W3C

- DRAFT -

RDF Working Group Teleconference

05 Dec 2012

See also: IRC log

Attendees

Present
+1.540.898.aaaa, +31.20.598.aabb, yvesr, Arnaud, pchampin_, gkellogg, davidwood, ericP, MacTed, AndyS, markus, zwu2, ivan, +1.603.897.aadd, Sandro, PatH, manu
Regrets
Chair
David Wood
Scribe
Arnaud

Contents


<ericP> trackbot, start meeting

<trackbot> Date: 05 December 2012

<scribe> scribe: Arnaud

<AndyS> I am muted

<davidwood> PROPOSED to accept the minutes of the 28 Nov telecon: http://www.w3.org/2011/rdf-wg/meeting/2012-11-28

Minutes of last meeting

<davidwood> RESOLVED to accept the minutes of the 28 Nov telecon: http://www.w3.org/2011/rdf-wg/meeting/2012-11-28

Action items

<davidwood> Review of action items

<davidwood> ▪ http://www.w3.org/2011/rdf-wg/track/actions/pendingreview

<davidwood> ▪ http://www.w3.org/2011/rdf-wg/track/actions/open

no pending review

davidwood: anyone claiming credit for any of the open actions?
... none, moving on

Updating W3C Web Summaries

<davidwood> Can we update http://www.w3.org/RDF/ ?

<sandro> sorry I'm late

<ivan> http://www.w3.org/standards/techs/rdf#w3c_all

ivan: this is wiki so it should be easy to update

<davidwood> Why doesn't http://www.w3.org/standards/techs/rdf#w3c_all list RDFa?

ivan: that page is automatically generated based on some magic formula

sandro: send an email to webmaster to request an update

<markus> Btw. JSON-LD API spec is also missing from the list at http://www.w3.org/standards/techs/rdf#w3c_all

<davidwood> ACTION: davidwood to arrange update of http://www.w3.org/2011/rdf-wg/track/actions/pendingreview and http://www.w3.org/2011/rdf-wg/track/actions/open [recorded in http://www.w3.org/2012/12/05-rdf-wg-minutes.html#action01]

<trackbot> Created ACTION-216 - Arrange update of http://www.w3.org/2011/rdf-wg/track/actions/pendingreview and http://www.w3.org/2011/rdf-wg/track/actions/open [on David Wood - due 2012-12-12].

Turtle

subtopic: test preparations

<ericP> local name //subject/iri/PrefixedName/PNAME_LN

<ericP> objectList with two objects //predicateObjectList[objectList/object[2]]

<ericP> predicateObjectList with two objectLists //predicateObjectList[objectList[2]]

ericp: have been working on a script for testing

<ericP> dvcs .... /rdf-turtle/coverage/paths

<ericP> dvcs .... /rdf-turtle/coverage

ericp: should I commit this stuff to mercurial?

sandro: concerned this will get published

<ericP> http://dvcs.w3.org/hg/rdf/raw-file/default/rdf-turtle/

discussion on where to put eric's stuff

ericp: could put a README to give instructions on publication
... will create a new directory

subtopic: LC comments

ericp: not sure where we stand on the I18N comments
... will ping Richard Ishida

ivan: we need to give a firm deadline
... you need to go to the chair

<ericP> is it better to mail the right person who won't respond or the wrong person who will respond?

ivan: specifying that by December 15 if we don't hear back from them we will consider the issue closed
... for Prov they didn't reply

ericp: ok, will do
... we have another issue with the grammar we need to figure out what to do with
... if we change the grammar I expect we'd have another LC

ivan: would only be required if there is a design change, don't think this applies

ericp: issue is that the language changes

this is because we didn't manage to make it an LL1 grammar

<sandro> AndyS ?

gkellogg: it's a performance issue

<AndyS> Let's be concrete - ptr to rule?

ericp: in any case the grammar now appears to be different, allows n trailing semi colons

<gkellogg> [7] predicateObjectList ::= verb objectList (";" (predicateObjectList)?)*

ericp: need to dig back into the history

sandro: still don'
... still don't think this qualifies for 2nd LC

ivan: according to ralph we could make note of the change when going to CR and still go to CR

<sandro> Ivan: quoting Ralph Swick -- how about we just make this AT RISK then we can go to CR without solving this first

<AndyS> eric wants something more ... non recursive which is a tool issue.

