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Re: JSON-LD Telecon Minutes for 2013-07-02

From: Niklas Lindström <lindstream@gmail.com>
Date: Wed, 3 Jul 2013 18:09:36 +0200
Message-ID: <CADjV5jew29=vcK5axFdLUjEbYxoOuV14xiEGkib1UmUUhktb1Q@mail.gmail.com>
To: Robert Sanderson <azaroth42@gmail.com>
Cc: Pat Hayes <phayes@ihmc.us>, Linked JSON <public-linked-json@w3.org>, RDF WG <public-rdf-wg@w3.org>, public-openannotation <public-openannotation@w3.org>
Hi Robert,

Great to hear that we're making progress!

It should be noted though that in JSON-LD you can define different terms
for the same property, with cases like this in mind. That is, you can
define a "listValue" term as:

    "listValue": {"@id": "rdf:value", "@container": "@list"}

which ensures that you can still use plain "rdf:value" keys (or for that
matter, define another term for it, like "value") with arrays without
turning those values into @list values. Only the use of the defined
"listValue" term above would turn the value into a JSON-LD @list (i.e. a
proper RDF list). Which is what we're after here.

I can understand if "owl:sameAs" feels more semantically apt for your needs
though, so I hope that works out. Still, in JSON-LD, unless you want to use
the verbose {"@list": [...]} expression inline all the time, I suggest that
you define something like this in the @context:

    "isList": {"@id": "owl:sameAs", "@container": "@list"}

Ensuring that you can write things like:

    {
      "@id": "target1",
      "@type": "oa:SpecificResource",
      "oa:hasSelector": {
        "@id": "list1",
        "@type": "oa:List",
        "isList": [1, 2]
      }
    }

To get the same RDF as this Turtle:

    <target1> a oa:SpecificResource;
      oa:hasSelector <list1> .
    <list1> a oa:List;
      owl:sameAs ( 1 2 ) .

(Otherwise you have to declare the list like: "owl:sameAs": {"@list": [1,
2]}).

Cheers,
Niklas



On Wed, Jul 3, 2013 at 5:15 PM, Robert Sanderson <azaroth42@gmail.com>wrote:

