README

使用方法

use Lmh\Enum\AbstractEnum;

/**
 * @method static self MONDAY()
 * @method static self TUESDAY()
 * @method static self WEDNESDAY()
 * @method static self THURSDAY()
 * @method static self FRIDAY()
 * @method static self SATURDAY()
 * @method static self SUNDAY()
 */
final class WeekDay extends AbstractEnum
{
    protected const MONDAY = null;
    protected const TUESDAY = null;
    protected const WEDNESDAY = null;
    protected const THURSDAY = null;
    protected const FRIDAY = null;
    protected const SATURDAY = null;
    protected const SUNDAY = null;
}

function tellItLikeItIs(WeekDay $weekDay)
{
    switch ($weekDay) {
        case WeekDay::MONDAY():
            echo 'Mondays are bad.';
            break;
            
        case WeekDay::FRIDAY():
            echo 'Fridays are better.';
            break;
            
        case WeekDay::SATURDAY():
        case WeekDay::SUNDAY():
            echo 'Weekends are best.';
            break;
            
        default:
            echo 'Midweek days are so-so.';
    }
}

tellItLikeItIs(WeekDay::MONDAY());
tellItLikeItIs(WeekDay::WEDNESDAY());
tellItLikeItIs(WeekDay::FRIDAY());
tellItLikeItIs(WeekDay::SATURDAY());
tellItLikeItIs(WeekDay::SUNDAY());

更复杂的示例

当然，所有的枚举都是单例，不能克隆或序列化。因此，您可以确信总是只有一个相同类型的实例。当然，常量的值并非完全无用，让我们看看一个更复杂的示例

use Lmh\Enum\AbstractEnum;

/**
 * @method static self MERCURY()
 * @method static self VENUS()
 * @method static self EARTH()
 * @method static self MARS()
 * @method static self JUPITER()
 * @method static self SATURN()
 * @method static self URANUS()
 * @method static self NEPTUNE()
 */
final class Planet extends AbstractEnum
{
    protected const MERCURY = [3.303e+23, 2.4397e6];
    protected const VENUS = [4.869e+24, 6.0518e6];
    protected const EARTH = [5.976e+24, 6.37814e6];
    protected const MARS = [6.421e+23, 3.3972e6];
    protected const JUPITER = [1.9e+27, 7.1492e7];
    protected const SATURN = [5.688e+26, 6.0268e7];
    protected const URANUS = [8.686e+25, 2.5559e7];
    protected const NEPTUNE = [1.024e+26, 2.4746e7];
    
    /**
     * Universal gravitational constant.
     *
     * @var float
     */
    private const G = 6.67300E-11;
    
    /**
     * Mass in kilograms.
     *
     * @var float
     */
    private $mass;

    /**
     * Radius in meters.
     *    
     * @var float
     */    
    private $radius;
    
    protected function __construct(float $mass, float $radius)
    {
        $this->mass = $mass;
        $this->radius = $radius;
    }
    
    public function mass() : float
    {
        return $this->mass;
    }
    
    public function radius() : float
    {
        return $this->radius; 
    }
    
    public function surfaceGravity() : float
    {
        return self::G * $this->mass / ($this->radius * $this->radius);
    }
    
    public function surfaceWeight(float $otherMass) : float
    {
        return $otherMass * $this->surfaceGravity();
    }
}

$myMass = 80;

foreach (Planet::values() as $planet) {
    printf("Your weight on %s is %f\n", $planet, $planet->surfaceWeight($myMass));
}