Re: [boost] [smart_ptr/static_pointer_cast] Trying to make ADL useful in my boost libraries

From: Ion Gaztañaga (igaztanaga_at_[hidden])
Date: 2006-06-16 14:02:19

> Please ignore the previous code. Kindly consider the following:
> 
> template<class T> struct type {};
> 
> // static_pointer_cast_impl overload for raw pointers
> template<class T, class U>
> inline T* static_pointer_cast_impl(U *ptr, type<T>)
> {
>      return static_cast<T*>(ptr);
> }
> 
> // static_pointer_cast ADL dispatcher function
> template<class T, class U>
> inline T static_pointer_cast(U u)
> {
>      return static_pointer_cast_impl(u, type<T>()); // ADL kicks in here
> }
> 
> // ...
> 
> template<class T> class smart_ptr { /* ... */ };
> 
> // static_pointer_cast_impl overload for raw smart_ptr
> template<class T, class U>
> inline smart_ptr<T> static_pointer_cast_impl(smart_ptr<U> const& p, type<T>)
> {
>      return smart_ptr<T>(p.get());
> }

Seems ok, although "type<T>" could be something like 
"cast_to_pointer<T>". Whatever we choose, I think we should add it to 
"shared_ptr" and "intrusive_ptr", and define well-known boost ADL 
casting functions.

Current "xxx_pointer_cast" is in TR1, so I don't know if we have arrived 
late for an standard C++ ADL friendly cast functions. Peter?

Regards,

Ion