Elao Enumerations

Provides additional, opinionated features to the PHP 8.1+ native enums as well as specific integrations with frameworks and libraries.

enum Suit: string implements ReadableEnumInterface
{
    use ReadableEnumTrait;

    #[EnumCase('suit.hearts')]
    case Hearts = 'H';

    #[EnumCase('suit.diamonds')]
    case Diamonds = 'D';

    #[EnumCase('suit.clubs')]
    case Clubs = 'C';

    #[EnumCase('suit.spades')]
    case Spades = 'S';
}

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📢 This project used to emulate enumerations before PHP 8.1.
For the 1.x documentation, click here

You can also consult this issue to follow objectives & progress for the V2 of this lib.

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Installation

composer require "elao/enum:^2.0@alpha"

Or, in order to help and test latest changes:

composer require "elao/enum:^2.x-dev"

Readable enums

Readable enums provide a way to expose human-readable labels for your enum cases, by adding a new ReadableEnumInterface contract to your enums.

The easiest way to implement this interface is by using the ReadableEnumTrait and the EnumCase attribute:

namespace App\Enum;

use Elao\Enum\ReadableEnumInterface;
use Elao\Enum\Attribute\EnumCase;

enum Suit: string implements ReadableEnumInterface
{
    use ReadableEnumTrait;

    #[EnumCase('suit.hearts')]
    case Hearts = 'H';

    #[EnumCase('suit.diamonds')]
    case Diamonds = 'D';

    #[EnumCase('suit.clubs')]
    case Clubs = 'C';

    #[EnumCase('suit.spades')]
    case Spades = 'S';
}

The following snippet shows how to get the human readable value of an enum:

Suit::Hearts->getReadable(); // returns 'suit.hearts'

It defines a proper contract to expose an enum case label instead of using the enum case internal name. Which is especially useful if the locale to expose labels to your users differs from the one you're writing your code, as well as for creating integrations with libraries requiring to expose such labels.

It's also especially useful in conjunction with a translation library like Symfony's Translation component, by using translation keys.

Given the following translation file:

# translations/messages.fr.yaml
suit.hearts: 'Coeurs'
suit.diamonds: 'Carreaux'
suit.clubs: 'Piques'
suit.spades: 'Trèfles'

$enum = Suit::Hearts;
$translator->trans($enum->getReadable(), locale: 'fr'); // returns 'Coeurs'

Flag enums

Flagged enumerations are used for bitwise operations.

namespace App\Enum;

enum Permissions: int
{
    case Execute = 1 << 0;
    case Write = 1 << 1;
    case Read = 1 << 2;
}

Each enumerated case is a bit flag and can be combined with other cases into a bitmask and manipulated using a FlagBag object:

use App\Enum\Permissions;
use Elao\Enum\FlagBag;

$permissions = FlagBag::from(Permissions::Execute, Permissions::Write, Permissions::Read);
// same as:
$permissions = new FlagBag(Permissions::class, 7); 
// where 7 is the "encoded" bits value for:
Permissions::Execute->value | Permissions::Write->value | Permissions::Read->value // 7

$permissions = $permissions->withoutFlags(Permissions::Execute); // Returns an instance without "execute" flag

$permissions->getValue(); // Returns 6, i.e: the encoded bits value
$permissions->getBits(); // Returns [2, 4], i.e: the decoded bits
$permissions->getFlags(); // Returns [Permissions::Write, Permissions::Read]

$permissions = $permissions->withoutFlags(Permissions::Read, Permissions::Write); // Returns an instance without "read" and "write" flags
$permissions->getBits(); // Returns []
$permissions->getFlags(); // Returns []

$permissions = new FlagBag(Permissions::class, FlagBag::NONE); // Returns an empty bag

$permissions = $permissions->withFlags(Permissions::Read, Permissions::Execute); // Returns an instance with "read" and "execute" flags

$permissions->hasFlags(Permissions::Read); // True
$permissions->hasFlags(Permissions::Read, Permissions::Execute); // True
$permissions->hasFlags(Permissions::Write); // False

Hence, using FlagBag::getValue() you can get an encoded value for any combination of flags from your enum, and use it for storage or communication between your processes.

Integrations

Symfony Form

Symfony already provides an EnumType for allowing the user to choose one or more options defined in a PHP enumeration.
It extends the ChoiceType field and defines the same options.

