About Classes as Unions

the .ice file is

class base
{
int d;
};
class stringbase extends base
{
string s;
};
class Hello
{
nonmutating void sayHello(base i);
idempotent void shutdown();
};
....

In the implement file , in the function

void sayHello(base i);
How can I dynamic_cast or static_cast the base pointer to stringbase pointer?

In C++, you can use the smart pointer dynamicCast method:

   void sayHello(basePtr i)
   {
         stringbasePtr s  = stringbasePtr::dynamicCast(i);
   }

In Java, you can just do a regular dynamic cast:

   void sayHello(base i)
   {
         stringbase s = (stringbase)i;
   }

Benoit.

It's ok
Thank a lot .