17:57:08 <RRSAgent> RRSAgent has joined #shapes
17:57:08 <RRSAgent> logging to http://www.w3.org/2015/07/02-shapes-irc
17:57:10 <trackbot> RRSAgent, make logs rdf-data-shapes
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17:57:12 <trackbot> Zakim, this will be SHAPES
17:57:12 <Zakim> I do not see a conference matching that name scheduled within the next hour, trackbot
17:57:13 <trackbot> Meeting: RDF Data Shapes Working Group Teleconference
17:57:13 <trackbot> Date: 02 July 2015
17:57:43 <kcoyle> kcoyle has joined #shapes
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18:01:40 <kcoyle> scribenick: kcoyle
<kcoyle> chair: Arnaud
<kcoyle> agenda: https://www.w3.org/2014/data-shapes/wiki/Meetings:Telecon2015.07.02
18:01:42 <Arnaud> present+ Arnaud
18:02:22 <kcoyle> present+ kcoyle
18:02:26 <pfps> present+ pfps
18:02:31 <Dimitris> Dimitris has joined #shapes
18:02:38 <aryman> present+ aryman
18:03:43 <Arnaud> regrets: ericp, simonstey
18:05:01 <Arnaud> present+ dimitris
18:05:03 <hknublau> present+ hknublau
18:06:58 <TallTed> present+ TallTed
18:07:54 <kcoyle> topic: Admin
18:07:59 <Arnaud> PROPOSED: Approve minutes of the 25 June Telecon: http://www.w3.org/2015/06/25-shapes-minutes.html
18:08:15 <aryman> +1
18:08:20 <Arnaud> RESOLVED: Approve minutes of the 25 June Telecon: http://www.w3.org/2015/06/25-shapes-minutes.html
18:08:36 <pfps> The minutes look OK, but it took me quite a bit of effort to figure out that the change was actually made to ISSUE-72.  I got an old version days after the change was made.
18:08:36 <kcoyle> Next meeting 9 July
18:09:19 <kcoyle> Arnaud: Should we go to lighter schedule for summer? hmmm, we're already behind, let's go on!
18:10:06 <pfps> ok by me :-(
<kcoyle> topic: SHACL FPWD
18:10:59 <pfps> What document are we discussing?
18:11:05 <kcoyle> Arnaud: SHACL 1st public working draft - where are we?
18:11:31 <Labra> Labra has joined #shapes
18:11:37 <aryman> q+
18:11:41 <kcoyle> ... what would it take to publist 1st draft?
18:11:58 <kcoyle> ... should makr issues that are open; status can be made clear
18:12:11 <kcoyle> ... s/makr/mark
18:12:31 <pfps> q+
18:12:32 <Arnaud> ack aryman
18:13:00 <kcoyle> aryman: would like to have 2 week lead before it goes public so group can review a stable draft
18:13:07 <pfps> Editor*s*???
18:13:10 <Arnaud> ack pfps
18:13:32 <kcoyle> pfps: not sure when I got to be an editor... am I?
18:13:45 <kcoyle> aryman: thought Peter ahd Holger working together
18:13:51 <kcoyle> pfps: Not so
18:13:51 <hknublau> +q
18:14:07 <kcoyle> pfps: things that need to be in place:
18:14:12 <kcoyle> ... well-founded semantics
18:14:21 <kcoyle> ... has to have notion of what direction is
18:14:25 <kcoyle> ... latter is not yet true
18:15:02 <kcoyle> ... what would it take? we still have issue that would negate bulk of the document: access to shape graph
18:16:12 <kcoyle> ... even more important, recursive shapes, which is not on our radar (not issue-22)
18:16:23 <Arnaud> ack hknublau
18:16:54 <kcoyle> hknublau: so many open issues that document is somewhat frozen; would welcome other editors
18:17:05 <pfps> the issue that needs to be worked in is ISSUE-66 non-convergence
18:17:07 <kcoyle> ... need to get shape graph issue out of the way
18:18:01 <pfps> ISSUE-68 should also be resolved, and this one can be done by Holger
18:18:37 <kcoyle> pfps: issue 68 could be done; editorial
18:18:39 <pfps> q+
18:18:46 <kcoyle> hknublau: am looking at that; more than just editorial
18:18:52 <Arnaud> ack pfps
18:19:29 <kcoyle> pfps: issue 68 is just missing from spec, doesn't need decisions. Go ahead and add it
18:20:58 <kcoyle> ... needs to be done for 1st public working draft
18:21:09 <pfps> pre-binding is a significant part of the document and needs to be done before FPWD
18:22:15 <pfps> There are holes that can be filled in later and there are sink-holes that can consume an entire document.