<PatH> Well, that was easy.

ivan: this is a corner case that doesn't seem worth losing weeks over
... very few implementers will actually be impacted

<gkellogg> Andy's rule: predicateObjectList ::= verb objectList (";" (predicateObjectList)?)?

andys: this matters to people who automatically produce data

sandro: as a user I would like the freedom of adding extra semi colons

gkellogg: I agree

ericp: we need to figure this out to exit LC

<sandro> http://www.w3.org/TR/turtle/#grammar-production-predicateObjectList

LC rule has a * at the end: predicateObjectList ::= verb objectList (';' predicateObjectList?)*

<gkellogg> [7] predicateObjectList ::= verb objectList ( ";" ( verb objectList)? )*

<PatH> It's semicolons all the way down.

<sandro> In LC: predicateObjectList ::= verb objectList (';' predicateObjectList?)*

sandys: we should focus on what we want, instead of what we have
... do we want to allow multiple semi colons or not?

<sandro> sandro: lets do test cases that have multiple and trailing semicolons

<PatH> allowing <anything> has obvious advantages. Are there any reasons to prohibit multiple semicolons? If not, I suggest we decide to allow them.

ericp: we had one that worked as LR1, changed for LL1

<AndyS> SPARQL allows multiple semis

<AndyS> therefore I think Turtle should.

ericp: concerned about what it will do to people who write tools

sandro: can we resolve on doing test cases for this?
... would like to have a resolution on what is allowed and not allowed, then see if we can get a grammar that matches it

ericp: would rather try to figure out the grammar

sandro: can you write test cases so I can test my implementation?

<AndyS> If it is LL(1) it is LALR(1) if the first part of the rule is clean (the trailing part is irrelevant)

ericp: yes

<ericP> <a> <b> <c> ; ;

<ericP> <a> <b> <c> ; ; .

<PatH> wherever we are, I vote for it.

ericp: will send mail to I18N giving a week for replying
... if we figure out the grammar by next week we can then publish

<sandro> ACTION: sandro to produce an LALR grammar that supports "<a> <b> <c> ; ;" and "<a> <b> <c> ; ; ." [recorded in http://www.w3.org/2012/12/05-rdf-wg-minutes.html#action02]

<trackbot> Created ACTION-217 - Produce an LALR grammar that supports "<a> <b> <c> ; ;" and "<a> <b> <c> ; ; ." [on Sandro Hawke - due 2012-12-12].

<AndyS> Err - the submission was LALR(1)

ericp: yes, but we changed it since then

JSON-LD

<markus> https://github.com/json-ld/json-ld.org/issues/157

markus: most controversial is issue-157

<markus> http://json-ld.org/spec/latest/json-ld-syntax/index.html#data-model

markus: trying to reuse the same terminology but there still are some differences

<markus> http://json-ld.org/spec/latest/json-ld-syntax/index.html#relationship-to-rdf

markus: also blank nodes are allowed as graph names, which isn't allowed in RDF

<ericP> can a datatype be a bnode?

markus: trying to address that with a note stating people shouldn't create such graphs

<PatH> eric: no.

<ericP> PatH, sorry, i meant in JSON-LD

<sandro> sandro: how about "it's not a JSON-LD document if it has a free-standing node"

<AndyS> can a graph name be a literal?

<PatH> Not inside a typed lieral, anyway.

<PatH> OK

sandro: why do you use SHOULD instead of MUST?

markus: trying to remain permissive

sandro: SHOULDs are trouble, and I see more value in aligning with RDF
... not a showstopper but I would vote no
... looks good otherwise

markus: other minor differences, like lists
... in json-ld there are arrays
... other issue is about graph vs dataset

<Zakim> davidwood, you wanted to discuss the JSON-LD data model

<davidwood> "Summarized these differences mean that JSON-LD is capable of serializing any RDF graph or dataset and most, but not all, JSON-LD documents can be transformed to RDF. "

davidwood: this statement means to me that there is still a significant difference despite the effort to minimize the diff
... is that a fundamental issue?
... or just syntactic?

markus: not sure

davidwood: if you state in the spec the difference is merely syntactic we don't have a problem

<PatH> Yup.

markus: but I don't think we can just reuse the RDF data model, because of where we allow blank nodes

<sandro> davidwood: is there a reason you need to allow blank nodes there?

