Different ways of a UUID-implementation

function.php

<?php 

function myFunction(\UUID $uuid) { echo $uuid->toString(); }

function myOtherFunction(\UUIDInterface $uuid) { echo $uuid->toString(); }

// No way!
myFunction(\Acme\UUID1::v4());
// Would work, but: really?
myFunction(\Acme\UUID1::v4()->getUUIDObject())

// would work
myFunction(\Acme\UUID2::v4());

// Could work
myOtherFunction(\Acme\UUID3::v4());

UUID1.php

<?php
namespace Acme;

class UUID1 
{
  private $uuid;
  
  public static function v4() { return new self(\UUID::v4())
  
  private function __construct(\UUID $uuid) { $this->uuid = $uuid; }
  
  public function toString() { return $this->uuid->toString(); }
  
  public function toBin() { return $this->uuid->toBin(); }
  
  public function toHex() { return $this->uuid->toHex(); }
  
  public function toArray() { return explode('-', $this->uuid->toString()); }
                               
  public function getUUIDObject() { return $this->uuid; }
}

UUID2.php

<?php
namespace Acme;

class UUID2 extends \UUID 
{
  public function toArray() { return explode('-', $this->toString()); }
}

UUID3.php

<?php
namespace Acme;

class UUID implements \UUIDInterface
{
  private $uuid;
  
  public static function v4() { return new self(\UUID::v4())
  
  private function __construct(\UUID $uuid) { $this->uuid = $uuid; }
  
  public function toString() { return $this->uuid->toString(); }
  
  public function toBin() { return $this->uuid->toBin(); }
  
  public function toHex() { return $this->uuid->toHex(); }
  
  public function toArray() { return explode('-', $this->uuid->toString()); }
}