Ruby 2.1

Gave this talk during January 2014 Singapore Ruby Brigade meetup.

1. Ruby 2.1 Benjamin Tan Wei Hao (@bentanweihao)!
4. What's New?! 1.  Rational Number & Complex ! Number Literals ! 2.  def‘s return value! 3.  Refinements! 4.  Required Keyword Arguments! 5.  Garbage Collector! 6.  Object Allocation Tracing!
5. BUT FIRST!
6. Getting Ruby 2.1
7. RVM! $ rvm get head! $ rvm install ruby-2.1.0! $ rvm use ruby-2.1.0!
8. RBENV! $ rbenv install 2.1.0! $ rbenv rehash! $ rbenv global 2.1.0!
9. what's new?
10. What's New?! 1.  Rational Number & Complex ! Number Literals ! 2.  def‘s return value! 3.  Refinements! 4.  Required Keyword Arguments! 5.  Garbage Collector! 6.  Object Allocation Tracing!
11. Complex/ Rational Literals
12. Complex Literals! > Complex(2, 3)! => (2+3i)! < Ruby 2.1
13. Complex Literals! > (2 + 3i)! => (2+3i)! > (2 + 3i) + Complex(5, 4i)! => (3+3i)! > Complex(2, 3)! => (2+3i)! < Ruby 2.1 Ruby 2.1
14. Rational Literals! > 2/3.0 + 5/4.0! => 1.91666666666665! < Ruby 2.1
15. Rational Literals! > 2/3r + 5/4r! => (23/12)! > 2/3.0 + 5/4.0! => 1.91666666666665! < Ruby 2.1 Ruby 2.1
16. def's return value
17. def's return value! > def foo; end! => nil! < Ruby 2.1
18. def's return value! > def foo; end! => :foo! > def foo; end! => nil! < Ruby 2.1 Ruby 2.1
19. def's return value! module Foo! def public_method! end! ! private # <- this sucks! def a_private_method! end! end!
21. def's return value! module Foo! def public_method! end! ! private def some_other_method! end! ! private def a_private_method! end! end! ! Foo.private_instance_methods! => [:some_other_method, :a_private_method]!
22. def's return value! module Foo! def public_method! end! ! private def some_other_method! end! ! private def a_private_method! end! end! ! Foo.private_instance_methods! => [:some_other_method, :a_private_method]!
23. Refinements
24. Refinements are no longer experimental.!
25. Refinements! class String! def count! Float::INFINITY! end! end!
26. Refinements let's us scope our modifications!
27. Defining a Refinement! module Permalinker! refine String do! def permalinkify! downcase.split.join("-")! end! end! end! !
28. Using a Refinement! module Permalinker! refine String do! def permalinkify! downcase.split.join("-")! end! end! end! ! class Post! ->using Permalinker! ! def initialize(title)! @title = title! end! ! def permalink! @title.permalinkify! end! end!
29. Using a Refinement! module Permalinker! refine String do! def permalinkify! downcase.split.join("-")! end! end! end! ! class Post! using Permalinker! ! def initialize(title)! @title = title! end! ! def permalink! ->@title.permalinkify! end! end!
30. Required Keyword ArGS
31. Required Keyword Args! def permalinkfiy(str, delimiter: "-")! str.downcase.split.join(delimiter)! end! < Ruby 2.1 Question: How do we make str required?!
32. Required Keyword Args! def permalinkfiy(str:, delimiter: "-")! str.downcase.split.join(delimiter)! end! Ruby 2.1
33. Required Keyword Args! > permalinkify(delimiter: "-lol-")! ArgumentError: missing keyword: str! from (irb):49! from /usr/local/var/rbenv/ versions/2.1.0/bin/irb:11:in `<main>'!
34. RGengc Restricted Generational Garbage Collector!
35. Ruby 1.8: Simple M&S! Credits: http://tmm1.net/ruby21-rgengc/!
36. Ruby 1.9.3: Lazy Sweep! Credits: http://tmm1.net/ruby21-rgengc/!
37. Ruby 2.0: Bitmap for COW-Safety! Credits: http://tmm1.net/ruby21-rgengc/!
38. Ruby 2.1: RGenGC! Credits: http://tmm1.net/ruby21-rgengc/!
39. Generational GC! Key Idea:! ! Objects that are most recently created often die young.!
40. Generational GC! •  split objects into young and old based on whether they survive a garbage collection run.! •  concentrate on freeing up memory on the young generation.!
41. Why "Restricted"?! •  still using Mark and Sweep to garbage collect young/ old generations! •  preserve compatibility with C extensions!
43. Ojbect Allocation Tracing
44. require 'objspace'! ! class Post! def initialize(title)! @title = title! end! ! def tags! %w(ruby programming code).map do |tag|! tag.upcase! end! end! end!
45. ObjectSpace.trace_object_allocations_start! a = Post.new("title")! b = a.tags! ObjectSpace.trace_object_allocations_stop! ! ! ObjectSpace.allocation_sourcefile(b) # post.rb! ObjectSpace.allocation_sourceline(b) # ObjectSpace.allocation_class_path(b) # Array! ObjectSpace.allocation_method_id(b) # map! Object Allocation Tracing!
46. Ojbect Allocation Tracing gives only raw data.!
47. gem install allocation_stats! https://github.com/srawlins/ allocation_stats!
48. require 'allocation_stats'! ! class Post! def initialize(title)! @title = title! end! ! def tags! %w(ruby programming code).map do |tag|! tag.upcase! end! end! end! ! stats = AllocationStats.trace do! post = Post.new("title")! post.tags! end! ! puts stats.allocations(alias_paths: true).to_text!
49. sourcefile sourceline class_path method_id memsize class! ---------- ---------- ---------- --------- ------- ------! post.rb 10 String upcase 0 String! post.rb 10 String upcase 0 String! post.rb 10 String upcase 0 String! post.rb 9 Array map 0 Array! post.rb 9 Post tags 0 Array! post.rb 9 Post tags 0 String! post.rb 9 Post tags 0 String! post.rb 9 Post tags 0 String! post.rb 17 Class new 0 Post! post.rb 17 0 String! Object Allocation Tracing!
51. gem install allocation_stats! https://github.com/srawlins/ allocation_stats!
52. What's New?! 1.  Rational Number & Complex ! Number Literals ! 2.  def‘s return value! 3.  Refinements! 4.  Required Keyword Arguments! 5.  Garbage Collector! 6.  Object Allocation Tracing!
53. USE Ruby 2.1!
54. FOllow me on twitter! @bentanweihao!
55. http://www.exotpbook.com/! Learn to build your own concurrent, distributed web application – The fun & easy way!
56. Thanks! <3
 @bentanweihao
 benjamintanweihao.github.io!