Re: [C++-sig] How to derive from an abstract base class

July 23, 2010


      On 07/23/2010 03:09 PM, Lutz Maibaum wrote:
...
Dear all,
I am totally new to Boost.Python, and I am going through the tutorial to get up to speed. I apologize if this is a very obvious question.
<snip>
...
class Base {
public:
   virtual int f() = 0;
};
class Derived : public Base {
public:
   int f() {return 1;}
};
class BaseWrap : public Base, public wrapper<Base>  {
public:
   int f() {return this->get_override("f")();}
};
int func(Base&  b) {
   return b.f();
}
BOOST_PYTHON_MODULE(foo) {
   class_<Derived, bases<Base>  >  ("Derived")
     .def("f",&Derived::f);
   class_<BaseWrap, boost::noncopyable>("Base")
     .def("f", pure_virtual(&Base::f));
   def("func", func, "Calls the method f of its argument");
}
Try this:

BOOST_PYTHON_MODULE(foo) {
     class_<BaseWrap, boost::noncopyable>("Base")
       .def("f", pure_virtual(&Base::f));
     class_<Derived, bases<Base>  >  ("Derived")
       .def("f",&Derived::f);
     def("func", func, "Calls the method f of its argument");
}

(just swap the order of the class_ statements)


Jim Bosch