On Wed, Apr 15, 2009 at 12:25 PM, Steven Watanabe wrote:
Dominique Devienne wrote:
So I used covariant return type, which AFAIK works only for raw
pointers. If I were to remove the raw pointer accessors, I'd have to
do either:
I would probably use a non-member template that
encapsulates the necessary logic:
template<class T>
shared_ptr<typename T::IdentType> getIdent(T& t);
I have:
template <class T> shared_ptr<typename T::ident_type> ident_of(T* t) {
BOOST_STATIC_ASSERT((is_base_of::value));
return static_pointer_cast<typename T::ident_type>(t->ident());
}
template <class T> shared_ptr<typename T::ident_type const>
ident_of(const T* t) {
BOOST_STATIC_ASSERT((is_base_of::value));
return static_pointer_cast<typename T::ident_type const>(t->ident());
}
but it chokes on:
scoped_ptr<Car> z(new Car("nissan", "370Z"));
ident_of(z)->set_make("datsun");
error C2784: 'boost::shared_ptr ident_of(T *)' :
could not deduce template argument for 'T *' from 'boost::scoped_ptr<T>'
Instead of doing overloads for various smart pointer types, is it
possible (and easy) to do the ChainedPtr thing that B.MI does for the
ident_of template functions above?
Thanks, --DD
