Enums

A PHP 8.1 enum defines a fixed, named set of values — safer than a string or int constant, since the compiler rejects anything not in the list.

enum Status
{
    case Active;
    case Inactive;
    case Banned;
}

function describe(Status $status): string
{
    return match ($status) {
        Status::Active => 'User is active',
        Status::Inactive => 'User is inactive',
        Status::Banned => 'User is banned',
    };
}

A backed enum attaches a scalar value to each case (useful for storing in a database):

enum Status: string
{
    case Active = 'active';
    case Inactive = 'inactive';
}

echo Status::Active->value; // "active"
echo Status::from('active') === Status::Active; // true