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Re: Change on typeof? (Was Re: The processing rules for property/rel)

From: Ivan Herman <ivan@w3.org>
Date: Tue, 1 Nov 2011 20:37:33 +0100
Message-Id: <96B388C1-B58F-4184-A87A-16CFE743A0EA@w3.org>
Cc: W3C RDFWA WG <public-rdfa-wg@w3.org>, P├ęter Mika <pmika@yahoo-inc.com>
To: Gregg Kellogg <gregg@kellogg-assoc.com>
Gregg,

just a quick reply from my phone, more details tomorow... What I tried to say is that the old behaviour of typeof remains valid outside my points. Ie, <div about="foo" typeof="Bar"/>  does assign type to foo. Same behaviour also if typeof is the only one.

Also, my goal was to keep rel and property as close as possible to one another...

See you tomorrow...

Ivan

----
Ivan Herman
Tel:+31 641044153
http://www.ivan-herman.net



On 1 Nov 2011, at 19:35, Gregg Kellogg <gregg@kellogg-assoc.com> wrote:

> On Nov 1, 2011, at 6:06 AM, Ivan Herman wrote:
> 
>> Gregg,
>> 
>> I just try to go down the line of concentrating on @typeof; maybe that reaches the same goal as what we wanted, but makes a change in RDFa that might be, possibly, cleaner. This is not fully worked out yet...
>> 
>> Let us consider changing the behaviour of @typeof such that:
>> 
>> 1. if (@rel/@rev is present, but no @resource/@href/@src) or 
>>     (@property is present, @rel/@rev is not, and no @resource/@href/@src)
>>   then 
>>      - @typeof creates a blank node
>>      - that blank node is the current_object (ie, the one going down the chain)
>>      - is the subject of the type triples
>> 2. if @resource/@href/@src is present _as well as_ @typeof, then no blank node is generated, and the subject of the type triples is the IRI resource of @resource/@href/@src
>> 
>> Both of these rules are different than what we have now; all other rules for @typeof remain unchanged. The advantage is that there is no difference between @rel/@rev on the one hand and @property on the other hand with respect to @typeof. Of course, what I called the 'minimalist' change for @property, as you described on the wiki, remains valid, too.
> 
> I think we break a lot if <div about="foo" typeof="Bar"/> does not assign the type to <foo>. However, saying <div typeof="Bar"/> or <div typeof="Bar" resource="baz"/> assigning the type to the object would be interesting.
> 
>> What we get is:
>> 
>> <div about="relV" rel="t:foo" typeof="t:Bar"><span property="t:yip">Yes</span></div>
>> =>
>> <relV> t:foo [ a t:Bar;
>>           t:yip "Yes" ] .
> 
> With my interpretation, presuming that @rel/@rev change to reference _new object_ and not _new subject_, and this would create the following:
> 
> <> t:foo <relV> .
> <relV> a t:Bar;  t:yip "Yes"  .
> 
> If @rel retained it's current interpretation, there would be no resource for @rel to operate on, and it would do the following: 
> 
> <relV> a t:Bar;  t:yip "Yes"  .
> 
>> <div about="relP" property="t:foo" typeof="t:Bar"><span property="t:yip">Yes</span></div>
>> =>
>> <relP> t:foo [ a t:Bar;
>>           t:yip "Yes" ] .
> 
> This should be consistent with the first interpretation above:
> 
> <> t:foo <relV> .
> <relV> a t:Bar;  t:yip "Yes"  .
> 
>> Both by virtue of #1 above. The reason for the #2 rule above is that if I have
>> 
>> <div about="relV2" rel="t:foo" typeof="t:Bar" href="http://example.org">
>> 
>> Our current rules would assign a type to <relV2>, but this is really not consistent with the fact that, without @href, the typing goes to the 'right hand' of @rel, so to say. With that modification, what we get is:
>> 
>> <div about="relV2" rel="t:foo" typeof="t:Bar" href="http://example.org">
>> <span property="t:yip">Yes</span>
>> </div>
>> =>
>> <relV2> t:foo <http://example.org> .
>> <http://example.org> a t:Bar;
>>   t:yip "Yes" .
>> 
>> <div about="relP2" property="t:foo" href="http://example2.org" typeof="t:Bar">
>>  <span property="t:yip">Yes</span>
>> </div>
>> =>
>> <relP2> t:foo <http://example2.org> .
>> <http://example2.org> a t:Bar;
>>   t:yip "Yes" .
>> 
>> Thoughts?
> 
> I would favor @typeof binding to either @about or @resource/@href/..., but not both. On it's own, having @typeof describe the type of the newly created object makes most sense to me, if we decide that some change is necessary.
> 
> Similarly, binding @rel and @property to the object, rather than the subject, produces what I believe to be the most sensible results, but does create a compatibility issue for @rel, which is why I only suggested it for @property.
> 
> My proposal had @property bind to _parent subject_ instead of _new subject_, but if we make these changes, I would support binding it to _new object_, so that the recommended pattern would be:
> 
> <div property="t:foo" typeof="t:Bar href="http://example2.org"><span property="t:yip">Yes<?span></div>
> 
> which would create
> 
> <> t:foo [ a t:Bar; t:yip "Yes" ] .
> 
> @href without an @typeof would not create a new object.
> 
> Gregg
> 
>> Ivan
>> 
>> 
>> 
>> ----
>> Ivan Herman, W3C Semantic Web Activity Lead
>> Home: http://www.w3.org/People/Ivan/
>> mobile: +31-641044153
>> PGP Key: http://www.ivan-herman.net/pgpkey.html
>> FOAF: http://www.ivan-herman.net/foaf.rdf
>> 
>> 
>> 
>> 
>> 
> 
> 
Received on Tuesday, 1 November 2011 19:38:04 GMT

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