x.rb

module Greeter
  def greet(name)
    "HELLO, #{Name.normalize(name)}!"
  end

  module Name
    def self.normalize(name)
      name.strip.upcase
    end
  end
end

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


class Person
  include Greeter

  def initialize(age)
    @age = normalize(age)

    @name = Name.new("Gregory")
  end

  private

  def normalize(age)
    [age.to_i, 25].min
  end
end

person = Person.new(12) #=> undefined method `new' for Greeter::Name:Module (NoMethodError)