e.swap('') causes subsequent elements to be skipped in traverse_element()

[davidroyalmartin]

swap with empty string causes the problem. swap with a space does not. this must be a bug? here is code that exhibits the problem. i'm using hpricot 0.6.

def hpricot_bug_report()
    s = '<!--comment--><a>x</a>'
    doc = Hpricot(s)
    doc.traverse_element do |e|
      if e.elem?
        puts "elem #{e}"
      elsif e.comment?
        puts "comment #{e}"
        e.swap('') # elem not visited
        # e.swap(' ') # elem still visited
      end
    end
  end