aspects.rb

class Proxy
  def initialize(obj, modules)
    @obj = obj

    modules.each do |mod|
      extend mod
    end
  end

  def method_missing(meth, *args, &block)
    @obj.send(meth, *args, &block).tap do |ret|
      return self if ret == @obj
    end
  end
end

class Object
  def with_aspects(*modules)
    proxy = Proxy.new(self, modules)
  end

  alias with_aspect with_aspects
end

class Person
  def initialize(name)
    @name = name
  end

  def hello
    "#{@name} says hello"
  end

  def myself
    self
  end
end

module Yeller
  def hello
    super.upcase
  end
end

yehuda = Person.new("Yehuda")

p yehuda.with_aspect(Yeller).hello
p yehuda.with_aspect(Yeller).myself.hello