🚀 go-pugleaf

In <MATT.95Sep9122342@physics10.Berkeley.EDU>, jason@cygnus.com (Jason Merrill) writes:
>Hmm?  What about
>
>if (Derived *p = dynamic_cast<Derived*>(possible_derived))

That is the approach I would take if the full capability is
not available.  This does not handle all of the cases of
interest, however.  It only handles the case of an object
relative to a known class.  It does not handle the case of
two objects, nor the case of two class names.  It also
does not handle the case where you have references to
two type_info instances.

The problem is that the above approach uses the side
effect of dynamic_cast<> returning a null pointer if
the case fails.  This only works where you have an
object to be casted, and further the cast itself requires
a know type.

It will, however, handle many cases of interest and is
an excellent approach.  The only difference is that
I would encasulate the test inside of an inline operator
defintion, because I don't really WANT the case, I want
the information about the inheritance dag.

Michael Lee Finney


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