On Friday, 16 August 2013 at 15:12:03 UTC, Joseph Rushton
Wakeling wrote:
Hi all,
I'm writing some class-based code and so my concerns have
turned to the issue of
final classes vs. inheritance.
Suppose that you want a particular class to be able to act as a
base class, but
also to perform at top speed. Is the following kind of pattern
worth considering:
class _A
{
// ... implementation, with virtual functions
}
final class A : _A
{
// ... don't add anything!
}
...? Or are there other recommended ways to handle how to get
speed while still
allowing the option of inheritance?
Thanks & best wishes,
-- Joe
Can you describe how this helps?
Sure, if you use A the compiler should be able to optimize method
calls but you can't use A in inheritance because it is a final
class. e.g.,
A a = new _A; // wrong
_A a = new A; // right, but a will use virtual functions.
The final class only prevents class B : A AFAIK but the vtable is
still intact.
