Creating classes with publicly visible bases

defineclasswithbases.cpp

#define BOOST_PP_VARIADICS 1

#include <boost/mpl/vector.hpp>
#include <iostream>
#include <memory>
#include <typeinfo>
#include <boost/preprocessor.hpp>

#define GETCLASS(elem) BOOST_PP_SEQ_HEAD(elem)

#define GETACCESS(elem)                                     \
    BOOST_PP_IF(BOOST_PP_EQUAL(BOOST_PP_SEQ_SIZE(elem), 2), \
                BOOST_PP_SEQ_HEAD(BOOST_PP_SEQ_REVERSE(elem)), private)

#define GETCOMPLETEDECL(d, data, elem) GETACCESS(elem) GETCLASS(elem)

#define GETONLYCLASSNAME(d, data, elem) GETCLASS(elem)

#define LISTOFCLASSNAMES(OPERATION, ...)        \
    BOOST_PP_LIST_ENUM(BOOST_PP_LIST_TRANSFORM( \
        OPERATION, _, BOOST_PP_VARIADIC_TO_LIST(__VA_ARGS__)))

#define DEFINECLASSWITHBASES(className, ...)                           \
    class className : LISTOFCLASSNAMES(GETCOMPLETEDECL, __VA_ARGS__) { \
    public:                                                            \
        using Bases = boost::mpl::vector<                              \
            LISTOFCLASSNAMES(GETONLYCLASSNAME, __VA_ARGS__)>;          \
                                                                       \
    private:
#define DEFINECLASSWITHBASESEND() }

struct Base1 {
    Base1() { std::cerr << __PRETTY_FUNCTION__ << std::endl; }
};

struct Base2 {
    Base2() { std::cerr << __PRETTY_FUNCTION__ << std::endl; }
};

struct Base3 {
    Base3() { std::cerr << __PRETTY_FUNCTION__ << std::endl; }
};

DEFINECLASSWITHBASES(A, (Base1), (Base2))
public:
void operator()() const { std::cerr << __PRETTY_FUNCTION__ << std::endl; }
DEFINECLASSWITHBASESEND();

DEFINECLASSWITHBASES(B, (Base1), (Base2), (Base3))
public:
DEFINECLASSWITHBASESEND();

DEFINECLASSWITHBASES(C, (Base1)(public), (Base2))
public:
DEFINECLASSWITHBASESEND();

int main() {
    static_assert(
        std::is_same<boost::mpl::vector<Base1, Base2>, A::Bases>::value, "");
    static_assert(
        std::is_same<boost::mpl::vector<Base1, Base2, Base3>, B::Bases>::value,
        "");
    std::shared_ptr<Base1> c = std::make_shared<C>();
}