>
> Dear all,
>
> TL;DR version:  I think that owl:sameAs is a great solution for the
> predicate.
>
> Thank you for the discussion!
>
> The primary use case for lists with identity (and other properties,
> potentially) in Open Annotation is to have an ordered workflow for
> selecting the correct part of a document. For example, EPub documents are
> just zip files with HTML and other resources packed inside them, so it
> would be beneficial to reuse the methods for selecting the correct segment
> of a resource on the web with the resources inside the EPub, but first the
> file within the zip must be selected.
>
> Thus we would want:
>
> <target1> a oa:SpecificResource ;
>   oa:hasSelector <list1> ;
>   oa:hasSource <epub1> .
>
> <list1> a oa:List, rdf:List ;
>   rdf:isList (<FileSelector>, <TextSelector>) .
> // Or something similar here
>
> <FileSelector> a idpf:EpubFileSelector ;
>   rdf:value "/chapter1.html" .
>
> <TextSelector> a oa:TextQuoteSelector ;
>   oa:prefix "bit before the segment"
>   oa:exact "The text of the annotated segment"
>   oa:suffix "bit after the segment"
>
>
> The relevant part of the specification is:
>     http://www.openannotation.org/spec/core/multiplicity.html#List
> (and you'll see the long red editor's note!)
>
> I think that Pat's suggestion of owl:sameAs is very appropriate. It works
> in the different syntaxes and has the semantics that the resources are the
> same -- in the case above the blank node that has first of <FileSelector>
> and the resource <list1>.
>
> The other options discussed were rdf:value, which is extremely fuzzy and
> in JSON-LD context you couldn't assert that it always had a list as its
> object if it was also used with a literal. In which case it would result in
> multiple rdf:value predicates, each with one of the list items as object.
> That led to discussing a new predicate, such as listItems, listValue,
> isList, or similar.  This would have the implication that the blank node
> and the main identified resource were different resources, as compared to
> the proposal of owl:sameAs which would mean they were the same resource.
>
> Rob
>
>
>
>
>
>
> On Wed, Jul 3, 2013 at 12:30 AM, Pat Hayes <phayes@ihmc.us> wrote:
>
>>
>> On Jul 2, 2013, at 11:38 PM, David Booth wrote:
>>
>> > On 07/03/2013 12:07 AM, Pat Hayes wrote:
>> >>
>> >> On Jul 2, 2013, at 12:40 PM, Manu Sporny wrote:
>> >>
>> >>> Thanks to Niklas for scribing. The minutes from this week's telecon
>> >>> are now available.
>> >>>
>> >>> http://json-ld.org/minutes/2013-07-02/
>> >>>
>> >>> Full text of the discussion follows including a link to the audio
>> >>> transcript:
>> >>>
>> >>> -------------------------------------------------------------------
>> >>>
>> >>>
>> > JSON-LD Community Group Telecon Minutes for 2013-07-02
>> >>>
>> >>> Agenda:
>> >>>
>> http://lists.w3.org/Archives/Public/public-linked-json/2013Jul/0000.html
>> >>>
>> >>>
>> > Topics:
>> >>> 1. Assigning Properties to Lists 2. GSoC update 3. JSON-LD / RDF
>> >>> Alignment 4. Lists in the JSON and RDF data models 5. Default
>> >>> interpretation of JSON arrays Resolutions: 1. Create an issue in
>> >>> the RDF WG to formalize a way to express lists that need to be
>> >>> identified with a URL and annotated using properties.
>> >>
>> >> If I understand this correctly, this can be done in RDF already. For
>> >> example, the list [ x:a, x:b, 27 ] identified by the URI ex:thisList
>> >> and possessing the property x:prop with value x:value is described by
>> >> this RDF:
>> >>
>> >> ex:thisList rdf:type rdf:List . ex:thisList rdf:first x:a .
>> >> ex:thisLIst rdf:rest _:1 . _:1 rdf:first x:b . _:1 rdf:rest _:2 . _:2
>> >> rdf:first "27"^^xsd:number . _:2 rdf:rest rdf:nil . ex:thisLIst
>> >> x:prop x:value .
>> >
>> > If I have understood the issue properly, the reason
>> > for raising this issue in the RDF working group is that this is not
>> > necessarily an advisable usage pattern for the RDF list vocabulary,
