[boost] [range] calling front() on iterator_range of const elements

From: Valentin Samko (boost_at_[hidden])
Date: 2006-06-06 16:45:30

Is it intentional that one can not call range.front() on an iterator
range of const values?

        #include <boost/range/iterator_range.hpp>
        int main() {
                typedef const char* iterator;
                iterator p = "test";
                boost::iterator_range<iterator> range(p, p+1);
                range.front();
        }

This fails to compile as
        value_type& front() const { ... return *m_Begin; }
        in iterator_range.hpp
tries to bind a const char lvalue to a non const reference.

The same happens with back() and operator[].

The fix is to return
        typename std::iterator_traits<IteratorT>::reference
and not
        value_type&

Thanks,
Valentin