# PHP Enum implementation inspired from SplEnum [](https://travis-ci.org/myclabs/php-enum) [](https://packagist.org/packages/myclabs/php-enum) [](https://packagist.org/packages/myclabs/php-enum) ## Why? First, and mainly, `SplEnum` is not integrated to PHP, you have to install it separately. Using an enum instead of class constants provides the following advantages: - You can type-hint: `function setAction(Action $action) {` - You can enrich the enum with methods (e.g. `format`, `parse`, …) - You can extend the enum to add new values (make your enum `final` to prevent it) - You can get a list of all the possible values (see below) This Enum class is not intended to replace class constants, but only to be used when it makes sense. ## Installation ``` composer require myclabs/php-enum ``` ## Declaration ```php use MyCLabs\Enum\Enum; /** * Action enum */ class Action extends Enum { private const VIEW = 'view'; private const EDIT = 'edit'; } ``` Note the `private` keyword requires PHP > 7.1, you can omit it on PHP 7.0. ## Usage ```php $action = new Action(Action::VIEW); // or $action = Action::VIEW(); ``` As you can see, static methods are automatically implemented to provide quick access to an enum value. One advantage over using class constants is to be able to type-hint enum values: ```php function setAction(Action $action) { // ... } ``` ## Documentation - `__construct()` The constructor checks that the value exist in the enum - `__toString()` You can `echo $myValue`, it will display the enum value (value of the constant) - `getValue()` Returns the current value of the enum - `getKey()` Returns the key of the current value on Enum - `equals()` Tests whether enum instances are equal (returns `true` if enum values are equal, `false` otherwise) Static methods: - `toArray()` method Returns all possible values as an array (constant name in key, constant value in value) - `keys()` Returns the names (keys) of all constants in the Enum class - `values()` Returns instances of the Enum class of all Enum constants (constant name in key, Enum instance in value) - `isValid()` Check if tested value is valid on enum set - `isValidKey()` Check if tested key is valid on enum set - `search()` Return key for searched value ### Static methods ```php class Action extends Enum { private const VIEW = 'view'; private const EDIT = 'edit'; } // Static method: $action = Action::VIEW(); $action = Action::EDIT(); ``` Static method helpers are implemented using [`__callStatic()`](http://www.php.net/manual/en/language.oop5.overloading.php#object.callstatic). If you care about IDE autocompletion, you can either implement the static methods yourself: ```php class Action extends Enum { private const VIEW = 'view'; /** * @return Action */ public static function VIEW() { return new Action(self::VIEW); } } ``` or you can use phpdoc (this is supported in PhpStorm for example): ```php /** * @method static Action VIEW() * @method static Action EDIT() */ class Action extends Enum { private const VIEW = 'view'; private const EDIT = 'edit'; } ``` ## Related projects - [Doctrine enum mapping](https://github.com/acelaya/doctrine-enum-type) - [Symfony 2/3 ParamConverter integration](https://github.com/Ex3v/MyCLabsEnumParamConverter)