Ruby class instance variables and inheritance

Question

I have a Ruby class called LibraryItem. I want to associate with every instance of this class an array of attributes. This array is long and looks something lik

Answer 1

Another solution would be to use the inherited hook:

class LibraryItem < Object
  class << self
    attr_accessor :attributes
    def inherit_attributes(attrs)
      @attributes ||= []
      @attributes.concat attrs
    end

    def inherited(sublass)
      sublass.inherit_attributes(@attributes)
    end
  end
  @attributes = ['title', 'authors', 'location',]
end

class LibraryBook < LibraryItem
  @attributes.push('ISBN', 'pages')
end