def next_regex regex
      if regex.is_a? Symbol
        regex = @text_patterns[regex]
        raise "Pattern specified #{regex} does not exist in text_patterns " unless regex
      end
      @last_regex = regex
      find_more
    end
def next_regex regex
      if regex.is_a? Symbol
        regex = @text_patterns[regex]
        raise "Pattern specified #{regex} does not exist in text_patterns " unless regex
      end
      @last_regex = regex
      find_more
    end
search for the next occurence of given regexp. Returns line and col if found, else nil.
 @param [String, Regexp] pattern to search for (uses :index)
 @return [nil] return value of no consequence