module Greeting
	def hello
		puts "#{self} Sir"
	end
end

include Greeting

# Or hello
Greeting::hello
puts Greeting.class

Greeting Sir
Module

module Foo
	def log
		puts "here is Foo"	
	end
end

module Bar
	include A
end

include Bar
Bar.log

here is A

module Foo
	def log
		puts "here is Foo"
	end
end

module Bar
	def log
		puts "here is Bar"
	end
end

module FooBar
	include Bar
	include Foo
end

include FooBar

FooBar::log

module Age
  def age
    @age
  end
  
  def age=(age)
    @age = age
  end
  
  def increment_age
    @age += 1
  end
end

module Runner
  def run
    puts "#{@name} is running"
  end
end
class Dog
  include Age
  include Runner
  def initialize(name, age)
		@name = name
		@age = age
  end
end

dog = Dog.new "Woof", 10

dog.age = 5
dog.increment_age
puts dog.age

dog.run

puts Dog.ancestors

6
Woof is running
Dog
Runner
Age
Object
Kernel
BasicObject

module Age
  def age
    @age
  end
  
  def age=(age)
    @age = age
  end
  
  def increment_age
    @age += 1
  end
end

module Runner
  def run
    puts "#{@name} is running"
  end
end
class Dog
  extend Age
  extend Runner
  def initialize(name, age)
		@name = name
		@age = age
  end
end

Dog::run
puts Dog::age == nil

dog = Dog.new
dog.age

 is running
true
(file): undefined method `age' for #<Dog:0x7466 @name=nil @age=nil> (NoMethodError)

module Foo
	def log
		super
		puts "Here is Foo"
	end
end

module Bar
	prepend Foo
	def log
		puts "Here is Bar"
	end
end

include Bar

Bar::log

Here is Bar
Here is Foo