    # File lib/action_view/helpers/text_helper.rb, line 44
          def excerpt(text, phrase, radius = 100, excerpt_string = "...")
            if text.nil? || phrase.nil? then return end
            phrase = Regexp.escape(phrase)

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

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

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