C++ logical object combiner (for analysis cuts)

#include <iostream>
#include "boost/static_assert.hpp"
#include <boost/type_traits.hpp>
#include <boost/utility.hpp>
#include <boost/any.hpp>
using namespace std;


/// Base class for all cut functors (toy classifier of ints)
struct Cut {
  virtual bool cut(int n) const = 0;
};

// Various cut functors operating on ints
struct Odd : public Cut {
  bool cut(int n) const { return n % 2 == 1; }
};
struct Even : public Cut {
  bool cut(int n) const { return n % 2 == 0; }
};
struct Less : public Cut {
  Less(int n) : val(n) { }
  bool cut(int n) const { return n < val; }
  int val;
};
struct LessEq : public Cut {
  LessEq(int n) : val(n) { }
  bool cut(int n) const { return n <= val; }
  int val;
};


// AND, OR and NOT objects for combining cuts

template <typename CUT1, typename CUT2>
struct CutsOr : public Cut {
  CutsOr(const CUT1& c1, const CUT2& c2) : cut1(c1), cut2(c2) { }
  bool cut(int n) const { return cut1.cut(n) || cut2.cut(n); }
  CUT1 cut1;
  CUT2 cut2;
  BOOST_STATIC_ASSERT((boost::is_base_of<Cut, CUT1>::value && boost::is_base_of<Cut, CUT2>::value));
};
template <typename CUT1, typename CUT2>
struct CutsAnd : public Cut {
  CutsAnd(const CUT1& c1, const CUT2& c2) : cut1(c1), cut2(c2) { }
  bool cut(int n) const { return cut1.cut(n) && cut2.cut(n); }
  CUT1 cut1;
  CUT2 cut2;
  BOOST_STATIC_ASSERT((boost::is_base_of<Cut, CUT1>::value && boost::is_base_of<Cut, CUT2>::value));
};
template <typename CUT>
struct CutInvert : public Cut {
  CutInvert(const CUT& c1) : poscut(c1) { }
  bool cut(int n) const { return !poscut.cut(n); }
  CUT poscut;
  BOOST_STATIC_ASSERT((boost::is_base_of<Cut, CUT>::value));
};


// operator &&, operator ||, and operator ! overloads
//
// The enable_if complexity is needed to avoid too-global template type matching;
// the code below is equivalent to simply
//
//   template <typename CUT1, typename CUT2>
//   CutsAnd<CUT1,CUT2> operator && (const CUT1& a, const CUT2& b) { ... }
//
//   template <typename CUT1, typename CUT2>
//   CutsAnd<CUT1,CUT2> operator || (const CUT1& a, const CUT2& b) { ... }
//
//   template <typename CUT>
//   CutInvert<CUT> operator ! (const CUT& c) { ... }

template <typename CUT1, typename CUT2>
typename boost::enable_if_c<
  boost::is_base_of<Cut, CUT1>::value && boost::is_base_of<Cut, CUT2>::value,
  CutsAnd<CUT1,CUT2>
  >::type
operator && (const CUT1& a, const CUT2& b) {
  return CutsAnd<CUT1,CUT2>(a,b);
}

template <typename CUT1, typename CUT2>
typename boost::enable_if_c<
  boost::is_base_of<Cut, CUT1>::value && boost::is_base_of<Cut, CUT2>::value,
  CutsOr<CUT1,CUT2>
  >::type
operator || (const CUT1& a, const CUT2& b) {
  return CutsOr<CUT1,CUT2>(a,b);
}

template <typename CUT>
typename boost::enable_if_c<
  boost::is_base_of<Cut, CUT>::value,
  CutInvert<CUT>
  >::type
operator ! (const CUT& c) {
  return CutInvert<CUT>(c);
}


//////////////////////////////////////////


int main() {
  const Cut& c1 = CutsAnd<Odd,Less>(Odd(), Less(5));
  const auto c2 = Odd() && Less(5);
  const auto c3 = c2 || Even();
  const auto c4 = (Odd() && Less(5)) || Even();
  const auto c5 = !( (Odd() && Less(5)) || Even() );
  for (int i = 0; i < 10; ++i) {
    cout << i << " ";
    cout << ((c1.cut(i)) ? "X" : " ");
    cout << ((c2.cut(i)) ? "X" : " ");
    cout << ((c3.cut(i)) ? "X" : " ");
    cout << ((c4.cut(i)) ? "X" : " ");
    cout << ((c5.cut(i)) ? "X" : " ");
    cout << endl;
  }
  return 0;
}

// Output:
// andy@duality:~/.../cxxdev/logic$ g++ logic.cc -o logic -std=c++11
// andy@duality:~/.../cxxdev/logic$ ./logic
// 0   XX
// 1 XXXX
// 2   XX
// 3 XXXX
// 4   XX
// 5     X
// 6   XX
// 7     X
// 8   XX
// 9     X