Compile time switch generation based on number of fields in structure

How in C++03 get in compile time number of members of chosen struct? I was experimenting with BOOST_FUSION_ADAPT_STRUCT but I did't get any working example.

I want to generate switch statement in compile time, where there will be one case per each member. So lets say we have struct with 3 members then I want to generate this switch:

switch(val)
{
   case 0:
       break;
   case 1:
       break;
   case 2:
       break;
}

In each statement I will call template function with some parameters. One of this parameters is a member of structure.

How I can do something like this?

After long searching, reading and finding this article. I managed to iterate over members from 0 to count - 1 (from that creating switch statement is easy).

#include <iostream>
#include <string>
#include <vector>
#include <boost/fusion/include/adapt_struct.hpp>
#include <boost/preprocessor/repetition/repeat.hpp>
#include <boost/fusion/include/define_struct.hpp>
#include <boost/preprocessor/seq/size.hpp>
#include <boost/preprocessor/seq/seq.hpp>
#include <boost/preprocessor/seq/cat.hpp>

struct MyStruct
{
    int x;
    int y;
};

#define GO(r, data, elem) elem
#define SEQ1 ((int,x))((int,y))

BOOST_FUSION_ADAPT_STRUCT( 
    MyStruct,
    BOOST_PP_SEQ_FOR_EACH(GO, ,SEQ1)      
    )

#define PRINT(unused, number, data) \
    std::cout << number << std::endl;

int main()
{
    BOOST_PP_REPEAT(BOOST_PP_SEQ_SIZE(SEQ1), PRINT, "data")
}

Now BOOST_PP_REPEAT may create case statements.