18:22:27 <kcoyle> Arnaud: FPWD will get more comments from folks outside the immediate group
18:22:46 <kcoyle> ... Holger - time estimate?
18:23:06 <kcoyle> hknublau: can put in placeholder in the next few days
18:23:53 <aryman> q+
18:24:13 <kcoyle> Arnaud: re:annotating the spec with the open issues -- is there still a respec problem?
18:25:23 <kcoyle> hknublau: respec adds numbering; so I'm adding link to documents; any help welcome
18:25:49 <Arnaud> ack aryman
18:26:19 <kcoyle> aryman: is it worth freezing the doc the way it is now; do a round of review? is it stable? would a detailed review be good now?
18:26:51 <pfps> The document has been stable for a while now.
18:26:52 <kcoyle> hknublau: has been stable for a while; and reflects my prototype
18:27:31 <kcoyle> aryman: can there be revision bars on changes? makes it easy to see what's changed
18:27:54 <pfps> There used to be a way to see revision changes in W3C WDs.  That was very useful.   Source diffs are very much less useful.
18:28:24 <kcoyle> Arnaud: maybe a history of changes section at the end for significant changes
18:29:55 <kcoyle> ... Holger will create a marked draft that represents current stable version
18:30:02 <pfps> Another problem with ReSpec is that it is not easy to see old versions of the document - the Wiki is very much better in this regard.
18:31:15 <kcoyle> topic: ISSUE-47: Can SPARQL-based constraints access the shape graph, and how?
18:31:15 <trackbot> Notes added to ISSUE-47 Can SPARQL-based constraints access the shape graph, and how?.
18:32:31 <kcoyle> Arnaud: had 3 different proposals; this should be a yes/no question: access or not?
18:32:44 <hknublau> https://lists.w3.org/Archives/Public/public-data-shapes-wg/2015Jun/0159.html
18:33:19 <aryman> what picture? link pls?
18:33:19 <kcoyle> hknublau: 2 ways that SHACL can be used with SPARQL
18:33:25 <aryman> aha
18:33:56 <kcoyle> ... 1- dataset with shacl; enterprise system with controlled set of named drafts and sparql functions; a kind of closed world
18:34:35 <kcoyle> ... 2 - sparql end point and shacl engine live in different environments; no control over endpoint
18:35:12 <kcoyle> ... solution 1: restrict language to only features that can be supported with sparql
18:36:04 <kcoyle> ... solution 2: go beyond limitation of sparql endpoints by encouraging implements to implement "shacl endpoint" where you send shacl graph to a server that applies shacl constraints on the graph
18:36:28 <kcoyle> ... solution 2 would be ideal, having shacl implemented natively in databases
18:36:46 <kcoyle> ... sparql solution is bridge until solution 2 is available
18:37:18 <pfps> There was quite an echo.
