IRC log of shapes on 2015-05-19

Timestamps are in UTC.

12:58:23 [RRSAgent]

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12:58:23 [RRSAgent]

logging to http://www.w3.org/2015/05/19-shapes-irc

12:58:25 [trackbot]

RRSAgent, make logs rdf-data-shapes

12:58:25 [Zakim]

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12:58:27 [trackbot]

Zakim, this will be SHAPES

12:58:27 [Zakim]

I do not see a conference matching that name scheduled within the next hour, trackbot

12:58:28 [trackbot]

Meeting: RDF Data Shapes Working Group Teleconference

12:58:28 [trackbot]

Date: 19 May 2015

12:59:41 [hknublau]

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13:00:02 [aryman]

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13:00:52 [Arnaud]

hi there

13:01:05 [Arnaud]

beware, we couldn't get Zakim for this meeting

13:01:11 [Arnaud]

and we have to use WebEx

13:01:12 [pfps]

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13:01:27 [pfps]

zakim, who is on the phone?

13:01:27 [Zakim]

sorry, pfps, I don't know what conference this is

13:01:29 [Zakim]

On IRC I see pfps, aryman, hknublau, Zakim, RRSAgent, kcoyle, Dimitris, elf-pavlik, rhiaro_, Arnaud, trackbot, ericP

13:01:30 [Arnaud]

we will use IRC for logging and queueing as usual

13:01:36 [pfps]

zakim, this is shapes

13:01:36 [Zakim]

sorry, pfps, I do not see a conference named 'shapes' in progress or scheduled at this time

13:01:42 [Arnaud]

but for voice we use webex

13:01:47 [Arnaud]

that won't work peter

13:01:58 [pfps]

grrr

13:02:15 [Arnaud]

zakim doesn't know anything about webex

13:04:33 [pfps]

the host has *ultimate* control on WebEx, and everyone else has squat

13:04:55 [Labra]

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13:04:56 [Arnaud]

are you on webex peter?

13:05:12 [Arnaud]

I see one "Call-in User_3"

13:06:46 [pfps]

Which webex?

13:07:41 [pfps]

which web interface??

13:08:01 [Dimitris]

http://www.webex.com/

13:08:14 [Dimitris]

and click join

13:08:17 [kcoyle]

https://mit.webex.com/mw0401lsp13/mywebex/default.do?siteurl=mit

13:08:29 [pfps]

the web interface wasn't in the email from Eric and thus I didn't put it on the meeting page

13:08:31 [kcoyle]

and you can use the audio there, no need to phone in

13:08:46 [kcoyle]

no, it wasn't in eric's email -- i sent a follow-up mail

13:08:54 [hsolbrig]

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13:09:34 [kcoyle]

hsolbrig: log on to https://mit.webex.com/mw0401lsp13/mywebex/default.do?siteurl=mit

13:09:49 [Arnaud]

Arnaud has changed the topic to: RDF Data Shapes WG: https://www.w3.org/2014/data-shapes/ - Next agenda: https://www.w3.org/2014/data-shapes/wiki/F2F3#Agenda Use WebEx for audio connection - see F2F page for details

13:11:01 [pfps]

WebEx is *not* very Linux compatible

13:11:53 [Dimitris]

pfps, it doesn't work from Linux, but there is an android app that works very well

13:12:26 [pfps]

That's astonishing - WebEx audio is known to be problematic

13:14:09 [pfps]

Screen sharing can require *lots* of bandwidth, which may not be possible for all

13:18:02 [Arnaud]

agenda: https://www.w3.org/2014/data-shapes/wiki/F2F3#Day_1_-_Tuesday_May_19

13:18:06 [Arnaud]

chair: Arnaud

13:18:12 [Arnaud]

scribenick: aryman

13:18:25 [aryman]

scribe: aryman

13:19:09 [aryman]

agenda: https://www.w3.org/2014/data-shapes/wiki/F2F3

13:19:48 [aryman]

agenda: https://www.w3.org/2014/data-shapes/wiki/F2F3#Day_1_-_Tuesday_May_19

13:20:09 [pfps]

but no muting from IRC using Zakim

13:20:20 [kcoyle]

aryman: I think we're getting feedback from you - can you mute?

13:20:34 [iovka]

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13:21:30 [aryman]

@kcoyle I muted. Is that better?

13:21:47 [kcoyle]

aryman: yes, thx

13:22:09 [Arnaud]

http://www.w3.org/2015/Talks/0519-shacl-egp/

13:22:15 [aryman]

TOPIC: ShEx proposal deep-dive

13:24:17 [pfps]

Why all the marketing stuff? I was expecting something technical.

