Why doesn't Ruby have Boolean class?

https://burikaigi.dev/speakers/004/
This is BuriKaigi, so I talked about "Boolean (Bu-rian)" :)

Transcript

1. ͳͥRubyʹ͸BooleanΫϥε ͕ͳ͍ͷ͔ BuriKaigi 2024 OKURA Masafumi, 2024-01-20
2. BuriKaigi
3. 3ճ໨ͷొஃ 2020, 2022, 2024
4. ࠓճͷ ݸਓత ϨΪϡϨʔγϣϯ
5. Ჳʹؔ܎ͷ͋Δ τʔΫ
6. Ჳ
8. ϒϦ
9. ϒʔϦ
10. ϒʔϦΞϯ
11. Boolean!
12. Rubyʹ͸ BooleanΫϥε͕ ͳ͍ʂ
13. ϒʔϦΞϯɿͳͥRubyʹ͸ BooleanΫϥε͕ͳ͍ͷ͔ BuriKaigi 2024 OKURA Masafumi, 2024-01-20
14. ࣗݾ঺հ
15. ࣗݾ঺հ • ໊લɿେ૔խ࢙ • ॴଐɿϑϦʔϥϯε • ՝֎׆ಈɿKaigi on RailsνʔϑΦʔΨφΠβʔɺOSS։ൃɺ֤छొஃ ʢEuruko, RubyConfTw, VimConf, σϒαϛ2024ʣ • ޷͖ͳݴޠͳͲɿRubyɺRailsɺNeovim • ෋ࢁྺɿ2ճ໨
16. ʲະঝ୚޿ࠂཝʳ ʲ͓࢓ࣄืूʳ ʲৄࡉ͸࠙਌ձʳ
17. ͓඼ॻ͖
18. ࠓ೔ͷ͓࿩ 1. Fact: Rubyʹ͓͚ΔBooleanͷѻ͍ʹ͍ͭͯ 2. Opinion: RubyʹBooleanΫϥε͕ͳͯ͘΋Α͍ཧ༝ʹ͍ͭͯ
19. ͋Εɺܕͷ࿩͸ʁ
20. 20෼ʹऩ·Βͳ ͔ͬͨͷͰׂѪ
21. ࠓճͷτʔΫͷ ࣋ͪؼΓ ʢTakeawayʣ
22. ࠓճͷτʔΫͰ࣋ͪؼͬͯ΄͍͜͠ͱ • Ruby͕ਅِ஋ؚΉΦϒδΣΫτʹରͯ͠औ͍ͬͯΔΞϓϩʔν • ʮϓϦϛςΟϒʯ͕ଘࡏ͠ͳ͍ͱ͍͏͜ͱ • ϓϩάϥϛϯάݴޠʹ͓͚ΔҙࢥܾఆͷҰྫ • BooleanΛ௥Ճ͠ͳ͍ͱ͍͏ܾఆ • ʮσβΠϯࢥߟʯ
23. 1. Rubyʹ͓͚Δ Booleanͷѻ͍
24. Seeing Is Believing
25. Rubyʹ͓͚ΔBooleanͷѻ͍ • TrueClassͱFalseClass͕ͦΕͧΕtrueͱfalseͷΫϥε • ͜ΕΒΫϥε͸newϝιουΛݺ΂ͳ͍ʢγϯάϧτϯʣ • TrueClassͱFalseClassʹ͸ڞ௨ͷ਌ΫϥεͳͲ͸ͳ͍ • to_boolͷΑ͏ͳϝιου͸ଘࡏ͠ͳ͍ʢ!!Ͱ୅༻Մೳʣ • Ifจʹ͸ͲͷΑ͏ͳΦϒδΣΫτͰ΋࢖͑ΔʢfalseͱnilҎ֎શͯtrueʣ
26. ଞͷݴޠͰ͸ɺ true/false͸ଈ஋ ͔΋͠Εͳ͍
27. Ұํɺ Rubyʹ͸ ଈ஋͕ͳ͍
28. શͯ͸ ΦϒδΣΫτ
29. શͯͷ ΦϒδΣΫτʹ Ϋϥε͕͋Δ
30. ଐ͍ͯ͠Δ Πϯελϯε͕ 1͔ͭ͠ͳ͍Ϋϥε
31. TrueClass FalseClass NilClass
32. ศ্ٓଘࡏͯ͠ ͍Δͱ΋ݴ͑Δ
33. ·ͣॻ͔ͳ͍
34. v.is_a?(TrueClass)
35. v == true
36. 2. Rubyʹ BooleanΫϥε͕ ͳͯ͘΋Α͍ཧ༝
37. https://bugs.ruby- lang.org/issues/ 12515
38. Create "Boolean" superclass of TrueClass / FalseClass
39. ɹɹɹɹɹɹɹ٫Լ Status: Rejected
