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
4. ܕ͸ॻ͖ͨ͘ͳ͍
5. ܕ͸ॻ͖ͨ͘ͳ͍ Duck Typingʹͳ͍ͬͯͯཉ͍͠
6. ܕ͸ॻ͖ͨ͘ͳ͍ Duck Typingʹͳ͍ͬͯͯཉ͍͠ ܕਪ࿦
7. ܕ͸ॻ͖ͨ͘ͳ͍ Duck Typingʹͳ͍ͬͯͯཉ͍͠ ܕਪ࿦ typo͙Β͍͸࣮ߦ͠ͳͯ͘΋ൃݟ͍ͨ͠
8. ܕ͸ॻ͖ͨ͘ͳ͍ Duck Typingʹͳ͍ͬͯͯཉ͍͠ ܕਪ࿦ typo͙Β͍͸࣮ߦ͠ͳͯ͘΋ൃݟ͍ͨ͠ ܕ͸ઈରʹॻ͖ͨ͘ͳ͍
9. ܕ͸ॻ͖ͨ͘ͳ͍ Duck Typingʹͳ͍ͬͯͯཉ͍͠ ܕਪ࿦ typo͙Β͍͸࣮ߦ͠ͳͯ͘΋ൃݟ͍ͨ͠ ܕ͸ઈରʹॻ͖ͨ͘ͳ͍ Gradual Typing
10. ͳΜ͔ྑ͍ײ͡ʹܕ͕͍ͭͨ Ruby͕ཉ͍͠ ܕ͸ॻ͖ͨ͘ͳ͍ Duck Typingʹͳ͍ͬͯͯཉ͍͠ ܕਪ࿦ typo͙Β͍͸࣮ߦ͠ͳͯ͘΋ൃݟ͍ͨ͠ ܕ͸ઈରʹॻ͖ͨ͘ͳ͍ Gradual Typing
11. զʑ͕ཉ͍͠΋ͷ ͳΜ͔ྑ͍ײ͡ʹܕ͕͍ͭͨRuby͕ཉ͍͠ ύϥϝʔλଟ૬
    
    ߏ଄తͳ෦෼ܕଟ૬

    
    ׬શͳܕਪ࿦
    
    Ruby
12. ଟ૬ܕ w ύϥϝʔλଟ૬
    Parametric Polymorphism
    w ෦෼ܕଟ૬
    Subtyping Polymorphism w ΞυϗοΫଟ૬
    Ad-hoc Polymorphism จ຺ʹԠͯ͡ɺҰఆͷ੍ݶͷݩͰɺ
 ࣜʹ͍Ζ͍ΖͳܕΛ༩͑Δ
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());
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
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
16. ໊લతɾߏ଄త w ໊લత
    Nominal
 ΫϥεఆٛͰએݴͯ͠෦෼ܕؔ܎Λఆٛ
    w ߏ଄త
    Structual
 ϝιουఆٛͷแؚؔ܎Ͱ෦෼ܕؔ܎ΛఆٛʢΑΓ ॊೈʣ
17. ܕਪ࿦ w ʢ׬શͳʣܕਪ࿦
    w ϩʔΧϧܕਪ࿦
18. ʢ׬શͳʣܕਪ࿦
    [Milner, 1978] w શ͘ܕΛॻ͔ͳͯ͘΋ྑ͍
 ʢܕਪ࿦ͷ׬શੑ
    Completenessʣ
    w ϓϩάϥϛϯάݴޠ΁ͷ੍໿͕େ͖͍ʢMLʣ # let has_even_leaf tree = exists_leaf (fun n -> n mod 2 = 0) tree;; val has_even_leaf : tree -> bool = <fun>
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 }
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
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
22. զʑ͕ཉ͍͠΋ͷ ύϥϝʔλଟ૬
    
