Re: [cpp-netlib-devel] URI processing (Was Re: Work Left)

[Dean M. B. <mik...@gm...>]

On Mon, Oct 13, 2008 at 8:05 PM, Kim Gräsman <kim...@gm...> wrote:
>
> I wonder if what Glyn is looking for is something like:
>
> template <> char_based_traits<network::tags::default_> {
>  typedef std::string string_type;
>  typedef std::ostringstream ostringstream_type;
>  typedef char char_type;
> };
>
> so that related traits are defined together, and orthogonal traits
> separately. Just guessing, though. But it doesn't make intuitive sense
> to me to specialize them separated from each other, when they're all
> based on the definition of char.
>

This is the same problem the standard iterator traits introduce -- a
blob -- which is bad design, and very unwieldy.

I think I've discussed this before as to why I don't like trait blobs
and why I prefer individual trait types. It has something to do with
extensibility and for enforcing good design.

At any rate, it _should_ remain as individual types instead of blobs
precisely because you only need to specify the trait supported --
sometimes it doesn't make sense to support for instance a
'transfer_buffer' trait type for other traits since it only applies to
protocol traits which involve customization of the
transfer_buffer<...>::type based on the tag.

Some traits don't need to be specialized for certain tags, and
mis-using these traits with unsupported tags should yield a clear
compile-time error which says that a specialization for a certain
trait type cannot be found.

-- 
Dean Michael C. Berris
Software Engineer, Friendster, Inc.