class lisp::RefType
{
public:
  RefType(TypeClass* type) :typeClass(type), refCount(1), weakRefCount(1) {}


  //type info pointer stored directly.
  TypeClass* typeClass;   //if it's cloneable etc. It'll actually be part of the typeclass, not the vtable.  typeClass pretty much replaces vtables here.

  //other refcounting functions here....
  int refCount, weakRefCount;
protected:
  ~RefType(){}  //deleted only by refcounting - heap object.  note it's non-virtual
  //unassignable, unmoveable.
};



class Array : public lisp::RefType
{
  public:
  Array() : RefType(reflect()) {}

  static TypeClass* reflect();

  //functions....


  private:
  Vector<lisp::Expr> data;
};

//inside s-expr

class Expr
{

...
void setRefType(RefType* refType){...}
RefType* refType(){} //getter

template <typename T>
T* refClass()
{
  if (auto out = refType())
  {
    if (T::reflect() == out->typeClass) return static_cast<T*>(out);
  }
  return nullptr;
}

{

}


}