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JSON-LD Telecon Minutes for 2012-06-05

From: Manu Sporny <msporny@digitalbazaar.com>
Date: Tue, 05 Jun 2012 12:19:33 -0400
Message-ID: <4FCE3195.2060004@digitalbazaar.com>
To: Linked JSON <public-linked-json@w3.org>
bcc: RDF WG

The minutes from today's call are now available here:

http://json-ld.org/minutes/2012-06-05/

Full text of the discussion follows including a link to the audio
transcript:

--------------------

JSON-LD Community Group Telecon Minutes for 2012-06-05

Agenda:
    http://lists.w3.org/Archives/Public/public-linked-json/2012Jun/0005.html
Topics:
    1. SemTech 2012
    2. ISSUE-127: JSON-LD API Introduction
    3. ISSUE-125: Define fromRDF()/toRDF() in terms of standard RDF
    4. RDF WG Invited Expert process
Chair:
    Manu Sporny
Scribe:
    Manu Sporny
Present:
    Manu Sporny, Markus Lanthaler, Niklas Lindström, François Daoust,
    David I. Lehn

Manu Sporny is scribing.

Topic: SemTech 2012

Manu Sporny:  Gregg is doing a presentation on JSON-LD on
    Thursday, try to support him via Twitter, G+
Manu Sporny:  Stephane is trying to add JSON-LD Drupal... he
    spoke about it yesterday at SemTech.
Manu Sporny:  There was concern that JSON-LD hasn't had enough
    review at W3C, so RDF WG folks are going to take a look at it and
    get people that they know to take a look at it.
Markus Lanthaler:  What needs to be changed in the spec?
Manu Sporny:  That's what we're going to discuss today.

