ass.cpp

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

struct MyStruct
{
    int x;
    int y;
};

BOOST_FUSION_ADAPT_STRUCT(
    MyStruct,
    (int, x)
    (int, y)    
    );


int main()
{

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

    
    MyStruct s;

    std::cout << boost::fusion::size(s) << std::endl;
    //line below works - it iterate and write output
    BOOST_PP_REPEAT(2, PRINT, "here I will pass my data")

    //this won't compile 
    BOOST_PP_REPEAT(boost::fusion::size(s), PRINT, "here i will pass my data")
}