Re: [sigc] C++0x lambdas

[Kjell Ahlstedt <kjell ahlstedt bredband net>]

2012-07-14 10:16, Chow Loong Jin skrev:
> On 13/07/2012 22:53, Kjell Ahlstedt wrote:
> > I'm also interested in the amendment you mention that compiles with -std=c++98.
> > Are you willing to show it? It's not very attractive to include BOOST_TYPEOF in
> > libsigc++, but still I'm interested, to see if it's something that I should
> > consider for my bug report.
> To be honest, I had actually lost that snippet of code, but it turns out it
> wasn't too difficult to re-do based on the C++11 version:
>
> //-------------------
> namespace sigc
> {
>      template <typename Functor>
>      struct functor_trait<Functor, false>
>      {
>          typedef BOOST_TYPEOF_TPL (sigc::mem_fun
>                                    (boost::declval<Functor&> (),
>                                     &Functor::operator())) _intermediate;
>
>
>          typedef typename _intermediate::result_type result_type;
>          typedef Functor functor_type;
>      };
> }
> //-------------------
Thanks.
I haven't tested it (and will probably not do it) but it seems quite 
reasonable. I suppose it will also require some calls to 
BOOST_TYPEOF_REGISTER_TEMPLATE.

But I will not propose it for inclusion in libsigc++. The aim of my bug 
report https://bugzilla.gnome.org/show_bug.cgi?id=672555 is to reduce 
the amount of code in the non-deprecated part of libsigc++. This would 
require quite a lot of Boost code. Your template specialization with 
C++11 decltype is much better in that respect, although it does require 
a C++11 compatible compiler. That will be no problem in the future.

Kjell