Topic: ISSUE-127: JSON-LD API Introduction

https://github.com/json-ld/json-ld.org/issues/127
Manu Sporny:  RDF WG had a few issues with the JSON-LD API spec,
    mostly because it wasn't quite ready for review.
Manu Sporny:  They want to publish the JSON-LD API spec, so
    that's good... we don't have to look for another WG to publish
    the spec.
Niklas Lindström:  Do we have to publish the entire JSON-LD spec?
    Do we have to separate anything in the specs?
Manu Sporny:  For now, we're going to publish the JSON-LD API
    spec without framing, that seemed to work for the RDF WG.
Manu Sporny:  Richard Cyganiak has asked for these changes:
Manu Sporny:  He wants an Introduction to basic API functionality
    with simple code examples.
Manu Sporny:  He also wants examples of converting to RDF from
    JSON-LD and to JSON-LD from RDF.
Markus Lanthaler:  Yes, good idea, we should do this.
Manu Sporny:  Dave Longley added conversion from RDFa API to
    JSON-LD API - green-turtle.js to jsonld.js - convert from RDF ->
    JSON-LD.
Niklas Lindström:  I've worked on this as well - kinda like an
    '.objectify()' call... using a JSON-LD context is very valuable
    in order to work with the object... very similar to the concept
    of a Projection...
Niklas Lindström:  Given that you're already in a programmatic
    context - having a way to get an object graph back, where you
    have the interconnections already in place, is very valuable - we
    should consider this for the RDFa API - it's easier to consume
    data this way than using framing in the general case... framing
    is useful for other kinds of scenarios.
Niklas Lindström:  The .objectify() idea is very valuable, we
    should consider it for the JSON-LD API...
Niklas Lindström:  If we get this in a simple way for the JSON-LD
    API, if we had that - we could have a nice way of working with
    RDF via JSON-LD in dynamic languages... any sort of mapping
    mechanism works this way - combine a context with the
    .objectify() is important.
Manu Sporny:  Can we have an implementation to play around with?
Niklas Lindström:  Josh Mandel and I have an implementation... we
    could use .prototype to invoke the .toJSON() method... it's an
    in-memory object graph, every reference is a clone of the
    original node... when you use .toJSON() you get a JSON-LD tree
    back. If we did that, we could produce the in-memory graph
    directly and then convert to JSON-LD... don't have to expand
    anything after-the-fact. It is more complex... but if we do this,
    we get the feature of parsing RDF into an object graph where the
    terms are named via JSON-LD @context definitions... no
    intermediate step.
Markus Lanthaler: Here's the link to the comment of Josh Mandel:
    https://github.com/json-ld/json-ld.org/issues/109#issuecomment-5758808
Manu Sporny:  We can develop this in another spec, and then merge
    it if it makes sense to do so at a later time.
Markus Lanthaler: and the pull request to add support for it to
    jsonld.js: https://github.com/digitalbazaar/jsonld.js/pull/15
Niklas Lindström:  I think this would be very appealing to the
    RDF WG - using RDF programmatically - much easier to present to
    web developers than navigating a triple store.
François Daoust:  I haven't had time yet to play around with
    JSON-LD as much as I would've liked to - convert to/from RDF -
    but yes, what Niklas describes sounds like almost exactly what
    we're looking for.
François Daoust:  I'm not sure I see the difference between
    .frame(), .objectify(), .compact(), etc... but in the end, I need
    something in-memory that I can easily process. So yes, this
    sounds good.
Markus Lanthaler:  Implementing it would be fairly
    straight-forward - pretty trivial, most of it is already there.
    Similar to framing, instead of embedding subject references,
    you'd just add a reference to the other object. Almost all of the
    code is already there.
Niklas Lindström:  I think that .objectify() and .frame() are
    complementary - different approaches to solving similar use
    cases.
Niklas Lindström:  This is useful when documenting vocabularies -
    I have to walk the structure quite a bit... useful when checking
    property ranges, etc. If you generate some neat description, you
    usually just navigate one way and rarely more than one step.
Markus Lanthaler:  Niklas, are you saying that you'd like to walk
    the reverse direction as well?
Niklas Lindström:
    https://github.com/niklasl/rdfa-lab/blob/gh-pages/test/test_ld.js#L31
Niklas Lindström:  Yes, I added reverse references in my
    .graphify() call - does not exist in tree-form of JSON-LD... I
    call the JavaScript property .via
Manu Sporny:  Let's back-burner this for a while, keep going
    through more immediate issues.
Niklas Lindström:  Yes, sounds good.
Niklas Lindström:  There has been concern that you can't
    shoe-horn RDF into JSON... but it seems that this allows a way to
    make it easier to use.
Manu Sporny:  So, other things from Richard: The Introduction of
    the API spec is mostly a copy-paste from the syntax spec. Remove
    the duplication, and replace it with a link if appropriate. Don't
    force people to read the same thing twice just so that they are
    sure they're not missing something essential.
Manu Sporny:  Also - The API spec needs its own introduction that
    explains what's in the API spec. This needs at least one sentence
    for each of the algorithms and other major sections of the spec,
    explaining what that thing is and how it fits into the bigger
    picture of publishing, consuming and processing JSON-LD. A quick
    overview of the document's contents. The current lack of such a
    high-level overview in the API spec is a major flaw, and makes
    the document almost inaccessible to JSON-LD outsiders. I'd
    consider this a blocker for FPWD publication of the API spec.
Manu Sporny:  The API spec should probably have one of those
    yellow Issue boxes near the beginning stating that the scope of
    the document, and what exactly is going to be included and
    excluded, is still somewhat unclear. (This is just to make clear
    that agreeing to FPWD publication does not necessary mean we
    agree to everything that's in there; RDF-WG members will need
    some time to review and understand the spec and how it all hangs
    together before being able to make informed commentary on what
    should and shouldn't be included.)
Manu Sporny:  The API spec should have one of those yellow Issue
    boxes pointing out that the WebIDL's terminology needs better
    alignment with RDF Concepts.
Manu Sporny:  Our primary goal is to create an API that is useful
    to Web developers... we want to align with RDF Concepts as well -
    clearly there may be difficulty making both of these happen.
Markus Lanthaler:  I don't see a problem as long as we define our
    terminology and we're consistent.
Niklas Lindström:  I think that when in doubt, we should use RDF
    Concepts... I think the issue is we're not clear whether we're
    talking about the node, or the thing identified by the node...
    resource vs. representation.
Manu Sporny:  Some of the issue is that we lifted language from
    RDF API and RDFa API spec.
Niklas Lindström:  Good to have the discussion... we should keep
    the stance that Web-developer friendly names trump pedantic
    specificity.
Manu Sporny:  My understanding is that the two “Contributing”
    sections in the two specs need to be changed to reflect the
    CG-to-WG transition of the documents.
Markus Lanthaler:  There was a discussion about that the
    algorithms should be described in a more mathematical sense.
Manu Sporny:  I think that we should focus on something that
    works for developers when discussing the algorithms.
Markus Lanthaler:  These algorithms work if you implement them in
    code, but hard to figure out what they mean if you just read it.
Manu Sporny:  Perhaps we need better introductions to the
    algorithm.
Niklas Lindström:  Perhaps we could write it in some kind of
    functional way.
Manu Sporny:  Maybe we expand the introduction, make each
    introduction to each algorithm a bit more verbose and see if that
    makes people like Ivan okay with the algorithms.
Manu Sporny:  Richard said: My understanding is that the two
    “Contributing” sections in the two specs need to be changed to
    reflect the CG-to-WG transition of the documents.
Manu Sporny:  This change is fine - there is some boilerplate
    text that we can use to fix those sections.
Manu Sporny:  Eric Prud'hommeaux wanted us to make this change:
    In a prominent place in the FPWD, document the intention to align
    with the RDF model and terminology. This will calm the RDF
    community and reduce the comments requesting something you
    already plan to do.
Manu Sporny:  Seems like a reasonable change to make - just
    adding an issue.
Manu Sporny:  Sandro asked us to make this change: even though
    this is a FPWD, it already has an 18-month history in the JSON-LD
    Community Group...
Markus Lanthaler:  Yes, we should definitely say that.
Manu Sporny:  Perhaps linking to the group that developed it -
    link to the JSON-LD community group.
Manu Sporny:  Do we need to propose and resolve, or can we just
    make the changes?
Markus Lanthaler:  I don't think so - let's just make the
    changes... these are editorial mostly.
No objections, make the changes.

