多相型、推論、Ruby

大江戸Ruby会議06 https://asakusarb.github.io/oedo06/

Transcript

1. ଟ૬ܕɺ
   ਪ࿦ɺ
   Ruby দຊफଠ࿠

   @soutaro
   

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4. ܕ͸ॻ͖ͨ͘ͳ͍
   

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5. ܕ͸ॻ͖ͨ͘ͳ͍
   Duck Typingʹͳ͍ͬͯͯཉ͍͠
   

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6. ܕ͸ॻ͖ͨ͘ͳ͍
   Duck Typingʹͳ͍ͬͯͯཉ͍͠
   ܕਪ࿦
   

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7. ܕ͸ॻ͖ͨ͘ͳ͍
   Duck Typingʹͳ͍ͬͯͯཉ͍͠
   ܕਪ࿦
   typo͙Β͍͸࣮ߦ͠ͳͯ͘΋ൃݟ͍ͨ͠
   

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8. ܕ͸ॻ͖ͨ͘ͳ͍
   Duck Typingʹͳ͍ͬͯͯཉ͍͠
   ܕਪ࿦
   typo͙Β͍͸࣮ߦ͠ͳͯ͘΋ൃݟ͍ͨ͠
   ܕ͸ઈରʹॻ͖ͨ͘ͳ͍
   

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9. ܕ͸ॻ͖ͨ͘ͳ͍
   Duck Typingʹͳ͍ͬͯͯཉ͍͠
   ܕਪ࿦
   typo͙Β͍͸࣮ߦ͠ͳͯ͘΋ൃݟ͍ͨ͠
   ܕ͸ઈରʹॻ͖ͨ͘ͳ͍
   Gradual Typing
   

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10. ͳΜ͔ྑ͍ײ͡ʹܕ͕͍ͭͨ
    Ruby͕ཉ͍͠
    ܕ͸ॻ͖ͨ͘ͳ͍
    Duck Typingʹͳ͍ͬͯͯཉ͍͠
    ܕਪ࿦
    typo͙Β͍͸࣮ߦ͠ͳͯ͘΋ൃݟ͍ͨ͠
    ܕ͸ઈରʹॻ͖ͨ͘ͳ͍
    Gradual Typing
    

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11. զʑ͕ཉ͍͠΋ͷ
    ͳΜ͔ྑ͍ײ͡ʹܕ͕͍ͭͨRuby͕ཉ͍͠
    ύϥϝʔλଟ૬ߏ଄తͳ෦෼ܕଟ૬

    ׬શͳܕਪ࿦Ruby
    

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12. ଟ૬ܕ
    w ύϥϝʔλଟ૬Parametric Polymorphism
    w ෦෼ܕଟ૬Subtyping Polymorphism
    w ΞυϗοΫଟ૬Ad-hoc Polymorphism
    จ຺ʹԠͯ͡ɺҰఆͷ੍ݶͷݩͰɺ

    ࣜʹ͍Ζ͍ΖͳܕΛ༩͑Δ
    

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13. ෦෼ܕଟ૬
    w ෦෼ܕ

    “String is a Object”
    interface X {
    void f(Object x);
    }
    X x = …;
    x.f("Ruby");
    x.f(new ArrayList());
    

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14. ෦෼ܕଟ૬
    w ෦෼ܕ

    “String is a Object”
    interface X {
    void f(Object x);
    }
    X x = …;
    x.f("Ruby");
    x.f(new ArrayList());
    Ҿ਺ͷܕ͸String
    

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15. ෦෼ܕଟ૬
    w ෦෼ܕ

    “String is a Object”
    interface X {
    void f(Object x);
    }
    X x = …;
    x.f("Ruby");
    x.f(new ArrayList());
    Ҿ਺ͷܕ͸String
    Ҿ਺ͷܕ͸ArrayList
    

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16. ໊લతɾߏ଄త
    w ໊લతNominal

    ΫϥεఆٛͰએݴͯ͠෦෼ܕؔ܎Λఆٛ
    w ߏ଄తStructual

    ϝιουఆٛͷแؚؔ܎Ͱ෦෼ܕؔ܎ΛఆٛʢΑΓ
    ॊೈʣ
    

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17. ܕਪ࿦
    w ʢ׬શͳʣܕਪ࿦
    w ϩʔΧϧܕਪ࿦
    

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18. ʢ׬શͳʣܕਪ࿦
    [Milner, 1978]
    w શ͘ܕΛॻ͔ͳͯ͘΋ྑ͍

    ʢܕਪ࿦ͷ׬શੑCompletenessʣ
    w ϓϩάϥϛϯάݴޠ΁ͷ੍໿͕େ͖͍ʢMLʣ
    # let has_even_leaf tree =
    exists_leaf (fun n -> n mod 2 = 0) tree;;
    val has_even_leaf : tree -> bool =
    

