Re: Interaction model vs data model

>>> <> a ShoppingCartContainer;
>>> ldp:membershipPredicate :order .
>>> 
>>> and the client  now knows that if he posts something like
>>> 
>>> <> a Order;
>>> content [ a BarbieDoll ];
>>> for <http://joe.example/#me >;
>>> address <http://joe.example/#address> .
>> 
>> I think this kind of example can join the BugTracker for input about doing "services" with LDP. 
>> 
>> I do think that one of the good things about REST is that it eliminates pre-knowledge for the client. For example, there is magic in your example, i.e., the client has to know it is a Toyshop. It could be a selling Pizza .... and then what ?

> Now your question is good one: how do you delimit the type of things ordered.
> There are many possible answers. One would be to restrict the order relation
> using an owl restriction on the elements of an rdf collection named by 
> reference. Clearly more work is to be done there...

In my proposal for this kind of thing at http://lists.w3.org/Archives/Public/public-ldp-wg/2012Dec/0118.html I'm taking large amounts of inspiration from HTML. Therefore, to accomplish the above, we just need a select/option element for a robot ... i.e., we might have a "suggested" property which points to a LDP container - this means pick your type of Doll from the contents of this container. For similar (copying-html) reasons, I prefer POSTing sets of properties, rather than POSTing a graph. 

Looking forward to more "service" discussions. 

regards, 
Roger