Microdata to RDF: First Editor's Draft (ACTION-6)

I have created a draft of the Microdata to RDF transformation and uploaded it to our Mercurial repository [1]. Note that the links to the draft go to the repository, and the actual draft can be used by selecting the "raw" form of the document [2]. (The lack of a current checked-out version of the Mercurial repository that can be used for direct references should be addressed at some point).

This version focuses exclusively on the @item* properties and leaves out the other GRDDL RDF generation steps from the original Microdata spec [3]. It also does not address recent changes to the Microdata Editor's draft [4] which allows multiple values for the @itemtop attribute (with restrictions).

Notable changes between this draft and the algorithm given in [3]:

* If a page has more than one top-level item, they are expressed in an RDF Collection to preserve original item order.
* If an item property has more than one value, all values are expressed in an RDF Collection to preserve original value order.
* @itemprop names which are not absolute URIs are resolved as relative URIs either to @itemtype or Document base.
* Resolving @itemprop names against @itemtype uses a modified algorithm using everything after "/" or "#" in the type URI.
* The property value definition is updated as follows:
  * Values are returned as Literal, URI Reference or Blank Node
  * Time elements with a @datetime attribute uses a lexical matching against xsd:date, xsd:time, and xsd:dateTime to create appropriate typed literal
  * Plain literals get language from elements' in-scope @lang
  * blockquote and q with @cite attribute generate a URI Reference value

Note that this first draft is intended for discussion and does not necessarily represent a consensus decision of the Task Force at this time.

Gregg Kellogg

[1] https://dvcs.w3.org/hg/htmldata/
[2] https://dvcs.w3.org/hg/htmldata/raw-file/24af1cde0da1/microdata-rdf/index.html
[3] http://www.w3.org/TR/2011/WD-microdata-20110525/
[4] http://dev.w3.org/html5/md/Overview.html