test dynamically add instance_variables or class_variables to class.

raw.rb

class Mine  
  @xxx = 1
  attr_accessor :some_var  
  
  def intialize  
    @some_var = true  
  end  
  
    class << self
      def my_number num  
        attr_accessor "my_#{num}"
        p self
        self.instance_variable_set("@my_#{num}", num)
        # self.send("my_#{num}=", num)  
        p self.methods.select {|x| x.start_with? "class"}
        class_variable_set("@@my_#{num}", num)
        # class_eval("@@class_#{num} = :m%s" % num.to_s)
      end  
  end
end  
  
dude = Mine.new  
Mine.my_number 1  
puts dude.class.instance_variables
puts dude.class.class_variables

puts "---------"

class Widget  
  # class instance variable pattern  
  class << self; attr_accessor :color; end  
  
  attr_accessor :size, :type

  def initialize()
    @yyy = 10
  end
  def show_color()  
    "This widget is #{self.class.color}"  
  end  
end 
# Widget.color = 100
puts Widget.instance_variables
puts "------------"
wdg = Widget.new
wdg.size = 10
puts wdg.instance_variables