Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
Reactive Collections
Search
Aleksandar Prokopec
July 30, 2014
Programming
0
190
Reactive Collections
Description of the reactive collections framework from the Scala 2014 workshop.
Aleksandar Prokopec
July 30, 2014
Tweet
Share
More Decks by Aleksandar Prokopec
See All by Aleksandar Prokopec
ScalaMeter in 2014
axel22
0
320
A Reactive 3D Game Engine in Scala
axel22
4
8.2k
ScalaBlitz
axel22
0
200
Work-stealing Tree Scheduler
axel22
1
68
ScalaMeter
axel22
0
130
Ctrie Data Structure
axel22
0
200
Parallel Collections Overview
axel22
0
100
Introduction to Scala
axel22
2
290
Other Decks in Programming
See All in Programming
datadog dash 2025 LLM observability for reliability and stability
ivry_presentationmaterials
0
350
Composerが「依存解決」のためにどんな工夫をしているか #phpcon
o0h
PRO
1
250
GoのGenericsによるslice操作との付き合い方
syumai
3
700
PHP 8.4の新機能「プロパティフック」から学ぶオブジェクト指向設計とリスコフの置換原則
kentaroutakeda
2
680
エンジニア向け採用ピッチ資料
inusan
0
180
Java on Azure で LangGraph!
kohei3110
0
170
第9回 情シス転職ミートアップ 株式会社IVRy(アイブリー)の紹介
ivry_presentationmaterials
1
260
『自分のデータだけ見せたい!』を叶える──Laravel × Casbin で複雑権限をスッキリ解きほぐす 25 分
akitotsukahara
1
590
NPOでのDevinの活用
codeforeveryone
0
480
Systèmes distribués, pour le meilleur et pour le pire - BreizhCamp 2025 - Conférence
slecache
0
110
Hypervel - A Coroutine Framework for Laravel Artisans
albertcht
1
110
ruby.wasmで多人数リアルタイム通信ゲームを作ろう
lnit
2
320
Featured
See All Featured
CoffeeScript is Beautiful & I Never Want to Write Plain JavaScript Again
sstephenson
161
15k
GraphQLの誤解/rethinking-graphql
sonatard
71
11k
Speed Design
sergeychernyshev
32
1k
CSS Pre-Processors: Stylus, Less & Sass
bermonpainter
357
30k
Gamification - CAS2011
davidbonilla
81
5.3k
The Psychology of Web Performance [Beyond Tellerrand 2023]
tammyeverts
48
2.9k
What's in a price? How to price your products and services
michaelherold
246
12k
Learning to Love Humans: Emotional Interface Design
aarron
273
40k
Building a Scalable Design System with Sketch
lauravandoore
462
33k
Java REST API Framework Comparison - PWX 2021
mraible
31
8.7k
A Modern Web Designer's Workflow
chriscoyier
694
190k
GraphQLとの向き合い方2022年版
quramy
49
14k
Transcript
1 Containers and Aggregates, Mutators and Isolates for Reactive Programming
Aleksandar Prokopec, Philipp Haller, Martin Odersky
Reactive Collections http://reactive-collections.com 2
Reactive 3
4
5 Observables (event streams)
6 Observables (event streams) • declarative val log = messages
.filter(_.length < 100) .scan(_ + “\n” + _)
7 Observables (event streams) • declarative val log = messages
.filter(_.length < 100) .scan(_ + “\n” + _) var log = “” def receive = { case s: String => if (s.length < 100) log = log + “\n” + s }
8 Actors • encapsulate mutable state
9 Actors • encapsulate mutable state var log = “”
def receive = { case s: String => if (s.length < 100) log = log + “\n” + s }
10 Reactive collections Isolate Reactive Channel Actor ? ActorRef ?
Observable Observable
11 Reactive values
Reactive[T] 12
val ticks: Reactive[Long] 13 ticks 1 1 2 2 3
3 4 4 60 60 61 61
ticks onEvent { x => log.debug(s”tick no.$x”) } 14 1
2 3 4 60 61 tick no.1 tick no.2 tick no.3 tick no.4 tick no.60 tick no.61 ...
ticks foreach { x => log.debug(s”tick no.$x”) } 15 1
2 3 4 60 61
16 for (x <- ticks) { log.debug(s”tick no.$x”) } Single-threaded!
