delegator.rb

require "delegate"

module X
  def initialize(*)
    super
    __getobj__.class.instance_methods(false).each do |meth|
      define_singleton_method(meth) { __getobj__.send(meth) || "Is nil"}
    end
  end
end

class A < SimpleDelegator
  include X
end

class B
  def hi
    "hi"
  end

  def ho
  end
end

b=B.new
a=A.new(b)
puts a.hi
puts a.ho

class C
  def hi
  end
  
  def ho
    "ho"
  end
end

c=C.new
a=A.new(c)
puts a.hi
puts a.ho