Reflex Skip Julien Verlaguet

Transcription

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2 Reflex Skip Julien Verlaguet Skip the things you ve already computed!

3 Skip A reactive programming language Skip is a language with spreadsheet semantics. The runtime keeps track of external dependencies: when something changes, things magically update efficiently.

4 Skip Why? Tools UI The skip compiler! Caches

5 Skip the Language Language principles Favor immutability at function boundaries Reactivity is implicit Skip is embeddable!

6 Skip the Language Language features Statically typed Generics Pattern-matching Closures Async/await Traits (type classes)

7 Example

8 Skip: example fun request(id: Int): String { user = buildprofile(id); renderhtml(user) }

9 Skip: call graph request(id) buildprofile(id) renderhtml(user) init() getuser(id) DATABASE

10 Skip: caching request(id) buildprofile(id) renderhtml(user) init() getuser(id) DATABASE

11 Skip: invalidation request(id) buildprofile(id) renderhtml(user) init() getuser(id) DATABASE

12 Skip: reactivity fun request(id: Int): String { user = buildprofile(id); renderhtml(user) }

13 Skip: mutation fun request(id: Int): String { user = buildprofile(id); renderhtml(user) } MUTATION?

14 Skip s Solution What invariants? Immutability guaranteed statically But local mutations are encouraged! Runtime tracks dependencies Automatically invalidate memoized values

15 Objects

16 Objects class User(name: String, age: Int) { fun onbirthday(): User { User(name, this.age + 1) } }

17 Objects class User{name: String, age: Int} { fun onbirthday(): User { User{name, age => this.age + 1} } }

18 Objects class User{name: String, age: Int} { fun onbirthday(): User {!this.age = this.age + 1; this } }

19 Objects class User{name:, mutable age: Int} { mutable fun onbirthday(): void { this.!age = this.age + 1 } }

20 Object creation: immutable user = User { name => julien, age => 35 }; Cannot access mutable methods!

21 Object creation: mutable user = mutable User { name => julien, age => 35 }; Mutable methods until freezing!

22 Skip: collections v1 = Vector[1, 2, 3]; v2 = mutable Vector[1, 2, 3]; m1 = Map[1, 2, 3]; m2 = mutable Map[1, 2, 3]; v1.filter(x -> x >= 0).map(x -> x + 1) // Make your own!

23 Skip: collections fun filterusers(): SMap<String> { result = mutable Map[]; freeze(result) }

24 OO = FP

25 Skip: pattern-matching fun isnull(value:?x): Bool { value match { Null -> true Box(x) -> x } }

26 OO Inheritance base class IntList class Nil() extends IntList class Cons(Int, IntList) extends IntList

27 FP inheritance base class IntList { children = Nil() Cons(Int, IntList) }

28 OO methods class Nil() extends IntList { } fun add1(): IntList { } class Cons(Int, IntList) { } fun add1(): IntList { }

29 FP methods base class IntList { fun add1(): IntList Nil() -> Cons(x, rl) -> }

30 OO/FP mix base class IntList { fun add1(): IntList Nil() -> } class Cons(Int, IntList) extends IntList { } fun add1(): IntList { }

31 Generics

32 Generics base class List<T> { children = Nil() Cons(T, List<T>) fun map<t2>(f: T -> T2): List<T2> Nil() -> Cons(x, rl) -> }

33 Generics base class List<T> { fun show[t: Showable](): String { //.. } }

34 Generics: traits trait Showable { fun tostring(): String { //.. } }

35 Lvalues

36 Lvalues local = C(X(1, 2), Y(3, 4)); X Y C

37 Lvalues local.field2.!field1 = 42; 42 Modified X Y C

38 Lvalues local.!field2.field1 = 42; 42 New value Modified X Y C

39 Lvalues!local.field2.field1 = 42; 42 New value Modified X Y C

40 Code: lvalues (!acc, result) = some_fun(acc, x);

41 Memoization

42 Skip: memoization is fast! fun request(id: Int): String { user = buildprofile(id); renderhtml(user) } Shared heap

43 Shared heap Objects are immutable 2 structurally equal object have the same address Supports multithreading (MVCC)

44 Skip: memoization is fast! fun request(id: Int): String { user = buildprofile(id); user = buildprofile(id); INSTANT renderhtml(user) }

