Adding virtual methods to Ruby

During a short conversation on the #ruby-lang IRC channel, someone asked whether Ruby supported C++ pure virtual methods. Out of the box, the answer is no. But the implementation is trivial:

class VirtualMethodCalledError < RuntimeError
  attr :name
  def initialize(name)
    super("Virtual function '#{name}' called")
    @name = name
  end
end

class Module
  def virtual(*methods)
    methods.each do |m|
      define_method(m) {
        raise VirtualMethodCalledError, m
      }
    end
  end
end

The usage is beautifully simple:

class VirtualThingy
  virtual :doThingy
end

class ConcreteThingy < VirtualThingy
  def doThingy
    puts "Doin' my thing!"
  end
end

begin
  VirtualThingy.new.doThingy
rescue VirtualMethodCalledError => e
  raise unless e.name == :doThingy
end
ConcreteThingy.new.doThingy

Please comment!