Procのススメ/recommendation-of-proc

Transcript

1. Procͷεεϝ
   ৿௩ɹਅ೥(@sanfrecce_osaka)

   ฏ੒Rubyձٞ01 #heiseirubykaigi
   

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2. ࣗݾ঺հ
   ➤ ৿௩ ਅ೥
   ➤ GitHub: @sanfrecce-osaka
   ➤ Twitter: @sanfrecce_osaka
   ➤ Qiita: @sanfrecce_osaka
   ➤ 9݄: େࡕ → ொా
   ➤ גࣜձࣾϥάβΠΞ
   ➤ ত࿨63೥ੜ·Ε
   ➤ ࣮࣭ฏ੒੎
   

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3. ձࣾ঺հ
   ➤ RubyɾRailsͷडୗ։ൃձࣾ
   ➤ at ொా
   ➤ ձࣾͷۙลͰ΋Ո௞͕͍҆ʂ
   ➤ ະܦݧ͔ΒͰ΋2ϲ݄ͷݚम༗
   ➤ We are hiring!
   

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4. Thanks
   ➤ ਆށ.rb & ੢࿬.rbͷϝϯόʔ
   

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5. ͳͥProcͷ࿩ʁ
   

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6. ॻ͖ํͷखஈΛ
   ଟ͍࣋ͬͯ͘Δ
   

   બ୒ࢶ͕ଟ͍

   

   ৔߹ʹԠͨ͡

   ॻ͖ํΛબ୒Ͱ͖Δ

   

   ίʔυͷ඼্࣭͕͕Δʂ
   

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7. ※஫
   ࠓͷ͸͋͘·Ͱ
   ݸਓతݟղͰ͢
   

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8. Proc
   ࢖ͬͯ·͔͢ʁ
   

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9. ஌Βͳ͍͏ͪʹ࢖͍ͬͯΔProc
   class ArticlesController < ApplicationController
   before_action -> do
   redirect_to root_path
   end
   def index
   # ॲཧ
   end
   end
   -> do
   redirect_to root_path
   end
   ͜ͷ෦෼΋Proc(lambda)
   

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10. ࣮͸Α͘ݟΔ͜ͷॻ͖ํ΋ɾɾɾ
    map(&:to_s)
    

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11. &म০ࢠ
    ➤ ࣮Ҿ਺ͷ࠷ޙͰ&Λ෇͚Δͱto_proc͕ݺ͹ΕΔ
    ➤ to_procΛ࣋ͭΫϥε
    ➤ Proc(lambda)ɾMethodɾSymbolɾHash
    ➤ ֤ΫϥεͰڍಈ͕ҟͳΔ
    

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12. Proc#to_proc
    

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13. Proc#to_procͷRuby࣮૷ͷΠϝʔδ
    class Proc
    def to_proc
    self
    end
    end
    

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14. Proc#to _procΛ࢖༻ͨ͠ྫͷ঺հ(ཁ݅)
    ૹΒΕ͖ͯͨ

    ࣸਅΛม׵
    ҹ࡮σʔλ(16ຕͷγʔϧ)
    ݩը૾
    

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15. MiniMagick::ToolΛ࢖༻ͯ͠ը૾Ճ޻
    # ը૾Λճసͤ͞Δॲཧ
    MiniMagick::Tool::Convert.new do |command|
    command << 'images/input.jpg'
    command.merge! %w[-rotate 90]
    command << 'images/output.jpg'
    end
    # ը૾Λ੾ΓऔΔॲཧ
    MiniMagick::Tool::Convert.new do |command|
    command << 'images/input.jpg'
    command.merge! %w(-crop 900x500+170+0)
    command << 'images/output.jpg'
    end
    

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16. ίϚϯυ૊Έཱͯ෦෼ΛϞδϡʔϧʹ੾Γग़͠
    def build_command
    -> (command) do
    args.each { |arg| add_arg(command, arg) }
    end
    end
    def add_arg(command, arg)
    command.send(merge_method(arg), arg)
    end
    def merge_method(arg)
    arg.kind_of?(Array) ? :merge! : :<<
    end
    ProcΛฦ͢ϝιουΛఆٛ
    

