oop - Get all defined classes of a parent class in php

Question

I need to determine, after all files have been included, which classes extend a parent class, so:

class foo{
}
class boo extends foo{
}
class bar extends foo{
}

and I'd like to be able to grab an array like:

array('boo','bar');

Answer 1

If you need that, it really smells like bad code, the base class shouldn't need to know this.

However, if you definitions have been included (i.e. you don't need to include new files with classes you possibly have), you could run:

$children  = array();
foreach(get_declared_classes() as $class){
    if($class instanceof foo) $children[] = $class;
}