>> because such a list cannot be serialized using Turtle's list syntax: (x:a
>> x:b 27).
>>
>> Yes, you are right, and I confess I had never noticed this limitation of
>> Turtle previously. OK, let me change the RDF to the following, keeping the
>> list bnodes but using owl:sameAs. (You can of course use some other
>> property indicating equality if y'all prefer.):
>>
>> ex:thisLIst rdf:type rdf:List .
>> ex:thisLIst x:prop x:value .
>> ex:thisList owl:sameAs _:3 .
>> _:3 rdf:first x:a .
>> _:3 rdf:rest _:1 .
>> _:1 rdf:rest _:2 .
>> _:2 rdf:first "27"^^xsd:number .
>> _:2 rdf:rest rdf:nil .
>>
>> Or, in Turtle:
>>
>> ex:thisList rdf:type rdf:List ;
>>       x:prop x:value ;
>>       owl:sameAs (x:a , x:b, 27 ) .
>>
>> and you could probably omit the first triple, or even introduce your own
>> category of JSON-lists and say it is one of those, instead, if that would
>> help with triggering appropriate translations into other formats (or to
>> distinguish these from eg RDF lists used to encode OWL syntax.)
>>
>> >  It falls into a  similar category as other uncommon uses of the RDF
>> List vocabulary:...
>>
>> ...no, it doesn't. See remark below.
>>
>> Pat
>>
>> > other uncommon uses of the RDF List vocabulary:
>> > http://www.w3.org/TR/rdf-schema/#ch_collectionvocab
>> > [[
>> > Note: RDFS does not require that there be only one first element of a
>> list-like structure, or even that a list-like structure have a first
>> element.
>> > ]]
>> >
>> > While not prohibited by RDF, such uncommon uses of the RDF list
>> vocabulary are certainly seen by some as being somewhat anti-social. Thus,
>> the question is whether such uses should be *encouraged*.
>> >
>> > David
>> >
>> >>
>> >> Pat
>> >>
>> >>> Chair: Manu Sporny Scribe: Niklas Lindström Present: Niklas
>> >>> Lindström, Robert Sanderson, Markus Lanthaler, Manu Sporny, David
>> >>> Booth, David I. Lehn, Vikash Agrawal Audio:
>> >>> http://json-ld.org/minutes/2013-07-02/audio.ogg
>> >>>
>> >>> Niklas Lindström is scribing.
>> >>>
>> >>> Topic: Assigning Properties to Lists
>> >>>
>> >>> Markus Lanthaler: https://github.com/json-ld/json-ld.org/issues/75
>> >>> Robert Sanderson:  we'd very much like to give rdf:Lists identity,
>> >>> so that they can be referenced from multiple graphs. Also to
>> >>> describe them with other properties ... in openannotation, we need
>> >>> lists to define a selector which determines which part is
>> >>> annotated ... for instance, which piece of a text is annotated,
>> >>> with "before" and "after" also recorded (most clients work like
>> >>> that) ... Futhermore, IDPF has agreed to use openannotation for
>> >>> all EPub books ... EPubs, being zip files with a bunch of files ...
>> >>> To define a selector here (take the EPub, select a file, then a
>> >>> part in there) ... So we don't want to reproduce every single
>> >>> selector mechanism. Thus, an ordered list of two selectors would
>> >>> be neeeded. ... We thus need to identify lists, so that we can
>> >>> reuse these selectors in multiple statements. ... I.e. a person
>> >>> wants to disagree with a specific annotation, or place being
>> >>> annotated. ... Furthermore, we have the order of multiple targets,
>> >>> e..g. "the first passage on page three, is derived from the second
>> >>> passage on page five" ... Not as essential, since it's not really
>> >>> machine actionable ... Another project using lists is Shared
>> >>> Canvas ... We'd very much like to use JSON-LD there too, for
>> >>> selecting pages, using a list of pages and so forth ... For this,
>> >>> we took the "list items" approach; the list doesn't need to be
>> >>> referenced directly. Markus Lanthaler: robert, do you have the link
>> >>> of an example at hand? ... But it might be nice to have this
>> >>> standardized, so people don't reinvent list items all the time. ...
>> >>> at the mailing list and also the OA community meeting in Europe, we
