[Boost-bugs] [Boost C++ Libraries] #2815: transform_iterator change stl iterator_category

Subject: [Boost-bugs] [Boost C++ Libraries] #2815: transform_iterator change stl iterator_category
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2009-03-02 21:45:43

#2815: transform_iterator change stl iterator_category
-----------------------------+----------------------------------------------
 Reporter:  bismuth_at_[hidden]  |       Owner:  dave    
     Type:  Bugs             |      Status:  new     
Milestone:                   |   Component:  iterator
  Version:  Boost 1.36.0     |    Severity:  Problem 
 Keywords:  iterators        |  
-----------------------------+----------------------------------------------
 Why does this code compile?


 {{{
 #include <stdio.h>
 #include <tchar.h>

 #include <vector>
 #include <boost/iterator/transform_iterator.hpp>
 #include <boost/static_assert.hpp>

 struct Tr1:
     std::unary_function<unsigned, unsigned>
 {
     unsigned operator()(unsigned a)const
     {
         return a;
     }
 };

 int _tmain(int argc, _TCHAR* argv[])
 {
     typedef std::vector<unsigned>::iterator some_ra_iterator_t;
     typedef boost::transform_iterator<Tr1, some_ra_iterator_t> tr_iter_t;

     BOOST_STATIC_ASSERT
     ((  boost::is_convertible
         <   std::iterator_traits<some_ra_iterator_t>::iterator_category,
             std::random_access_iterator_tag
         >::value
     ));

     BOOST_STATIC_ASSERT
     ((  ! boost::is_convertible
         <   std::iterator_traits<tr_iter_t>::iterator_category,
             std::random_access_iterator_tag
         >::value
     ));

     BOOST_STATIC_ASSERT
     ((  boost::is_same
         <   std::iterator_traits<tr_iter_t>::iterator_category,
             boost::detail::iterator_category_with_traversal
             <   std::input_iterator_tag,  //?!
                 boost::random_access_traversal_tag
             >
         >::value
     ));

     return 0;
 }

 }}}

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/2815>
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