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.
composer require dkulyk/enum
use DKulyk\Enum\Enum;
/**
* Action enum
*/
class Action extends Enum
{
const VIEW = 'view';
const EDIT = 'edit';
}
$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:
function setAction(Action $action) {
// ...
}
__construct()
The constructor checks that the value exist in the enum__toString()
You canecho $myValue
, it will display the enum value (value of the constant)getValue()
Returns the current value of the enumgetKey()
Returns the key of the current value on Enumequals()
Tests whether enum instances are equal (returnstrue
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 classvalues()
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 setisValidKey()
Check if tested key is valid on enum setsearch()
Return key for searched value
class Action extends Enum
{
const VIEW = 'view';
const EDIT = 'edit';
}
// Static method:
$action = Action::VIEW();
$action = Action::EDIT();
Static method helpers are implemented using __callStatic()
.
If you care about IDE autocompletion, you can either implement the static methods yourself:
class Action extends Enum
{
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):
/**
* @method static Action VIEW()
* @method static Action EDIT()
*/
class Action extends Enum
{
const VIEW = 'view';
const EDIT = 'edit';
}