17 Reactive combinators
for (x <- ticks) yield { x / 60 }
18
val seconds: Reactive[Long] = for (x <- ticks) yield {
x / 60 } 19
60 61 val seconds: Reactive[Long] = for (x <- ticks)
yield { x / 60 } 20 ticks 1 1 2 2 3 3 60 61 seconds 0 0 0 1 1 ticks seconds 0 0 0 1 1
val days: Reactive[Long] = seconds.map(_ / 86400) 21
val days: Reactive[Long] = seconds.map(_ / 86400) val secondsToday =
22
val days: Reactive[Long] = seconds.map(_ / 86400) val secondsToday =
(seconds zip days) { (s, d) => s – d * 86400 } 23
val angle = secondsInDay.map(angleFunc) 24
val angle = secondsInDay.map(angleFunc) val light = secondsInDay.map(lightFunc) 25
26
27 val rotate = keys a ↓ shift ↓ a
↑ shift ↑ pgup ↓ pgup ↑ keys
28 val rotate = keys.filter(_ == PAGEUP) a ↓ shift
↓ a ↑ shift ↑ pgup ↓ pgup ↑ keys pgup ↓ pgup ↑ filter
29 val rotate = keys.filter(_ == PAGEUP) .map(_.down) a ↓
shift ↓ a ↑ shift ↑ pgup ↓ pgup ↑ keys pgup ↓ pgup ↑ filter true false map
30 if (rotate()) viewAngle += 1 true false map
31 Signals
32 trait Signal[T] extends Reactive[T] { def apply(): T }
33 val rotate = keys.filter(_ == PAGEUP) .map(_.down) .signal(false) true
false map signal
34 val rotate: Signal[Boolean] = keys.filter(_ == PAGEUP) .map(_.down) .signal(false)
true false map signal
35 val rotate: Signal[Boolean] val ticks: Reactive[Long] ticks
36 val rotate: Signal[Boolean] val ticks: Reactive[Long] ticks rotate
37 val rotate: Signal[Boolean] val ticks: Reactive[Long] val viewAngle: Signal[Double]
= ticks rotate viewAngle
38 val rotate: Signal[Boolean] val ticks: Reactive[Long] val viewAngle: Signal[Double]
= ticks.scanPast(0.0) ticks rotate viewAngle
39 val rotate: Signal[Boolean] val ticks: Reactive[Long] val viewAngle: Signal[Double]
= ticks.scanPast(0.0) { (a, _) => if (rotate()) a + 1 else a } ticks rotate viewAngle
40
41 val velocity = ticks.scanPast(0.0) { (v, _) => }
val viewAngle =
42 val velocity = ticks.scanPast(0.0) { (v, _) => if
(rotate()) v + 1 } val viewAngle =
43 val velocity = ticks.scanPast(0.0) { (v, _) => if
(rotate()) v + 1 else v – 0.5 } val viewAngle =
44 val velocity = ticks.scanPast(0.0) { (v, _) => if
(rotate()) v + 1 else v – 0.5 } val viewAngle = velocity.scanPast(0.0)(_ + _)
45
46 Reactive mutators
47 class Matrix { def apply(x: Int, y: Int): Double
def update(x: Int, y: Int, v: Double) }
48 val screenMat: Signal[Matrix] = (projMat zip viewMat)(_ * _)
val invScreenMat = screenMat.map(_.inverse)
49 Reactive[immutable.Matrix[T]]
50 val screenMat: Signal[Matrix] = (projMat zip viewMat)(_ * _)
val invScreenMat = screenMat.map(_.inverse) (4*4*8 + 16 + 16)*4*100 = 64 kb/s
51 val screenMat = Mutable(new Matrix) (projMat, viewMat).mutate(screenMat) { (p,
v) => screenMat().assignMul(p, v) } val invScreenMat = Mutable(new Matrix) screenMat.mutate(invScreenMat) { m => invScreenMat().assignInv(m) }
52 Reactive collections
53
54 val selected: Reactive[Set[Character]]
55 val selected: ReactSet[Character]
56 trait ReactSet[T] extends ReactContainer[T] { def apply(x: T): Boolean
}
57 trait ReactContainer[T] { def inserts: Reactive[T] def removes: Reactive[T]
}
58 A reactive collection is a pair of reactive values
59 val selected = new ReactHashSet[Character]
60
61 val selected = new ReactHashSet[Character] val decorations = selected
.map(c => (c, decoFor(c)))
62 class ReactContainer[T] { self => def inserts: Reactive[T] def
removes: Reactive[T] def map[S](f: T => S) = new ReactContainer[S] { def inserts: Reactive[T] = self.inserts.map(f) def removes: Reactive[T] = self.removes.map(f) } }
63 val selected = new ReactHashSet[Character] val decorations = selected
.map(c => (c, decoFor(c))) .to[ReactHashMap]
64 val selected = new ReactHashSet[Character] val decorations = selected
.map(c => (c, decoFor(c))) .to[ReactHashMap]
65 val selected = new ReactHashSet[Character] val decorations = selected
.map(c => (c, decoFor(c))) .to[ReactHashMap]
66 val selected = new ReactHashSet[Character] val decorations = selected
.map(c => (c, decoFor(c))) .to[ReactHashMap]
67 val selected = new ReactHashSet[Character] val decorations = selected
.map(c => (c, decoFor(c))) .react.to[ReactHashMap]
68 val selected = new ReactHashSet[Character] val decorations = selected
.map(c => (c, decoFor(c))) .react.to[ReactHashMap]
69 val selected = new ReactHashSet[Character] val decorations = selected
.map(c => (c, decoFor(c))) .react.to[ReactHashMap]
70 val selected = new ReactHashSet[Character] val decorations = selected
.map(c => (c, decoFor(c))) .react.to[ReactHashMap]
71 Isolates
72 UI isolate class UI extends Isolate[UI.Message] { val frames
= source.filter(_ == UI.Frame) val exit = source onCase { case UI.Exit => exit() } } Source
73 UI Isolate Source AI Isolate Source Channel[AI.Message]
Channel[UI.Message]
74 Reactive collections Isolate Reactive Channel Actor ? ActorRef ?
Observable Observable
75 Thank you!