set('+', fn (...$args) => array_sum($args)); $env->set('-', fn ($a, $b) => $a - $b); $env->set('*', fn ($a, $b) => $a * $b); $env->set('/', fn ($a, $b) => $a / $b); $env->set('%', fn ($a, $b) => $a % $b); return $env; }