# File lib/ruote/dboard/process_status.rb, line 469
    def to_dot(opts={})

      s = [ "digraph \"process wfid #{wfid}\" {" ]
      @expressions.each { |e| s.push(*e.send(:to_dot, opts)) }
      @errors.each { |e| s.push(*e.send(:to_dot, opts)) }
      s << '}'

      s.join("\n")
    end