[boost] Re: "invariants" class; Version 1.00

From: Dan W. (danw_at_[hidden])
Date: 2004-01-09 01:13:20

Daniel Wallin wrote:
>   template<class T>
>   struct B
>   {
>      struct type {};
>   };
>   template<class T>
>   struct A : B<A<T> >
>   {
>      void f()
>      {
>          /* typename */ B<A<T> >::type x;
>          /* ^^^^^^^^ needed here */
>      }
>   };
...
> You can try this example, which does the same thing that your code
> does, out at:
> 
>   http://www.comeaucomputing.com/tryitout/

You're absolutely right. Thanks. Handy link to have.
I've ended up with something pretty similar to your solution, no more 
inheritance, etc. Now I have a problem: your trick of assigning a 
temporary to a reference on the stack doesn't seem to work on my 
compiler. Is that required to work in the standard? Namely,

struct base {};

struct derived {};

derived make_temp_derived(){ return derived; }

//scope..
{
    base const & b = make_temp_derived();
    ...
} <- the created temporary should last till here?