# File lib/action_view/helpers/text_helper.rb, line 101
      def excerpt(text, phrase, radius = 100, excerpt_string = "...")
        if text.nil? || phrase.nil? then return end
        phrase = Regexp.escape(phrase)

        if found_pos = text.chars =~ /(#{phrase})/i
          start_pos = [ found_pos - radius, 0 ].max
          end_pos   = [ found_pos + phrase.chars.length + radius, text.chars.length ].min

          prefix  = start_pos > 0 ? excerpt_string : ""
          postfix = end_pos < text.chars.length ? excerpt_string : ""

          prefix + text.chars[start_pos..end_pos].strip + postfix
        else
          nil
        end
      end