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

[Jim Bosch]

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



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