Krdytkyu

I have used Enum objects before in PHP as shown here.

However, I often find it's a requirement to have further attributes or metadata available on the instances.

I came up with the example solution below:

<?php



class Month {

    const January = 1;

    const February = 2;

    const March = 3;

    const April = 4;

    const May = 5;

    const June = 6;

    const July = 7;

    const August = 8;

    const September = 9;

    const October = 10;

    const November = 11;

    const December = 12;



    protected $value;



    protected static $metadata = [

        1 => ['days_in_month' => 31],

        2 => ['days_in_month' => 28],

        3 => ['days_in_month' => 31], 

        4 => ['days_in_month' => 30], 

        5 => ['days_in_month' => 31], 

        6 => ['days_in_month' => 30], 

        7 => ['days_in_month' => 31], 

        8 => ['days_in_month' => 31], 

        9 => ['days_in_month' => 30], 

        10 => ['days_in_month' => 31], 

        11 => ['days_in_month' => 30], 

        12 => ['days_in_month' => 31]

    ];



    public function __construct($value)

    {

        $this->value = $value;

    }



    public function __get($name)

    {

        if (array_key_exists($name, static::$metadata[$this->value])) {

            return static::$metadata[$this->value][$name];

        }

    }

}



$month = new Month(Month::February); // Returns Month instance

$month->days_in_month; // Returns 28 (for February)

Obviously the metadata array can be expanded to include further attributes that should be available for each enumerable option. And of course this need to throw exceptions / handle problems.

Feedback appreciated. Is there a better way to have an Enumerable-type approach which can include additional attributes?

February doesn't necessarily have 28 days. In some years, it has 29 days. This code produces the wrong answer for around ¼ of Februaries.