    ߏ଄తͳ෦෼ܕଟ૬

    
    ׬શͳܕਪ࿦
    
    Ruby ͳΜ͔ྑ͍ײ͡ʹܕ͕͍ͭͨRuby͕ཉ͍͠
23. OCamlͳΜ͔͍ۙͷͰ͸ ύϥϝʔλଟ૬
    
    ߏ଄తͳ෦෼ܕଟ૬

    
    ׬શͳܕਪ࿦
    
    Ruby # let f x = print_string x#to_s;; val f : < to_s : string; .. >
 -> unit = <fun>
24. OCamlͳΜ͔͍ۙͷͰ͸ ύϥϝʔλଟ૬
    
    ߏ଄తͳ෦෼ܕଟ૬

    
    ׬શͳܕਪ࿦
    
    Ruby # let f x = print_string x#to_s;; val f : < to_s : string; .. >
 -> unit = <fun> #Ͱϝιουݺͼग़͠
25. OCamlͳΜ͔͍ۙͷͰ͸ ύϥϝʔλଟ૬
    
    ߏ଄తͳ෦෼ܕଟ૬

    
    ׬શͳܕਪ࿦
    
    Ruby # let f x = print_string x#to_s;; val f : < to_s : string; .. >
 -> unit = <fun> to_sͱ͍͏ϝιου͕͋Ε͹ͳΜͰ΋͍͍ #Ͱϝιουݺͼग़͠
26. OCamlͰ͸μϝͳͱ͜Ζ w OCaml΋ΦϒδΣΫτͷपΓͰ͸ܕΛॻ͘ඞཁ͕ ͋Δ
    w OCamlͰ͸ॻ͚ͳ͍ϝιου
    w Array#map
    String#split
27. զʑ͕ཉ͍͠΋ͷ w ·ʔແཧ
 ͳʹ͔ΛఘΊͳ͍ͱ͍͚ͳ͍ɻ ύϥϝʔλଟ૬
    
    ߏ଄తͳ෦෼ܕଟ૬

    
    ׬શͳܕਪ࿦
    
    Ruby
28. զʑ͕ཉ͍͠΋ͷ ύϥϝʔλଟ૬
    
    ߏ଄తͳ෦෼ܕଟ૬

    
    ׬શͳܕਪ࿦
    
    Ruby
29. զʑ͕ཉ͍͠΋ͷ RubyͷػೳΛ੍ݶ͍ͯͬͯ͠ɺܕਪ࿦Ͱ͖ ΔΑ͏ʹͳΒͳ͍͔ʁʁ ύϥϝʔλଟ૬
    
    ߏ଄తͳ෦෼ܕଟ૬

    
    ׬શͳܕਪ࿦
    
    Ruby
30. eval w ແཧ
    w evalͷฦΓ஋ͷܕ͸anyΈ͍ͨͳܕʹͯ͠͠·͑͹ ͍͍ͷͰ͸ʢGradual Typing [Siek and Taha, 2006]ʣ eval(gets)
31. ActiveRecord w DBʹ઀ଓ͠ͳ͍ͱΞτϦϏϡʔτ͕Θ͔Βͳ͍
    w anyͰͳΜͱ͔͠Α͏ class Person < ApplicationRecord belongs_to :group has_many :contacts end
32. ϝλϓϩάϥϛϯά define_method(:name=) do |x| @attributes[:name] = x end
33. ϝλϓϩάϥϛϯά class Location attr_reader :line attr_reader :column end
34. require w require͕࣮ߦ͞ΕΔॠؒ·ͰͲͷϓϩάϥϜ͕ಡ· ΕΔ͔Θ͔Βͳ͍
    w require͸ϝιουͳͷͰɺ࠶ఆٛͰ͖Δ͠ɺͲ͜ ʹͰ΋ॻ͚Δ͠ɺҾ਺ʹ͕ࣜॻ͚Δ
    w $LOAD_PATH΋͋ΔΑʂ
    w requireΛߏจʹͯ͠จࣈྻ͔͠ड͚औΕͳ͍ˍτο ϓϨϕϧʹ͔͠ॻ͚ͳ͍Α͏ʹ͢Ε͹ྑ͍ͷͰ͸
35. RubyGems ⚰Bundler
36. RubyΛ੍ݶͯ͠΋͏·͍͔͘ͳ͍ w ଞʹ΋໰୊͕͋Γɺݱ࣮తͳ੍ݶ͕ݟ͚ͭΒΕͳ͍ ʢࠓޙɺݟ͔ͭΔ͔΋͠Εͳ͍ʣ
    w ܕΛॻ͔ͳ͍લఏͰ͸ɺҰճanyʹࣦΘΕͨܕ৘ใ ΛऔΓ໭͢ํ๏͕ͳ͍
37. զʑ͕ཉ͍͠΋ͷ ύϥϝʔλଟ૬
    