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17. Ճ޻ॲཧBeforeAfter
    MiniMagick::Tool::Convert.new do |command|
    command << 'images/input.jpg'
    command.merge! %W[-rotate 90]
    command << 'images/output.jpg'
    end
    def execute
    MiniMagick::Tool::Convert.new(&build_command)
    end
    def args
    [input_path, rotate_arg, output_path]
    end
    def rotate_arg
    %w[-rotate 90]
    end
    ໋໊ʹΑΓ

    ԿΛ͢Δͷ͔Ұ໨ͰΘ͔Δ
    Before
    After
    

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18. ࠷ऴతͳݺͼग़͠ଆ
    [
    Cutting.new,
    Rotation.new,
    Montage.new,
    Positioning.new
    ].each(&:execute)
    

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19. Method#to_proc
    

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20. Method#to_procͷRuby࣮૷(̘࣮૷ͷίϝϯτ͔ΒҾ༻)
    class Method
    def to_proc
    lambda do |*_1|
    self.call(*_1)
    end
    end
    end
    શͯͷ

    ϒϩοΫҾ਺Λ
    ࣮ߦ͢Δϝιουͷ
    Ҿ਺ʹల։
    શͯͷ

    ϒϩοΫҾ਺Λ

    splatͰ഑ྻʹ
    ϝιουΛ࣮ߦ
    

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21. Method#to_procΛ࢖ͬͯΈΔ
    [8, 0, 10]
    .map
    .with_index(1, &Report.method(:new))
    # => [#,…]
    [8, 0, 10]
    .map
    .with_index(1) do |*args|
    Report.new(*args)
    end
    <= ೔෇ॱʹۈ຿࣌ؒΛ֨ೲͨ͠഑ྻ
    ex. ϧʔϓ1ճ໨: Report.new(8, 1)
    

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22. Method#to_proc͕ศརͳ৔໘
    ➤ ໋໊ʹ࢖͏໊લΛઅ໿͍ͨ͠ͱ͖
    ➤ ໋໊ʹ͔͔Δ࣌ؒɾ࿑ྗΛݮΒ͍ͨ͠ͱ͖
    ➤ ໋໊͢Δࡍ͸ͳΔ΂͖ͪ͘Μͱ໊ͨ͠લΛ͚͍ͭͨ৔߹
    ➤ ex. είʔϓ͕୹͍ͱͯ͠΋1จࣈͷ໊લ͸࢖͍ͨ͘ͳ͍
    

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23. Method#to_procͷ࢖͍Έͪ
    title =
    titles.find { |title| … }
    Article.new(title)
    titles
    .find { |title| … }
    .then(&Article.method(:new))
    

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24. ʲRuby2.7.0ʙʳϝιουࢀরԋࢉࢠ
    titles
    .find { |title| … }
    .then(&Article.method(:new))
    titles
    .find { |title| … }
    .then(&Article.:new)
    .:method_name == .method(:method_name)
    

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25. revert͞Ε·ͨ͠(ůЧ`)ŢŞŢŞ
    

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26. ʲRuby2.7.0ʙʳNumbered Parameters
    titles
    .find { |title| … }
    .then(&Article.method(:new))
    titles
    .find { |title| … }
    .then { Article.new(_1) }
    _1ͰୈҰϒϩοΫҾ਺ΛࢀরͰ͖Δ
    

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27. ʲTIPSʳprintσόοάͰͷར༻
    users
    .reject(&:admin?)
    .tap(&method(:p))
    .reject(&:retired?)
    

