# File lib/xml/xpath.rb, line 691
    def to_str
      if @value.nan? then
        'NaN'
      elsif @value.infinite? then
        if @value < 0 then
          '-Infinity'
        else
          'Infinity'
        end
      else
        sprintf("%.100f", @value).gsub(/\.?0+\z/, '')    # enough?
      end
    end