    ߏ଄తͳ෦෼ܕଟ૬

    
    ׬શͳܕਪ࿦
    
    Ruby
38. ͝ఏҊ w ߏ଄తͳ෦෼ܕଟ૬
    
    ϩʔΧϧܕਪ࿦
    
    Gradual Typing
    w ʢΘΓͱʣDuck TypingͰ͖ΔͷͰخ͍͠
    w ॻ͔ͳͯ͘ྑ͍ܕ͸ॻ͔ͳ͍
    w ܕ͕ॻ͍ͯͳ͍ͱ͖͸ࠓͷRubyͱಉ͡
    w ܕͷͨΊͷݴޠ͸Rubyͱผ
 requireͱ͔ΦʔϓϯΫϥεͱ͔ϝλϓϩάϥϛϯάͱ ͔͸ߟ͑ͳ͍ɻ
39. ͍͍ͩͨTypeScript
40. # group.rbi interface String def gsub: (Regexp, String) -> String end interface IGroup def people: ActiveRecord.Association<IPerson> 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| … }
41. # group.rbi interface String def gsub: (Regexp, String) -> String end interface IGroup def people: ActiveRecord.Association<IPerson> 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
42. # group.rbi interface String def gsub: (Regexp, String) -> String end interface IGroup def people: ActiveRecord.Association<IPerson> 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
43. # group.rbi interface String def gsub: (Regexp, String) -> String end interface IGroup def people: ActiveRecord.Association<IPerson> 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
44. # group.rbi interface String def gsub: (Regexp, String) -> String end interface IGroup def people: ActiveRecord.Association<IPerson> 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
45. # group.rbi interface String def gsub: (Regexp, String) -> String end interface IGroup def people: ActiveRecord.Association<IPerson> 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
46. ܕ஫ऍ͕ͳ͚Ε͹͜Ε·ͰͷRubyͱಉ͡ group = Group.create!(name: name) person = group.people.new escaped = person.email.map {|x| … }
47. ܕ஫ऍ͕ͳ͚Ε͹͜Ε·ͰͷRubyͱಉ͡ group = Group.create!(name: name) person = group.people.new escaped = person.email.map {|x| … } ܕ஫ऍ͕ͳ͍ͷͰશ෦anyʹͳΔ
    
    Կ΋ݕࠪ͠ͳ͍
48. ܕ஫ऍ͕ͳ͚Ε͹͜Ε·ͰͷRubyͱಉ͡ group = Group.create!(name: name) person = group.people.new escaped = person.email.map {|x| … } map͕ແ͍͜ͱ͸࣮ߦ࣌ʹൃ֮ ܕ஫ऍ͕ͳ͍ͷͰશ෦anyʹͳΔ
    
    Կ΋ݕࠪ͠ͳ͍
49. # group.rbi interface String def gsub: (Regexp, String) -> String ... end interface IGroup def people: ActiveRecord.Association<IPerson> 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| … }
50. – Rubyͷ෕
    Matz lܕ͸ઈରॻ͖ͨ͘ͳ͍z
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