Enums in Tyhpdef

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Tyhpdef lets you describe existing PHP enums to the Tyhp compiler. PHP supports two kinds of enums: unit enums (no backing value) and backed enums (each case has a string or int value). Both are fully supported in Tyhpdef, along with methods, interface implementations, and constants.

Unit Enums

A unit enum has no backing type. Each case is a standalone value with no associated scalar.

<?tyhpdef

enum Status {
    case Active;
    case Pending;
    case Deleted;
}

Backed Enums

A backed enum associates each case with a scalar value of a specific type — either string or int. When importing a backed enum in Tyhpdef, specifying case values is optional. The checker validates values that are present; omitted values are not treated as “matches any int/string.” Prefer listing known values when you have them.

<?tyhpdef

// String-backed enum
enum HttpMethod: string {
    case GET = "GET";
    case POST = "POST";
    case PUT = "PUT";
    case DELETE = "DELETE";
    case PATCH = "PATCH";
}

// Int-backed enum — values optional
enum LogLevel: int {
    case Debug = 0;
    case Info;
    case Warning;
    case Error = 3;
    case Critical;
}

Enums with Methods

PHP enums can have methods. In Tyhpdef, you declare the method signatures just like class methods — signatures only, ending with semicolons.

<?tyhpdef

enum Color: string {
    case Red = "#FF0000";
    case Green = "#00FF00";
    case Blue = "#0000FF";

    public function toRgb(): array<int>;
    public function darken(float $amount): string;
    public static function fromRgb(int $r, int $g, int $b): self;
}

Enums with Interface Implementation

Enums can implement interfaces. The implements clause follows the backing type (if any), and the interface methods are declared within the enum body.

<?tyhpdef

enum Permission: int implements \Stringable {
    case None = 0;
    case Read = 1;
    case Write = 2;
    case Admin = 4;

    public function __toString(): string;
    public function includes(self $other): bool;
}

Enum Constants

Enums can declare constants, just like classes.

<?tyhpdef

enum Suit: string {
    case Hearts = "H";
    case Diamonds = "D";
    case Clubs = "C";
    case Spades = "S";

    public const int TOTAL_SUITS;
    public const array<string> RED_SUITS;
}

Enum Aliasing

The same PHP enum can be imported multiple times with different aliases. This is useful when you need to import an enum under a different name or re-import it with different backing type information.

<?tyhpdef

// Import as unit enum (no backing type)
enum BadgeType {
    case GUEST;
    case EMPLOYEE;
    case MANAGER;
}

// Same enum imported with alias and backing type
enum BadgeType as BackedBadgeType: string {
    case GUEST;
    case EMPLOYEE = "emp";
    case MANAGER;
}

Deprecated and Obsolete

The enum itself can be marked deprecated or obsolete (top-level). Markers on cases and methods parse but are not enforced in this alpha.

<?tyhpdef

deprecated enum LegacyPriority: int {
    case Low = 0;
    case Medium = 1;
    case High = 2;
    case Urgent = 3;
}

Best Practices