Re: Property Copying

On May 14, 2013, at 2:54 PM, Alex Milowski <alex@milowski.com> wrote:

> The property copying "feature" of the HTML+RDFa 1.1 specification feels to me like it is in the wrong place.  It should be part of the core for RDFa.  

Agreed, but the only spec in process is HTML5, and we thought it was important to get in there. Expect this to go into an RDFa 1.2 (or 2.0) in the future.

> This feature would be better placed on the top priority list for RDFa 1.2.
> 
> I fail to see why we need to complicate HTML processing nor introduce the complexity of "in HTML but not elsewhere" for this feature right now.

the community requires a mechanism similar to @itemref in microdata, and this is what we came up with. it's too late to put it into the RDFa Core recommendation, so we're adding it to HTML+RDFa. I expect that processors will implement it across all base syntaxes, but it's only specified for HTML+RDFa for now.

In particular, Good Relations depends on this pattern to prevent massive data copying across a page of similar products. @itemref is useful when using microdata, but RDFa had no similar facility prior to property copying.

> I also worry about the complexity of adding this for in-browser implementations at this stage of RDFa adoption.

It's actually pretty simple to do, and I believe Manu has an efficient implementation in his streaming processor. It just requires running fairly simple rules across the pattern triples, which you can either do while processing, or after the fact.

Gregg

> -- 
> --Alex Milowski
> "The excellence of grammar as a guide is proportional to the paucity of the
> inflexions, i.e. to the degree of analysis effected by the language
> considered."
> 
> Bertrand Russell in a footnote of Principles of Mathematics

Received on Tuesday, 14 May 2013 23:43:26 UTC