Class X

edrav2/eprj/boost/libs/python/test/operators.cpp:30–39

using namespace boost::python;

struct X : test_class<>
{
    typedef test_class<> base_t;
    
    X(int x) : base_t(x) {}
    X const operator+(X const& r) const { return X(value() + r.value()); }
    
//    typedef int (X::*safe_bool)() const;
//    operator safe_bool() const { return value() != 0 ? &X::value : 0; }
};

X operator-(X const& l, X const& r) { return X(l.value() - r.value()); }
X operator-(int l, X const& r) { return X(l - r.value()); }