Rangeに存在しないけど、Arrayに存在するメソッドの場合は委譲する

range-behaves_as_array.rb

# coding: utf-8
class Range
  def method_missing(name, *args, &block)
    if Array.public_instance_methods.include?(name)
      to_a.send(name, *args, &block)
    else
      super
    end
  end

  def respond_to_missing?(name, include_private)
    array_methos = include_private ? Array.instance_methods : Array.public_instance_methods
    if array_methos.include?(name)
      true
    else
      super
    end
  end
end