Implementing Class Instantiation from a Variable in PHP

In PHP, you may encounter a scenario where you need to instantiate a class from a variable's value. Let's illustrate this with an example:

$var = 'bar';
$bar = new {$var}Class('var for __construct()'); //$bar = new barClass('var for __construct()');

This method attempts to create an instance of the class specified by the $var variable. However, PHP does not support this syntax natively.

Alternative Approach without eval()

To achieve this without using eval(), you can utilize a variable to hold the class name:

$classname = $var . 'Class'; // e.g. $classname = 'barClass'

$bar = new $classname('var for __construct()');

Factory Pattern

This technique is often employed in the Factory pattern, which is used to centralize class creation and decouple it from the creation process. In such scenarios, a factory class would create the desired class instances dynamically based on configuration or other parameters.

Further Resources

For more information on dynamic language features andnamespaces, refer to the following resources:

• [Namespaces](https://www.php.net/manual/en/language.namespaces.php)
• [Dynamic Language Features](https://www.php.net/manual/en/language.types.dynamic.php)