1. Tribal Ownership Nicholas Cameron James Noble Tobias Wrigstad Victoria University of Wellington Uppsala University

2. ncameron@ecs.vuw.ac.nz2 Tribe c1:Canvas world s1:Shape s2:Shape r1:Rectangle c2:Canvas s3:Shape s4:Shape r2:Rectangle c3:InCanvas...

3. ncameron@ecs.vuw.ac.nz3 Ownership c1:Canvas world s1:Shape s2:Shape r1:Rectangle c2:Canvas s3:Shape s4:Shape r2:Rectangle c3:InCanvas...

4. ncameron@ecs.vuw.ac.nz4 Tribal Ownership c1:Canvas world s1:Shape s2:Shape r1:Rectangle c2:Canvas s3:Shape s4:Shape r2:Rectangle c3:InCanvas...

5. ? ncameron@ecs.vuw.ac.nz5 Questions

6. Virtual Classes Nested Classes Family Polymorphism Class Families Nested Inheritance... ncameron@ecs.vuw.ac.nz6

7. Virtual Classes Scala Newspeak GBeta... ncameron@ecs.vuw.ac.nz7

8. Tribe class Canvas { class Shape {... } class Circle extends Shape {... } class Rectangle extends Shape {... }... } class ICanvas extends Canvas { class Shape { void onClick() {... } } ncameron@ecs.vuw.ac.nz8

9. Tribe class Canvas { class Shape {... } class Circle extends Shape {... } class Rectangle extends Shape {... }... } class InCanvas extends Canvas { class Shape { void onClick() {... } } ncameron@ecs.vuw.ac.nz9

10. 10 Tribe Canvas Shape Circle Rectangle

11. ncameron@ecs.vuw.ac.nz11 Tribe Canvas Shape Circle Rectangle InCanvas Shape Circle Rectangle onClick()

12. ncameron@ecs.vuw.ac.nz12 Canvas Shape Circle Rectangle InCanvas Shape Circle Rectangle onClick()

13. ncameron@ecs.vuw.ac.nz13 Tribe c1:Canvas world s1:Shape s2:Shape r1:Rectangle c2:Canvas s3:Shape s4:Shape r2:Rectangle c3:InCanvas...

14. c1.Shape c2.Shape ncameron@ecs.vuw.ac.nz14 Tribe Types

15. class Canvas { this.Shape f1; world.Canvas f2; class Shape { this.out.out.Canvas f3; this.out.Circle f4; } class Circle extends Shape {... } } ncameron@ecs.vuw.ac.nz15 Tribe Types

16. ncameron@ecs.vuw.ac.nz16 Tribe Types class Canvas { this.Shape f1; world.Canvas f2; class Shape {... } } :Canvas f1:Shape world f2:Canvasf4:Canvas f3:Circle :Shape

17. ncameron@ecs.vuw.ac.nz17 Tribe Types :Canvas f1:Shape world f2:Canvasf4:Canvas f3:Circle :Shape class Canvas {... class Shape { this.out.Circle f3; this.out.out.Canvas f4; }

18. ncameron@ecs.vuw.ac.nz18

19. ncameron@ecs.vuw.ac.nz19 Ownership Types

20. class List { ListNode first;... } class ListNode { ListNode next; Object datum;... } new List (); ncameron@ecs.vuw.ac.nz20 Ownership Types

21. ? ncameron@ecs.vuw.ac.nz21 What if...

22. ncameron@ecs.vuw.ac.nz22ncameron@ecs.vuw.ac.nz22 c1:Canvas world s1:Shape r1:Rectangle c2:Canvas s3:Shape r2:Rectangle

23. c1.Shape ncameron@ecs.vuw.ac.nz23 Tribal Ownership

24. class Canvas { this.Shape f1; world.Canvas f2; class Shape { this.out.Circle f3; this.out.out.Canvas f4; } class Circle extends Shape {... } } ncameron@ecs.vuw.ac.nz24 Tribe

25. class Canvas { this.Shape f1; world.Canvas f2; class Shape { this.out.Circle f3; this.out.out.Canvas f4; } class Circle extends Shape {... } } ncameron@ecs.vuw.ac.nz25 Tribal Ownership

26. class List { ListNode first;... } class ListNode { ListNode next; Object datum;... } new List (); ncameron@ecs.vuw.ac.nz26 What about List?

27. class List { this.ListNode first; class ListNode { this.out.ListNode next; X datum;... }... } new this.List (); ncameron@ecs.vuw.ac.nz27 What about List? - Generics

28. class List { this.ListNode first; class ListNode { this.out.ListNode next; X datum;... }... } new this.List (); ncameron@ecs.vuw.ac.nz28 What about List? - Generics

29. class List { this.ListNode first; class ListNode { this.out.ListNode next; X datum;... }... } new this.List (); ncameron@ecs.vuw.ac.nz29 What about List?

30. module Collections { class List {... } class Foo imports world.Collections { this.List f; } ncameron@ecs.vuw.ac.nz30 What about List? – Module classes

31. ncameron@ecs.vuw.ac.nz31 Encapsulation

32. Owners-as-Dominators Owners-as-Modifiers ncameron@ecs.vuw.ac.nz32 Encapsulation

33. ncameron@ecs.vuw.ac.nz33 Descriptive Ownership

34. ncameron@ecs.vuw.ac.nz34 O-as-D

35. Owners-as-Local-Dominators ncameron@ecs.vuw.ac.nz35 Encapsulation

36. ncameron@ecs.vuw.ac.nz36 O-as-LD

37. ncameron@ecs.vuw.ac.nz37 O-as-LD private public Only public classes can be named externally

38. Virtual classes in Tribe give ownership – No syntactic overhead Generics Module classes – Cross family inheritance Owners-as-Local-Dominators ncameron@ecs.vuw.ac.nz38 Summary

39. ncameron@ecs.vuw.ac.nz39 Thank you!

41. ? ncameron@ecs.vuw.ac.nz41 Questions