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Re: HTML5 Polyglot spec and RDFa

From: Nathan <nathan@webr3.org>
Date: Sat, 09 Oct 2010 21:38:52 +0100
Message-ID: <4CB0D2DC.2080806@webr3.org>
To: RDFa WG <public-rdfa-wg@w3.org>
CC: Gregg Kellogg <gregg@kellogg-assoc.com>, Ivan Herman <ivan@w3.org>, Shane McCarron <shane@aptest.com>, Manu Sporny <msporny@digitalbazaar.com>
Nathan wrote:
> Gregg Kellogg wrote:
>> Manu shared a thought in a separate chat, where we could potentially 
>> resolve this problem by first doing a case-sensitive match and falling 
>> back to a case-insensitive match if one wasn't found in the first 
>> case. So, you might have the following markup:
>>
>>  <div about="http://example.com/#me" typeof="Agent">
>>   <span rel="agent"> ..
>>   <a rel="CiTE">..
>>
>> It could correctly match typeof="Agent" to foaf:Agent and rel="agent" 
>> to event:agent, but would match rel="CiTE" to xhv:cite because it 
>> would fall back to a case-insensitive match.
> 
> but it would fail to correctly match
> 
> <div about="http://example.com/#me" typeof="AGENT">
>   <span rel="agenT">

The only places TERMs can appear are:
   @datatype    // can only be a Datatype
   @typeof      // can only be a Class

   @property    // can only be a Property
   @rel         // can only be a Property
   @rev         // can only be a Property

Thus we can clear up some of the ambiguity by adding some types to the 
rdfa vocab rdfa:ClassAlias, rdfa:DatatypeAlias, rdfa:PropertyAlias - 
this means that:

   only a rdfa:ClassAlias could be used with @typeof
   only a rdfa:DatatypeAlias could be used with @datatype

leaving property, rel, rev to only ever consider rdfa:PropertyAlias

thus with a practical example:

[ a rdfa:PropertyAlias; rdfa:term "agent"; rdfa:uri 
"http://purl.org/NET/c4dm/event.owl#agent" ] .

[ a rdfa:ClassAlias; rdfa:term "Agent"; rdfa:uri 
"http://xmlns.com/foaf/0.1/Agent" ] .

So this way:
   <div about="http://example.com/#me" typeof="Agent">
   <div about="http://example.com/#me" typeof="AGENT">
   <div about="http://example.com/#me" typeof="agent">

could only ever resolve to foaf:Agent

whilst:
   <span rel="Agent">
   <span rel="AGENT">
   <span rel="agent">

could only ever resolve to event:agent

Make sense or have I missed something?

notes:
- might need to add a rdfa:TermAlias which the others subclass so we can 
set the domain appropriately
- not suggesting those exact names for the classes, just first thing I 
could think of for this mail!

Best,

Nathan
Received on Saturday, 9 October 2010 20:40:12 UTC

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