IRC log of shapes on 2016-03-31

Timestamps are in UTC.

18:01:04 [RRSAgent]
RRSAgent has joined #shapes
18:01:04 [RRSAgent]
logging to http://www.w3.org/2016/03/31-shapes-irc
18:01:06 [trackbot]
RRSAgent, make logs rdf-data-shapes
18:01:06 [Zakim]
Zakim has joined #shapes
18:01:08 [trackbot]
Zakim, this will be SHAPES
18:01:08 [Zakim]
ok, trackbot
18:01:09 [trackbot]
Meeting: RDF Data Shapes Working Group Teleconference
18:01:09 [trackbot]
Date: 31 March 2016
18:02:03 [pfps]
pfps has joined #shapes
18:02:06 [pfps]
present+
18:02:12 [jamsden]
jamsden has joined #shapes
18:02:18 [Arnaud]
present+
18:03:41 [Arnaud]
regrets: hknublau, labra
18:03:45 [kcoyle]
present+
18:09:15 [kcoyle]
do we have a scribe?
18:11:07 [Arnaud]
scribe: jamsden
18:12:17 [jamsden]
Mark Hadley joined the meeting today, in the process of joining
18:13:20 [jamsden]
Mark: 3 years involved in metadata specifications, metadata used for international exchange of linked data.
18:14:10 [jamsden]
Looking at validation of instances of metadata, exploring shapes as a means of specifications of descriptions that can be used for constraints, and apply to existing work
18:15:44 [Arnaud]
PROPOSED: Approve minutes of the 24 March 2016 Telecon: http://www.w3.org/2016/03/24-shapes-minutes.html
18:15:45 [pfps]
the minutes are a bit sparse, but cover the bases
18:16:31 [Arnaud]
RESOLVED: Approve minutes of the 24 March 2016 Telecon: http://www.w3.org/2016/03/24-shapes-minutes.html
18:17:49 [jamsden]
Topic: issue raised with lack of consistency in use of technology especially related to SPARQL and RDFS/OWL. Primarily editorial.
18:18:01 [Arnaud]
PROPOSED: Open ISSUE-142: loose terminology
18:18:10 [kcoyle]
+1
18:18:13 [pfps]
+1
18:18:38 [jamsden]
+1
18:18:42 [Dimitris]
+1
18:19:05 [TallTed]
+1
18:19:28 [pfps]
This issue arose from my reading of section 6 of the document, which needs significant work.
18:19:37 [Arnaud]
RESOLVED: Open ISSUE-142: loose terminology
18:19:52 [jamsden]
resolutions are provisional until approval of the minutes in the next meeting.
18:20:32 [jamsden]
Topic: Issue-93
18:21:20 [TallTed]
Issue-93?
18:21:20 [trackbot]
Issue-93 -- SHACL engine vs. SHACL instance requirements -- open
18:21:20 [trackbot]
http://www.w3.org/2014/data-shapes/track/issues/93
18:23:47 [kcoyle]
q+
18:23:53 [Arnaud]
ack kcoyle
18:24:03 [pfps]
q+
18:24:13 [jamsden]
Issue describe SHACL as a language and its semantics. And also talks about an engine that mixes implementation with vocabulary and meaning.
18:24:55 [Dimitris]
q+
18:24:56 [jamsden]
Karen, suggests we re-read the document to explore the use of the proposed new language
18:25:00 [Arnaud]
ack pfps
18:25:39 [jamsden]
Peter agrees fresh eyes would be good. Still mixing of what the language is and what a conformant engine must to.
18:26:02 [jamsden]
Not just a matter of looking for engine and making changes, might be more organizational
18:26:54 [jamsden]
Discuss the language separately from what "conformance levels" implementations might need to implement for interoperability
18:26:56 [Arnaud]
ack Dimitris
18:27:34 [jamsden]
Scribe can't hear Dimitris
18:27:38 [pfps]
It looks as if there has been some work to change SHACL engine to SHACL validation engine.
18:28:11 [pfps]
dimitris: there is a core and extension section which makes teasing out the engine stuff harder.