45 Skip: memoization is super fast! fun request(id: Int): String { user = buildprofile(id); _ = renderhtml(user); renderhtml(user); INSTANT }

46 Memory model

47 Memory model Skip is safe, garbage-collected Minor heap Fast, bump a pointer allocator Shared heap Long-lived, immutable Unique ( interned ) objects only

48 Skip: fun request(id: Int): String { user = buildprofile(id); renderhtml(user) }

49 Memory model properties O(allocated)!= O(heap_size) Annotations to memoize You can reason about performance!

50 Future applications

51 Future applications Time shift Compute in the morning, use in the afternoon Eases At peak traffic

52 Future applications Remote cache Use local data as if it was remote Maintaining a reactive version Push changes

53 Thank you!

54 Example Slide Subtitle

55 Runtime Slide Subtitle Lorem ipsum dolor sit amet, consectetur. Donec vitae ipsum quis elit ultricies aliquam Pellentesque in nibh quis est cursus fermentum. Donec vel justo ut erat hendrerit nec non leo. Lorem ipsum dolor sit amet, consectetur. Donec vitae ipsum quis elit ultricies aliquam

56 Applications Slide Subtitle Lorem ipsum dolor sit amet, consectetur. Donec vitae ipsum quis elit ultricies aliquam Pellentesque in nibh quis est cursus fermentum. Donec vel justo ut erat hendrerit nec non leo. Lorem ipsum dolor sit amet, consectetur. Donec vitae ipsum quis elit ultricies aliquam

57 Slide Title Slide Subtitle Lorem ipsum dolor sit amet, consectetur. Donec vitae ipsum quis elit ultricies aliquam Pellentesque in nibh quis est cursus fermentum. Donec vel justo ut erat hendrerit nec non leo. Lorem ipsum dolor sit amet, consectetur. Donec vitae ipsum quis elit ultricies aliquam

58 Slide Title Slide Subtitle Lorem ipsum dolor sit amet, consectetur. Donec vitae ipsum quis elit ultricies aliquam Pellentesque in nibh quis est cursus fermentum. Donec vel justo ut erat hendrerit nec non leo. Lorem ipsum dolor sit amet, consectetur. Donec vitae ipsum quis elit ultricies aliquam

59 Slide Title Slide Subtitle Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed semper mauris quis sem finibus, a feugiat eros sodales. Aliquam vel turpis eleifend, suscipit tortor venenatis, luctus metus. Phasellus lorem massa, venenatis quis maximus ut, consectetur vel libero. Phasellus lorem massa.

60 Slide Title Slide Subtitle Lorem ipsum dolor sit amet, consectetur. Donec vitae ipsum quis elit ultricies aliquam Pellentesque in nibh quis est cursus fermentum. Donec vel justo ut erat hendrerit nec non leo. Lorem ipsum dolor sit amet, consectetur. Donec vitae ipsum quis elit ultricies aliquam

61 Slide Title Lorem ipsum dolor sit amet, consectetur. Donec vitae ipsum quis elit ultricies aliquam Pellentesque in nibh quis est cursus fermentum. Donec vel justo ut erat hendrerit nec non leo. Lorem ipsum dolor sit amet, consectetur. Donec vitae ipsum quis elit ultricies aliquam

62 Interstitial Title

63 Lorem ipsum dolor sit amet, adipiscing elit. Nam facilisis erat nunc, maximus auctor libero ornare at. Ut nec nisl sodales quam feugiat. Quote Author

64 Source: sed ut unde omnis

65 Slide Title Slide Subtitle <code></code> <code></code> <code></code> <code></code> <code></code> <code></code> <code></code> <code></code> <code></code>

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