"Tobias Schwinger" <tschwinger@neoscientists.org> wrote
Agreed. Also I think Steve Dewhurst (who apparently did a lot of research in this area) once published an article about decomposing a type and bringing it back together...
Are you talking about the 'typeints'- or the 'typeof'-article ? Can you perhaps post a link ?
I'm talking about making the client code for the registration look like
Can't find it :-( I think he used type tags instead if integers, decomposed a type into a typelist of these tags with the help of partial template specialization, applied some transformation to the list, and then reassembled the new type. I don't remember if he mentioned any practical usage of this, though... this (e.g.):
#define BOOST_TYPEOF_REGISTRATION \ ( typename(boost::lambda::greater_action) ) \ ( template(boost::lambda::functor,1) ) \ ( template(boost::lambda::lambda_functor_base,2) ) \ [...] #include BOOST_TYPEOF_REGISTER()
Understood. Let me think about this...
We did some work with Aleksandr Nasonov to port the library to Intel 8.0, and we came pretty close -- only the exotic case "template<class T, Tn>" didn't work, and we proved to ourselves that this was because of the compiler bug. So I think Intel will be among first compilers to extend our support.
Good to hear it's a compiler bug. Btw. I had to do something like this once and got away with member templates:
template<typename T> class X { template<T n> [...]
(IIRC this works with Intel) and to be honest I didn't even know it is a valid possibilty to do it within a single template parameter list, until now (well, don't know for sure - I just believe you ;-) ).
Here is the final minimal example Alexander (sorry for misspelling his name the first time) came up with: //------ template<class T, T n> struct a {}; template<class V, class T> struct traits; template<class V, class T, T n> struct traits<V, a<T, n> > {}; struct X {}; int main() { traits<int, a<int,0> > good; traits<X , a<int,0> > bad; // error: incomplete type is not allowed. } //------ This was the only problem with Intel 8.0, but I think other versions have a few more (your experience demonstrated it). Regards, Arkadiy