Re: [cpp-netlib-devel] Modern C++

[K. G. <kim...@gm...>]

Hi Dean,

On Mon, Sep 15, 2008 at 09:37, Dean Michael Berris
<mik...@gm...> wrote:
>
> If you had your own message tag (that's not the same message tag
> that's provided in the library) where you specialized the behavior of
> the actual message object(s) -- an example of a streaming/asynchronous
> message comes to mind -- allows you to either re-use the existing
> client implementation (basic_client<your_tag, 1, 0>) or extend the
> implementation such that you have tag-specific behavior (use futures,
> buffered asynchronous streams, etc.) without compromising existing
> usage of default-tagged implementations.

Right. so at the moment, most/all associated traits are just typedefs
(string_type, etc.), but given a more complex message/client, we could
add behaviors associated with the tag as well, without disturbing the
existing code.

> The bad part about blobs (or traits grouped together) is that it's
> hard to extend that design -- you cannot add new traits around tags
> and designs without running into the 'too many member' problem.

Yup, it makes sense. We can add or change functionality of the class
without modifying the class. Sweet.

>> 2) directives -- I don't see what benefit these added over member
>> functions on the message... Help?
>
> The directives can also be specialized by tags, so that you can make
> it do other things based on the tag. This is also built in with
> extensibility in mind.

Cool. I think I understand.

Thanks,
- Kim