Multiverse Ruby

Slides from my talk by the same name at RubyKaigi 2023, given in Japanese.

shioyama/im
shioyama/rails_on_im

Transcript

1. Multiverse Ruby
   Multiverse Ruby
   Chris Salzberg
   Chris Salzberg
   

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2. @shioyama
   

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3. Chris Salzberg
   Staff developer, Ruby and Rails Infra
   

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4. 箱
   

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5. 1.Sharing code in Ruby
   2.Modules as Universes
   3.Isolated Module Autoloader
   

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6. Sharing code in Ruby
   

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7. n = 10
   a, b = 0, 1
   n.times do
   a, b = b, a + b
   end
   puts a
   

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8. def self.fib(n)
   a, b = 0, 1
   n.times do
   a, b = b, a + b
   end
   a
   end
   

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9. module Fibonacci
   def self.fib(n)
   a, b = 0, 1
   n.times do
   a, b = b, a + b
   end
   a
   end
   end
   

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10. module Fibonacci
    def self.fib(n)
    a, b = 0, 1
    n.times do
    a, b = b, a + b
    end
    a
    end
    end
    code
    

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11. module Fibonacci
    def self.fib(n)
    a, b = 0, 1
    n.times do
    a, b = b, a + b
    end
    a
    end
    end
    architecture
    

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12. In Ruby, we share code
    by sharing architecture.
    

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13. that architecture is...
    

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14. global
    

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15. finite
    

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16. permanent
    

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17. Ruby’s architecture is not portable
    

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19. Modules as Universes
    

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20. Named Anonymous
    Modules
    

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21. module Foo
    class Bar
    end
    end
    Named
    

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22. module Foo
    class Bar
    end
    end
    mod = Module.new
    mod.name
    #=> nil
    Named Anonymous
    

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23. mod = Module.new
    

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24. mod = Module.new
    mod::Foo = Module.new
    

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25. mod = Module.new
    mod::Foo = Module.new
    mod::Foo.name
    

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26. mod = Module.new
    mod::Foo = Module.new
    mod::Foo.name
    #=> "#::Foo"
    

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27. mod = Module.new
    mod::Foo = Module.new
    mod::Foo.name
    #=> "#::Foo"
    temporary name
    

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28. // variable.c:138
    static VALUE
    make_temporary_path(VALUE obj, VALUE klass)
    {
    VALUE path;
    switch (klass) {
    case Qnil:
    path = rb_sprintf("#", (void*)obj);
    break;
    case Qfalse:
    path = rb_sprintf("#", (void*)obj);
    break;
    default:
    path = rb_sprintf("#<%"PRIsVALUE":%p>", klass, (void*)obj);
    break;
    }
    OBJ_FREEZE(path);
    return path;
    }
    

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29. mod::Foo.name
    #=> "#::Foo"
    temporary name
    

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30. mod::Foo.name
    #=> "#::Foo"
    MyFoo = mod::Foo
    temporary name
    

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31. mod::Foo.name
    #=> "#::Foo"
    MyFoo = mod::Foo
    mod::Foo.name
    #=> "MyFoo"
    permanent name
    temporary name
    

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32. Modules
    Named Anonymous
    

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33. Modules
    temporary
    

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34. temporary == portable
    

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35. module Foo
    class Bar
    end
    end
    

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36. mod = Module.new
    module mod::Foo
    class Bar
    end
    end
    

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37. mod = Module.new
    module mod::Foo
    class Bar
    end
    end
    mod::Foo::Bar.name
    #=> "#::Foo::Bar"
    

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38. Object::Foo Object::Baz
    Object::Foo::Bar
    Object::Foo::Qux
    

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39. Object
    Object::Foo Object::Baz
    Object::Foo::Bar
    Object::Foo::Qux
    Permanent Root
    

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40. mod
    

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41. mod::Foo mod::Baz
    mod::Foo::Bar
    mod::Foo::Qux
    mod
    Temporary Root
    

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42. MyFoo = mod::Foo
    MyFoo::Bar
    MyFoo::Qux
    mod
    mod::Baz
    

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43. MyGem::Foo MyGem::Baz
    MyGem::Foo::Bar
    MyGem::Foo::Qux
    MyGem = mod
    

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44. a module is the root of a universe
    

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45. Isolated Module Autoloader
    

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46. require "my_gem"
    

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47. 📦= import "my_gem"
    

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48. RUBY 3.2
    RUBY 3.2
    

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54. module Fibonacci
    end
    fibonacci.rb
    module Fibonacci
    end
    load "fibonacci.rb"
    

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55. module Fibonacci
    end
    fibonacci.rb module MyWrapper
    end
    load "fibonacci.rb", MyWrapper
    module Fibonacci
    end
    

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56. module Fibonacci
    end
    fibonacci.rb module
    📦
    end
    load "fibonacci.rb",
    📦
    module Fibonacci
    end
    

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57. import load
    ⇨ ?
    

