code: public function getFunctions()
      {
          return array(
              new ExpressionFunction(
                  'match',
                  function ($pattern, $value) {
                      return sprintf('preg_match(%1$s, %2$s) === 1', $pattern, $value);
                  },
                  function ($arguments, $pattern, $value) {
                      return preg_match($pattern, $value) === 1;
                  }
              ),
          );
      }
docs: {@inheritdoc}