MongoLite\UtilArrayQuery::evaluate PHP Method

    private static function evaluate($func, $a, $b)
    {
        $r = false;
        switch ($func) {
            case '$eq':
                $r = $a == $b;
                break;
            case '$not':
                $r = $a != $b;
                break;
            case '$gte':
            case '$gt':
                if (is_numeric($a) && is_numeric($b)) {
                    $r = $a > $b;
                }
                break;
            case '$lte':
            case '$lt':
                if (is_numeric($a) && is_numeric($b)) {
                    $r = $a < $b;
                }
                break;
            case '$in':
                if (!is_array($b)) {
                    throw new \InvalidArgumentException('Invalid argument for $in option must be array');
                }
                $r = in_array($a, $b);
                break;
            case '$has':
                if (is_array($b)) {
                    throw new \InvalidArgumentException('Invalid argument for $has array not supported');
                }
                if (!is_array($a)) {
                    $a = @json_decode($a, true) ?: array();
                }
                $r = in_array($b, $a);
                break;
            case '$all':
                if (!is_array($a)) {
                    $a = @json_decode($a, true) ?: array();
                }
                if (!is_array($b)) {
                    throw new \InvalidArgumentException('Invalid argument for $all option must be array');
                }
                $r = count(array_intersect_key($a, $b)) == count($b);
                break;
            case '$regex':
            case '$preg':
            case '$match':
                $r = (bool) @preg_match(isset($b[0]) && $b[0] == '/' ? $b : '/' . $b . '/i', $a, $match);
                break;
            case '$size':
                if (!is_array($a)) {
                    $a = @json_decode($a, true) ?: array();
                }
                $r = (int) $b == count($a);
                break;
            case '$mod':
                if (!is_array($b)) {
                    throw new \InvalidArgumentException('Invalid argument for $mod option must be array');
                }
                list($x, $y) = each($b);
                $r = $a % $x == 0;
                break;
            case '$func':
            case '$fn':
            case '$f':
                if (!is_callable($b)) {
                    throw new \InvalidArgumentException('Function should be callable');
                }
                $r = $b($a);
                break;
            default:
                throw new \ErrorException("Condition not valid ... Use {$func} for custom operations");
                break;
        }
        return $r;
    }