Re: [boost] Sealed C++ class (Correct template friends by Matthew Wilson, refactored. Please review)

From: David Abrahams (dave_at_[hidden])
Date: 2006-04-08 10:51:46

Vladislav Lazarenko <snail_at_[hidden]> writes:

> # define BOOST_DECLARE_TEMPLATE_FRIEND(T)           \
>    namespace boost { namespace template_friend {     \
>      struct friend_maker {                           \
>        typedef T T2;                                 \
>      };                                              \
>      typedef typename friend_maker::T2 friend_type;  \
>      friend friend_type;

<snip>

Okay, this macro opens new namespaces whereever I use it.

> namespace boost
> {
>    // protection from unintended ADL
>    namespace sealed_
>    {
>      template <typename T1, typename T2>
>      class sealed_impl
>      {
>        BOOST_DECLARE_TEMPLATE_FRIEND(T1);
>        BOOST_DECLARE_TEMPLATE_FRIEND(T2);

And here we are opening namespace within a class template body.  Last
time I checked that was illegal.

What am I missing?

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