forwardable.rb

forwardable.rb

module Forwardable
  def delegate_methods(obj, *methods)
    methods.each {|method| delegate_method(obj, method)}
  end
  def delegate_method1(obj, method)
    self.module_eval %Q{
      def #{method}(*args, &block)
        _#{obj}.#{method}(*args, &block)
      end
    }
  end
  def delegate_method2(obj, method)
    self.module_eval do
      define_method(method) {|*args, &block|
        _ = eval("#{obj}", binding, __FILE__, __LINE__)
        _.__send__(method, *args, &block)
      }
    end
  end
  alias :delegate_method :delegate_method2
end
class Impl
  def self.service
    puts "service!"
  end
end
class MyQueue
  extend Forwardable
  delegate_method :Impl, :service
  delegate_methods :@q, :push, :shift, :pop
  def initialize()
    @q = []
  end
end

q = MyQueue.new
q.push 1, 2, 3, 4, 5
q.pop
q.shift
q.service
p q