18:28:43 [jamsden]
semantics of language is sometime commingled with what a conformant engine must do
18:29:24 [jamsden]
q+
18:29:28 [pfps]
so - "Here is SHACL core. Here is SHACL extension. SHACL validation engines must do X"
18:30:25 [Arnaud]
ack jamsden
18:32:48 [jamsden]
jamsden: separate language definition and semantics organized as capabilities that can then be included in different conformance levels implementations should support
18:34:06 [kcoyle]
Dmitris, can you point to the exact section? Editor's draft?
18:34:45 [Dimitris]
http://w3c.github.io/data-shapes/shacl/#validation
18:34:52 [kcoyle]
thANKS
18:35:01 [jamsden]
Dimitris: requests that we review the document and provide feedback in the context of this issue
18:35:34 [jamsden]
Do we want to agree on the language for the definition of SHACL in the email list?
18:35:38 [kcoyle]
q+
18:35:42 [Arnaud]
ack kcoyle
18:35:45 [Dimitris]
mainly sections 2 and section 4
18:36:54 [Dimitris]
http://w3c.github.io/data-shapes/shacl/#terms
18:36:59 [Arnaud]
https://www.w3.org/2014/data-shapes/wiki/Glossary
18:37:04 [jamsden]
kcoyle: can we agree on the definition of and common language for what SHACL is? Then use this as a means of normalizing the spec?
18:37:44 [jamsden]
Arnaud: might be useful to take a look at the glossary and terms, using the links above.
18:38:44 [jamsden]
Editors should make sure the terms are defined and used consistently, use the group to raise challenges and and clarify terms and their use.
18:38:53 [ericP]
q+ to describe XML Schema approach
18:39:07 [pfps]
At least there is a document that provides a firm basis for the official RDF and RDFS terminology, including resource, node, property, etc.
18:39:07 [Arnaud]
ack ericP
18:39:07 [Zakim]
ericP, you wanted to describe XML Schema approach
18:40:09 [jamsden]
ericP: turtle uses a classification of documents, SPARQL something similar, provde a template for defining a W3C language.
18:41:05 [jamsden]
XML Schema went further: rules for parsing, rules for validation, these provide models that could be used for SHACL.
18:42:33 [jamsden]
Topic: ISSUE-99 special cases
18:42:49 [pfps]
q+
18:43:02 [Arnaud]
ack pfps
18:43:03 [jamsden]
Anaud: peter made a proposal and holger agreed, what is left to close this?
18:44:06 [jamsden]
peter: issue was resolve, but morphed to 99.5 to have something else for lists, sh:list - the value is the head of a list whose members are validated by the shape
18:44:43 [jamsden]
tricky to get right. Could be too complicated to address, or SHACL should provide a construct that address is
18:45:45 [Arnaud]
https://www.w3.org/2014/data-shapes/wiki/Proposals#ISSUE-99:_special_cases
18:46:00 [jamsden]
peter: there are currently 6 proposals, many of which do not have concensus. One gets rid of the special cases (this was done). Others all have to do with whether to have an sh:list construct.
18:46:39 [jamsden]
Arnaud: could close issue-99 and possibly introduce a new issue/construct for sh:list in order to focus on that issue.
18:47:17 [jamsden]
peter: issue-46 was an issue for lists, closed with a lot of discussion. Could reopen this issue if we decide to revisit sh:lists
18:47:37 [jamsden]
Arnaud: this was about requirements, closed because we added the requirements
18:47:58 [jamsden]
Agreed on the requirements, but not the solution.
18:48:12 [pfps]
issue-119
18:48:12 [trackbot]
issue-119 -- Defining constraints on (values of) rdf:Lists -- closed
18:48:12 [trackbot]
http://www.w3.org/2014/data-shapes/track/issues/119
18:48:34 [jamsden]
peter: issue-119 also addresses this issue and has been closed.
