Re: [boost] Problem with range (make_iterator_range)?

From: Neal Becker (ndbecker2_at_[hidden])
Date: 2006-05-30 12:38:14

Thorsten Ottosen wrote:

> Neal Becker wrote:
>> #include <boost/range.hpp>
>> #include <vector>
>> 
>> template<typename in_t, typename out_t>
>> void copy (in_t const& in, out_t &out) {}
> 
> What makes you think you can bind a temporary to
> an non-const reference (out)?
> 

Yeah, same old problem.  I think the c+ standard should be changed.  It's
quite clear (to me) that this is an important use of the range concept.  In
the meantime, here's a workaround:

template<class T>
inline T& lvalue_cast (const T& rvalue) {
  return const_cast<T&> (rvalue);
}

template<typename in_t, typename out_t>
void copy (in_t const& in, out_t &out) {}

int main() {

  std::vector<int> out (2);

  copy (boost::sub_range<std::vector<int> > (out.begin(), out.begin()+2),
lvalue_cast (boost::sub_range<std::vector<int> > (out.begin(),
out.begin()+2)));
}