Simple Object-oriented example in Ruby

sample_objs.rb

# Official site for the Ruby language: "https://www.ruby-lang.org/"

class C1
  attr :a, :b
  def initialize(a)
    @a = a
  end
  def self.hi
    puts 'hello world'
  end
  def hi
    puts 'hi there'
  end
end

module M1
  def foo
    puts self.class
    return 123
  end
end

class C2 < C1
  include M1
  def initialize(a,b)
    super(a)
    @b = b
  end
end

module M2
  def b
    @b=8
  end
  def bar(a)
    'bar '*a
  end
end

class C3 < C1
  include M1
  include M2
  
  def widget
    bar(@a)
  end
end

C1.hi
puts

o1 = C1.new(1)
o1.hi
puts "o1.a == #{o1.a}"
puts "o1.b == #{o1.b}"
puts "o1.b.nil? == #{o1.b.nil?}"
puts

o2 = C2.new(2,7)
puts "o2.a == #{o2.a}"
puts "o2.b == #{o2.b}"
puts "o2.b.nil? == #{o2.b.nil?}"
puts "o2.foo == #{o2.foo}"
puts

o3 = C3.new(3)
puts "o3.a == #{o3.a}"
puts "o3.b == #{o3.b}"
puts "o3.b.nil? == #{o3.b.nil?}"
puts "o3.foo == #{o3.foo}"
puts "o3.bar(30) == #{o3.bar(30)}"
puts "o3.widget == #{o3.widget}"
puts