Re: [sigc] How to use sigc::bind<>

[Jeff Franks <jcf tpg com au>]

Martin Schulze wrote:

> Unfortunately, C++ doesn't allow us to specify default template
> arguments for functions. Therefore, the number always needs to be
> specified. Or does somebody know a trick to make the number optional?
But it lets you overload template functions: This works. I added the 
following three function template to <sigc++/adaptors/bind.h> as a test. 
I quickly tested each one with the example I sent you previously - and 
they all works Ok.

template <class T_bound1, class T_functor>
template <class T_bound1, class T_functor>
inline bind_functor<0, typename unwrap_reference<T_bound1>::type, T_functor>
bind(const T_functor& _A_func, T_bound1 _A_b1)
{
 return bind_functor<0, typename unwrap_reference<T_bound1>::type, 
T_functor>
          (_A_func, _A_b1);
}

template <class T_bound1, class T_bound2, class T_functor>
inline bind_functor<0, typename unwrap_reference<T_bound1>::type,
      bind_functor<0, typename unwrap_reference<T_bound2>::type, 
T_functor> >
bind(const T_functor& _A_functor, T_bound1 _A_b1, T_bound2 _A_b2)
{
 return bind_functor<0, typename unwrap_reference<T_bound1>::type,
        bind_functor<0, typename unwrap_reference<T_bound2>::type, 
T_functor> >
          (bind<0>(_A_functor, _A_b2), _A_b1);
}

template <class T_bound1, class T_bound2, class T_bound3, class T_functor>
inline bind_functor<0, typename unwrap_reference<T_bound1>::type,
      bind_functor<0, typename unwrap_reference<T_bound2>::type,
      bind_functor<0, typename unwrap_reference<T_bound3>::type, 
T_functor> > >
bind(const T_functor& _A_functor, T_bound1 _A_b1, T_bound2 
_A_b2,T_bound3 _A_b3)
{
 return bind_functor<0, typename unwrap_reference<T_bound1>::type,
        bind_functor<0, typename unwrap_reference<T_bound2>::type,
        bind_functor<0, typename unwrap_reference<T_bound3>::type, 
T_functor> > >
          (bind<0>(_A_functor, _A_b2, _A_b3),_A_b1);
}

Regards,

Jeff Franks.