Alterntaive to visitor pattern

AnotherVisitor.rb

class Visitor
  def traverse(enum)
    enum.each do |node|
      visit node
    end
    self
  end

  def visit(node)
    node.class.ancestors.each do |cl|
      m = get_method_name cl
      return send(m, node) if respond_to? m
    end
    raise ArgumentError, "Do not know how to visit #{node.inspect}"
  end

  private
  def get_method_name(cl)
      "visit_#{cl.name.gsub(/::/, '_')}".freeze
  end
end

class DumpVisitor < Visitor
  def visit_Object(o)
    p o
  end
end

DumpVisitor.new.traverse %w{foo bar baz}

class OptimizedVisitor < Visitor
  def initialize(*a,&b)
    super

    @cache = Hash.new do |h, cl|
      f = cl.ancestors.each do |acl|
        m = get_method_name acl
        break(h[cl] = method(m)) if respond_to? m
      end
      raise ArgumentError, "Do not know how to visit #{cl.inspect}" unless Method === f
      f
    end
  end

  def visit(node)
    @cache[node.class][node]
  end
end

class DumpVisitor2 < OptimizedVisitor
  def visit_Object(o)
    p o
  end
end

DumpVisitor2.new.traverse %w{foo bar baz}