prepend_prepend.rb

Module.new do
  def prepend(m=nil, &blk)
    if block_given?
      super(Module.new(&blk))
    else
      super
    end
  end
end.tap { |pre| Module.prepend pre }

class Foo
  def bar
    puts "class"
  end
end


Foo.prepend do
  def bar
    puts "prepended"
    super
  end
end

module Bar
  def bar
    puts "module"
    super
  end
end

Foo.prepend Bar

Foo.new.bar # => module
            #    prepended
            #    class

@rwz Fixed.