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Re: ISSUE-127 (Empty Lists?): What is the effect of @inlist when no triples are generated? [3rd LC Comments - RDFa 1.1 Core]

From: Ivan Herman <ivan@w3.org>
Date: Thu, 23 Feb 2012 11:18:36 +0100
Cc: RDF Web Applications Working Group <public-rdfa-wg@w3.org>
Message-Id: <5663D935-58F8-4BFD-9256-8D62EE57EF45@w3.org>
To: Niklas Lindström <lindstream@gmail.com>
Niklas,

to be honest, I have no idea which one is better, although I raised the issue. And to make my position clear: I am actually fine to leave things as is (following the principle of minimal change:-), ie, to generate an empty list, I just wanted to make it so that the WG knows what it is doing:-)

Ivan


On Feb 23, 2012, at 10:58 , Niklas Lindström wrote:

> This is an interesting question. I can think of arguments for both
> sides of the issue.
> 
> One perspective is that @inlist "collects" members and then puts them
> in a list if there were any collected.
> 
> Another perspective might consider @inlist to create the list
> immediately. This way, it's also more natural to create an empty list
> if one intends to, rather than using rdf:nil (which is reasonably too
> technical for casual use). While this can be seen as a difference to
> how hanging rels behave, I think the difference really lies in the
> difference between a concrete list of items, and the (perhaps harder
> to grasp) case of producing multiple statements with the hanging rel
> "magic". (We had a similar discussion on the JSON-LD telecon
> yesterday.)
> 
> Compare this to RDF/XML:
> 
>  <owl:Class rdf:about="#c">
>    <owl:unionOf rdf:parseType="Collection"/>
>  </owl:Class>
> 
> which produces:
> 
>  <#c> owl:unionOf () .
> 
> If one does not want an empty list, one should either leave out the
> @inlist, or better leave out the entire "list wrapper". This is just
> like how one have to use a condition for an <ul> depending on whether
> there will be any <li>:s (since <ul> is not allowed to be empty in
> HTML). Like in this pseudo-code template:
> 
>  {% if items %}
>    <ul rel="owl:unionOf" inlist>
>      {% for item in items %}
>        <li resource="{{ item.iri }}">{{ item.label }}</li>
>      {% endfor %}
>    </ul>
>  {% endif %}
> 
> Does anyone have more concrete usage examples we can consider, to
> determine which way would be most confusing for authors?
> 
> Best regards,
> Niklas
> 
> 
> On Thu, Feb 9, 2012 at 11:26 AM, RDF Web Applications Working Group
> Issue Tracker <sysbot+tracker@w3.org> wrote:
>> ISSUE-127 (Empty Lists?): What is the effect of @inlist when no triples are generated? [3rd LC Comments - RDFa 1.1 Core]
>> 
>> http://www.w3.org/2010/02/rdfa/track/issues/127
>> 
>> Raised by: Ivan Herman
>> On product: 3rd LC Comments - RDFa 1.1 Core
>> 
>> See http://www.w3.org/mid/CA894838-BFE8-48CC-984D-F304A6D32251@w3.org for further details, this is just to add this question to the issue list.
>> 
>> 
>> 
> 


----
Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
FOAF: http://www.ivan-herman.net/foaf.rdf






Received on Thursday, 23 February 2012 10:19:01 UTC

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