RubyMotion: Under the Hood

1. RubyMotion: Under the Hood Inspired by Click and Clack Monday, October 14, 2013

2. A brief introduction Monday, October 14, 2013

3. About Me Name: Joshua Ballanco Monday, October 14, 2013

4. About Me Employer: Burnside Digital Monday, October 14, 2013

5. About Me Location: Ankara, Turkey Monday, October 14, 2013

6. A slightly longer introduction Monday, October 14, 2013

7. Before... Monday, October 14, 2013

8. About Me Employer: Patch Monday, October 14, 2013

9. About Me Location: New York City Monday, October 14, 2013

10. Before that... Monday, October 14, 2013

11. About Me Employer: Apple Monday, October 14, 2013

12. About Me Location: Cupertino Monday, October 14, 2013

13. Before that... Monday, October 14, 2013

14. About Me School: University of Miami Monday, October 14, 2013

15. About Me Location: Miami Monday, October 14, 2013

16. A bit of history Monday, October 14, 2013

17. In graduate school Monday, October 14, 2013

18. In graduate school Monday, October 14, 2013

19. At Apple... Retail Monday, October 14, 2013

20. At Apple Laurent Sansonetti Monday, October 14, 2013

21. After Apple... Monday, October 14, 2013

22. Episode VI - The Return of The RubyMotion Monday, October 14, 2013

23. What is RubyMotion? • Use Ruby to build apps for iOS and OS X • Native apps • Interface directly with Obj-C libraries • CLI-based build system Monday, October 14, 2013

24. What is RubyMotion? • RubyMotion: http://www.rubymotion.com/ • MotionCasts: http://motioncasts.tv/ • RubyMotion Wrappers: ! http://rubymotion-wrappers.com/ • ...and lot’s more Monday, October 14, 2013

25. What is MacRuby? • Intended to be the implementation of Ruby 2.0 for OS X • Target RubySpec compliance • JIT or AOT Compiled • Uses libauto for Garbage Collection Monday, October 14, 2013

26. What is MacRuby? Ruby Syntax Parser Compiler VM (sans GVL) LLVM (with JIT) Objective-C Runtime Monday, October 14, 2013

27. Running a “something.rb” ﬁle Ruby Syntax Parser Compiler VM (sans GVL) LLVM (with JIT) Objective-C Runtime Monday, October 14, 2013

30. AOT compiling “something.rb” Ruby Syntax Parser Compiler VM (sans GVL) Objective-C Runtime Monday, October 14, 2013 LLVM something.o

31. AOT compiling “something.rb” Ruby Syntax Parser Compiler VM (sans GVL) Objective-C Runtime Monday, October 14, 2013 LLVM something.o

32. Running an AOT compiled “something.rb” Parser Compiler VM (sans GVL) Objective-C Runtime Monday, October 14, 2013 something.o

33. Running an AOT compiled “something.rb” Parser Compiler VM (sans GVL) Objective-C Runtime Monday, October 14, 2013 something.o

34. Running an AOT compiled “something.rb” Parser Compiler LLVM VM (sans GVL) Objective-C Runtime Monday, October 14, 2013 something.o

37. What is RubyMotion? • Descendent of MacRuby • “Ruby, the Good Parts” • Static Compiled • Retain/release reference counting Monday, October 14, 2013

38. Static compiling “something.rb” Ruby Syntax Parser Compiler VM (sans GVL) Objective-C Runtime Monday, October 14, 2013 LLVM something.o

39. Static compiling “something.rb” Ruby Syntax Parser Compiler VM (sans GVL) Objective-C Runtime Monday, October 14, 2013 LLVM something.o

40. Running a static compiled “something.rb” VM (sans GVL) Objective-C Runtime Monday, October 14, 2013 something.o

41. Running a static compiled “something.rb” VM (sans GVL) Objective-C Runtime Monday, October 14, 2013 something.o

42. Why must we statically compile? • On OS X • Compile writes code to a memory page • Runtime runs the code from that memory page Monday, October 14, 2013

43. Why must we statically compile? • On iOS Memory pages must be writable or executable, NOT BOTH! • • • Monday, October 14, 2013 • OS prohibits runtime compilation Apple prohibits interpreting arbitrary scripts ...but you wouldn’t want an interpreter anyway

44. Garbage Collection Monday, October 14, 2013

45. What happened to the Garbage Collector? It required extra threads, so we had to kill it... Monday, October 14, 2013

46. So RubyMotion Uses ARC? Yes... Uh...no ...sorta? Monday, October 14, 2013

47. ARC vs “ARC” • Objective-C’s ARC modiﬁes your code before compilation • RubyMotion VM knows when retain and/or release should be called...your code is not touched Monday, October 14, 2013

48. ARC vs “ARC” Isn’t the distinction rather academic? Probably... Monday, October 14, 2013

49. “ARC” Caveats • Collection happens when the autorelease pool drains • Need to be careful with tight loops that generate many objects • Use “autorelease do...end” • Detects almost all cycles • Use WeakRefs if cycles become problematic Monday, October 14, 2013

50. Debugging RubyMotion • Remember, RubyMotion objects are Objective-C objects... • All the usual tricks are valid! Monday, October 14, 2013

51. Let’s Play! Monday, October 14, 2013

52. The Victim app/app_delegate.rb Monday, October 14, 2013

53. The Victim app/app_delegate.rb Monday, October 14, 2013

54. REPL Magic Monday, October 14, 2013

58. That’s cool...but can you do it in a debugger??? Monday, October 14, 2013

59. Debugger Wizardry Monday, October 14, 2013

63. That’s CRAZY! I know...but it’s fun! Monday, October 14, 2013

64. Debugging RubyMotion • Helper methods “pro” and “pri” • http://www.rubymotion.com/developercenter/articles/debugging/ • Watch for more/better tooling to come... Monday, October 14, 2013

65. Questions? Joshua Ballanco @manhattanmetric https://github.com/jballanc Monday, October 14, 2013