Subclass Type

[Mason Green]

Hi, does anyone know how to return a Subclass's type?  I would like to create a new instance of the subclass based on its type. Here is my example code....

class FooBar {

 
class Foo : FooBar {
       
    this() {
        super(1);
    }
    
    override void printKey() {
        Stdout(key).newline;
    }    
    
}

class Bar : FooBar {

    this() {
        super(2);
    }
    
    override void printKey() {
        Stdout(key).newline;
    }
}

void main() {

    FooBar x = new Foo();
    FooBar y = new typeof(x);
    
    x.key++;
    y.printKey(); // This prints 0. I want it to print 1
    
}

As is, y is created as type FooBar.  Instead I would like to be of type Foo. i.e the equivalent of:

FooBar y = new Foo();

I've seen this done in other languages such as ActionScript fairly easily:

public function createJoint(data:JointData):Joint
{	
    var c:Class = data.getJointClass();		
    var j:Joint = new c(data) as Joint;
}

In this case, Joint is the superclass.  data.getJointClass returns the subclass type.  j is created as a new subclass. The normal D equivalent would be:

Joint j = new MouseJoint();  // or some other subclass that getJointClass     
                                        // returns.

Thanks,
Mason