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28. Symbol#to_proc
    

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29. Symbol#to_procͷRuby࣮૷
    class Symbol
    def to_proc
    proc do |_1, *_2|
    _1.method(self)
    .call(*_2)
    end
    end
    end
    ࠷ॳͷϒϩοΫҾ਺

    ͕Ϩγʔό
    &෇͖Ͱ౉ͨ͠

    Symbolͷ໊લͷ

    ϝιουΛ࣮ߦ
    2൪໨Ҏ߱ͷ

    ϒϩοΫҾ਺͸

    splatͰ഑ྻʹ
    2൪໨Ҏ߱ͷ

    ϒϩοΫҾ਺Λ

    ࣮ߦ͢Δϝιουͷ
    Ҿ਺ʹల։
    

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30. Symbol#to_procΛ࢖ͬͯΈΔ
    [10, 20, 30]
    .map
    .with_index(1, &:+)
    # => [11, 22, 33]
    [10, 20, 30]
    .map
    .with_index(1) do |n1, *n2|
    n1.+(*n2)
    end
    ex. ϧʔϓ1ճ໨: 10.+(1)
    

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31. ͲΜͳ৔໘Ͱ
    ࢖͑Δʁ
    

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32. (ƅшƅ)ɾɾɾ
    

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33. ʢʀ^ω^ʣ
    

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34. Symbol#to_procʹҾ਺Λෳ਺౉͢ػձ͸΄ͱΜͲͳͦ͞͏
    ➤ ༗ޮͳϢʔεέʔε͕͋·Γͳ͍
    ➤ ୈೋϒϩοΫҾ਺ʹ഑ྻ౉ͯ͠ల։ɾɾɾ͸Ͱ͖ͳ͍
    ➤ ϒϩοΫҾ਺ʹ౉ͬͨ࣌఺ͰҰ౓഑ྻʹ֨ೲ͞ΕΔͨΊ
    ➤ EnumeratorΛ֦ுͨ͠Βϫϯνϟϯ͋ΔՄೳੑ
    

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35. Hash#to_proc
    

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36. Hash#to_procͷRuby࣮૷ͷΠϝʔδ
    class Hash
    def to_proc
    proc do |_1|
    self[_1]
    end
    end
    end
    

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37. Hash#to_procΛ࢖ͬͯΈΔ
    generations = {
    S: 'ত࿨',
    H: 'ฏ੒',
    R: 'ྩ࿨'
    }
    %i(S H).map(&generations)
    # => ['ত࿨', 'ฏ੒']
    %i(S H).map { |key| generations[key] }
    

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38. ͲΜͳͱ͖ʹ
    خ͍͠ͷʁ
    

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39. JSON΍CSVΛ
    ѻ͏ࡍʹ
    ͨ·ʹศར
    

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40. ࣌ؒ಺ʹ͓͞·Βͳͯ͘ল͍ͨ΋ͷ
    ➤ ಠࣗʹto_procΛఆٛ
    ➤ ؔ਺߹੒(Proc#>>ɺProc#<➤ ϝιουͷҾ਺ʹϒϩοΫ(proc)Λ౉͢
    ➤ Enumerator::Lazy
    

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41. ଓ͖͸QiitaͰʂ
    

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42. ʲࢀߟʳ̘࣮૷ͰͷఆٛՕॴ(2019/12/14࣌఺)
    ➤ Ҿ਺ͷύʔεՕॴ
    ➤ parse.y#L2422
    ➤ Proc#to_proc
    ➤ proc.c#L1408
    ➤ Symbol#to_proc
    ➤ proc.c#L791
    ➤ Method#to_proc
    ➤ proc.c#L2880
    ➤ Hash#to_proc
    ➤ proc.c#L2880
    ➤ ஫ɿઙ͍Cͷ஌ࣝͰಡΜͩͷͰఆٛՕॴҧ͏͔΋
    

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43. ࠷ޙʹ
    ➤ ࠓճ঺հͨ͠ςΫχοΫ͸޷͖ݏ͍͕෼͔ΕΔ
    ➤ ਓʹΑͬͯಡΈ΍͍͢ɾಡΈਏ͍ͷج४͕ҟͳΔ
    ➤ νʔϜͰೝࣝ͋ΘͤΛ͓ͯ͘͠ͱྑͦ͞͏
    

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44. ͝ਗ਼ௌ
    ͋Γ͕ͱ͏
    ͍͟͝·ͨ͠ʂ
    

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