Transition Request to advance GRDDL to Candidate Recommendation

Compiled by Harry Halpin, GRDDL WG Chair; with Jeremy Carroll

This is a transition request to Candidate Recommendation for

Gleaning Resource Descriptions from Dialects of Languages (GRDDL)

available at:

Estimated publication date May 2nd.

The URI cited above is for the most recent editor's version of the specification as of 26th April.

That file, after final editorial corrections, is set up to be published by moving it to:

Gleaning Resource Descriptions from Dialects of Languages (GRDDL) had been published on 2 March 2007 at as a Last Call Specification.

This document going to CR is in partial requirement of our charter, that states that the WG should produce: "a GRDDL specification with all issues addressed."

Table of Contents

Record of the WG decision

The WG's decision to request publication as a Candidate Recommendation was taken during a teleconference on 25 April 2007 whose minutes may be found at

The decision was subject to a number of minor editorial changes, still to be made, i.e. 6 actions above + SOTD + missing "a" + whatever we figure for the STYPI

No substantive change

There is a detailed change log included in the document.

While these include changes to the normative text of the specification, such changes have all been clarifications: for example, more clearly specifying the nature of space separated. Another example is being clearer about the relationship between GRDDL and the definition of the rel attribute from HTML, which many implementors had initially misunderstood.

Relationship with requirements

The GRDDL Use Cases: Scenarios of extracting RDF data from XML documents WG Note, lists a number of requirements. The specification addresses all but one of these, which we postponed addressing because of a dependency on the HTTP Header Linking Draft , which is not progressing in line with our schedule.

Dependencies with other groups

Although we require no formal comments from other W3C Working Groups, we have requested comments from all groups mentioned in our charter. We have received comment from the XML Schema WG giving explicit approval. We have received recognition, although no formal comments, from DIWG Working Group.

The Semantic Web Deployment WG responded in their review that "We encourage you to go ahead and publish the documents." Due to their review, we believe we have discharged our dependencies between SWD and GRDDL. We address the relationship between RDFa and GRDDL both in the GRDDL Primer and with a test case .

We also notified the TAG. We have unfortunately not received a response, despite three TAG issues being listed in our charter: RDFinXHTML-35, fragmentInXML-28, rdfURImeaning-39

Summary of Review and Comments

We have received no formal objections. All Last Call comments have been considered, and a notification of the fact sent to every commenter. There is a Disposition of Comments below. As of April 26th, we have either explicitly satisfied the commenter or are waiting for a response from a commenter.

The evidence for wide review entails our disposition of comments, our communications with other Working Groups, articles for developers and in the technology press, as well as bookmarks for GRDDL on

Disposition of Comments

The document being sent to CR contains the changes that were made to accommodate comments made during the Last Call status.

This table summarizes the disposition of last call comments on the GRDDL Specification, of 2nd March, 2007.

Comment Commentator WG Responses Closure Summary of Changes
2007AprJun/0015 SW Deployment WG 2007AprJun/0021 go ahead and publish No change.
2007AprJun/0016 (namespace doc) Berrueta 2007AprJun/0022 awaiting response Two editorial changes.
2007AprJun/0003 (namespace doc) Beckett 2007AprJun/0004 2007AprJun/0019 Yes it does address my concerns Comment against the GRDDL namespace document, not the specification. Editorial changes to the namespace document will be made during the CR phase.
2007AprJun/0003 (whitespace) Beckett 2007AprJun/0006 Great Clarifying text
2007AprJun/0003 (other) Beckett 2007AprJun/0023 all the significant concerns are addressed Misc. editorial.
2007JanMar/0079 Carroll 2007AprJun/0007 2007AprJun/0005 addressed Misc. editorial.
2007JanMar/0068 which langs? Mazzocchi 2007AprJun/0000 2007AprJun/0014 I remove my dissatisfaction clarification in primer
2007JanMar/0068 output formats? Mazzocchi 2007AprJun/0000 solves my previous issues entirely added tests illustrating use of <xsl:output>
2007JanMar/0071 Harold 2007JanMar/0078 2007JanMar/0081 none added clarifying test
2007JanMar/0075 Hammond 2007JanMar/0076 2007AprJun/0002 none No change - philosophical disagreement
2007JanMar/0080 no comment XML Schema WG none thank you none
2007AprJun/0028 2007AprJun/0029.html Booth none awaiting response none