>> >>> agreed that we don't want to change the model to accomodate
>> >>> different syntaxes ... We want to recommend JSON-LD Manu Sporny:
>> >>> what's the timeline for these needs / when would the WG close
>> >>> Robert Sanderson:  at the moment, the CG is in an implementation
>> >>> phase. We need to dicuss with Ivan, but we hope to move from CG to
>> >>> WG next year Manu Sporny:  we're very close to CR in JSON-LD. If
>> >>> we'd add his feature in, it would put us back for many months.
>> >>> Could we add this for JSON-LD 1.1? ... If we think we can put the
>> >>> feature in, I think we can easily convince implementers to add it.
>> >>> If we add it to the test suite, other implementers would add it.
>> >>> ... So for practical purposes, we aim for it to be added within a
>> >>> year or so. Robert Sanderson:  Yes, that approach could work for
>> >>> us. Given that your'e much further ahead. It's not our prefered
>> >>> option, since for implementations, it might be unpredictable. ...
>> >>> Also, changing this for OA now is much easier than when in a WG ...
>> >>> I don't believe anyone has implemented it yet, but IDPF needs this
>> >>> to be implementable Manu Sporny:  so we may put it in jSON-LD 1.1
>> >>> Niklas Lindström:  First thing, as far as I know, Turtle doesn't
>> >>> support this syntax either. Given that you have a shorthand in
>> >>> Turtle.... actually, none of the formats in RDF/XML and Turtle
>> >>> support this sort of list syntax. [scribe assist by Manu Sporny]
>> >>> Markus Lanthaler: niklasl, AFAICT they currently set rdf:rest to a
>> >>> Turtle list Niklas Lindström:  Have you discussed that as well? Am
>> >>> I missing something? [scribe assist by Manu Sporny] Robert
>> >>> Sanderson:  No, I don't think you missed anything. [scribe assist
>> >>> by Manu Sporny] Robert Sanderson:  The identity is easier in
>> >>> RDF/XML - you have the property for the URI. [scribe assist by Manu
>> >>> Sporny] Robert Sanderson:  We did consider the other
>> >>> serializations, it's not a ubiquitous feature, but it would be nice
>> >>> to have in JSON-LD. [scribe assist by Manu Sporny] Niklas
>> >>> Lindström:  Right, the main argument when we had the issue, even
>> >>> though it's in the Primer that says there is nothing preventing
>> >>> lists from being described, multiple start properties, etc. None of
>> >>> the core syntaxes allow it, it's not intended to be used like that.
>> >>> [scribe assist by Manu Sporny] Niklas Lindström:  They're supposed
>> >>> to be used as syntactic constructs.... model-wise, they're not
>> >>> really a part of RDF.
>>
>> That is not correct. Collections were intended to be an integral part of
>> RDF. They were used by OWL as a syntactic device for encoding OWL syntax in
>> RDF, making them unavailable inside OWL, but that is an OWL/RDF issue.
>> (IMO, with hindsight, this was a serious mistake in designing the OWL/RDF
>> layering. But I was there at the time and didn't see the danger myself, so
>> mia culpa.)
>>
>> >>> [scribe assist by Manu Sporny] Niklas
>> >>> Lindström:  If this is supported in JSON-LD, it would be a lot
>> >>> easier to deviate from the recommended usage pattern.... also
>> >>> making it harder for a future RDF spec, who wants to add lists as a
>> >>> native part of the model [scribe assist by Manu Sporny] Niklas
>> >>> Lindström:  You can still use rdf:first / rdf:next explicitly
>> >>> today. [scribe assist by Manu Sporny] Robert Sanderson:  I agree.
>> >>> The notion of order in a graph is always problematic. Not the
>> >>> common method to have a resource that is a list and has identity.
>> >>> [scribe assist by Manu Sporny] Robert Sanderson:  Maybe RDF
>> >>> COncepts 1.1 should discuss it. [scribe assist by Manu Sporny]
>> >>> David Booth:  Yeah, RDF WG should consider this. I agree with
>> >>> Niklas. It doesn't fit w/ the usual list pattern. Important to
>> >>> consider implications. [scribe assist by Manu Sporny] ... Here's an