13:25:33 [Arnaud]

present: Arnaud, Arthur, Dimitris, Eric, Holger, Harold, Holger, Iovka, Jose, Karen, Peter

13:26:45 [aryman]

ericP is presenting the ShEx/SHACL deep dive

13:30:31 [hsolbrig]

slide 7

13:30:48 [pfps]

agenda+ How does ShEx compile to SPARQL?

13:33:02 [iovka]

sorry, I thought I was muted

13:34:50 [pfps]

q+ I'm confused: a triple constraint can be datatype?

13:35:11 [pfps]

q+ i'm confused - a triple constraint can be datatpe?

13:35:31 [pfps]

q+

13:36:40 [Arnaud]

ack pfps

13:37:48 [pfps]

DNF is your friend

13:38:31 [pfps]

s/DNF/BNF/

13:39:32 [pfps]

agenda+ this presentation does not appear to allow conjunction in valueClass

13:40:41 [aryman]

q+ What does the .* mean? (on 11)

13:40:59 [aryman]

q+

13:41:44 [Arnaud]

ack aryman

13:44:19 [pfps]

q+

13:44:46 [Arnaud]

ack pfps

13:46:26 [aryman]

pfps: the ShEx language in this presentation does not match the language in the semantics document

13:46:43 [aryman]

iovka: yes, there are some differences

13:47:30 [aryman]

pfps: in the presentation, value class and conjunction appear to be missing

13:48:13 [ericP]

http://www.w3.org/2005/01/yacker/uploads/ShEx2?lang=perl&markup=html#prod-ShEx2-tripleConstraint

13:48:21 [aryman]

ericP: conjunction is not part of a triple constraint, but appears elsewhere

13:48:37 [pfps]

conjunction is in the valueClass position

13:49:26 [aryman]

pfps: I am concerned that the syntax is different than the published semantics

13:51:59 [aryman]

detailed discussion of semantics

13:53:54 [aryman]

moving on to discussion of closed shapes

13:55:03 [pfps]

A big difference between the presentation and the language in the semantics is that the semantics permits negated shapes whereas the presentation has negated tripleConstraints

13:57:02 [aryman]

Arnaud: how are shapes associated with data?

13:58:01 [aryman]

ericP: two mechanisms 1) the data points to shape, e.g. instanceShape, classShape, 2) defined by the application (uses XSD and WSDL analogy)

13:58:07 [Arnaud]

agenda+ how does ShEx associate a node with a shape?

13:58:07 [ericP]

http://w3c.github.io/data-shapes/data-shapes-primer/#h-associations

14:02:34 [pfps]

What is the contract between the semantics and the semantic actions?

14:06:12 [aryman]

What about backtracking? Are actions undone?

14:07:12 [aryman]

iovka: in the semantics doc, semantic actions have no side effects

14:07:40 [aryman]

ericP: in addition we can use semantic actions with side effects

14:07:50 [aryman]

q+

14:09:36 [aryman]

ericP: we don't have semantics for actions with side effects

14:09:56 [aryman]

pfps: if no semantics for side effects, then it is out of scope

14:10:18 [Arnaud]

ack aryman

14:10:27 [aryman]

one sec

14:11:09 [aryman]

can't find the window!!

14:11:11 [aryman]

go on

14:11:56 [aryman]

found it!

14:11:59 [aryman]

may I ask?

14:12:10 [aryman]

q+

14:12:16 [Arnaud]

let him finish that slide and we'll get to you

14:13:20 [Arnaud]

ack aryman

14:14:46 [pfps]

The semantics (now) needs multiple models, so determining whether to call an action with side effects becomes very problematic

14:15:44 [aryman]

aryman: semantic actions with side effects is useful, e.g. to generate code, but we need deterministic semantics, e.g. like ANTLR

14:15:51 [pfps]

q+

14:16:11 [Arnaud]

ack pfps

14:16:36 [aryman]

ericP: our implementation does this in two passes, first generating a tree of recognized triples, second traversing the tree depth first

14:19:06 [pfps]

I don't believe either of the examples work in the semantics, which gives the interface to the semantic extensions in terms of three arguments, graph, focus node, and language

14:20:09 [iovka]

the focus node is ?this

14:20:30 [iovka]

s/is this/is linked to this/

14:21:16 [pfps]

The examples include other variables that do not seem to be free

14:21:45 [simonstey]

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14:22:38 [iovka]

I think that usually eric uses ?o for the focus node, and in the second example on slide 18 he mixed ?o and ?this, which both stand for the focus node

14:23:03 [iovka]

sorry, I'm wrong !

14:23:59 [aryman]

q+

14:24:10 [Arnaud]

ack aryman

14:25:22 [Arnaud]

the question is when is the semantics doc going to be stable?

