PHP enum

Simple and fast implementation of enumerations

Introduction

Definition

In computer programming, an enumerated type (also called enumeration or enum) is a data type consisting of a set of named values called elements, members or enumerators of the type. — Wikipedia

SplEnum

SplEnum is not integrated to PHP, you have to install it separately:

$ sudo pecl install SPL_Types.

In addition, it's not a panacea:

class Month extends SplEnum {
    const JANUARY  = 1;
    const FEBRUARY = 2;
}

class Fruit extends SplEnum {
    const APPLE  = 1;
    const ORANGE = 2;
}

// you must create new instance before each use:
$jan   = new Month(Month::JANUARY);
$jan2  = new Month(Month::JANUARY);
$apple = new Fruit(Fruit::APPLE);

var_dump($jan === $jan2);          // false
var_dump($jan === Month::JANUARY); // false
var_dump($jan ==  Fruit::APPLE);   // true

Benchmark

Enum benchmark on PHP 7

$ tests/benchmark/enum.php 100000

 ------------------------------- ------------ --------------
  Test                            Memory Avg   Duration All
 ------------------------------- ------------ --------------
  Reflection enum                 1.52 KiB     1820 ms
  Reflection enum (no magic)      1.52 KiB     1718 ms
  Explicit enum                   0.71 KiB     959 ms
  myclabs/php-enum                0.68 KiB     1971 ms
  marc-mabe/php-enum              1.59 KiB     2219 ms
  marc-mabe/php-enum (no magic)   1.59 KiB     1969 ms
  happy-types/enumerable-type     1.81 KiB     2322 ms
 ------------------------------- ------------ --------------

Set benchmark on PHP 7

$ tests/benchmark/set.php 100000

 -------------------- ------------ --------------
  Test                 Memory Avg   Duration All
 -------------------- ------------ --------------
  Reflection set       1.36 KiB     1238 ms
  marc-mabe/php-enum   1.59 KiB     2861 ms
 -------------------- ------------ --------------

How to get enum with default value?

final class Color extends ReflectionEnum implements EnumDefault
{
    const RED = 1;
    const GREEN = 2;
    const BLUE = 3;

    /**
     * @return Color
     */
    public static function byDefault()
    {
        return self::byValue(self::RED);
    }
}