*/ protected $supported_comparison_operators = array(); /** * Check if comparer supports the specified comparison sign * * @param string $comparison_operator * @return bool */ public function supports_comparison_operator( $comparison_operator ) { return in_array( $comparison_operator, $this->supported_comparison_operators ); } /** * Check if comparison is true for $a and $b * * @param mixed $a * @param string $comparison_operator * @param mixed $b * @return bool */ abstract public function is_correct( $a, $comparison_operator, $b ); }