[Boost-users] [Boost][mpl] vector_c boolean operations

From: Noel Belcourt (kbelco_at_[hidden])
Date: 2005-09-28 17:08:52

Hi,

I'm new to the list so this may have been answered elsewhere (like a 
FAQ for MPL) but I couldn't find it.

I've got 2 vector_c types like this

typedef vector_c<int, 1,2,1,1,-2,0,1> p1;
typedef vector_c<int, 0,3,0,-1,1,3,5> p2;

and a resultant type defined as

typedef vector_c<int, 1,1,0,1,1,0,1> r;

that I want to compare at compile time using logic like this

r = p1 || p1 && p2

This pseudo code is what I want to do but I know this doesn't work.  
Can anyone can suggest a better approach?

template <class R, class P1, class P2>
struct validate_checkin : boost::mpl::equal<
   boost::mpl::placeholders::_1,
   boost::mpl::or_<
     boost::mpl::placeholders::_2,
     boost::mpl::and_<
       boost::mpl::placeholders::_2,
       boost::mpl::placeholders::_3
     >,
   >,
 >
{};

Regards,

-- Noel Belcourt