Other changes have been made during last call, laregly to clarify the impact of some of the more obscure parts of the normative dependency chain, in response to Working Group discussion. Almost all of these were areas in which the early implementations did not implement the other specifications correctly, this largely motivates the decision to have a call for implementations, as opposed to transitioning straight to Proposed Recommendation. Specific messages, raising such issues, on the WG list include:


We propose a publication date of May 2nd 2007.

We propose that the CR period lasts from the date of publication until 1 June 2007. Given the brevity of the specification, the length of time the specification has been around previous to the creation of the WG, and the current active development of several implementations, we expect to collect the necessary implementation experience in that time.

Preliminary Implementation Report

There is a preliminary Implementation Report at Note that this implementation report shows three implementations in three different languages undergoing active development: (Python), Jena (Java), and Raptor (C).

Proposed CR Abstract, Title, and Status Section


Gleaning Resource Descriptions from Dialects of Languages (GRDDL)


GRDDL is a mechanism for Gleaning Resource Descriptions from Dialects of Languages. This GRDDL specification introduces markup based on existing standards for declaring that an XML document includes data compatible with the Resource Description Framework (RDF) and for linking to algorithms (typically represented in XSLT), for extracting this data from the document.

The markup includes a namespace-qualified attribute for use in general-purpose XML documents and a profile-qualified link relationship for use in valid XHTML documents. The GRDDL mechanism also allows an XML namespace document (or XHTML profile document) to declare that every document associated with that namespace (or profile) includes gleanable data and for linking to an algorithm for gleaning the data.

A corresponding GRDDL Test Cases document illustrates specific issues in this design and provides materials to aid in test-driven development of GRDDL-aware agents. A GRDDL Use Case Working Draft provides motivating examples. A GRDDL Primer demonstrates the mechanism on XHTML documents which include widely-deployed dialects known as microformats.


This section describes the status of this document at the time of its publication[PUBFIX which hasn't happened yet]. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at

This 2nd May 2007 [PUBFIX check date] release of the GRDDL Specification is a Candidate Recommendation; it been widely reviewed and satisfies the requirements documented in GRDDL Charter; W3C publishes a Candidate Recommendation to gather implementation experience. A log of changes is maintained for the convenience of editors and reviewers. Normative assertions are marked up in this way.

The first release of this document as a Working Draft was 24 Oct 2006 and the GRDDL Working Group has made its best effort to address comments received since then, and has also resolved all outstanding issues list of issues meanwhile.There are no normative dependencies to this document that would prevent it from being advanced to Proposed Recommendation status. The design has stabilized and the Working Group intends to advance this specification to Proposed Recommendation once the exit criteria below are met:

This specification will remain a Candidate Recommendation until at least 30 May 2007.

Comments on this document should be sent to, a mailing list with a public archive.

Publication as a Candidate Recommendation does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.

This document was produced by a group operating under the 5 February 2004 W3C Patent Policy. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.

Implementation Experience: Test Cases, Software, and Services

A draft GRDDL Test Cases are available, upon which an in progress implementation report is based.

W3C provides pair of online services on an experimental, best-effort basis:

The GrddlImplementations topic in the ESW Wiki is a community-maintained lists of GRDDL implementations in C, Java, Python, PHP and perhaps other languages.


We maintain a public list of any patent disclosures

Other Deliverables

The GRDDL WG has produced three other documents Test Cases, a Use-Case Scenario, and a GRDDL Primer as well as a Standard Library of Transforms. However, all of these documents currently exist as Working Drafts or Notes, and we believe by the time that Gleaning Resource Descriptions from Dialects of Languages (GRDDL) reaches Proposed Recommendation status, all of these deliverables will be complete and our charter will be fulfilled.