refine / using で安全にオブジェクトへメソッド追加

using.rb

module StringExtend
  refine String do
    def reverse
      "aaa"
    end
  end
end

module TestModule
  def output_from_module
    puts "my_string".reverse
  end
end

class TestClass
  using StringExtend
  include TestModule

  def output_from_class
    puts "my_string".reverse
  end
end

test = TestClass.new
test.output_from_module # Output: gnirts_ym
test.output_from_class # Output: aaa