>> >>> example:
>> >>> http://www.openannotation.org/spec/core/multiplicity.html#List
>> >>> Robert Sanderson: That's it exactly, thanks Niklas1 Manu Sporny:
>> >>> any other thoughs on this? Markus Lanthaler:  it would make it hard
>> >>> to expect compaction to behave as predicted ... also, compaction
>> >>> might be more complex Manu Sporny:  Yes. We wanted to stay away
>> >>> from it since it might be a mine field in general. ... that said,
>> >>> there might be a case for this. Niklas Lindström:  Agree with
>> >>> Manu's point - there might be something new that's interesting
>> >>> here. I don't think we should do it w/o discussing implications.
>> >>> Algorithmic complexity for JSON-LD API and implementations. It
>> >>> might be almost as problematic as bnodes as predicates. It's
>> >>> possible to do this in raw RDF. It seems highly obvious that you
>> >>> can add ID in other properties. On the other hands you... [scribe
>> >>> assist by Manu Sporny] Manu Sporny: ...can do it w/ literals.
>> >>> Niklas Lindström:  This borders on the syntactical collapse.
>> >>> [scribe assist by Manu Sporny] Markus Lanthaler:  syntactically
>> >>> having a property carrying the actual list is nearly
>> >>> indistinguishable as the requested form (using "@list" as key)
>> >>> Robert Sanderson:  I agree. The easisest solution for everyone
>> >>> would be to have a "listItem" as a property. ... and for the RDF
>> >>> WG, it might be good to define a dedicated predicate for it.
>> >>> rdf:value is explicitly fuzzy, so you can't always expect a list.
>> >>> David Booth: Robert, would it be feasible to just wrap the list in
>> >>> another object, and attach the additional info to the wrapper
>> >>> object? (I apologize that I have not fully grokked the problem, so
>> >>> this suggestion may not be helpful.) ... It would be easier to sell
>> >>> changing the model if there was another predicate for this. Manu
>> >>> Sporny:  so a specific vocabulary for lists would be beneficial in
>> >>> general, working in all syntaxes ... would that adress this issue?
>> >>> If we quickly create a list vocabulary? Robert Sanderson:  I think
>> >>> so. Not preferable duing the discussions we had, but the syntactic
>> >>> arguments may sway this position. ... A single, interoperable
>> >>> solution is preferable. Manu Sporny:  anyone objects to open issue
>> >>> 75, to continue this dicussion? Niklas Lindström:  I think we
>> >>> should try to have this as an RDF issue - it really would not come
>> >>> up if lists were core to the RDF model. It's a sore spot in RDF
>> >>> Concepts. I think we should push it over to the RDF WG immediately.
>> >>> It's arbitrary if we or OA try to push something forward, it won't
>> >>> solve the real problem.... not in rdf schema vocab. [scribe assist
>> >>> by Manu Sporny] Robert Sanderson: +1 to Niklas
>> >>>
>> >>> PROPOSAL: Create an issue in the RDF WG to formalize a way to
>> >>> express lists that need to be identified with a URL and annotated
>> >>> using properties.
>> >>>
>> >>> Manu Sporny: +1 David Booth: +1 Robert Sanderson: +1 Niklas
>> >>> Lindström: +1 could be someything like rdf:listValue David I. Lehn:
>> >>> +1 Markus Lanthaler: +1
>> >>>
>> >>> RESOLUTION: Create an issue in the RDF WG to formalize a way to
>> >>> express lists that need to be identified with a URL and annotated
>> >>> using properties.
>> >>>
>> >>> Topic: GSoC update
>> >>>
>> >>> Vikash Agrawal:  what's broken in the playground? Manu Sporny:  a
>> >>> bit weird ui paradigm when clicking on expanded form; headings for
>> >>> JSON-LD Context stay, but the input box disappears. Markus
>> >>> Lanthaler: http://www.markus-lanthaler.com/jsonld/playground/
>> >>> Markus Lanthaler:  the headers stay but the inputs disappear.
>> >>> Previously headers were toggled off if input areas weren't
>> >>> applicable Manu Sporny:  play around a bit. I think the old way is