Topic: ISSUE-125: Define fromRDF()/toRDF() in terms of standard RDF

https://github.com/json-ld/json-ld.org/issues/125
Manu Sporny:  Richard said: I'd prefer if the algorithms were
    defined in terms of standard RDF terminology (RDF graph, triple,
    IRI, etc.) rather than API interfaces that use quite different
    terminology (array of Statements, Statement, NamedNode, etc.)
Manu Sporny:  The terminology in the document is a mish-mash of
    stuff from RDF API, which was created before the new RDF Concepts
    document. It also contains terminology for concepts that aren't
    necessarily in the RDF Concepts document (like Quads), and there
    or other words that we use here that are easier for developers
    (like 'property' vs. 'predicate'). So, some of the changes are
    easy, some of them are mistakes, and some of the terminology may
    be problematic to Web developers if we change it. The core of the
    agreement, however, is that we're going to attempt to align as
    much as possible and where it makes sense.
Niklas Lindström:  I can see Richard's point - I can see why he'd
    prefer to see Triples in datasets... so seeing triple and
    triple.dataset - giving items the same level of meaning - value
    properties of a triple... conceptually when discussing datasets
    and layers - the general idea of it... a 'dataset' is something
    on another level.
Markus Lanthaler:  I think it might be reasonable to specify the
    toRDF()/fromRDF() in RDF terms... but that being said, do we have
    a Quad, or do we have an object that represents the dataset that
    contains triples?
Markus Lanthaler: Richard said: Would it be possible at all to
    redefine the API to use something closer to RDF datasets? Having
    a Graph interface, and then Dataset with defaultGraph and
    multiple namedGraphs?
David I. Lehn: General concern about how long the named graphs
    discussion has been going on in RDF WG.
Markus Lanthaler: This is of importance to this discussion:
    https://github.com/json-ld/json-ld.org/issues/125#issuecomment-5886644
Markus Lanthaler:  I'm concerned that they want us to re-define
    the API using RDF Concepts terminology... but just in
    toRDF/fromRDF - but I don't think we should change the API
    itself, dramatically.
Manu Sporny:  I think we want this API to be very useful to Web
    Developers and using RDF Concepts could make them have to delve
    very deeply into objects... which is not useful ... being
    overly-pedantic isn't good for APIs...
Niklas Lindström: .. Richard wrote: A “triple” is the things in
    the data model; a “statement” is the meaning of a triple, the
    thing that you make when asserting the triple.
Manu Sporny:  The issue is that once we add more information to a
    triple... it's no longer a triple...
Niklas Lindström:  We could add an accessor method - on a
    Projection() for working with the data.
Niklas Lindström:  I can see how you'd say X is a triple and it
    has this origin... and this creation date... etc.
Manu Sporny:  Yes, but in that case - is it still a triple? or
    something else?
Niklas Lindström:  Right - you could group all triples from a
    certain origin in a dataset and then describe the dataset using
    triples... like date, etc. If you want to describe individual
    triples, you can have one dataset for each triple.
Manu Sporny:  I guess we can just make the changes and try to
    align with RDF Concepts where it makes sense to do so... but then
    we'll get feedback on the changes to see if they work for
    Richard.
Niklas Lindström:  Yes, I think that makes sense - since it's
    happening in RDF WG, they'll have feedback.
Niklas Lindström:  In discussions, I've seen "Quad" viewed as
    (subject, predicate, object, and datatype) in discussions between
    people that don't know about RDF... may be a case against Quad...
    it's in the same area as the idea that the thing identifying the
    graph is a 'meta-property' and not part of the data.

Topic: RDF WG Invited Expert process

Manu Sporny:  Markus, Niklas, have you guys sent in your Invited
    Expert application yet?
Markus Lanthaler:  Yes.
Niklas Lindström:  I'm waiting to hear back from SIXX.
Manu Sporny:  Let us know how we can help.
Manu Sporny:  Also, a big thanks to Markus, Niklas, Francois,
    Gregg, Dave Lehn, Dave Longley and everyone else that continues
    to volunteer their unpaid time to move this stuff forward - we
    recognize that it's a big sacrifice and all the hard work is
    very, very much appreciated.

-- manu

-- 
Manu Sporny (skype: msporny, twitter: manusporny)
President/CEO - Digital Bazaar, Inc.
blog: PaySwarm Website for Developers Launched
http://digitalbazaar.com/2012/02/22/new-payswarm-alpha/
Received on Tuesday, 5 June 2012 16:20:11 GMT

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