18:37:50 <kcoyle> ... implement by allowing different types of shacl language; create a subset that is not supported by sparql
18:38:29 <kcoyle> ... would not implmenet custom functions; requests outside of the subset could be detected
18:39:56 <kcoyle> pfps: view: access to shpaes graph gets you a little but prevents a lot of functions
18:40:41 <Dimitris> +q
18:40:51 <kcoyle> ... shacl engine allows access to graph; not true that blank nodes are problematic for this proposal; well-handled by sparql endpoints
18:41:30 <kcoyle> ... access to shapes graph when evaluating constraints on data graph permits a jparticular execution methodology that is inefficient
18:42:03 <kcoyle> ... because of top-down implementation there is redundancy that can be costly
18:42:40 <hknublau> +q
18:43:05 <kcoyle> ... gain little by access to shapes graph except for recursion, which you may have to give up; preferably where you cannot load data locally, e.g. dbpedia
18:43:19 <aryman> q+
18:43:40 <pfps> q+
18:43:47 <Arnaud> ack Dimitris
18:44:40 <pfps> q-
18:44:53 <kcoyle> Dimitris: agree with Peter; blank nodes not a problem; looking for use case for access beyond core language
18:45:01 <Arnaud> ack hknublau
18:45:36 <pfps> q+
18:45:40 <kcoyle> hknublau: blank nodes not handled because not persistent; only work locally;
18:45:50 <Dimitris> +q
18:46:18 <kcoyle> ... peter's proposal would be a re-write of the document, and may have efficicency issues -- so details will be needed.
18:46:21 <pfps> The details have been worked out *and* implemented!
18:46:27 <kcoyle> ... also need alternative to shapes graph access
18:46:46 <aryman> the SHACL engine of course needs to access the SHACL program, so are we talking about having the SHACL in the same dataset as the data graph?
18:46:51 <Arnaud> ack aryman
18:47:25 <kcoyle> aryman: shacl engine obviously needs to read the shacl program - are we debating whether shacl program in same dataset as datagraph?
18:47:30 <Arnaud> ack pfps
18:48:23 <kcoyle> pfps: if shacl control graph is in dataset, then you can access it using sparql and everything is easier; but you might say that the shacl control graph is not part of target dataset, but is accessible using some sparql extension
18:48:43 <Arnaud> ack Dimitris
18:49:15 <pfps> q+
18:49:22 <kcoyle> Dimitris: suggestion was to use holger's proposal but limit some things outside of core until we get use cases to support
18:49:42 <Arnaud> ack pfps
18:49:42 <pfps> q-
18:49:47 <kcoyle> Arnaud: let's stick just to the two options
18:52:00 <kcoyle> ... straw poll (binary) or third way, to have it as an optional feature (which isn't great for interoperability)
18:52:11 <hknublau> +q
18:52:18 <Arnaud> ack hknublau
18:52:24 <aryman> q+
18:52:25 <pfps> q+
18:52:28 <kcoyle> hknublau: third option is what I am proposing
18:52:46 <Arnaud> ack aryman
18:52:47 <kcoyle> ... it's an optional feature
18:53:43 <pfps> q-
18:53:45 <kcoyle> aryman: from a pragmatic point of view if we have close tie between shacl and sparql engine we will limit shacl use; needs to be the shape graph, but cannot require that shape graph be in same dataset as dataset
18:53:59 <Arnaud> STRAWPOLL: a) allow access to the shape graph, b) do not allow access to the shape graph, c) allow access to the shape graph as an optional feature
18:54:31 <hknublau> a +0.5 b -1 c +1
18:54:33 <aryman> a:-1,b:+1,c:-1
18:54:42 <pfps> a: -1, b: +1, c: maybe - it really depends on how it plays out - the version that Holger appears to be promoting would be a -1
18:54:43 <kcoyle> a) +1 b) -1 c) +1
18:54:44 <Labra> a: -1, b: +1, c: -0.5
18:55:05 <Dimitris> a)-0.9, b)+1, c)0
18:55:12 <TallTed> a +0.5, b -0.5, c +0.5
18:55:31 <ericP> -.5, +1, -.5
18:55:46 <hknublau> +q
18:55:55 <Arnaud> ack hknublau
18:56:26 <aryman> I'm OK with the semantics being expressed in terms of the SHACL graph
18:56:50 <kcoyle> hknublau: need to keep in mind that some of this is implementation details
18:57:07 <pfps> If in c access to the SHACL control graph was *truly* optional, and not specified throughout the document, then it would be much more palatable
18:57:50 <hknublau> +q
18:57:50 <kcoyle> aryman: we should focus on defining things for remote sparql end point case first, since that's the most important case; a matter of priorities
18:57:56 <pfps> I agree that there is currently only *one* worked-out specification for SHACL.  It is https://www.w3.org/2014/data-shapes/wiki/Shacl-sparql
18:58:21 <Arnaud> ack hknublau
18:58:25 <kcoyle> Arnaud: spec would have to allow that you may not have access
18:59:02 <pfps> q+
18:59:09 <aryman> q+
18:59:17 <Arnaud> ack pfps
18:59:19 <kcoyle> Arnaud: discuss online - what would it take for option c to work
18:59:41 <kcoyle> pfps: there is only one worked out proposal, and that is not current editor's draft
18:59:58 <hknublau> +q
19:00:13 <kcoyle> ... current editor's graph has holes in it; other doc (linked above) is fully worked out
19:00:29 <kcoyle> ... and is the way it is done in startdoc ICV
19:01:32 <Arnaud> ack aryman
19:02:24 <kcoyle> aryman: would like to see compelling use case for not having access to graph;
19:03:00 <pfps> Having an implementation is not sufficient to show well-foundedness.
