Ruby module (abstract) example

ruby_abstract.rb

module Abstract
  def self.included(base)
    base.extend(ClassMethods)
  end

  def hello
    'hello from instance method'
  end

  module ClassMethods
    def hello
      'hello from class method'
    end
  end
end

begin
  puts Abstract.hello
rescue => e
  warn e.message
end

puts '----------------------------------'

class Concrete
  include Abstract

  def say_toto
    'I say toto'
  end
end

puts Concrete.hello

concrete = Concrete.new
puts concrete.say_toto
puts concrete.hello

puts '----------------------------------'

class Concrete2
  def say_titi
    'I say titi'
  end
end

concrete_2 = Concrete2.new
puts concrete_2.say_titi

begin
  puts concrete_2.hello
rescue => e
  warn e.message
end

concrete_2.extend(Abstract)
puts concrete_2.hello