How to create a class-valued variable?

Benjamin Schaaf ben.schaaf at
Wed Feb 20 04:29:36 UTC 2019

On Tuesday, 19 February 2019 at 22:04:58 UTC, Victor Porton wrote:
> What is the right way to store in a structure a class (not an 
> instance) derived from a given interface(s)?

What are you trying to do with the "class"? If you just want a 
static "reference" to it you can use an `alias`:

   class A {}
   struct B {
     alias C = A;
   new B.C();

If you want dynamic information on the type you can use TypeInfo:

   class A {}
   struct B {
     TypeInfo i;
   B b;
   b.i = typeid(A);

Or more simply if you just want to construct instances, just use 
a delegate:

   interface I {}
   class A : I {}
   struct B {
     I delegate() factory;
   B b;
   b.factory = () => new A();

You *can't* do something like the following because types need to 
be validated at compile time:

   struct A {
     Class cls;
   A a;
   a.cls b;;

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