event_bus.rb

class EventBus

  @@events = {}

  def self.register(name, callback)
    @@events[name] ||= []   
    @@events[name] << callback
  end

  def self.publish(name, *args)
    return if @@events[name].nil?
    @@events[name].each do |callback|
      callback.call(*args)
    end
  end

end


# register
EventBus.register("testing", Proc.new { |a| puts "testing was executed once: #{a}" })
EventBus.register("testing", Proc.new { |a, b| puts "testing was executed again: #{a}, #{b}" })
# publish
EventBus.publish("testing", "arg 1", "arg2")