[boost] Re: [interfaces] Hand written interfaces

From: Jonathan Turkanis (technews_at_[hidden])
Date: 2005-03-04 17:22:41

Jonathan Turkanis wrote:

> Is the following definition of IBar so complex that it would be
> pointless to offer it as an alternative?
>
>    template< typename Derived,
>              typename Base,
>              typename Flags >
>    struct ibar_impl {
>         struct type : Base {
>             struct interface_metadata : metadata_base<Derived, Base,
>                 Flags> { const char* names = { "foo", "foo" };
>                 typedef mpl::vector<
>                             void(const char*),
>                             int(int, int)
>                         > signatures;
>             };
>             void foo(const char* name)
>             {
>                 return invoker<interface_metadata, 1>::execute(this,
>             name); }
>
>             int foo(int n, int m)
>             {
>                 return invoker<interface_metadata, 2>::execute(this,
>             int, int); }
>         };
>    };

I simplified it a bit:

   template< typename Derived,
             typename Base,
             typename Flags >
   struct ibar_impl {
        struct type : Base {
            struct interface_metadata : metadata_base<Derived, Base, Flags> {
                const char* names = { "foo", "foo" };
                typedef mpl::vector<
                            void(const char*),
                            int(int, int)
                        > signatures;
            };
            void foo(const char* name) { return execute<1>(this, name); }
            int foo(int n, int m) { return execute<2>(this, int, int); }
        };
   };

   typedef interface< ibar_impl<_, _, _> > IBar;

Jonathan