Daniel Schierbeck wrote:
>    class Object
>      def quacks_like? (klass)
>        klass.public_instance_methods.each do |method|
>          return false unless respond_to? method
>        end
>        return true
>      end
>    end

Austin's post answers your question, but I'd just like to point out
that this method could more cleanly be implemented as:

  class Object
    def quacks_like? (klass)
      klass.public_instance_methods.all? { |method| respond_to? method
}
    end
  end