19:03:09 <kcoyle> ... Peter asserts that the spec isn't founded; but there is an implementation, so we should focus on areas where spec needs work; tighten spec before we add features
19:03:18 <Arnaud> ack hknublau
19:03:54 <kcoyle> hknublau: feature is already there, and isn't a big issue
19:04:06 <aryman> q+
19:04:57 <Arnaud> ack aryman
19:05:25 <hknublau> +q
19:05:36 <kcoyle> aryman: that it is in the spec has implications for developers
19:05:48 <kcoyle> hknublau: right hand picture already works
19:07:00 <Arnaud> ack hknublau
19:07:21 <kcoyle> ... if you want to run against remote endpoint, that works. option B would require re-writing draft
19:08:00 <pfps> There is lots of noise.
19:08:15 <kcoyle> aryman: recursion should not be linked to access to data graph; there are lots of things tied together here that are muddying the discussion
19:09:29 <pfps> Both a and b use SPARQL as their specification language.   Both a and b could have the core implemented without access to a full SPARQL implementation.
19:10:51 <aryman> a triple API is not a SPARQL endpoint
19:12:29 <aryman> it must be possible to implement core SHACL without SPARQL
19:12:36 <kcoyle> pfps: "sparql" here means any access to the data graph
19:15:22 <kcoyle> kcoyle: should we really call it sparql if it doesn't acutally use sparql but has its own software
19:16:42 <Arnaud> https://lists.w3.org/Archives/Public/public-data-shapes-wg/2015Jun/att-0159/SHACL-Engines.png
19:17:48 <hknublau> +q
19:18:25 <aryman> q+
19:18:41 <Arnaud> ack hknublau
19:19:24 <aryman> question: does the SHACL graph just contain the SHACL program, or are you allowing arbitrary other triples in it?
19:20:17 <Arnaud> ack aryman
19:20:46 <kcoyle> aryman: in the shapes graph, are you assuming that the graph is closed, that it just contains what is in the shacl language?
19:21:17 <kcoyle> ... e.g. xslt - xslt doc is an xml document, can be used to get to arbitrary other data
19:22:19 <kcoyle> hknublau: main reason to access it is to query the shapes; uses formalisms eg classes, members of rdflist. Those are stored in the shapes graph
19:24:17 <pfps> It would be nice to get more people involved in the discussion. There are at least two WG members who were not present today.
19:24:38 <kcoyle> Arnaud: that's enough for today
19:25:05 <hknublau> hknublau has left #shapes
19:25:13 <Arnaud> present+ labra
19:25:25 <Arnaud> trackbot, end meeting
19:25:25 <trackbot> Zakim, list attendees
19:25:25 <Zakim> sorry, trackbot, I don't know what conference this is
19:25:34 <trackbot> RRSAgent, please draft minutes
19:25:34 <RRSAgent> I have made the request to generate http://www.w3.org/2015/07/02-shapes-minutes.html trackbot
19:25:34 <Dimitris> Dimitris has left #shapes
19:25:35 <trackbot> RRSAgent, bye
19:25:35 <RRSAgent> I see no action items