40. Rejected for several reasons: many gems and libraries had already introduced Boolean class. I don't want to break them. true and false are the only representative of true-false values. In Ruby. nil and false are falsy values, and everything else is a true value. There's no meaning for having a superclass of TrueClass and FalseClass as Boolean. Matz. ʢԼઢ͸Ҿ༻ऀʣ
41. Rubyʹ͓͍ͯ͸ trueͱfalse͸ ਅِ஋ͷ୅ද
42. ਅͷ୅දɿtrue ِͷ୅දɿfalse
43. ͦΕҎ֎ͷɺ ਅͷྫɿ42, [], … ِͷྫɿnil
44. trueͱfalse͸ 1Ϗοτͷ৘ใྔ
45. trueͱfalse͸ Կ΋ڞ༗ ͍ͯ͠ͳ͍
46. trueͱfalse͕ ಉ͡Ϋϥεʹ ଐ͢Δͱ͸ʁ
47. Ϋϥεͱ͸ʁ
48. ڞ௨͢Δ΋ͷ͕ ·ͱ·͍ͬͯΔ
49. ଐ͍ͯ͠Δ Πϯελϯε͕ ଐੑΛڞ༗͠ͳ͍ʁ
50. BooleanΫϥεʹ ϝιου͕ଘࡏ ͠ͳ͍ʁ
51. Rejected for several reasons: many gems and libraries had already introduced Boolean class. I don't want to break them. true and false are the only representative of true-false values. In Ruby. nil and false are falsy values, and everything else is a true value. There's no meaning for having a superclass of TrueClass and FalseClass as Boolean. Matz. ʢԼઢ͸Ҿ༻ऀʣ
52. ڞ௨ͷ਌Ϋϥε ʹ͸ҙຯ͕ͳ͍
53. Ͱ΋Boolean͕ ͋ͬͨ΄͏͕ ศརͳͷͰ͸ʁ
54. https://bugs.ruby- lang.org/issues/ 12515
55. Ϣʔεέʔε
56. v.is_a?(Boolean)
57. ಉ͡ػೳɿ v == true || v == false
58. ΄΅͜Ε͚ͩ
59. Rejected for several reasons: many gems and libraries had already introduced Boolean class. I don't want to break them. true and false are the only representative of true-false values. In Ruby. nil and false are falsy values, and everything else is a true value. There's no meaning for having a superclass of TrueClass and FalseClass as Boolean. Matz. ʢԼઢ͸Ҿ༻ऀʣ
60. Θ͟Θ͟ޓ׵ੑΛ ؾʹͯ͠·Ͱ௥Ճ ͠ͳͯ͘Α͍
61. RubyʹBoolean Ϋϥε͕ͳͯ͘΋ Α͍ཧ༝·ͱΊ
62. RubyʹBooleanΫϥε͕ͳͯ͘΋Α͍ཧ༝ • trueͱfalse͕ڞ༗͢Δ΋ͷ͕Կ΋ͳ͍ • ڞ௨ͷ਌ΫϥεΛ࣋ͭ͜ͱʹҙຯ͕ͳ͍ • Ϣʔεέʔε͕গͳ͍ • ͦ͏·Ͱͯ͠࡞Δ΄ͲͰ͸ͳ͍ • ྺ࢙తཧ༝΋͋Γͦ͏ • طଘͷBooleanΫϥεΛഁյͯ͠͠·͏
63. ࠓճͷൃදͰ ࢲֶ͕Μͩ͜ͱ
64. ࠓճͷֶͼ • ҰͭͷissueΛਂ۷Δͱ৭ʑͳҙݟ͕ަΘ͞Ε͍ͯͯ໘ന͍ • ʮࣗવʯʮศརʯ͸ܾఆతͳཧ༝ʹͳΒͳ͍ͱ͖͕͋Δ • ࣮͸ଞͷݴޠʹ͸͍͍ͩͨBoolean͕͋Δ • ϓϩάϥϛϯάݴޠͷઃܭͰࣗ໌ͳ͜ͱ͸গͳ͍ʢͱࢥͬͨʣ
65. Thank you!