However, it uses the enum case name as label, which might not be convenient.
Since this library specifically supports readable enums, it ships its own EnumType, extending Symfony's one and using the human representation of each case instead of their names.

Use it instead of Symfony's one:

namespace App\Form\Type;

use App\Enum\Suit;
use Symfony\Component\Form\AbstractType;
use Elao\Enum\Bridge\Symfony\Form\Type\EnumType;
use Symfony\Component\Form\Extension\Core\Type\SubmitType;
use Symfony\Component\Form\FormBuilderInterface;

class CardType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options): void
    {
        $builder
            ->add('suit', EnumType::class, [
                'class' => Suit::class, 
                'expanded' => true,
            ])
        ;
    }

    // ...
}

Symfony HttpKernel

Resolve controller arguments from route path

As of Symfony 6.1+, backed enum cases will be resolved from route path parameters:

class CardController
{
    #[Route('/cards/{suit}')]
    public function list(Suit $suit): Response
    {
        // [...]
    }
}

➜ A call to /cards/H will resolve the $suit argument as the Suit::Hearts enum case.

If you're not yet using Symfony HttpKernel 6.1+, this library will still make this working by registering its own resolver.

Resolve controller arguments from query or body

You can also resolve from query params or from the request body:

use Elao\Enum\Bridge\Symfony\HttpKernel\Controller\ArgumentResolver\Attributes\BackedEnumFromQuery;

class DefaultController
{
    #[Route('/cards')]
    public function list(
        #[BackedEnumFromQuery]
        ?Suit $suit = null,
    ): Response
    {
        // [...]
    }
}

➜ A call to /cards?suit=H will resolve the $suit argument as the Suit::Hearts enum case.

Use BackedEnumFromBody to resolve from the request body ($_POST).

It also supports variadics:

use Elao\Enum\Bridge\Symfony\HttpKernel\Controller\ArgumentResolver\Attributes\BackedEnumFromQuery;

class DefaultController
{
    #[Route('/cards')]
    public function list(
        #[BackedEnumFromQuery]
        ?Suit ...$suits = null,
    ): Response
    {
        // [...]
    }
}

➜ A call to /cards?suits[]=H&suits[]=S will resolve the $suits argument as [Suit::Hearts, Suit::Spades].

Doctrine

As of doctrine/orm 2.11, PHP 8.1 enum types are supported natively:

#[Entity]
class Card
{
    #[Column(type: 'string', enumType: Suit::class)]
    public $suit;
}

⚠️ Unless you have specific needs for a DBAL type as described below, we recommend using the official ORM integration for backed enums.

PhpEnums however also provides some base classes to save your PHP backed enumerations in your database. In a near future, custom DBAL classes for use-cases specific to this library, such as storing a flag bag or a collection of backed enum cases, would also be provided.

In a Symfony app

This configuration is equivalent to the following sections explaining how to create a custom Doctrine DBAL type:

elao_enum:
  doctrine:
    types:
      App\Enum\Suit: ~ # Defaults to `{ class: App\Enum\Suit, default: null }`
      permissions: { class: App\Enum\Permission } # You can set a name different from the enum FQCN
      App\Enum\RequestStatus: { default: 200 } # Default value from enum cases, in case the db value is NULL

It'll actually generate & register the types classes for you, saving you from writing this boilerplate code.

Manually

Read the Doctrine DBAL docs first.

Extend the AbstractEnumType:

namespace App\Doctrine\DBAL\Type;

use Elao\Enum\Bridge\Doctrine\DBAL\Types\AbstractEnumType;
use App\Enum\Suit;

class SuitType extends AbstractEnumType
{
    protected function getEnumClass(): string
    {
        return Suit::class; // By default, the enum FQCN is used as the DBAL type name as well
    }
}

In your application bootstrapping code:

use App\Doctrine\DBAL\Type\SuitType;
use Doctrine\DBAL\Types\Type;

Type::addType(Suit::class, SuitType::class);

To convert the underlying database type of your new "Suit" type directly into an instance of Suit when performing schema operations, the type has to be registered with the database platform as well:

$conn = $em->getConnection();
$conn->getDatabasePlatform()->registerDoctrineTypeMapping(Suit::class, SuitType::class);

Then, use it as a column type:

use App\Enum\Suit;
use Doctrine\ORM\Mapping as ORM;

#[ORM\Entity]
class Card
{
    #[ORM\Column(Suit::class, nullable: false)]
    private Suit $field;
}