Functional Programming for Fun and Profit!!

Presented at RubyConf Mini 2022

Transcript

1. @jenny-codes
   Functional programming for fun
   and profit!!
   

   View Slide

2. @jenny_codes https://github.com/readme/featured/functional-programming
   

   View Slide

3. @jenny_codes Source: https://youtu.be/ADqLBc1vFwI
   

   View Slide

4. @jenny_codes Source: https://giphy.com/gifs/emoji-idk-thinking-3o7buirYcmV5nSwIRW
   What is functional programming?
   

   View Slide

5. @jenny_codes Source: https://giphy.com/gifs/emoji-idk-thinking-3o7buirYcmV5nSwIRW
   What is functional programming?
   Should I care about it
   if I just want to write Ruby code?
   

   View Slide

6. Functional programming helps
   us write better Ruby code
   

   View Slide

7. @jenny_codes
   Jenny Shih / 施靜樺
   

   View Slide

8. @jenny_codes
   Jenny Shih / 施靜樺
   🇹🇼 Taiwan -> 🇨🇦 Canada
   
   
   💎 💧
   
   
   https://codecharms.me
   

   View Slide

9. Programming paradigms
   A way to classify programming languages
   based on their features
   

   View Slide

10. @jenny_codes
    Programming paradigms
    • Object Oriented Programming (OO)
    
    
    • Functional Programming (FP)
    

    View Slide

11. Mental model
    

    View Slide

12. @jenny_codes
    Value
    Time Behavior
    A program
    

    View Slide

13. @jenny_codes
    

    View Slide

14. @jenny_codes
    Value
    Behavior
    

    View Slide

15. @jenny_codes
    

    View Slide

16. @jenny_codes
    Time
    

    View Slide

17. @jenny_codes
    Value
    Time Behavior
    A program
    State
    

    View Slide

18. @jenny_codes
    Object
    An OO program
    Value Behavior
    Time Time
    

    View Slide

19. @jenny_codes
    An OO program
    Object
    Value Behavior
    Object
    Value Behavior
    Object
    Value Behavior
    Time
    Time
    Time
    Time Time
    Time
    

    View Slide

20. @jenny_codes
    A FP program
    Value Time
    Behavior
    

    View Slide

21. @jenny_codes
    A FP program
    Value Time
    Behavior
    

    View Slide

22. Immutability
    

    View Slide

23. Immutability
    Don’t change a value once you initialize it.
    

    View Slide

24. @jenny_codes
    Immutability
    

    View Slide

25. @jenny_codes
    Immutability
    

    View Slide

26. @jenny_codes
    Immutability
    

    View Slide

27. @jenny_codes
    Immutability
    

    View Slide

28. @jenny_codes Source: https://giphy.com/gifs/emoji-idk-thinking-3o7buirYcmV5nSwIRW
    Why?
    

    View Slide

29. @jenny_codes
    Immutability: Why??
    • Peace of mind
    

    View Slide

30. @jenny_codes
    Immutability: Why??
    

    View Slide

31. @jenny_codes
    Immutability: Why??
    • Peace of mind
    

    View Slide

32. @jenny_codes
    Immutability: Why??
    • Peace of mind
    
    
    • Eliminate shared state
    

    View Slide

33. @jenny_codes
    Immutability: Why??
    • Peace of mind
    
    
    • Eliminate shared state
    

    View Slide

34. @jenny_codes
    Immutability: How???
    

    View Slide

35. @jenny_codes
    Immutability: How???
    • Provide a good reason for every value mutation.
    

    View Slide

36. @jenny_codes
    Immutability: How???
    • Provide a good reason for every value mutation.
    
    
    • Use tools
    

    View Slide

37. @jenny_codes
    

    View Slide

38. @jenny_codes
    https://dry-rb.org/
    

    View Slide

39. @jenny_codes
    Immutability: How???
    • Provide a good reason for every value mutation.
    
    
    • Use tools
    
    
    • `dry-struct`: https://dry-rb.org/gems/dry-struct/main/
    

    View Slide

40. @jenny_codes
    Immutability: How???
    • Provide a good reason for every value mutation.
    
    
    • Use tools
    
    
    • `dry-struct`: https://dry-rb.org/gems/dry-struct/main/
    
    
    • `Data.de
    fi
    ne` in Ruby
    

    View Slide

41. @jenny_codes
    

    View Slide

42. @jenny_codes
    

    View Slide

43. @jenny_codes https://dev.to/baweaver/new-in-ruby-32-datade
    fi
    ne-2819
    

    View Slide

44. @jenny_codes
    Immutability: How???
    • Provide a good reason for every value mutation.
    
