README

Lightweight implementation of enum value object in PHP.

Installation

Use Composer to install the package:

composer require intraworlds/enum

Usage

Extend IW\Enum and add arbitrary constants which becomes your enum keys.

final class Hash extends Enum
{
  const MD5 = 'md5';
  const SHA1 = 'sha1';
}

Obtain instance of enum value by calling static function <classname>::<key>().

$md5 = Hash::MD5();

Main advantage of use this library is of cource type hinting. Therefore given instance is always valid in principle of DDD value object.

function crack(Hash $hash) {
  echo 'cracking ... ' . $hash; // notice that enum is implementing __toString() method
}

crack(Hash::SHA1()); // cracking ... sha1
crack(Hash::SHA1);   // throws TypeError

The function is returning a singleton so you can compare it with ===

var_dump($md5 === MD5()); // true
var_dump($md5 === SHA1()); // false

Actually you must use === for strict comparison. With == loose comparison PHP compares only that objects are the same class.

var_dump($md5 == MD5()); // true
var_dump($md5 == SHA1()); // true - DON'T use == comparison!

Access actual value with method getValue()

var_dump($md5->getValue() === Hash::MD5); // true

Switch statements must be defined by values because of loose comparison.

switch ($hash->getValue()) {
  case Hash::MD5: ...
  case Hash::SHA1: ...
}

You can user method search() for obtaining instance of enum by a value.

$contentType = ContentTypeEnum::search(apache_request_headers()['Content-Type']);

PHPStan integration

This library is distributed with PHPStan extension which's providing magic methods reflection. Just add following configuration to your phpstan.neon

services:
    -
        class: IW\PHPStan\Reflection\EnumMethodsReflectionExtension
        tags:
            - phpstan.broker.methodsClassReflectionExtension

Alternatives

we took most of the inspiration from library myclabs/php-enum. It's nice implementation but it's missing singletons and it's not optimized for PHP7.
PHP's SplEnum needs an extension and also does not support singletons.

License

All contents of this package are licensed under the MIT license.

intraworlds / enum

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