[Boost.Iterators] Reasoning for boost::pointee<> not supporting back_insert_iterator?

[Richard Hazlewood <richard@…>]

The C++ Standard specifies that std::back_insert_iterator does not pass the value_type down to the base output-iterator class. This means (by default) that the value_type is typed to void and thus unsuitable for boost::pointee to determine the value type.

E.g.:

typedef std::vector<int> Ints; 
typedef std::back_insert_iterator<Ints> Iter; 
typedef boost::pointee<Iter>::type IntType; // Errors

The following specialization can be used to support back_insert_iterator:

namespace boost 
{ 
    template <class T> 
    struct pointee<std::back_insert_iterator<T> > 
    { 
        typedef typename T::value_type type; 
    }; 
}

Is there a particular reasoning why this is not available in the library?

Note: this also applies to std::front_insert_iterator.

[Dave Abrahams]

It was overlooked, I guess. If you want to add it, it would help to have patches for the library, documentation (source .rst files), and tests.

[Dave Abrahams]

Since it isn't possible in general to support this for all output iterators, this would be a special case. As such, it especially needs documentation. Since I don't have a doc patch or even a plaintext description of the required doc changes, I'm going to close this one as wontfix.