On Mon, 2003-12-01 at 02:11, Glen Mazza wrote:
> --- John Austin <[EMAIL PROTECTED]> wrote:
> > I mentioned yesterday that I thought I had read a
> BTW, The third drawback listed in the link above gave
> "weak references" as an alternative implmentation--I'm
> unsure what that construct is about--is this the
> vtable you were speaking of in an earlier message?
The Vtable is used to dispatch virtual functions in (some
implementations) of C++. There is one such table for each class
and it contains a pointer to each virtual function defined. Each
object holds a pointer to it's actual class vtable. This is the
mechanism used to implement polymorphism for C++ virtual functions.
I think a similar means can be used for the inheritence of
properties in FOP.
class a {
virtual int f() { return 3; }
}
class b : a {
virtual int f() { return 33; }
}
...
a* z = new b;
cout << "a" << z->f() << endl;
class a vTable contains address of a::f()
b b::f()
instance z includes pointer to the class b vTable
and is function b::f() is called using pointer to
object of type a.
--
John Austin <[EMAIL PROTECTED]>
