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Procͷεεϝ
௩ɹਅ(@sanfrecce_osaka)
ฏRubyձٞ01 #heiseirubykaigi
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ࣗݾհ
➤ ௩ ਅ
➤ GitHub: @sanfrecce-osaka
➤ Twitter: @sanfrecce_osaka
➤ Qiita: @sanfrecce_osaka
➤ 9݄: େࡕ → ொా
➤ גࣜձࣾϥάβΠΞ
➤ ত63ੜ·Ε
➤ ࣮࣭ฏ
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ձࣾհ
➤ RubyɾRailsͷडୗ։ൃձࣾ
➤ at ொా
➤ ձࣾͷۙลͰՈ͕͍҆ʂ
➤ ະܦݧ͔ΒͰ2ϲ݄ͷݚम༗
➤ We are hiring!
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Thanks
➤ ਆށ.rb & .rbͷϝϯόʔ
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ͳͥProcͷʁ
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ॻ͖ํͷखஈΛ
ଟ͍࣋ͬͯ͘Δ
બࢶ͕ଟ͍
߹ʹԠͨ͡
ॻ͖ํΛબͰ͖Δ
ίʔυͷ্࣭͕͕Δʂ
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※
ࠓͷ͋͘·Ͱ
ݸਓతݟղͰ͢
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Proc
ͬͯ·͔͢ʁ
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Βͳ͍͏ͪʹ͍ͬͯΔProc
class ArticlesController < ApplicationController
before_action -> do
redirect_to root_path
end
def index
# ॲཧ
end
end
-> do
redirect_to root_path
end
͜ͷ෦Proc(lambda)
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࣮Α͘ݟΔ͜ͷॻ͖ํɾɾɾ
map(&:to_s)
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&म০ࢠ
➤ ࣮Ҿͷ࠷ޙͰ&Λ͚Δͱto_proc͕ݺΕΔ
➤ to_procΛ࣋ͭΫϥε
➤ Proc(lambda)ɾMethodɾSymbolɾHash
➤ ֤ΫϥεͰڍಈ͕ҟͳΔ
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Proc#to_proc
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Proc#to_procͷRuby࣮ͷΠϝʔδ
class Proc
def to_proc
self
end
end
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Proc#to _procΛ༻ͨ͠ྫͷհ(ཁ݅)
ૹΒΕ͖ͯͨ
ࣸਅΛม
ҹσʔλ(16ຕͷγʔϧ)
ݩը૾
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MiniMagick::ToolΛ༻ͯ͠ը૾Ճ
# ը૾Λճసͤ͞Δॲཧ
MiniMagick::Tool::Convert.new do |command|
command << 'images/input.jpg'
command.merge! %w[-rotate 90]
command << 'images/output.jpg'
end
# ը૾ΛΓऔΔॲཧ
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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ίϚϯυΈཱͯ෦ΛϞδϡʔϧʹΓग़͠
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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ՃॲཧBeforeAfter
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
ԿΛ͢Δͷ͔ҰͰΘ͔Δ
Before
After
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࠷ऴతͳݺͼग़͠ଆ
[
Cutting.new,
Rotation.new,
Montage.new,
Positioning.new
].each(&:execute)
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Method#to_proc
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Method#to_procͷRuby࣮(̘࣮ͷίϝϯτ͔ΒҾ༻)
class Method
def to_proc
lambda do |*_1|
self.call(*_1)
end
end
end
શͯͷ
ϒϩοΫҾΛ
࣮ߦ͢Δϝιουͷ
Ҿʹల։
શͯͷ
ϒϩοΫҾΛ
splatͰྻʹ
ϝιουΛ࣮ߦ
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Method#to_procΛͬͯΈΔ
[8, 0, 10]
.map
.with_index(1, &Report.method(:new))
# => [#,…]
[8, 0, 10]
.map
.with_index(1) do |*args|
Report.new(*args)
end
<= ॱʹۈ࣌ؒΛ֨ೲͨ͠ྻ
ex. ϧʔϓ1ճ: Report.new(8, 1)
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Method#to_proc͕ศརͳ໘
➤ ໋໊ʹ͏໊લΛઅ͍ͨ͠ͱ͖
➤ ໋໊ʹ͔͔Δ࣌ؒɾ࿑ྗΛݮΒ͍ͨ͠ͱ͖
➤ ໋໊͢ΔࡍͳΔ͖ͪ͘Μͱ໊ͨ͠લΛ͚͍ͭͨ߹
➤ ex. είʔϓ͕͍ͱͯ͠1จࣈͷ໊લ͍ͨ͘ͳ͍
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Method#to_procͷ͍Έͪ
title =
titles.find { |title| … }
Article.new(title)
titles
.find { |title| … }
.then(&Article.method(:new))
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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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revert͞Ε·ͨ͠(ůЧ`)ŢŞŢŞ
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ʲRuby2.7.0ʙʳNumbered Parameters
titles
.find { |title| … }
.then(&Article.method(:new))
titles
.find { |title| … }
.then { Article.new(_1) }
_1ͰୈҰϒϩοΫҾΛࢀরͰ͖Δ
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ʲTIPSʳprintσόοάͰͷར༻
users
.reject(&:admin?)