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58. require "my_gem"
    # my_gem.rb
    require "foo"
    require "bar"
    # foo.rb
    # bar.rb
    require
    require
    require
    require
    require
    

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59. mod = import "my_gem"
    # my_gem.rb
    require "foo"
    require "bar"
    # foo.rb
    # bar.rb
    require
    require
    require
    require
    require
    load
    load
    load
    load
    load
    load
    load
    

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60. mod = import "my_gem"
    # my_gem.rb
    require "foo"
    require "bar"
    # foo.rb
    # bar.rb
    require
    require
    require
    require
    require
    load
    load
    load
    load
    load
    load
    load
    

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61. View Slide

62. autoload
    

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63. Object.autoload(:MyGem, "lib/my_gem.rb")
    

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64. Object.autoload(:MyGem, "lib/my_gem.rb")
    mod
    

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65. im i
    isolated
    solated
    m
    module
    odule
    autoloader
    autoloader
    i
    isolated
    solated
    m
    module
    odule
    autoloader
    autoloader
    

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66. Im is a Zeitwerk fork
    

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67. lib/my_gem.rb → MyGem
    lib/my_gem/foo.rb → MyGem::Foo
    lib/my_gem/bar_baz.rb → MyGem::BarBaz
    lib/my_gem/woo/zoo.rb → MyGem::Woo::Zoo
    Zeitwerk: Code Loader
    

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68. Zeitwerk: Code Loader
    lib/my_gem.rb → MyGem
    lib/my_gem/foo.rb → MyGem::Foo
    lib/my_gem/bar_baz.rb → MyGem::BarBaz
    lib/my_gem/woo/zoo.rb → MyGem::Woo::Zoo
    Object::
    Object::
    Object::
    Object::
    

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69. lib/my_gem.rb → MyGem
    lib/my_gem/foo.rb → MyGem::Foo
    lib/my_gem/bar_baz.rb → MyGem::BarBaz
    lib/my_gem/woo/zoo.rb → MyGem::Woo::Zoo
    Im: Isolated Code Loader
    mod::
    mod::
    mod::
    mod::
    temporary root
    

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70. mod = import "my_gem"
    

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71. mod = import "my_gem"
    mod::MyGem::Foo
    #=> loads "lib/my_gem/foo.rb"
    

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72. mod = import "my_gem"
    mod::MyGem::Foo
    #=> loads "lib/my_gem/foo.rb"
    mod::MyGem::Foo::BarBaz
    #=> loads "lib/my_gem/foo/bar_baz.rb"
    

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73. mod = import "my_gem"
    mod::MyGem::Foo
    #=> loads "lib/my_gem/foo.rb"
    mod::MyGem::Foo::BarBaz
    #=> loads "lib/my_gem/foo/bar_baz.rb"
    mod::MyGem::Foo::Woo::Zoo
    #=> loads "lib/my_gem/foo/woo/zoo.rb"
    

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74. Im is compatible with Zeitwerk
    

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75. 実装
    

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76. # lib/zeitwerk/loader/config.rb
    unless real_mod_name(namespace)
    raise Zeitwerk::Error,
    "root namespaces cannot be anonymous"
    end
    

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77. # lib/zeitwerk/loader/config.rb
    unless real_mod_name(namespace)
    raise Zeitwerk::Error,
    "root namespaces cannot be anonymous"
    end
    

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78. # lib/zeitwerk/loader.rb
    module Zeitwerk
    class Loader
    

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79. # lib/im/loader.rb
    module Im
    class Loader < Module
    root of the universe
    

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80. loader::Foo loader::Baz
    loader::Foo::Bar
    loader::Foo::Qux
    loader
    

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81. # lib/my_gem.rb (main file)
    require "zeitwerk"
    loader = Zeitwerk::Loader.for_gem
    loader.setup # ready!
    module MyGem
    # ...
    end
    loader.eager_load # optionally
    

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82. # lib/my_gem.rb (main file)
    require "im"
    loader = Im::Loader.for_gem
    loader.setup # ready!
    module loader::MyGem
    # ...
    end
    loader.eager_load # optionally
    define under loader,
    not at top-level!
    

