Zamonaviy PHP 8

// Har bir misol qat'iy turlar rejimida ishlaydi.

// PHP 8.1 dan oldin: doimiylar va hech qanday kafolat yo'q
final class EskiHolat
{
    public const YANGI = "yangi";
    public const YUBORILGAN = "yuborilgan";
    public const YAKUNLANGAN = "yakunlangan";
}

function eskiUsul(string $holat): string
{
    // Har safar QO'LDA tekshirish kerak
    $ruxsat = [EskiHolat::YANGI, EskiHolat::YUBORILGAN, EskiHolat::YAKUNLANGAN];
    if (!in_array($holat, $ruxsat, true)) {
        return "NOMA'LUM holat: {$holat}";
    }
    return "Holat: {$holat}";
}

echo eskiUsul(EskiHolat::YANGI) . "\n";
echo eskiUsul("qandaydir-narsa") . "\n";
echo "(satr bo'lgani uchun ISTALGAN qiymat kelishi mumkin)\n";

echo "\n" . str_repeat("=", 50) . "\n\n";

// PHP 8.1 dan: enum - noto'g'ri qiymatni TUR TIZIMI rad etadi
enum Holat: string
{
    case Yangi = "yangi";
    case Yuborilgan = "yuborilgan";
    case Yakunlangan = "yakunlangan";
    case Bekor = "bekor";

    // Enum ichida usul bo'lishi mumkin
    public function matni(): string
    {
        return match ($this) {
            Holat::Yangi       => "Yangi buyurtma",
            Holat::Yuborilgan  => "Yo'lda",
            Holat::Yakunlangan => "Yetkazildi",
            Holat::Bekor       => "Bekor qilingan",
        };
    }

    public function yakunlanganmi(): bool
    {
        return $this === Holat::Yakunlangan || $this === Holat::Bekor;
    }

    public function keyingisi(): ?Holat
    {
        return match ($this) {
            Holat::Yangi      => Holat::Yuborilgan,
            Holat::Yuborilgan => Holat::Yakunlangan,
            default           => null,
        };
    }
}

function yangiUsul(Holat $holat): string
{
    // Tekshirish KERAK EMAS - tur kafolatlaydi
    return sprintf("%-12s %-16s yakunmi: %s", $holat->value, $holat->matni(),
                   $holat->yakunlanganmi() ? "ha" : "yo'q");
}

foreach (Holat::cases() as $h) {
    echo yangiUsul($h) . "\n";
}

echo "\n";
echo "Zanjir: ";
$h = Holat::Yangi;
$yol = [$h->value];
while (($h = $h->keyingisi()) !== null) {
    $yol[] = $h->value;
}
echo implode(" -> ", $yol) . "\n";

enum Daraja: int
{
    case Nosozlik = 10;
    case Ogohlantirish = 20;
    case Xato = 30;
    case Halokat = 40;

    public function belgi(): string
    {
        return match ($this) {
            Daraja::Nosozlik      => "i",
            Daraja::Ogohlantirish => "!",
            Daraja::Xato          => "X",
            Daraja::Halokat       => "#",
        };
    }

    public static function engKamidan(int $qiymat): array
    {
        return array_values(array_filter(
            self::cases(),
            static fn(Daraja $d): bool => $d->value >= $qiymat
        ));
    }
}

echo "Barcha darajalar:\n";
foreach (Daraja::cases() as $d) {
    printf("  [%s] %-14s = %d\n", $d->belgi(), $d->name, $d->value);
}

echo "\n";
echo "Bazadan kelgan qiymatlarni aylantirish:\n";
foreach ([10, 30, 99] as $xom) {
    $d = Daraja::tryFrom($xom);
    printf("  %-4d -> %s\n", $xom, $d?->name ?? "(noma'lum - null)");
}

echo "\n";
echo "from() esa istisno tashlaydi:\n";
try {
    Daraja::from(99);
} catch (ValueError $x) {
    echo "  ValueError: " . $x->getMessage() . "\n";
}

echo "\n";
$jiddiy = Daraja::engKamidan(30);
echo "Xato va undan yuqori: " . implode(", ", array_column($jiddiy, "name")) . "\n";

final class Manzil
{
    public function __construct(
        public readonly string $shahar,
        public readonly ?string $kocha = null,
    ) {}

    public function toliq(): string
    {
        return $this->kocha === null ? $this->shahar : "{$this->shahar}, {$this->kocha}";
    }
}

final class Foydalanuvchi
{
    public function __construct(
        public readonly string $ism,
        public readonly ?Manzil $manzil = null,
    ) {}
}

