Primes Generator

<?php

$isPrime = function($num) {
    for ($divider = 2; $divider < $num; $divider++) {
        if ($num % $divider == 0) return false;
    }
    return true;
};

$primesGen = function($stop=3000) use ($isPrime) {
    $lastPrime = 1;
    while($lastPrime < $stop) {
        if ($isPrime(++$lastPrime)) yield $lastPrime;
    }
};

$primes = $primesGen();
echo join(',',iterator_to_array($primes));