Dynamic Ruby callbacks, from http://www.mattsears.com/articles/2011/11/27/ruby-blocks-as-dynamic-callbacks

callback.rb

class Proc
  def callback(callable, *args)
    self === Class.new do
      method_name = callable.to_sym
      define_method(method_name) { |&block| block.nil? ? true : block.call(*args) }
      define_method("#{method_name}?") { true }
      def method_missing(method_name, *args, &block) false; end
    end.new
  end
end

implementation.rb

publish "some content" do |receiver|
  receiver.success do
    puts 'published'
  end
  receiver.failure do |failure|
    puts "not published because #{failure}"
  end
end

publish.rb

def publish(content, &block)
  display content
  block.callback :success
rescue => e
  block.callback :failure, e.message
end