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19. ϩʔΧϧܕਪ࿦
    [Pierce, 1997]
    w ϩʔΧϧม਺ͷܕ͸ॻ͔ͳͯ͘΋ྑ͍

    ϝιουͱ͔ͷܕ͸ॻ͘ɻ
    w ͍ΖΜͳϓϩάϥϛϯάݴޠʹಋೖͰ͖Δ

    ʢScala/Swift/C#/C++ʣ
    func greet(person: String) -> String {
    let greeting = "Hello, " + person + "!"
    return greeting
    }
    

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20. ϩʔΧϧܕਪ࿦
    [Pierce, 1997]
    w ϩʔΧϧม਺ͷܕ͸ॻ͔ͳͯ͘΋ྑ͍

    ϝιουͱ͔ͷܕ͸ॻ͘ɻ
    w ͍ΖΜͳϓϩάϥϛϯάݴޠʹಋೖͰ͖Δ

    ʢScala/Swift/C#/C++ʣ
    func greet(person: String) -> String {
    let greeting = "Hello, " + person + "!"
    return greeting
    } greetingͷܕ͸ਪ࿦͞ΕΔ
    

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21. ϩʔΧϧܕਪ࿦
    [Pierce, 1997]
    w ϩʔΧϧม਺ͷܕ͸ॻ͔ͳͯ͘΋ྑ͍

    ϝιουͱ͔ͷܕ͸ॻ͘ɻ
    w ͍ΖΜͳϓϩάϥϛϯάݴޠʹಋೖͰ͖Δ

    ʢScala/Swift/C#/C++ʣ
    func greet(person: String) -> String {
    let greeting = "Hello, " + person + "!"
    return greeting
    } greetingͷܕ͸ਪ࿦͞ΕΔ
    ؔ਺ͷܕ͸ॻ͘
    

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22. զʑ͕ཉ͍͠΋ͷ
    ύϥϝʔλଟ૬ߏ଄తͳ෦෼ܕଟ૬

    ׬શͳܕਪ࿦Ruby
    ͳΜ͔ྑ͍ײ͡ʹܕ͕͍ͭͨRuby͕ཉ͍͠
    

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23. OCamlͳΜ͔͍ۙͷͰ͸
    ύϥϝʔλଟ૬ߏ଄తͳ෦෼ܕଟ૬

    ׬શͳܕਪ࿦Ruby
    # let f x = print_string x#to_s;;
    val f : < to_s : string; .. >

    -> unit =
    

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24. OCamlͳΜ͔͍ۙͷͰ͸
    ύϥϝʔλଟ૬ߏ଄తͳ෦෼ܕଟ૬

    ׬શͳܕਪ࿦Ruby
    # let f x = print_string x#to_s;;
    val f : < to_s : string; .. >

    -> unit =
    #Ͱϝιουݺͼग़͠
    

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25. OCamlͳΜ͔͍ۙͷͰ͸
    ύϥϝʔλଟ૬ߏ଄తͳ෦෼ܕଟ૬

    ׬શͳܕਪ࿦Ruby
    # let f x = print_string x#to_s;;
    val f : < to_s : string; .. >

    -> unit =
    to_sͱ͍͏ϝιου͕͋Ε͹ͳΜͰ΋͍͍
    #Ͱϝιουݺͼग़͠
    

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26. OCamlͰ͸μϝͳͱ͜Ζ
    w OCaml΋ΦϒδΣΫτͷपΓͰ͸ܕΛॻ͘ඞཁ͕
    ͋Δ
    w OCamlͰ͸ॻ͚ͳ͍ϝιου
    w Array#map String#split
    

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27. զʑ͕ཉ͍͠΋ͷ
    w ·ʔແཧ

    ͳʹ͔ΛఘΊͳ͍ͱ͍͚ͳ͍ɻ
    ύϥϝʔλଟ૬ߏ଄తͳ෦෼ܕଟ૬

    ׬શͳܕਪ࿦Ruby
    

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28. զʑ͕ཉ͍͠΋ͷ
    ύϥϝʔλଟ૬ߏ଄తͳ෦෼ܕଟ૬

    ׬શͳܕਪ࿦Ruby
    

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29. զʑ͕ཉ͍͠΋ͷ
    RubyͷػೳΛ੍ݶ͍ͯͬͯ͠ɺܕਪ࿦Ͱ͖
    ΔΑ͏ʹͳΒͳ͍͔ʁʁ
    ύϥϝʔλଟ૬ߏ଄తͳ෦෼ܕଟ૬

