Ruby 2.7 - Beyond the CHANGELOG

Let's go beyond the CHANGELOG and answer the important questions. In this talk I will give you some insights what ruby 2.7 is about, what kinds of problems you are going to find ahead and answer the ultimate question: Is it worth upgrading?

2. @brodock Gabriel Mazetto 2 ɡ a b ɾ i ˈ ɛ w m a z ˈ ɛ t t u
12. https://ruby-lang.org
14. 14 Highlights
15. 15 [experimental]
16. irb(main):001:0> [1,2,3] in [a,b,c] irb(main):002:0> c => 3 16
17. irb(main):001:0> [1,2,3] in [a,b,c] (irb):1: warning: Pattern matching is experimental, and the behavior may change in future versions of Ruby! => nil irb(main):002:0> c => 3 17
20. GC.compact 20
22. def something(args = {}) # ... end args = {a: 1, b: 2} something(args) 22
23. def something(a:, b:) # ... end args = {a: 1, b: 2} something(args) 23
24. def something(a:, b:) # ... end args = {a: 1, b: 2} something(args) warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call warning: The called method `something' is defined here 24
25. def something(a:, b:) # ... end args = {a: 1, b: 2} something( **args) 25
26. What is the ** syntax? 26
27. def something( **args) # args => {a: 1, b: 2} end something(a: 1, b: 2) 27
28. def something(a:, b:) # a = 1 # b = 2 end args = {a: 1, b: 2} something( **args) 28
29. def something(*args) # args = [1, 2, 3] end something(1,2,3) 29
30. def something(a, b, c) # a = 1 # b = 2 # c = 3 end args = [1,2,3] something(*args) 30
31. def something(*args, **kwargs) # args = [1] # kwargs = {b: 2} end something(1, b: 2) 31
32. def something(a, b:) end args = [1] kwargs = {b:2} something(*args, **kwargs) 32
36. 36 Lowlights
38. 38 # Ruby <= 2.6 10.times { |value| puts value } # Ruby 2.7 10.times { puts _1 }
40. # Ruby 2.7 el = %W(a b c d e f a b a b c d a b) el.tally # => {"a" =>4, "b" =>4, "c" =>2, "d" =>2, "e" =>1, "f" =>1} 40
41. # Ruby <= 2.6 V1 el.group_by { |v| v }.transform_values(&:size) 41
42. # Ruby <= 2.6 V2 el.group_by { |v| v }.map { |k, v| [k, v.size] }.to_h 42
43. # Ruby <= 2.6 V3 el.group_by { |v| v }.to_h { |k, v| [k, v.size] } 43
44. # Ruby <= 2.6 V4 el.each_with_object(Hash.new(0)) { |v, h| h[v] += 1 } 44
46. [1,2,3,4].intersection [2,3] # => [2, 3] 46
48. enum = 1.upto(1_000) enum.filter_map { |i| i + 1 if i.even? } # => [3, 5, 7, 9, 11, 13, ...] 48
50. CGI.escapeHTML(html) EscapeUtils.escape_html(html) 50
51. Haml ::Helpers.html_escape(html) ERB ::Util.html_escape(html) String.gsub(/[&"'><]/, html_escape) Rack ::Utils.escape_html(html) 51
52. 52 One interesting story...
54. New Japanese Era 54 Heisei Reiwa
55. Unicode 12.1: 令和 U+32FF ㋿ (SQUARE ERA NAME REIWA) 55
56. "\u4EE4\u548C" == "\u32FF".unicode_normalize(:nfkc) 56 令和 ㋿ 令和
57. Unicode 12.1: New Emojis 57 ⚕⚕⚖ ✈
58. 58 The remaining question: Is Ruby 2.7 worth upgrading?