Import Aliases in Tyhpdef

Tier 0 · Story 02Complete

Almost anything declared in a tyhpdef file can be aliased using the as keyword. Aliasing lets you expose PHP items under different names in Tyhp — renaming functions, classes, methods, properties, constants, and even enum cases. When an item is aliased, only the aliased name is available in Tyhp code; the original name is not accessible unless it is also imported separately without an alias. You can import the same PHP item multiple times with different aliases.

Use Statement Aliases

Tyhpdef supports standard PHP use statement syntax for importing and aliasing classes, functions, and constants from other namespaces. This includes single imports, aliased imports, and grouped imports.

<?tyhpdef

use App\Models\User;
use App\Models\Post as BlogPost;

use function App\Helpers\formatDate;
use function App\Helpers\sanitize as clean;

use const App\Config\MAX_RETRIES;
use const App\Config\DEFAULT_TIMEOUT as TIMEOUT;

Group Use Declarations

Multiple imports from the same namespace can be grouped using brace syntax, just like in PHP.

<?tyhpdef

use App\Models\{
    User,
    Post as BlogPost,
    Comment
};

use function App\Helpers\{
    formatDate,
    sanitize as clean,
    truncate
};

Function Aliases

Functions can be aliased at the declaration level. The original PHP function name comes first, then as, then the name Tyhp code will use.

<?tyhpdef

function \testEmail as test_email(string $emailAddress): bool;

function \array_key_exists as keyExists(
    int|string $key,
    array $array
): bool;

// Generic function with alias
function \array_map<T, U> as map(
    callable<T, U> $callback,
    array<T> $array
): array<U>;

Variable and Constant Aliases

<?tyhpdef

int $myGlobalPHPVar as $myGlobalTyhpVar;

const int \MAX_LOOPS_ALLOWED as MAX_LOOPS;

const string \APP_VERSION as VERSION;

Class, Interface, Trait, and Enum Aliases

Object type declarations can be aliased at the declaration level. The original PHP name is specified with as followed by the alias name that Tyhp will use.

<?tyhpdef

class Guest as Ghost implements Person {
    protected string $placeOfEntry as $placeOfHaunt;

    public function isFirstVisit as justDied(): bool;
}

interface BasketInterface as BucketInterface {}

trait HasTools as isHandyman {}

enum USAStates as CountryProvinces {}

Member Aliases Within Classes

Properties, methods, and constants within a class or interface declaration can be individually aliased. This lets you rename members without changing the underlying PHP class.

<?tyhpdef

class LegacyApi as Api {
    public string $usr_nm as $username;
    public string $eml_addr as $email;
    protected int $crt_dt as $createdAt;

    public function get_usr as getUser(int $id): ?User;
    public function upd_usr as updateUser(int $id, User $data): bool;
    public function del_usr as deleteUser(int $id): bool;
}

Enum Aliases with Backing Types

An enum can be imported multiple times with different aliases, and can even be given a backing type that differs from the original PHP enum definition.

<?tyhpdef

enum BadgeType as BackedBadgeType: string implements PersonalInfoAttachmentInterface {
    case GUEST;
    case EMPLOYEE;
    case MANAGER;
    case OWNER = 'o';

    public function canAccessBreakRoom as canAccessServerRoom(): bool;
}

Extension Import Aliases

Extension classes (Tyhp's extension method feature) can be imported with use extension and aliased using trait adaptation syntax.

<?tyhpdef

use extension StringExtensions {
    StringExtensions::toCamelCase as toCC;
    StringExtensions::toSnakeCase as toSC;
}

Alias Restrictions

Do not alias these — PHP dispatches them by their real names. This alpha does not reject the aliases at compile time:

• A class's __construct or __destruct method
• Any magic methods (__get, __set, __isset, __unset, __call, __callStatic, __sleep, __wakeup, __toString, __invoke, __clone, etc.)

Summary

• When an item is aliased, only the aliased name is available in Tyhp
• The same PHP item can be imported multiple times with different aliases
• Items imported multiple times with different aliases are treated as distinct types in Tyhp
• Tyhp compiles back to the original PHP names — aliases are a compile-time concept
• Alias names must be simple identifiers (no namespace separators)
• Use statement aliases follow standard PHP use ... as ... syntax
• Group use declarations with aliases are supported
• Class members (properties, methods, constants) can be individually aliased