[fusion] joint_view bug?
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? -- Eric Niebler BoostPro Computing http://www.boostpro.com
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
On 8/6/2011 4:52 PM, Joel de Guzman wrote:
On 8/7/2011 5:09 AM, Eric Niebler wrote:
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.
Committed: https://svn.boost.org/trac/boost/changeset/73583 Thanks Joel. -- Eric Niebler BoostPro Computing http://www.boostpro.com
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Eric Niebler -
Joel de Guzman