>> >>> better. There may be something even better, but right now, the
>> >>> problem is that something not used is still shown. Vikash Agrawal:
>> >>> this is bug 50 ... by this week, this should be done. Next week is
>> >>> a creator app. Markus Lanthaler: could we discuss these things on
>> >>> the mailing list or the issue tracker? Manu Sporny:  email danbri
>> >>> and gregg regarding a schema.org JSON-LD context Markus Lanthaler:
>> >>> vikash, here's Sandro's schema.org context:
>> >>> http://www.w3.org/People/Sandro/schema-org-context.jsonld Markus
>> >>> Lanthaler: for the creator app, have a look at:
>> >>> http://schema-creator.org/
>> >>>
>> >>> Topic: JSON-LD / RDF Alignment
>> >>>
>> >>> Manu Sporny:
>> >>> http://lists.w3.org/Archives/Public/public-rdf-wg/2013Jun/0233.html
>> >>>
>> >>>
>> > Manu Sporny:  I went into the spec and tried to integrate what we
>> >>> have consensus on. ... see the email link above for a list of
>> >>> things. ... everything should be there except for skolemization
>> >>> David Booth:  I just found it, but I think it looks great (just
>> >>> some minor things) Manu Sporny:  would it adress the LC comment?
>> >>> David Booth:  It might. It's in the right direction. Manu Sporny:
>> >>>
>> http://json-ld.org/spec/ED/json-ld/20130630/diff-20130411.html#data-model
>> >>>
>> >>>
>> > Manu Sporny:  next, Peter's changes. Appendix A was changed to
>> >>> flat out say that JSON-LD uses an extended RDF model. ... we just
>> >>> say "Data Model", and that it's an extension of the RDF data
>> >>> model. Markus Lanthaler:
>> >>> http://lists.w3.org/Archives/Public/public-rdf-wg/2013Jul/0010.html
>> >>>
>> >>>
>> > ... we need to have a resonse from Peter on this.
>> >>> David Booth:  I'd expect it to be, to the extent that I can channel
>> >>> Peter. David Booth: Every node is an IRI , a blank node , a
>> >>> JSON-LD value , or a list . David Booth:  restricting the literal
>> >>> space to JSON-LD values is a restriction rather than an extension
>> >>> to the RDF model. Robert Sanderson: Sorry, have to attend another
>> >>> call now, though would like to have stayed for the rest of the
>> >>> conversation. Thanks everyone for the discussion re lists. ... and
>> >>> I don't think that lists need to be mentioned there; they are just
>> >>> sugar. Markus Lanthaler: "A JSON-LD value is a string, a number,
>> >>> true or false, a typed value, or a language-tagged string." Markus
>> >>> Lanthaler: thanks for joining robert Manu Sporny:  on top, we
>> >>> extension the value space to json true and false, numbers and
>> >>> strings. David Booth: A JSON-LD value is a string , a number , true
>> >>> or false , a typed value , or a language-tagged string . David
>> >>> Booth:  it wasn't clear that those lined up with the corresponding
>> >>> RDF value space. Manu and David agree that the JSON number value
>> >>> space is more general. Manu Sporny:  different lexical spaces for
>> >>> booleans in xsd and json
>> >>>
>> >>> Topic: Lists in the JSON and RDF data models
>> >>>
>> >>> David Booth:  What about lists, aren't they the same as expressed
>> >>> in RDF? Manu Sporny:  not convinced that they are.. ... we need to
>> >>> translate it to something in the data model. In RDF, it translates
>> >>> to the list properties. There is nothing in RDF concepts to point
>> >>> to. ... many just assumes that it's basically part of the data
>> >>> model, but it's formally not David Booth:  why not point to rdf
>> >>> schema? Manu Sporny:  not part of the rdf data model. Niklas
>> >>> Lindström:  Yeah, just a comment. Could we correlate this RDF
>> >>> Concepts problem w/ the suggestion wrt. list values. [scribe assist
>> >>> by Manu Sporny] David Booth: RDF lists: David Booth:
>> >>> http://www.w3.org/TR/rdf-schema/#ch_list Niklas Lindström:
>> >>> Clearly, lists are under-specified. [scribe assist by Manu Sporny]
>> >>> Niklas Lindström:  Maybe we should expand RDF Concepts that is
