Collection of entities

Another common use cases could be to have an unknown number of entities. Our User may want to specify multiple addresses.

You can do it like this:

User.php

use Formal\ORM\{
    Id,
    Definition\Contains,
};
use Innmind\Immutable\Set;

final readonly class User
{
    /**
     * @param Id<self> $id
     * @param Set<Address> $address
     */
    private function __construct(
        private Id $id,
        private Name $name,
        #[Contains(Address::class)]
        private Set $addresses,
    ) {}

    public static function new(Name $name): self
    {
        return new self(Id::new(self::class), $name, Set::of());
    }

    public function name(): Name
    {
        return $this->name;
    }

    public function rename(Name $name): self
    {
        return new self($this->id, $name, $this->addresses);
    }

    public function addAddress(Address $address): self
    {
        return new self(
            $this->id,
            $this->name,
            $this->addresses->add($address),
        );
    }
}

This is very similar to optional entities.

The Set monad represents an unordered collection of unique values.

Warning

When a Set contains objects, the uniqueness is defined by the reference of the objects and not their values.

This means that these 2 sets are not the same:

$address = new Address('foo', 'bar', 'baz');
$set1 = Set::of($address, $address);
$set2 = Set::of(
    new Address('foo', 'bar', 'baz'),
    new Address('foo', 'bar', 'baz'),
);

$set1 only contains 1 Address while $set2 contains 2.

Note

If you're not familiar with the Set monad you can head to this documentation describing all its methods.