[boost] Re: Perfect moving (almost)

From: David Abrahams (dave_at_[hidden])
Date: 2004-02-11 16:21:08

"Powell, Gary" <powellg_at_[hidden]> writes:

> One other thing that makes writing base class and derived classes easier is to add this to the ref struct
>
> class X {
>    ....
> private:
>    struct ref {
>       ref (X *rhs) : p (rhs) {}
>
>       template<class T>           // new
>       ref (T *rhs) : p(rhs) {}    // compiles if T is derived from X.
>
>       X *p;
>   };
>
> .....
> };
>
>   Then in the derived class you can call:
>
> class Y : public X {
>
> ....
>
>    Y(ref rhs)
>    : X (rhs.p)   // no cast needed to call X::ref 
>    , id(++cnt)
>    , owner(true)
>    {
>     ....
>    }
>
> ....
> };
>
>
> Anyway the more I play with this the better I like it.

If Rani is right about the reference binding I'd like to find some way
to library-ize this idiom, so your "ref" converting constructor will
come in handy.  BTW, you don't need the other "ref" constructor
anymore.

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com