Re: [boost] [fusion] joint_view bug?

Subject: Re: [boost] [fusion] joint_view bug?
From: Joel de Guzman (joel_at_[hidden])
Date: 2011-08-06 19:52:56

On 8/7/2011 5:09 AM, Eric Niebler wrote:
> The following code asserts at compile time for me. Am I doing something
> wrong?
> 
>     typedef fusion::vector2<int,int> pair;
>     pair p(1,2);
>     fusion::joint_view<pair, pair> x(p, p);
>     auto begin = fusion::begin(x);
>     auto end = fusion::end(x);
>     int i = fusion::distance(begin, end);
> 
> The assert is on line 39 of fusion/iterator/distance.hpp:
> 
>     template <typename Tag>
>     struct distance_impl
>     {
>         // default implementation
>         template <typename First, typename Last>
>         struct apply : distance_detail::linear_distance<First, Last>
>         {
>             BOOST_MPL_ASSERT_NOT((traits::is_random_access<First>));
>             BOOST_MPL_ASSERT_NOT((traits::is_random_access<Last>));
>         };
>     };
> 
> In this case, First is a joint_view iterator and Last is a vector
> iterator, which is indeed random-access. If I simply comment out the
> compile-time asserts, the code compiles and works as expected. I think
> these asserts are bogus. OK to remove them?

Indeed, it looks bogus. Feel free to remove, Eric.

Regards,
-- 
Joel de Guzman
http://www.boostpro.com
http://boost-spirit.com