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
310
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
VS Code Update for GitHub Copilot
74th
1
210
統一感のある Go コードを生成 AI の力で手にいれる
otakakot
1
3k
XSLTで作るBrainfuck処理系
makki_d
0
210
明示と暗黙 ー PHPとGoの インターフェイスの違いを知る
shimabox
2
210
ASP.NETアプリケーションのモダナイズ インフラ編
tomokusaba
1
400
Kotlin エンジニアへ送る:Swift 案件に参加させられる日に備えて~似てるけど色々違う Swift の仕様 / from Kotlin to Swift
lovee
1
250
Create a website using Spatial Web
akkeylab
0
300
コードの90%をAIが書く世界で何が待っているのか / What awaits us in a world where 90% of the code is written by AI
rkaga
44
29k
git worktree × Claude Code × MCP ~生成AI時代の並列開発フロー~
hisuzuya
1
300
Cursor AI Agentと伴走する アプリケーションの高速リプレイス
daisuketakeda
1
120
Is Xcode slowly dying out in 2025?
uetyo
1
180
KotlinConf 2025 現地で感じたServer-Side Kotlin
n_takehata
1
220
Featured
See All Featured
The Art of Delivering Value - GDevCon NA Keynote
reverentgeek
15
1.5k
個人開発の失敗を避けるイケてる考え方 / tips for indie hackers
panda_program
107
19k
XXLCSS - How to scale CSS and keep your sanity
sugarenia
248
1.3M
Making the Leap to Tech Lead
cromwellryan
134
9.3k
Chrome DevTools: State of the Union 2024 - Debugging React & Beyond
addyosmani
7
700
Build your cross-platform service in a week with App Engine
jlugia
231
18k
[RailsConf 2023 Opening Keynote] The Magic of Rails
eileencodes
29
9.5k
Embracing the Ebb and Flow
colly
86
4.7k
Visualizing Your Data: Incorporating Mongo into Loggly Infrastructure
mongodb
46
9.6k
Documentation Writing (for coders)
carmenintech
71
4.9k
Rebuilding a faster, lazier Slack
samanthasiow
81
9k
Git: the NoSQL Database
bkeepers
PRO
430
65k
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!