# File lib/mof/helper.rb, line 141
    def to_s
      ret = "#{super}\tnear token #{@token_value.inspect}\n"
      ret << "\tStack [#{@stack.size}]:\n"
      idx = stack.size-1
      (1..12).each do |i|
        s = stack[idx]
        c = s.class
        case s
        when String, NilClass
          s = s.inspect
        else
          s = s.to_s
        end
        if s.size > 80
          ret << "[#{i}:#{c}]\t#{s[0,80]}..."
        else
          ret << "[#{i}:#{c}]\t#{s}"
        end
        ret << "\n"
        idx -= 1
        break if idx < 0
      end
      ret
    end