code: public function addPattern($pattern, $label = true)
      {
          $count                  = count($this->patterns);
          $this->patterns[$count] = $pattern;
          $this->labels[$count]   = $label;
          $this->regex            = null;
      }
docs: Adds a pattern with an optional label.
  
  @param string $pattern      Perl style regex, but ( and ) lose the usual meaning.
  @param string $label        Label of regex to be returned on a match.