Function Reactive Programming in iOS

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Functional Reactive iOS

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Functional Reactive iOS

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Functional Reactive OSX

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Functional Reactive .NET

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Functional Reactive JS

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Functional Reactive

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Functional Reactive Why you should consider programming

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@iwantmyrealname

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iwantmyreal.name

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leanpub.com/ios7daybyday

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@shinobicontrols

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shinobicontrols.com

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what is functional reactive programming?

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what is functional reactive programming?

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programming

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computer programming is a process that leads from an original formulation of a computing problem to executable programs programming

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what is functional reactive programming?

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functional

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functional stateless immutable 1st class functions

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what is functional reactive programming?

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reactive

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reactive dataﬂow spreadsheets

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what is functional reactive programming?

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frp obvious

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frp immutable events functional pipeline reactive signals

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frp a standard interface for events

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signals

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signals what are

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represent a stream of immutable events signals

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events are signals next completed error

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signals what can model?

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delegation observer/databinding target-action blocks/lambdas/closures modelling

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async tasks network events user interaction ﬂow control modelling

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signals what can be used for?

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signals most useful when a functional pipeline is formed uses

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map ﬁlter combine buffer signal operations zip concat takeUntil …

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real world example

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demo

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example username password s sa sam p pa pas pass submit

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example username password s sa sam p pa pas pass submit username password 1 2 3 1 2 3 4 string.length map

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example username password s sa sam p pa pas pass submit username password 3 3 4 greater than 2 ﬁlter

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example let usernameSignal = tf.rac_textSignal() .mapAs({ (value: NSString) -> NSNumber in return value.length }) .filterAs({ (value: NSNumber) -> Bool in return value.intValue > 2 })

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example let usernameSignal = tf.rac_textSignal() .mapAs({ (value: NSString) -> NSNumber in return value.length }) .filterAs({ (value: NSNumber) -> Bool in return value.intValue > 2 })

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example let usernameSignal = tf.rac_textSignal() .mapAs({ (value: NSString) -> NSNumber in return value.length }) .filterAs({ (value: NSNumber) -> Bool in return value.intValue > 2 })

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example RACSignal.combineLatest([usernameSignal, passwordSignal]) .subscribeNext({ (value: AnyObject!) in button.enabled = true })

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example RACSignal.combineLatest([usernameSignal, passwordSignal]) .subscribeNext({ (value: AnyObject!) in button.enabled = true })

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more interesting example

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example connect to a websocket which streams live edits from wikipedia

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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" }

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example show the names of the edited pages

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ﬁlter to get “unspeciﬁed” map to extract “content” subscribe and update label example

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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 })

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example plot the live edit rate on a chart

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buffer to collect sample map to count samples subscribe to add to chart example

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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) })

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example annotate new-user events on the chart

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ﬁlter to get “newuser” map to create annotation subscribe to add to chart example

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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() })