Boost QVM

#include <boost/qvm/map_mv.hpp>

namespace boost
{
    namespace qvm
    {
        //Only enabled if: is_m<A>::value
        template <int C,class A>
        -unspecified-return-type- col( A & a );        
        
        //Only enabled if: is_m<A>::value
        template <int C,class A>
        -unspecified-return-type- row( A & a );        
        
        //Only enabled if: is_m<A>::value
        template <class A>
        -unspecified-return-type- diag( A & a );        
        
        //Only enabled if:
        //  is_m<A>::value &&
        //  m_traits<A>::rows==m_traits<A>::cols && m_traits<A>::rows>=3
        template <class A>
        -unspecified-return-type- trans( A & a );
    }
}