extconf.rb

require 'mkmf-rice'

create_makefile('virtual')

test.rb

require 'virtual'

class Toto < VirtualBase
	def initialize
                super
		puts "init"
	end
end


b = Toto.new

virtual.cpp

 class VirtualBase {
      public:
        VirtualBase();
       // virtual int doWork() {return 0;}
      //  virtual int processWorker() = 0;
    };



#include "rice/Director.hpp"
  using namespace Rice;
  
    class VirtualBaseProxy : public VirtualBase, public Rice::Director {
      public:
        VirtualBaseProxy(Object self) : Rice::Director(self) { }
  /*
        virtual int doWork() {
          if(callIsFromRuby("do_work")) {
            return VirtualBase::doWork();
          } else {
            return from_ruby<int>( getSelf().call("do_work") );
          }
        }
  
        virtual int processWorker() {
          if(callIsFromRuby("process_worker")) {
            raisePureVirtual();
          } else {
            return from_ruby<int>( getSelf().call("process_worker") );
          }
        }*/
    };

#include "rice/Constructor.hpp"

extern "C"
  void Init_virtual() {
    // See Caveat below
    define_class<VirtualBase>("__VirtualBase__");
  
    define_class<VirtualBaseProxy, VirtualBase>("VirtualBase")
     .define_constructor(Constructor<VirtualBaseProxy, Object>());
     // .define_method("do_work", &VirtualBaseProxy::doWork);
     // .define_method("process_worker", &VirtualBaseProxy::processWorker);
  }