ruby: create a comparable class

comparable.rb

class Person
  include Comparable
  # Comparable adds methods, which allow to compare objects
  attr_reader :age
  
  def initialize(age)
    @age = age
  end

  def <=>(another) # method is obligatory, as Comparable uses it to construct methods
    age <=> another.age
  end
end

p1 = Person.new(44)
p2 = Person.new(22)

p1 > p2  # true
p1 == p2 # false
p1 < p2  # false

p3 = Person.new(33)
p3.between?(p2, p1) # true

puts [p1, p2, p3].sort.map{|p| p.inspect} # p2, p3, p1