protected function parse_compare() {
		if ((($this->pos + 1) < $this->size) && ($this->doc[$this->pos + 1] === '=')) {
			switch($this->doc[$this->pos++]) {
				case '$':
					return ($this->token = self::TOK_COMPARE_ENDS);
				case '%':
					return ($this->token = self::TOK_COMPARE_REGEX);
				case '^':
					return ($this->token = self::TOK_COMPARE_STARTS);
				case '<':
					return ($this->token = self::TOK_COMPARE_SMALLER_THAN);
			}
		}
		return false;
	}