On 12/25/2010 6:39 AM, Hossein Haeri wrote:
Hi Eric,
Thank you for confirming the error. But, more than having it confirmed, I was looking for what's going wrong there. Especially, how do I demystify the error message? What is it saying basically?
Merry Christmas, BTW! :)
If you look at line 61 of cons.hpp, you see this: template <typename Car, typename Cdr = nil> struct cons : sequence_base<cons<Car, Cdr> > { typedef mpl::int_<Cdr::size::value+1> size; --------------------------^^^^^^^^^ If you instantiate cons with boost::proto::_state as the Cdr parameter, you'll get the error you saw because _state doesn't have a nested "size" type. So somehow, Proto is instantiating cons prematurely, or else Proto's evaluation engine failed to replace _state with the right thing before instantiating cons. It's either a Proto bug that got fixed sometime between then and now, or else a compiler bug that has been worked around. Probably the former. Merry Christmas! -- Eric Niebler BoostPro Computing http://www.boostpro.com