18:50:43 [jamsden]
Arnaud: should close issue-99 and if anyone has specific interest in sh:list proposals to take this forward, could reopen 119 and close with a new proposal
18:50:50 [pfps]
+1
18:50:53 [jamsden]
+1
18:52:00 [Arnaud]
PROPOSED: Close ISSUE-99, issue has been addressed, related proposals on handling of rdf:List should be made related to ISSUE-119, which would then need to be re-opened
18:52:09 [pfps]
+1
18:52:10 [Dimitris]
+1
18:52:12 [jamsden]
+1
18:52:16 [kcoyle]
+1
18:52:16 [TallTed]
+1
18:52:24 [ericP]
+1
18:52:34 [Arnaud]
RESOLVED: Close ISSUE-99, issue has been addressed, related proposals on handling of rdf:List should be made related to ISSUE-119, which would then need to be re-opened
18:53:08 [jamsden]
Topic: ISSUE-80 Shceme URIs
18:54:34 [jamsden]
Arnaud: this is something that can already been done, and this is a convenience, asking Eric to see if the convenience has sufficient value to include
18:55:06 [Arnaud]
issue-80
18:55:06 [trackbot]
issue-80 -- Constraint to limit IRIs against scheme/namespace, possibly with dereferencing -- open
18:55:06 [trackbot]
http://www.w3.org/2014/data-shapes/track/issues/80
18:56:46 [jamsden]
Arnaud: close action-36. the change doesn't seem that great
18:57:03 [jamsden]
peter: more or less agrees
18:57:16 [jamsden]
"as sugar its not very sweet"
18:58:13 [pfps]
the other advantage of new syntax is that it can use curies where pattern cannot
18:58:35 [jamsden]
kcoyle: worth it to her. doing it with patterns could be helpful. sh:stem makes it more specific, easier for more casual users.
18:59:12 [ericP]
q+
18:59:33 [Arnaud]
ack ericP
19:00:33 [pfps]
I don't see why not.
19:04:00 [jamsden]
can someone summarize the discussion for the scribe?
19:04:55 [pfps]
the point was whether to have this construct have an implicit disjunction somehow, either along with the current top-level disjunction (which would be new) or like in sh:classIn'
19:05:24 [jamsden]
Aranud: be sure everyone has the information needed to assess the issue, postpoine to next week?
19:06:12 [jamsden]
Can be done with sh:pattern, but may occur often enough to justify specific supporting syntax.
19:06:30 [Arnaud]
STRAWPOLL: add support sh:stem per Eric's proposal
19:06:47 [pfps]
0
19:06:56 [Dimitris]
0
19:07:07 [TallTed]
+0.25
19:07:13 [kcoyle]
+1
19:07:21 [ericP]
+.75
19:07:23 [jamsden]
0 - I don't think the problem in the issue is well enough defined to assess the proposal
19:08:46 [Dimitris]
DC Profiles have a related property "Value Encoding Scheme URI"
19:09:18 [jamsden]
kcoyle: data refers to other data sources/lists, and these URIs need to be supported, constrain the URLs in the graph. Identfy an external force in a URI stem
19:10:36 [jamsden]
ericP: clinical space, codes from different nomenclatures,
19:11:33 [jamsden]
Topic: issue-105: define prefixes
19:11:36 [Dimitris]
https://www.w3.org/2014/data-shapes/wiki/Proposals#ISSUE-105:_Defined_prefixes
19:11:51 [jamsden]
holger added a proposal, but there was no discussion.
19:12:52 [pfps]
New readers should beware of editorializing on the proposals page. Any WG member can put anything there.
19:14:04 [pfps]
q+
19:14:14 [jamsden]
https://www.w3.org/2014/data-shapes/wiki/Proposals#ISSUE-105:_Defined_prefixes
19:14:15 [Arnaud]
ack pfps
19:15:12 [kcoyle]
q+
19:15:13 [jamsden]
peter: SHACL talkes about the namespaces of an RDF graph, but RDF doesn't have this except for in syntaxes. SHACL could internalize these prefixes, it needs to do something to support them
19:15:48 [Arnaud]
ack kcoyle
19:15:59 [pfps]
the problem is how to get this to happen in some reasonable fashion
19:16:00 [jamsden]
how is SHACL extension mechanism who want to write the SPARQL and don't want to have to write all the PREFIX definitions
19:16:13 [jamsden]
kcoyle: what have other languages done
19:16:13 [TallTed]
q+
19:16:53 [ericP]
q+ to note the exception of SPIN
19:16:54 [jamsden]
peter: nothing, they don't need to do it. SPARQL isn't generating turtle docments, working with an RDF graph, this is only concerning the external syntax.