$foydalanuvchilar = [
    new Foydalanuvchi("Husanboy", new Manzil("Namangan", "Alisher Navoiy ko'chasi")),
    new Foydalanuvchi("Malika", new Manzil("Toshkent")),
    new Foydalanuvchi("Nodira"),
];

echo "Nullsafe operatori (?->):\n";
foreach ($foydalanuvchilar as $f) {
    // Eski usul: $f->manzil !== null ? $f->manzil->toliq() : "noma'lum"
    printf("  %-10s %s\n", $f->ism, $f->manzil?->toliq() ?? "(manzil ko'rsatilmagan)");
}

echo "\n";
echo "Zanjir ham ishlaydi - birinchi null da to'xtaydi:\n";
foreach ($foydalanuvchilar as $f) {
    printf("  %-10s shahar: %s\n", $f->ism, $f->manzil?->shahar ?? "-");
}

echo "\n";
// Birinchi darajali chaqiriluvchi sintaksisi (PHP 8.1)
$ismlar = array_map(
    static fn(Foydalanuvchi $f): string => $f->ism,
    $foydalanuvchilar
);

echo "Birinchi darajali chaqiriluvchi (...):\n";
$kattaHarf = mb_strtoupper(...);          // funksiyaga HAVOLA
$uzunlik   = mb_strlen(...);

echo "  katta harf: " . implode(", ", array_map($kattaHarf, $ismlar)) . "\n";
echo "  uzunliklar: " . implode(", ", array_map($uzunlik, $ismlar)) . "\n";

echo "\n";
echo "Eski usul \"mb_strtoupper\" satri edi - unda:\n";
echo "  - muharrir funksiyani topa olmaydi\n";
echo "  - nomini xato yozsangiz, ish paytida bilinadi\n";
echo "  - qayta nomlash vositasi ishlamaydi\n";

final readonly class Sahifalash
{
    public function __construct(
        public int $sahifa = 1,
        public int $hajm = 20,
        public string $tartib = "sana",
        public bool $kamayish = true,
    ) {}

    public function ofset(): int
    {
        return ($this->sahifa - 1) * $this->hajm;
    }

    public function sql(): string
    {
        $yonalish = $this->kamayish ? "DESC" : "ASC";
        return sprintf(
            "ORDER BY %s %s LIMIT %d OFFSET %d",
            $this->tartib, $yonalish, $this->hajm, $this->ofset()
        );
    }

    // O'zgarmas obyektni "o'zgartirish" - YANGISINI qaytarish
    public function sahifaBilan(int $sahifa): self
    {
        return new self($sahifa, $this->hajm, $this->tartib, $this->kamayish);
    }
}

$s = new Sahifalash();
echo "Standart:        " . $s->sql() . "\n";

// Nomli argumentlar - faqat kerakligini beramiz
$s2 = new Sahifalash(hajm: 50, tartib: "narx");
echo "Nomli argument:  " . $s2->sql() . "\n";

$s3 = new Sahifalash(sahifa: 3, hajm: 10, kamayish: false);
echo "Uchinchi sahifa: " . $s3->sql() . "\n";

echo "\n";
$s4 = $s3->sahifaBilan(5);
echo "sahifaBilan(5):  " . $s4->sql() . "\n";
echo "Asl obyekt:      " . $s3->sql() . "\n";
echo "(o'zgarmadi - yangi obyekt qaytarildi)\n";

echo "\n";
try {
    $s3->sahifa = 99;
} catch (Error $x) {
    echo "readonly class himoyasi: " . $x->getMessage() . "\n";
}