    ׬શͳܕਪ࿦Ruby
    

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30. eval
    w ແཧ
    w evalͷฦΓ஋ͷܕ͸anyΈ͍ͨͳܕʹͯ͠͠·͑͹
    ͍͍ͷͰ͸ʢGradual Typing [Siek and Taha, 2006]ʣ
    eval(gets)
    

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31. ActiveRecord
    w DBʹ઀ଓ͠ͳ͍ͱΞτϦϏϡʔτ͕Θ͔Βͳ͍
    w anyͰͳΜͱ͔͠Α͏
    class Person < ApplicationRecord
    belongs_to :group
    has_many :contacts
    end
    

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32. ϝλϓϩάϥϛϯά
    define_method(:name=) do |x|
    @attributes[:name] = x
    end
    

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33. ϝλϓϩάϥϛϯά
    class Location
    attr_reader :line
    attr_reader :column
    end
    

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34. require
    w require͕࣮ߦ͞ΕΔॠؒ·ͰͲͷϓϩάϥϜ͕ಡ·
    ΕΔ͔Θ͔Βͳ͍
    w require͸ϝιουͳͷͰɺ࠶ఆٛͰ͖Δ͠ɺͲ͜
    ʹͰ΋ॻ͚Δ͠ɺҾ਺ʹ͕ࣜॻ͚Δ
    w $LOAD_PATH΋͋ΔΑʂ
    w requireΛߏจʹͯ͠จࣈྻ͔͠ड͚औΕͳ͍ˍτο
    ϓϨϕϧʹ͔͠ॻ͚ͳ͍Α͏ʹ͢Ε͹ྑ͍ͷͰ͸
    

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35. RubyGems
    ⚰Bundler
    

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36. RubyΛ੍ݶͯ͠΋͏·͍͔͘ͳ͍
    w ଞʹ΋໰୊͕͋Γɺݱ࣮తͳ੍ݶ͕ݟ͚ͭΒΕͳ͍
    ʢࠓޙɺݟ͔ͭΔ͔΋͠Εͳ͍ʣ
    w ܕΛॻ͔ͳ͍લఏͰ͸ɺҰճanyʹࣦΘΕͨܕ৘ใ
    ΛऔΓ໭͢ํ๏͕ͳ͍
    

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37. զʑ͕ཉ͍͠΋ͷ
    ύϥϝʔλଟ૬ߏ଄తͳ෦෼ܕଟ૬

    ׬શͳܕਪ࿦Ruby
    

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38. ͝ఏҊ
    w ߏ଄తͳ෦෼ܕଟ૬ϩʔΧϧܕਪ࿦Gradual Typing
    w ʢΘΓͱʣDuck TypingͰ͖ΔͷͰخ͍͠
    w ॻ͔ͳͯ͘ྑ͍ܕ͸ॻ͔ͳ͍
    w ܕ͕ॻ͍ͯͳ͍ͱ͖͸ࠓͷRubyͱಉ͡
    w ܕͷͨΊͷݴޠ͸Rubyͱผ

    requireͱ͔ΦʔϓϯΫϥεͱ͔ϝλϓϩάϥϛϯάͱ
    ͔͸ߟ͑ͳ͍ɻ
    

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39. ͍͍ͩͨTypeScript
    

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40. # group.rbi
    interface String
    def gsub: (Regexp, String) -> String
    end
    interface IGroup
    def people: ActiveRecord.Association
    end
    interface IPerson
    def email: String
    end
    # foo_controller.rb
    group: IGroup = Group.create!(name: name)
    person = group.people.new
    escaped = person.email.map {|x| … }
    

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41. # group.rbi
    interface String
    def gsub: (Regexp, String) -> String
    end
    interface IGroup
    def people: ActiveRecord.Association
    end
    interface IPerson
    def email: String
    end
    # foo_controller.rb
    group: IGroup = Group.create!(name: name)
    person = group.people.new
    escaped = person.email.map {|x| … }
    ผͷϑΝΠϧͰɺΠϯλʔϑΣΠεΛએݴ͢Δ
    

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42. # group.rbi
    interface String
    def gsub: (Regexp, String) -> String
    end
    interface IGroup
    def people: ActiveRecord.Association
    end
    interface IPerson
    def email: String
    end
    # foo_controller.rb
    group: IGroup = Group.create!(name: name)
    person = group.people.new
    escaped = person.email.map {|x| … }
    ผͷϑΝΠϧͰɺΠϯλʔϑΣΠεΛએݴ͢Δ
    ΠϯλϑΣʔεʹϝιουͱܕΛએݴ͢Δ
    