>> >>> present in the 2004 Primer and the Syntax that I scanned
>> >>> previously. [scribe assist by Manu Sporny] Manu Sporny:  but does
>> >>> rdf schema extend the rdf data model? David Booth:  no, just a
>> >>> convention which is using the rdf data model Markus Lanthaler:
>> >>> but's still just a vocabulary. In JSON-LD, we use [a keyword and]
>> >>> an array ... it's like a node type [just as literals] Manu Sporny:
>> >>> the JSON-LD data model does not talk about rdf:first and rdf:rest
>> >>> David Booth:  I don't think any test cases needs to be changed by
>> >>> the way this is described. So it's just a question of how this
>> >>> concept is being described. At present, it's described as a
>> >>> difference. Manu Sporny:  True. We only change how you think about
>> >>> the data model. Manu Sporny:  if we make an argument about the
>> >>> difference between native JSON literals and RDF literals, we need
>> >>> to explain the difference of expressing lists as well. David Booth:
>> >>> I don't see the benefit as a difference, from an RDF perspective.
>> >>> Niklas Lindström:  I think I can answer re: benefit of having
>> >>> different model wrt. JSON lists and RDF lists. In JSON, there are
>> >>> arrays, those arrays represent repeated statements in RDF> [scribe
>> >>> assist by Manu Sporny] Niklas Lindström:  RDF people understands
>> >>> that intuitively. We mention @set because people that don't
>> >>> understand RDF, but do understand mathematical sets.... ordered
>> >>> list is more popular than sets in programming. [scribe assist by
>> >>> Manu Sporny] Niklas Lindström:  We need a way to explain lists in
>> >>> JSON-LD, in the same way that we explain sets, and other things.
>> >>> Not in a way that introduces rdf:first and rdf:next. [scribe assist
>> >>> by Manu Sporny] David Booth: Bottom line: I do not see a need to
>> >>> call out lists as being a difference from the RDF model, but I'm
>> >>> okay with it being mentioned, in part because I'd like to push RDF
>> >>> to have native lists. Markus Lanthaler: manu, did you see
>> >>> http://lists.w3.org/Archives/Public/public-rdf-wg/2013Jul/0010.html
>> >>>
>> >>>
>> > already?
>> >>>
>> >>> Topic: Default interpretation of JSON arrays
>> >>>
>> >>> David Booth:  it seems strange to have @set (unordered) as the
>> >>> default ... in regular json, the default is ordered Markus
>> >>> Lanthaler:  We discussed this quite a bit in the beginning, the
>> >>> rationale was that the RDF that was generated would be unmanageable
>> >>> - lots of blank nodes, lots of rdf:first/rdf:rest, you couldn't
>> >>> work w/ the RDF anymore. [scribe assist by Manu Sporny] Markus
>> >>> Lanthaler:  we discussed it quite a bit in the beginning. The
>> >>> rationale we came up with is that the generated RDF would be very
>> >>> gruesome, using rdf lists for everything. ... hundreds of blank
>> >>> nodes for everything. Niklas Lindström:  Yeah, I agree. That's the
>> >>> rationale. While it's true that arrays in JSON are ordered in their
>> >>> nature, in all the JSON-LD examples, they are commonly only sets.
>> >>> There is no real order. JSON-LD is intended to be used w/ RDF
>> >>> properties, there are only a handful of common RDF properties -
>> >>> author, contributorList, propertyChainAction, where the order is
>> >>> semantic, it means something. [scribe assist by Manu Sporny] Niklas
>> >>> Lindström:  In every other case, it's just a bundle of things. I
>> >>> think that's the better case - explicitly say order doesn't mean
>> >>> anything. The same thinking has obscured lots of things wrt. XML.
>> >>> You can rely on the order of the elements, not sure if you should.
>> >>> It's better to say that "you can't rely on the order", unless
>> >>> someone says so explicitly. [scribe assist by Manu Sporny] David
>> >>> Booth:  As a programmer, I'd use the exact opposite rationale.
>> >>> [scribe assist by Manu Sporny] David Booth: So if the default were