    
    • Use tools
    
    
    • `dry-struct`: https://dry-rb.org/gems/dry-struct/main/
    
    
    • `Data.de
    fi
    ne` in Ruby
    

    View Slide

45. @jenny_codes
    A FP program
    Value Time
    Behavior
    

    View Slide

46. @jenny_codes
    A FP program
    Value Time
    Behavior
    Immutable data
    

    View Slide

47. @jenny_codes
    A FP program
    Value Time
    Behavior
    Immutable data
    

    View Slide

48. Pure functions
    

    View Slide

49. @jenny_codes
    1. Only depends on its input argument
    
    
    2. Does not mutate states
    (no side effects)
    A pure function
    

    View Slide

50. @jenny_codes
    1. Only depends on its input argument
    
    
    2. Does not mutate states
    (no side effects)
    A pure function
    

    View Slide

51. @jenny_codes
    1. Only depends on its input argument
    
    
    2. Does not mutate states
    (no side effects)
    A pure function
    

    View Slide

52. @jenny_codes
    1. Only depends on its input argument
    
    
    2. Does not mutate states
    (no side effects)
    A pure function
    

    View Slide

53. @jenny_codes
    1. Only depends on its input argument
    
    
    2. Does not mutate states
    (no side effects)
    A pure function
    

    View Slide

54. @jenny_codes
    1. Only depends on its input argument
    
    
    2. Does not mutate states
    (no side effects)
    A pure function
    

    View Slide

55. @jenny_codes
    1. Only depends on its input argument
    
    
    2. Does not mutate states
    (no side effects)
    A pure function
    

    View Slide

56. @jenny_codes
    1. Only depends on its input argument
    
    
    2. Does not mutate states
    (no side effects)
    A pure function
    

    View Slide

57. @jenny_codes
    1. Only depends on its input argument
    
    
    2. Does not mutate states
    (no side effects)
    A pure function
    

    View Slide

58. @jenny_codes
    Source: https://giphy.com/gifs/emoji-idk-thinking-3o7buirYcmV5nSwIRW
    Why?
    

    View Slide

59. @jenny_codes
    “The problem with OO languages is they’ve got all this
    implicit environment that they carry around with them.
    You wanted a banana but what you got was a gorilla
    holding the banana and the entire jungle.”
    
    
    – Joe Armstrong, Creator of Erlang
    Pure functions: Why??
    

    View Slide

60. @jenny_codes
    “The problem with OO languages is they’ve got all this
    implicit environment that they carry around with them.
    You wanted a banana but what you got was a gorilla
    holding the banana and the entire jungle.”
    
    
    – Joe Armstrong, Creator of Erlang
    Pure functions: Why??
    

    View Slide

61. @jenny_codes
    Pure functions: Why??
    No implicit environment!!
    Source: https://thenounproject.com/icon/forest-5299391/
    Source: https://thenounproject.com/icon/monkey-298282/
    

    View Slide

62. @jenny_codes
    Pure functions: Why??
    No implicit environment!!
    Source: https://thenounproject.com/icon/forest-5299391/
    Source: https://thenounproject.com/icon/monkey-298282/
    

    View Slide

63. @jenny_codes
    Pure functions: Why??
    No implicit environment!!
    🤯
    

    View Slide

64. @jenny_codes
    Pure functions: Why??
    No implicit environment!!
    

    View Slide

65. @jenny_codes
    Pure functions: Why??
    No implicit environment!!
    🤘
    

    View Slide

66. @jenny_codes
    Pure functions: Why??
    No implicit environment!!
    🤘🐛
    🔪
    

    View Slide

67. @jenny_codes
    Pure functions: Why??
    No implicit environment!!
    🤘🐛
    🔪
    🧪
    

    View Slide

68. @jenny_codes
    Pure functions: Why??
    No implicit environment!!
    🤘🐛
    🔪
    🧪 ✅
    

    View Slide

69. @jenny_codes
    Pure functions: Why??
    No implicit environment!!
    🤘🐛
    🔪
    🧪 ✅ ✌
    

    View Slide

70. @jenny_codes
    Pure functions: Why??
    No implicit environment!!
    🤘🐛
    🔪
    🧪 ✅ ✌
    Source: https://www.ktiv.com/2022/10/07/nobel-peace-prize-awarded-human-rights-advocates/
    

    View Slide

71. @jenny_codes
    Pure functions: How???
    

    View Slide

72. @jenny_codes
    Pure functions: How???
    • Parameterization/Dependency Injections
    

    View Slide

73. @jenny_codes
    Pure functions: Parameterization
    

    View Slide

74. @jenny_codes
    Pure functions: Parameterization
    

    View Slide

75. @jenny_codes
    Pure functions: Parameterization
    

    View Slide

76. @jenny_codes
    Pure functions: Parameterization
    

    View Slide

77. @jenny_codes
    Pure functions: Parameterization
    

    View Slide

78. @jenny_codes
    Pure functions: Parameterization
    

    View Slide

79. @jenny_codes
    Pure functions: Parameterization
    

    View Slide

80. @jenny_codes
    Pure functions: Parameterization
    

    View Slide

81. @jenny_codes
    Pure functions: Parameterization
    

    View Slide

82. @jenny_codes
    Pure functions: Parameterization
    

    View Slide

83. @jenny_codes
    Pure functions: How???
    • Parameterization/Dependency Injections
    