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43. # group.rbi
    interface String
    def gsub: (Regexp, String) -> String
    end
    interface IGroup
    def people: ActiveRecord.Association
    end
    interface IPerson
    def email: String
    end
    # foo_controller.rb
    group: IGroup = Group.create!(name: name)
    person = group.people.new
    escaped = person.email.map {|x| … }
    ผͷϑΝΠϧͰɺΠϯλʔϑΣΠεΛએݴ͢Δ
    ܕ஫ऍ
    ΠϯλϑΣʔεʹϝιουͱܕΛએݴ͢Δ
    

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44. # group.rbi
    interface String
    def gsub: (Regexp, String) -> String
    end
    interface IGroup
    def people: ActiveRecord.Association
    end
    interface IPerson
    def email: String
    end
    # foo_controller.rb
    group: IGroup = Group.create!(name: name)
    person = group.people.new
    escaped = person.email.map {|x| … }
    ผͷϑΝΠϧͰɺΠϯλʔϑΣΠεΛએݴ͢Δ
    ܕ஫ऍ
    ӈลͷܕ͕Θ͔ΔͷͰɺܕ஫ऍ͸ෆཁ
    ΠϯλϑΣʔεʹϝιουͱܕΛએݴ͢Δ
    

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45. # group.rbi
    interface String
    def gsub: (Regexp, String) -> String
    end
    interface IGroup
    def people: ActiveRecord.Association
    end
    interface IPerson
    def email: String
    end
    # foo_controller.rb
    group: IGroup = Group.create!(name: name)
    person = group.people.new
    escaped = person.email.map {|x| … }
    ผͷϑΝΠϧͰɺΠϯλʔϑΣΠεΛએݴ͢Δ
    ܕ஫ऍ
    ӈลͷܕ͕Θ͔ΔͷͰɺܕ஫ऍ͸ෆཁ
    person.emailͷܕ͕StringͩͱΘ
    ͔ΔͷͰɺmap͕ͳ͍͜ͱ͕Θ͔Δ
    ΠϯλϑΣʔεʹϝιουͱܕΛએݴ͢Δ
    

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46. ܕ஫ऍ͕ͳ͚Ε͹͜Ε·ͰͷRubyͱಉ͡
    group = Group.create!(name: name)
    person = group.people.new
    escaped = person.email.map {|x| … }
    

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47. ܕ஫ऍ͕ͳ͚Ε͹͜Ε·ͰͷRubyͱಉ͡
    group = Group.create!(name: name)
    person = group.people.new
    escaped = person.email.map {|x| … }
    ܕ஫ऍ͕ͳ͍ͷͰશ෦anyʹͳΔԿ΋ݕࠪ͠ͳ͍
    

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48. ܕ஫ऍ͕ͳ͚Ε͹͜Ε·ͰͷRubyͱಉ͡
    group = Group.create!(name: name)
    person = group.people.new
    escaped = person.email.map {|x| … }
    map͕ແ͍͜ͱ͸࣮ߦ࣌ʹൃ֮
    ܕ஫ऍ͕ͳ͍ͷͰશ෦anyʹͳΔԿ΋ݕࠪ͠ͳ͍
    

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49. # group.rbi
    interface String
    def gsub: (Regexp, String) -> String
    ...
    end
    interface IGroup
    def people: ActiveRecord.Association
    end
    interface IPerson
    def email: String
    end
    # foo_controller.rb
    group: IGroup = Group.create!(name: name)
    person = group.people.new
    escaped = person.email.map {|x| … }
    

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50. – Rubyͷ෕Matz
    lܕ͸ઈରॻ͖ͨ͘ͳ͍z
    

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51. w Group.create!ͷܕ͕GroupʹͳΔͷ͸Θ͔Βͳ͍ͷʁ

    Groupͷܕ͕Θ͔ΔͱࢥͬͯΔͷʁʁ
    w ܕΛҰͭ΋ॻ͍͍ͯͳ͍ͱͳʹ΋Θ͔Βͳ͍ͷʁʁ

    ϦςϥϧͳΜ͔͸Θ͔Δ͸ͣɻҙ֎ͱ͍Ζ͍Ζݟ͔ͭΔͷͰ͸ɻ
    w Ϋϥεఆٛʹ͸ܕΛॻ͚ͳ͍ͷʁΦʔϓϯΫϥε͸Ͳ͏ͳΔͷʁ

    ࠓޙͷ՝୊ɻΦʔϓϯΫϥεͱ0CKFDUJWF$ͷ$BUFHPSZͳΜ͔
    ͸͍ۙؾ͕͢Δɻ
    w ࣮૷͸ͳ͍ͷʁ

    Α͘ݟΔͱɺʢܕ஫ऍΛίϝϯτͱ͔Ͱॻ͘͜ͱʹ͢Ε͹ʣ͙͢
    ʹ࣮૷Ͱ͖Δͳ͜Εʜʜ
    

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