>> >>> changed to being ordered, then the examples would have to be
>> >>> changed to add @set? Markus Lanthaler:
>> >>> https://github.com/json-ld/json-ld.org/issues/12 Niklas Lindström:
>> >>> We discussed whether we should do it in the @context, we could
>> >>> define @set to be the default. [scribe assist by Manu Sporny]
>> >>> Niklas Lindström:  I agree w/ David that as a programmer, you think
>> >>> like that. Unless you think otherwise. [scribe assist by Manu
>> >>> Sporny] David Booth:  There is also minimal changes going from JSON
>> >>> to JSON-LD. [scribe assist by Manu Sporny] Niklas Lindström:
>> >>> Datasets on the Web, you never know if the order is intentional or
>> >>> not. It's better to assume that it's not ordered. [scribe assist by
>> >>> Manu Sporny] Markus Lanthaler:  JSON-LD can already serialize the
>> >>> same data in so many ways already - remote contexts, you can't
>> >>> really interpret the data anymore by just looking at it. Maybe
>> >>> doing it in a processor flag, but not in the context. [scribe
>> >>> assist by Manu Sporny] Niklas Lindström:  I'd like to be able to do
>> >>> this in the context. "@container": "@set" would be useful to me.
>> >>> [scribe assist by Manu Sporny] David Booth: Can we have a global
>> >>> way to indicate @set ? Niklas Lindström:  Yeah, but I could wait
>> >>> for this feature. [scribe assist by Manu Sporny] David Booth:  I'm
>> >>> worried about the element of surprise. It reverses the common
>> >>> expectation. Manu Sporny:  It has not come up as a real issue from
>> >>> anywere though. Markus Lanthaler:  Is there a use case for this?
>> >>> [scribe assist by Manu Sporny] Markus Lanthaler:  In the majority
>> >>> of instances, the order is irrelevant David Booth:  yes, quite
>> >>> possible Manu Sporny:  a change could also backfire at this stage
>> >>> ... we could potentially have a JSON-LD 1.1, for e.g. this. David
>> >>> Booth: I think the best solution would be a simple global way to
>> >>> specify @set, and user get used to always doing that. Niklas
>> >>> Lindström:  I think that it can't fly from my point of view - given
>> >>> that for every case where I've seen order having meaning, it's
>> >>> always been a very specific technical reason. Implicitly ordered
>> >>> things as properties on the object. In every specific scenario
>> >>> where order is used.... [scribe missed] [scribe assist by Manu
>> >>> Sporny] Niklas Lindström:  check out schema.org· only a handful
>> >>> where the meaning is explicitly ordered:
>> >>> http://www.w3.org/People/Sandro/schema-org-context.jsonld Niklas
>> >>> Lindström:  I might be open that it should be ordered, but not by
>> >>> default. [scribe assist by Manu Sporny]
>> >>>
>> >>> -- manu
>> >>>
>> >>> -- Manu Sporny (skype: msporny, twitter: manusporny, G+: +Manu
>> >>> Sporny) Founder/CEO - Digital Bazaar, Inc. blog: Meritora - Web
>> >>> payments commercial launch http://blog.meritora.com/launch/
>> >>>
>> >>>
>> >>>
>> >>
>> >> ------------------------------------------------------------ IHMC
>> >> (850)434 8903 or (650)494 3973 40 South Alcaniz St.
>> >> (850)202 4416   office Pensacola                            (850)202
>> >> 4440   fax FL 32502                              (850)291 0667
>> >> mobile phayesAT-SIGNihmc.us       http://www.ihmc.us/users/phayes
>> >>
>> >>
>> >>
>> >>
>> >>
>> >>
>> >>
>> >>
>> >>
>> >
>>
>> ------------------------------------------------------------
>> IHMC                                     (850)434 8903 or (650)494 3973
>> 40 South Alcaniz St.           (850)202 4416   office
>> Pensacola                            (850)202 4440   fax
>> FL 32502                              (850)291 0667   mobile
>> phayesAT-SIGNihmc.us       http://www.ihmc.us/users/phayes
>>
>>
>>
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>
Received on Wednesday, 3 July 2013 16:10:37 UTC

This archive was generated by hypermail 2.3.1 : Wednesday, 3 July 2013 16:10:37 UTC