Re: [boost] How to convert a vector of base classes to template based code?

11 Jul 2008

      On Thu, Jul 10, 2008 at 2:47 AM, Sergei Politov <spolitov@gmail.com> wrote:
...
Peng Yu <pengyu.ut <at> gmail.com> writes:
...
The following program uses virtual functions. Essentially I need to go
[skip]
...
}
Am I correctly understand that you are looking for something link this:
===================================================
#include <iostream>
#include <boost/fusion/algorithm.hpp>
#include <boost/fusion/container.hpp>
struct square {
 void show_me() const {
   std::cout << "square";
 }
};
struct circle {
 void show_me() const {
   std::cout << "circle";
 }
};
struct triangle {
 void show_me() const {
   std::cout << "triangle";
 }
};
template<class T, class End>
void out_pair(const T &, const End &, const End &) {}
template<class T, class Begin, class End>
void out_pair(const T & t, const Begin & begin, const End & end)
{
   t.show_me();
   std::cout << " vs. ";
   deref(begin).show_me();
   std::cout << std::endl;
   out_pair(t, next(begin), end);
}
template<class End>
void out(const End &, const End &) {}
template<class Begin, class End>
void out(const Begin & begin, const End & end)
{
   out_pair(deref(begin), next(begin), end);
   out(next(begin), end);
}
int main()
{
   typedef boost::fusion::vector<square, circle, square, triangle> Vec;
   Vec v;
   out(begin(v), end(v));
}
===================================================
Best Regards,
 Sergei
Hi,

You understood me correctly. But it seems the transform from my code
to your code is a little complicated. Is there any more direct analog
between boost::fusion and the runtime algorithm. In particular, how to
directly use two iterations with the second iteration start with
something like it + 1 in my original code?

Thanks,
Peng