Functor Class Template - 2

template < typename R , class TList >
class Functor
{
public:
  Functor ();
  Functor (const Functor& );
  Functor& operator= (const Functor& );
  explicit Functor (std::auto_ptr<Impl> spImpl) : spImpl_(spImpl) {}
  ...
private:
  typedef FunctorImpl<R, TList> Impl;
  std::auto_ptr<Impl> spImpl_; // stored by (smart) pointer
};