    
    • Transformation instead of mutation
    

    View Slide

84. @jenny_codes
    Pure functions: Transformation over Mutation
    

    View Slide

85. @jenny_codes
    Pure functions: Transformation over Mutation
    

    View Slide

86. @jenny_codes
    Pure functions: Transformation over Mutation
    

    View Slide

87. @jenny_codes
    1. Only depends on its input argument
    
    
    2. Does not mutate states
    (no side effects)
    A pure function
    

    View Slide

88. @jenny_codes
    A pure function
    1. Only depends on its input argument ✅
    
    
    2. Does not mutate states
    (no side effects)
    

    View Slide

89. @jenny_codes
    A pure function
    1. Only depends on its input argument ✅
    
    
    2. Does not mutate states ✅
    (no side effects)
    

    View Slide

90. @jenny_codes
    A FP program
    Value Time
    Behavior
    Immutable data
    

    View Slide

91. @jenny_codes
    A FP program
    Value Time
    Behavior
    Immutable data Pure functions
    

    View Slide

92. @jenny_codes
    A FP program
    Value Time
    Behavior
    Immutable data Pure functions
    

    View Slide

93. Concurrency
    

    View Slide

94. @jenny_codes
    An OO program
    Object
    Value Behavior
    Object
    Value Behavior
    Object
    Value Behavior
    Time
    Time
    Time
    Time Time
    Time
    

    View Slide

95. @jenny_codes
    An OO program
    Object
    Value Behavior
    Object
    Value Behavior
    Object
    Value Behavior
    Time
    Time
    Time
    Time Time
    Time
    Global Interpreter Lock
    🔐
    

    View Slide

96. @jenny_codes
    A FP program
    Value Time
    Behavior
    Immutable data Pure functions Concurrency 💯
    

    View Slide

97. @jenny_codes
    Elixir’s concurrency model: Actors
    Actor /
    Process
    Actor /
    Process
    Actor /
    Process
    

    View Slide

98. @jenny_codes
    Elixir’s concurrency model: Actors
    Thread Thread Thread
    

    View Slide

99. @jenny_codes
    “It’s multi-core age today. Concurrency is very important. With
    Ractor, along with Async Fiber, Ruby will be a real concurrent
    language.”
    
    
    — Matz
    
    
    Ruby’s concurrency abstraction: Ractor
    https://www.ruby-lang.org/en/news/2020/12/25/ruby-3-0-0-released/
    

    View Slide

100. @jenny_codes
     Ractor
     Ractor
     Ractor
     ︴︴︴
     ︴︴︴
     ︴︴︴
     Ruby’s concurrency abstraction: Ractor
     ︴︴︴= threads
     

     View Slide

101. @jenny_codes
     Ractor
     Ractor
     Ractor
     🔐
     🔐
     🔐
     ︴︴︴
     ︴︴︴
     ︴︴︴
     🔐 = Global Interpreter Lock
     Ruby’s concurrency abstraction: Ractor
     ︴︴︴= threads
     

     View Slide

102. @jenny_codes
     Ractor
     Ractor
     Ractor
     🔐
     🔐
     🔐
     ︴︴︴
     ︴︴︴
     ︴︴︴
     🔐 = Global Interpretation Lock
     Ruby’s concurrency abstraction: Ractor
     ︴︴︴= threads
     ❓
     

     View Slide

103. @jenny_codes
     

     View Slide

104. @jenny_codes
     A FP program
     Value Time
     Behavior
     Immutable data Pure functions Concurrency
     

     View Slide

105. Recap
     

     View Slide

106. @jenny_codes
     We are defined not so much by what we
     can do, but what we don’t do.
     

     View Slide

107. @jenny_codes
     A FP program
     Value Time
     Behavior
     Immutable data Pure functions Concurrency
     

     View Slide

108. @jenny_codes
     A FP program
     Value Time
     Behavior
     Immutable data Pure functions Concurrency
     

     View Slide

109. @jenny_codes
     A FP program
     Value Time
     Behavior
     Immutable data Pure functions Concurrency
     

     View Slide

110. @jenny_codes
     A FP program
     Value Time
     Behavior
     Immutable data Pure functions Concurrency
     

     View Slide

111. Functional programming helps
     us write better Ruby code
     

     View Slide

112. @jenny_codes
     Resources: Functional programming mental model
     • Jose Valim’s ElixirConf 2017 Keynote by Jose Valim
     
     
     • Are we there yet by Rich Hickey
     
     
     • The language of programming by Anjana Vakil
     
     
     • Value Object by Martin Fowler
     

     View Slide

113. @jenny_codes
     Resources: Functional programming architecture
     (That I didn’t get to talk about because I’d get too excited
     
     
     and run overtime)
     • Functional Architecture for the Practical Rubyist by Tim Riley
     
     
     • Functional web with Ruby by Luca Luigi
     
     
     • Boundaries by Gary Bernhardt
     
     
     • The Hanami Ruby framework
     
     
     • (Book) Domain Modelling Made Functional by Scott Wlaschin
     

     View Slide

114. @jenny_codes
     Resources: Ruby docs
     • https://ruby-doc.org/core-3.2.0_preview2/Ractor.html
     
     
     • https://scoutapm.com/blog/ruby-ractor
     
     
     • https://dev.to/baweaver/new-in-ruby-32-datade
     fi
     ne-2819
     
     
     • https://github.com/ruby/ruby/pull/6353
     

     View Slide