XDI TC Notes Unofficial Telecon Friday 2015-10-12

[Markus Sabadello <markus.sabadello@xdi.org>]

XDI TC Notes

Following are the notes of the unofficial telecon of the XDI TC held on:

Date: Monday, 12 October 2015 USA
Time: 10:00AM - 11:30AM Pacific Time (17:00-18:30 UTC)

The TC operates under a standing rule approved 17 July 2008 under which the TC does not hold regular official meetings and conducts all business by electronic ballot only. Unofficial weekly meetings are held to enable discussion among members but no business is conducted nor actions taken.

ATTENDING

Phil Windley
Peter Davis
Joseph Boyle
Markus Sabadello
Drummond Reed
Les Chasen
Christopher Allen
Lionel Wolberger

Preparations for our Committee Specification Draft Vote

Chet Ensign was not able to join us for this call.

#DRUMMOND to email Chet and request a call this week.

XDI Core: Spec Draft Update

We have now moved all editing to DocBook. Joseph and Drummond reviewed Working Draft 05 which now has all existing content incorporated and is largely formatted.

http://xdi.org/xdi-spec-docbook/xdi/xdi-core-1.0/xdi-core-1.0-wd05-2015-10-11.xml

See the remaining task list below.

XDI Core ABNF Closure

The “last call” thread on the mailing list appears to have closed all issues on the ABNF for Working Draft 05.

https://wiki.oasis-open.org/xdi/XdiAbnf

We confirmed that there are no outstanding issues other than the discussion about XDI literals as the subjects of relational statements (see the XDI to RDF conversion topic below).

XDI Core Remaining Steps

The remaining steps necessary to hold the Committee Specification Draft vote beginning October 19 fall into five buckets.

Editing tasks.

1. Drummond to add (and Markus and Joseph to review) text to the Literal Arcs and Literal Statements clarifying the use of a literal address as an XDI subject.

2. Joseph complete review of ABNF

3. Joseph to propose any new text for Normalization and Canonicalization section

4. Organize and annotate ABNF section

1. Include explanation of how it is normative

5. Complete organization and annotation of Serialization section

6. Update examples in the Serialization section to conform with spec conventions

7. Introduction section

1. Introduction

2. Example XDI Graphs

3. XDI Specifications Table

8. Appendices

9. Full-spec read-through

Formatting tasks:

1. Add references at “see” and [ref] markers.

2. Fix SVG and JPEG graphics to make sure display correctly.

OASIS conformance tasks:

1. Joseph to hook up with Chet about file/directory naming updates

Packaging tasks (files that must be included in the ZIP file for the vote):

1. ABNF file should be a separate text file that is labeled normative.

2. All graphics files.

3. Dependent files include DocBook fragments.

Special XDI Core Final Review Call

We discussed whether we need to hold a special call next Friday Oct 16 to review the final new content. The decision was to not to hold a call, but rather:

1. Publish the final new sections ASAP.

2. Have all TC members review and post comments to JIRA (or worst case to the TC mailing list).

3. The editors will prepare the Committee Specification Draft copy for final review at next Monday’s meeting.

4. We will open the Committee Specification Draft vote after next Monday’s meeting.

Converting XDI to RDF and JSON-LD

On the mailing list this week the subject was raised of whether we should publish a specification for XDI to RDF conversion, and if so, should it be in a separate spec.

Peter suggested that this should be a separate spec—that it does not belong in Core.

Christopher said that we should also pay attention to the mindshare that JSON-LD has now, because it has made RDF more approachable and usable by developers.

Peter reminded that he and Hubert Le van Gong brought up an RDF translation of XDI almost a year ago. He suggested that if we want to pursue this, we revive this proposal for XDI to JSON-LD conversion.

WE discussed the difference between specifying a direct mapping from an XDI JSON document to an RDF JSON-LD document. Peter supported the idea of a direct, practical XDI-to-JSON-LD mapping. Markus suggested that the mapping could also be done at the conceptual graph level—between the graph models—as then it could be applied to any serialization.

Markus said that XDI2 has already implemented a translation of XDI graphs to RDF graphs. He said that there are two key challenges in the translation:

1. XDI contextual arcs do not exist in RDF.

2. XDI graphs permit a relation to a literal node. In RDF, a literal node is not addressable, nor can it be used as a subject.

On #2, Markus suggests one of two options:

1. Defining a special RDF resource to represent literals.

2. Reify the RDF statement defining the literal.

Markus said that XDI2 currently does the “XDI to RDF conceptual mapping” first, then maps into specific RDF serialization formats like JSON-LD and TRIG. This implementation currently produces an error if an XDI graph contains a relational arc pointing to an literal, because of uncertainty how to map this XDI feature to RDF.

We discussed the use cases for being able to make an XDI statement with a literal as a subject. Both Peter and Markus were unsure what the semantic meaning of a literal-as-a-subject is. Peter pointed out that he believed it would be useful if not required for a robust XDI query language. Markus was not sure, and wants to do more testing of use cases.

In any case, there was a consensus that an XDI-to-RDF mapping should not be in XDI Core, but in a separate spec. We also agreed we would not add this spec to the XDI 1.0 list until there is a critical mass of interest.

Lastly, we discussed the “How XDI Builds on RDF” white paper that we planned to reference from the Introduction section of XDI Core 1.0. There was a consensus that since this paper has not been written yet (Drummond only has an outline), we will not reference the paper from this first Committee Specification Draft. After the paper is completed (and goes through its separate approval process), we can reference it in a subsequent version of Core.

NEXT REGULAR CALL

The next call is next week at the usual time (Monday 10AM PT). The link to where agenda items can be posted for the next meeting is: https://docs.google.com/document/d/19oDl0lbb56Grehx2a5flZnhrgnua5l8cVvC_dJ8fTXk/edit?usp=sharing