<sandro> manu: it would be complicated to prevent

<sandro> davidwood: lots of RDF tools don't prevent it either.

gkellogg: if we don't need to enforce this in the algos then I think we can do that

<sandro> I'm also happy with the algorithms allowing it.

<AndyS> RDF/XML does not allow bNodes as predicates ... easy to add to Turtle, RDF/XML less so.

PatH: json-ld doesn't have the same limitations as RDF and it allows users to experiment, don't think we should discourage that

sandro: could have a strict mode

markus: that creates interoperability problems

andys: this isn't just about parsers, it also affects data producers

<AndyS> So does this matter: receive JSON-LD -> publish Turtle -> someone else converts to JSON-LD

davidwood: where does that this leave us?

sandro: not happy but don't blame them for doing this

ivan: I can live with it

sandro: would like a procedure check, maybe consider that AT RISK

davidwood: could certainly prompt the community for feedback on whether this is really a problem

ivan: could say that the algos only work for generalized triples
... but ok with leaving it as is
... not a showstopper for me

<markus> https://github.com/json-ld/json-ld.org/issues/182

markus: another thing is graph vs dataset

<markus> http://json-ld.org/spec/latest/json-ld-syntax/index.html#relationship-to-rdf

<sandro> Essential -- is JSON restricted to RDF, or is it Generalized RDF Triples? *shrug* Either way is okay with me, but GRT will cause some big problems, I'm sure.

markus: resolved it saying a json-ld doc can be used as a graph store

ivan: how do I find out whether the doc I get from the web is a graph or data set?

markus: it's always a dataset with json-ld

<PatH> I like that. Everything on the Web is a dataset. that makes perfect sense.

ivan: whether it's in the default graph is up to the application

markus: yes

<PatH> LOL

<sandro> issue-105?

<trackbot> ISSUE-105 -- Graphs, datasets, authoritative representations, and content negotiation -- open

<trackbot> http://www.w3.org/2011/rdf-wg/track/issues/105

<yvesr> PatH, but then we might need to group datasets together or track their provenance, and we end up with datasets of datasets :)

sandro: I think proposed resolution would work, can we use the same thing for TRIGG?

gkellogg: I think the solution we came up with for json-ld should work generically

markus: will send an email on that to the mailing list later

sandro: I think there is an issue with that but will get it in email

<AndyS> TriG isn't a grammar superset of TTL so works less cleanly.

markus: algos are still first in the spec but not as prominent anymore

ivan: what about compliance section?

markus: define two products: 1: compliant to algos, 2: compliant to algos and apis

ivan: I think the approach to separate json-ld processor is fine
... I'm fine with the content of the document but not the title

markus: I think that's something the wg can address
... any suggestions?

ivan: needs alcohol for that :)

<PatH> I have to leave. Use it well.

<markus> https://github.com/json-ld/json-ld.org/issues/178

davidwood: any other business for today?
... meeting adjourned

<zwu2> bye

<manu> great work on the call today, markus! :)

<markus> thanks :-)

<manu> (as well as all of the editing work you've been doing - great job all around!) :)

<Guus> trackbot, end meeting

Summary of Action Items

[NEW] ACTION: davidwood to arrange update of http://www.w3.org/2011/rdf-wg/track/actions/pendingreview and http://www.w3.org/2011/rdf-wg/track/actions/open [recorded in http://www.w3.org/2012/12/05-rdf-wg-minutes.html#action01]
[NEW] ACTION: sandro to produce an LALR grammar that supports "<a> <b> <c> ; ;" and "<a> <b> <c> ; ; ." [recorded in http://www.w3.org/2012/12/05-rdf-wg-minutes.html#action02]
 
[End of minutes]

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$Date: 2012/12/05 17:16:56 $

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Default Present: +1.540.898.aaaa, +31.20.598.aabb, yvesr, Arnaud, pchampin_, gkellogg, davidwood, ericP, MacTed, AndyS, markus, zwu2, ivan, +1.603.897.aadd, Sandro, PatH, manu
Present: +1.540.898.aaaa +31.20.598.aabb yvesr Arnaud pchampin_ gkellogg davidwood ericP MacTed AndyS markus zwu2 ivan +1.603.897.aadd Sandro PatH manu
Found Date: 05 Dec 2012
Guessing minutes URL: http://www.w3.org/2012/12/05-rdf-wg-minutes.html
People with action items: davidwood sandro

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