A tribute to abstract classes

abstract.rb

module Abstract
  def abstract(meth, args=[])
    define_method(meth.to_sym) do |*params|
      raise NotImplementedError, "method ##{meth} should be implemented with arguments (#{ args.join(', ') })"
    end
  end
end

class Hello
  extend Abstract

  ##
  # Say something to the world
  #
  # Params:
  # - msg  {String} Message to say (default: "World")
  # - name {String} Your name (optional)
  #
  abstract :say, [:msg, :name]
end

Hello.new.say("Hello", "Ptico") #=> NotImplementedError: method #say should be implemented with arguments (msg, name)