.tap(&method(:p))
.reject(&:retired?)
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Symbol#to_proc
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Symbol#to_procͷRuby࣮
class Symbol
def to_proc
proc do |_1, *_2|
_1.method(self)
.call(*_2)
end
end
end
࠷ॳͷϒϩοΫҾ
͕Ϩγʔό
&͖Ͱͨ͠
Symbolͷ໊લͷ
ϝιουΛ࣮ߦ
2൪Ҏ߱ͷ
ϒϩοΫҾ
splatͰྻʹ
2൪Ҏ߱ͷ
ϒϩοΫҾΛ
࣮ߦ͢Δϝιουͷ
Ҿʹల։
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Symbol#to_procΛͬͯΈΔ
[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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ͲΜͳ໘Ͱ
͑Δʁ
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(ƅшƅ)ɾɾɾ
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ʢʀ^ω^ʣ
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Symbol#to_procʹҾΛෳ͢ػձ΄ͱΜͲͳͦ͞͏
➤ ༗ޮͳϢʔεέʔε͕͋·Γͳ͍
➤ ୈೋϒϩοΫҾʹྻͯ͠ల։ɾɾɾͰ͖ͳ͍
➤ ϒϩοΫҾʹͬͨ࣌ͰҰྻʹ֨ೲ͞ΕΔͨΊ
➤ EnumeratorΛ֦ுͨ͠Βϫϯνϟϯ͋ΔՄೳੑ
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Hash#to_proc
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Hash#to_procͷRuby࣮ͷΠϝʔδ
class Hash
def to_proc
proc do |_1|
self[_1]
end
end
end
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Hash#to_procΛͬͯΈΔ
generations = {
S: 'ত',
H: 'ฏ',
R: 'ྩ'
}
%i(S H).map(&generations)
# => ['ত', 'ฏ']
%i(S H).map { |key| generations[key] }
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ͲΜͳͱ͖ʹ
خ͍͠ͷʁ
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JSONCSVΛ
ѻ͏ࡍʹ
ͨ·ʹศར
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࣌ؒʹ͓͞·Βͳͯ͘ল͍ͨͷ
➤ ಠࣗʹto_procΛఆٛ
➤ ؔ߹(Proc#>>ɺProc#<<)
➤ ϝιουͷҾʹϒϩοΫ(proc)Λ͢
➤ Enumerator::Lazy
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ଓ͖QiitaͰʂ
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ʲࢀߟʳ̘࣮ͰͷఆٛՕॴ(2019/12/14࣌)
➤ ҾͷύʔεՕॴ
➤ 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
➤ ɿઙ͍CͷࣝͰಡΜͩͷͰఆٛՕॴҧ͏͔
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࠷ޙʹ
➤ ࠓճհͨ͠ςΫχοΫ͖ݏ͍͕͔ΕΔ
➤ ਓʹΑͬͯಡΈ͍͢ɾಡΈਏ͍ͷج४͕ҟͳΔ
➤ νʔϜͰೝࣝ͋ΘͤΛ͓ͯ͘͠ͱྑͦ͞͏
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͝ਗ਼ௌ
͋Γ͕ͱ͏
͍͟͝·ͨ͠ʂ