lmh/enum

PHP 7.1 enum implementation

1.0.8 2020-10-14 02:19 UTC

Requires

• php: >=7.1.0

MIT

• map
• enum

README

Usage

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());

More complex example

Of course, all enums are singletons, which are not cloneable or serializable. Thus you can be sure that there is always just one instance of the same type. Of course, the values of constants are not completely useless, let's have a look at a more complex example:

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));
}