheduler: scheduler) .mapAs({ (value: RACTuple) -> NSNumber in return NSNumber(double: Double(value.count) / 5.0) }) .deliverOn(RACScheduler.mainThreadScheduler()) .logNext() .subscribeNext({(x: AnyObject!) in self.datasource!.appendValue(x as NSNumber) })
59. example wsConnector.messages .bufferWithTime(5, onScheduler: scheduler) .mapAs({ (value: RACTuple) -> NSNumber in return NSNumber(double: Double(value.count) / 5.0) }) .deliverOn(RACScheduler.mainThreadScheduler()) .logNext() .subscribeNext({(x: AnyObject!) in self.datasource!.appendValue(x as NSNumber) })
60. example annotate new-user events on the chart
61. filter to get “newuser” map to create annotation subscribe to add to chart example
62. example wsConnector.messages .filterAs({ (value: NSDictionary) -> Bool in return (value["type"] as NSString).isEqualToString("newuser") }) .mapAs({ (value: NSDictionary) -> SChartAnnotation in return self.createNewUserAnnotation(value["time"]) }) .deliverOn(RACScheduler.mainThreadScheduler()) .subscribeNextAs({ (value: SChartAnnotation) in self.chart.addAnnotation(value) self.chart.redrawChart() })
63. example wsConnector.messages .filterAs({ (value: NSDictionary) -> Bool in return (value["type"] as NSString).isEqualToString("newuser") }) .mapAs({ (value: NSDictionary) -> SChartAnnotation in return self.createNewUserAnnotation(value["time"]) }) .deliverOn(RACScheduler.mainThreadScheduler()) .subscribeNextAs({ (value: SChartAnnotation) in self.chart.addAnnotation(value) self.chart.redrawChart() })
64. example wsConnector.messages .filterAs({ (value: NSDictionary) -> Bool in return (value["type"] as NSString).isEqualToString("newuser") }) .mapAs({ (value: NSDictionary) -> SChartAnnotation in return self.createNewUserAnnotation(value["time"]) }) .deliverOn(RACScheduler.mainThreadScheduler()) .subscribeNextAs({ (value: SChartAnnotation) in self.chart.addAnnotation(value) self.chart.redrawChart() })
65. demo
66. in summary
67. cool functional reactive programming is
68. powerful functional reactive programming is
69. fun functional reactive programming is
70. you should give it a try
71. you should give it a try ReactiveCocoa
72. you should give it a try ReactiveExtensions
73. you should give it a try Elm
74. thanks github.com/sammyd @iwantmyrealname