class Author

class Author {
    
    /** @var string */
    private $name;
    
    /** @var null|Email */
    private $email;
    public function __construct(string $name, ?Email $email = null) {
        $this->name = $name;
        $this->email = $email;
    }
    public function asString() : string {
        if (!$this->hasEmail()) {
            return $this->name;
        }
        return sprintf('%s <%s>', $this->name, $this->email
            ->asString());
    }
    public function getName() : string {
        return $this->name;
    }
    
    /**
     * @psalm-assert-if-true Email $this->email
     */
    public function hasEmail() : bool {
        return $this->email !== null;
    }
    public function getEmail() : Email {
        if (!$this->hasEmail()) {
            throw new NoEmailAddressException();
        }
        return $this->email;
    }

}