19:17:24 [jamsden]
SHACL extension mechanism is writen to create SPARQL fragments that require the prefixes
19:17:42 [Arnaud]
ack TallTed
19:18:48 [Dimitris]
q+
19:18:51 [jamsden]
TallTed: definition says we are starting wtih two graphs (not turtle or any specific syntax for the graph). Graphs don't have prefixes. The graphs might be serialized with prefixes, but this doesn't need to be addressed in SHACL
19:19:08 [Arnaud]
ack Dimitris
19:19:50 [pfps]
the SPARQL extensinon needs to generate SPARQL documents and these may include curies and the prefix declarations then need to be part of the document
19:19:56 [jamsden]
Dimitris: write extension mechanisms, sometimes convenient to use prefixes, in order to create a valid SPARQL query.
19:20:40 [jamsden]
There could be many related queries that all need the same prefixes, where would these common prefixes defined?
19:21:31 [jamsden]
Arnaud: issues with mixing information from different layers (representation vs actual graph).
19:21:39 [Arnaud]
ack ericP
19:21:39 [Zakim]
ericP, you wanted to note the exception of SPIN
19:22:09 [pfps]
So, is SELECT $this ($this AS ?subject) $predicate (?value AS ?object)
19:22:11 [pfps]
WHERE {
19:22:12 [pfps]
$this $predicate ?value .
19:22:14 [pfps]
FILTER (isLiteral(?value) || NOT EXISTS {
19:22:15 [pfps]
GRAPH $shapesGraph {
19:22:17 [pfps]
$classIn (rdf:rest*)/rdf:first ?class .
19:22:18 [pfps]
}
19:22:20 [pfps]
FILTER NOT EXISTS { ?value rdf:type/rdfs:subClassOf* ?class }
19:22:21 [pfps]
})
19:22:23 [pfps]
}
19:22:24 [pfps]
suitable as a query template in SHACL?
19:23:02 [jamsden]
ericP: say extension that aren't SPARQL but something that has prebound extensions already defined. Betterh than having the SPARQL have access to prefixes in some turtle document which may not be accessible
19:23:34 [TallTed]
so we're extending SPARQL now?
19:24:36 [pfps]
Not really. The "string" sent to the SPARQL query engine would have prefix declarations added to the beginning.
19:25:13 [Dimitris]
q+
19:25:26 [pfps]
There are other, more important extensions to SPARQL that are needed in the current setup.
19:25:47 [Dimitris]
http://dbpedia.org/sparql?nsdecl
19:26:03 [jamsden]
Not putting SHACL into a SPARQL engine, so not extending SPARQL.
19:26:03 [Arnaud]
ack Dimitris
19:26:19 [pfps]
My understanding is that the current design needs SHACL-in-SPARQL.
19:27:44 [jamsden]
peter: SHACL document contains lots of things that look like SPARQL queries that could not be directly executed. Missing the prefix declarations requried to parse them.
19:28:27 [jamsden]
Something needs to be done to provide the prefixes before these fragments are submitted to a SPARQL processor.
19:29:49 [jamsden]
peter: prefix definitions can be included in SPARQL. adding the right prefix definitions should not be an issue.
19:30:16 [ericP]
-> https://www.w3.org/TR/sparql11-query/#rPrologue prefix and base decls in the SPARQL 1.1 grammar
19:30:32 [jamsden]
handling them outside the SPARQL opens the possibilit of the prefixes not being properly or consistently defined.
19:31:11 [jamsden]
holger wanted to be able to define the prefixes in one place in the SHACL extensions, and have them implicitly applied to SPARQL in the extensions.
19:31:48 [Arnaud]
trackbot, end meeting
19:31:48 [trackbot]
Zakim, list attendees
19:31:48 [Zakim]
As of this point the attendees have been pfps, Arnaud, kcoyle, .75
19:31:56 [trackbot]
RRSAgent, please draft minutes
19:31:56 [RRSAgent]
I have made the request to generate http://www.w3.org/2016/03/31-shapes-minutes.html trackbot
19:31:57 [trackbot]
RRSAgent, bye
19:31:57 [RRSAgent]
I see no action items