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83. def require(path)
    filetype, feature_path =
    $:.resolve_feature_path(path)
    if (loader = Im::Registry.loader_for(path))
    # ...
    $LOADED_FEATURES << feature_path
    begin
    load path, loader
    rescue => e
    $LOADED_FEATURES.delete(feature_path)
    raise e
    end
    

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84. def require(path)
    filetype, feature_path =
    $:.resolve_feature_path(path)
    if (loader = Im::Registry.loader_for(path))
    # ...
    $LOADED_FEATURES << feature_path
    begin
    load path, loader
    rescue => e
    $LOADED_FEATURES.delete(feature_path)
    raise e
    end
    

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85. def require(path)
    filetype, feature_path =
    $:.resolve_feature_path(path)
    if (loader = Im::Registry.loader_for(path))
    # ...
    $LOADED_FEATURES << feature_path
    begin
    load path, loader
    rescue => e
    $LOADED_FEATURES.delete(feature_path)
    raise e
    end
    

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86. def require(path)
    filetype, feature_path =
    $:.resolve_feature_path(path)
    if (loader = Im::Registry.loader_for(path))
    # ...
    $LOADED_FEATURES << feature_path
    begin
    load path, loader
    rescue => e
    $LOADED_FEATURES.delete(feature_path)
    raise e
    end
    🙈
    

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87. - assert A::X
    - assert B::X
    + assert loader::A::X
    + assert loader::B::X
    

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88. ...........................................................
    ...........................................................
    ...........................................................
    ...........................................................
    ...........................................................
    ...........................................................
    ....................................
    Finished tests in 2.968770s, 131.3675 tests/s, 319.6610
    assertions/s.
    390 tests, 949 assertions, 0 failures, 0 errors, 0 skips
    🎉
    

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89. The cpath problem
    

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90. def cpath(parent, cname)
    "#{parent.name}::#{cname}"
    end
    

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91. def cpath(parent, cname)
    "#{parent.name}::#{cname}"
    end
    Foo :Bar
    

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92. def cpath(parent, cname)
    "#{parent.name}::#{cname}"
    end
    Foo :Bar
    #=> "Foo::Bar" cpath
    

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93. {
    "Foo" ⇨ <#Zeitwerk::Loader>,
    "Foo::Bar" ⇨ <#Zeitwerk::Loader>,
    # ...
    }
    cpath
    Zeitwerk
    

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94. {
    "<#Im::Loader>::Foo" ⇨ ...
    "<#Im::Loader>::Foo::Bar" ⇨ ...
    # ...
    }
    cpath
    Im
    

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95. MyFoo = mod::Foo
    

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96. temporary permanent
    "#<...>::Foo" "MyFoo"
    MyFoo = mod::Foo
    

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97. {
    "<#Im::Loader>::Foo" ⇨ ...
    "<#Im::Loader>::Foo::Bar" ⇨ ...
    # ...
    }
    cpaths["MyFoo"] #=> nil
    

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98. assert loader::A
    X = loader::A
    assert loader::A
    assert loader::A::B
    assert loader::A::B::C
    assert_equal(X::B::C, loader::A::B::C)
    FAIL
    ❌
    

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99. RUBY
    RUBY
    3.2
    3.2
    

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101. Foo::BAR = 42
     Foo.const_added(:BAR)
     callback
     

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102. MyFoo = mod::Foo
     Object.const_added(:MyFoo)
     callback
     

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103. module Im::ModuleConstAdded
     def const_added(const_name)
     # ...
     ::Im::ExplicitNamespace.__update_cpaths(
     prefix, "#{cpath}::#{const_name}"
     )
     super
     end
     end
     ::Module.prepend(Im::ModuleConstAdded)
     

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104. module Im::ModuleConstAdded
     def const_added(const_name)
     # ...
     ::Im::ExplicitNamespace.__update_cpaths(
     prefix, "#{cpath}::#{const_name}"
     )
     super
     end
     end
     ::Module.prepend(Im::ModuleConstAdded)
     

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105. {
     "<#Im::Loader ...>" ⇨ ...
     "<#Im::Loader ...>::Foo" ⇨ ...
     "<#Im::Loader ...>::Foo::Bar" ⇨ ...
     ...
     }
     cpath
     

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106. {
     "<#Im::Loader ...>" ⇨ ...
     "MyFoo" ⇨ ...
     "MyFoo::Bar" ⇨ ...
     ...
     }
     cpath
     Object.const_added(:MyFoo)
     

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107. assert loader::A
     X = loader::A
     assert loader::A
     assert loader::A::B
     assert loader::A::B::C
     assert_equal(X::B::C, loader::A::B::C)
     PASS
     ✅
     

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108. gem "im", "~> 0.2.2"
     

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113. Chris Salzberg
     @shioyama github:shioyama/im
     github:shioyama/rails_on_im
     

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