Re: [boost] Indirect PTS( was Re: typeof integrated

From: Peder Holt (peder.holt_at_[hidden])
Date: 2004-12-10 07:03:47

On Fri, 10 Dec 2004 04:49:41 -0700, Larry Evans
<cppljevans_at_[hidden]> wrote:
> On 12/10/2004 03:19 AM, Peder Holt wrote:
> [snip]
> > Still, the problem in his post applies to typedefs.
> > If A<T>::B is a nested class or struct under A<T>, and not a typedef,
> > deduction should always be possible.
> Yes.  Our posts crossed.  I had same idea.
> >
> > In the case where B is a typedef:
> > typedef typename some_class<T> B;
> > you can deduce some_class<T> instead of A<T>::B
> 
> Do you mean in the case of Roni's example, that
> you can deduce by substitution, i.e.
> 
>    can_deduce: select<B, int, int *>::type
>    --substitute-->
>    can_deduce: select<(C1<T>::value != C2<T>::value), int, int *>::type
> 
> ?

Nope. 
can_deduce<T>::type is either int or int*, so we need to make
specializations for int and int*, and can ignore can_deduce<T>
altogether.

Type deduction of nested typedefs would as far as I can see require that
can_deduce<T>::type be a separate type from int and int*. 
> 
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