Creating a new object from string of class name

I think that this has answered my question: https://php.net/manual/en/language.variables.variable.php

Thinking about this again, I'm not sure whether variable variables is the reason that this works. Variable variables would suggest I should be saying new $$mystr? But it works just going new $mystr... Very strange to me! What am I missing?

not sure how/why but I would expect these also to work

new 'My' . 'Model'

new $this->model

new $this->evaluateClass()

new is a php keyword, followed by the string of the name of the object to instantiate. Whether it's the classname, or a variable representing the string of the classname doesn't matter.

If a string containing the name of a class is used with new, a new instance of that class will be created. If the class is in a namespace, its fully qualified name must be used when doing this.

See the PHP docs for the new keyword: https://www.php.net/manual/en/language.oop5.basic.php

They have an example:

$instance = new SimpleClass();

// This can also be done with a variable:
$className = 'SimpleClass';
$instance = new $className(); // new SimpleClass()

// Way #1
$className = "App\MyClass";
$instance = new $className();

// ----------------------

// Way #2
$className = "App\MyClass";
$class = new \ReflectionClass($className);

// Create a new Instance without arguments:
$instance = $class->newInstance();

// Create a new Instance with arguments (need a contructor):
$instance = $class->newInstanceArgs(["Banana", "Apple"]);