14:25:24 [aryman]

aryman: when will your semantics doc be frozen so we can review it in detail?

14:26:20 [aryman]

iovka: will announce the version when it is ready for review

14:27:06 [Arnaud]

agenda?

14:27:16 [ericP]

ACTION: iovka to announce a stable version of the semantics document so we can have a review cycle

14:27:17 [trackbot]

Created ACTION-25 - Announce a stable version of the semantics document so we can have a review cycle [on Iovka Boneva - due 2015-05-26].

14:27:44 [ericP]

Zakim, next agendum

14:27:44 [Zakim]

agendum 1. "How does ShEx compile to SPARQL?" taken up [from pfps]

14:29:10 [aryman]

q+

14:29:55 [iovka]

q+

14:30:23 [aryman]

pfps: Is every aspect of ShEx compilable to SPARQL?

14:30:44 [aryman]

ericP: Not if valueShape is present

14:31:04 [aryman]

q-

14:31:50 [iovka]

q-

14:31:52 [aryman]

pfps: How can you assure the translation to SPARQL is correct?

14:32:04 [iovka]

q+

14:32:12 [aryman]

ericP: Just wrote some test cases. Is it possible?

14:32:40 [Arnaud]

ack iovka

14:32:41 [aryman]

pfps: There is some work on translating OWL constraints to SPARQL

14:33:19 [aryman]

iovka: Without recursion, ShEx can be translated to SPARQL

14:33:46 [aryman]

iovka: We could potentially prove the translated is correct

14:34:05 [aryman]

s/translated/translation/

14:34:11 [pfps]

The treatment of negation in the semantics does not appear to have an obvious translation into SPARQL.

14:34:52 [aryman]

ericP: iovka has done some analysis of complexity

14:35:18 [aryman]

iovka discusses some complexity results

14:35:49 [pfps]

How is VIRTUAL handled in the semantics?

14:36:13 [aryman]

Take a 15 minute break now

14:36:21 [aryman]

Resume at 10:50 AM

14:41:30 [ericP]

karen, i just updated the title of http://www.w3.org/2015/Talks/0519-shacl-egp/#(22) to clarify that it was for your 2nd use case

14:44:43 [hknublau]

http://www.slideshare.net/HolgerKnublauch/shacl-specification-draft

14:50:31 [simonstey]

+1

14:50:33 [iovka]

+!

14:50:43 [iovka]

+1

14:50:56 [aryman]

TOPIC: Holger's proposal deep-dive

14:56:26 [pfps]

agenda+ Status of recursive shapes

14:57:01 [aryman]

q+

14:57:59 [aryman]

Does the prototype depend on TBC?

14:58:28 [kcoyle]

aryman: you need to mute - we get echo from you

14:58:32 [kcoyle]

aryman: sorry

14:58:53 [Arnaud]

ack aryman

15:00:28 [aryman]

hknublau: the prototyoe includes a stand-alone SHACL engine based on the Jena API, also an editor in TBC

15:09:01 [aryman]

s/prototyoe/prototype/

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15:22:57 [iovka]

+q

15:28:04 [iovka]

-q

15:28:30 [Arnaud]

sorry iovka, if I missed your request in a timely manner!

15:39:33 [aryman]

q+

15:39:49 [aryman]

valueShape appears to be missing from slide 25

15:40:39 [Arnaud]

ack aryman

15:43:48 [hsolbrig]

Apologies for having leave. Have to catch a plane. Fascinating talk, Holger and I want to pursue it further...

15:44:20 [aryman]

I see valueShape in Slide 26 in sh:PropertyConstraint

15:45:35 [aryman]

q+

15:46:25 [aryman]

Shouldn't NativeConstraint be language neutral?

15:46:44 [aryman]

i.e have subclasses for SPARQL, JS.

15:46:53 [Arnaud]

ack aryman

15:48:40 [iovka]

+q

15:49:13 [Arnaud]

ack iovka

15:49:33 [aryman]

hknublau: NativeConstraint can have more than one language, all being equivalent, the engine picks the language it supports

15:50:11 [aryman]

iovka: how do you ensure that alternate language strings are equivalent

15:50:52 [aryman]

hknublau: it is the responsibility of the constraint author to write equivalent definitions

15:51:25 [aryman]

Arnaud: this is a general problem with extensions

15:52:03 [aryman]

hknublau: we only defines SPARQL since there is no API for JS

15:52:05 [aryman]

q+

15:52:16 [Arnaud]

ack aryman

15:52:58 [aryman]

why not use JSON-LD

15:54:01 [pfps]

Arthur is talking about the JSON encoding of SPARQL results, I think.

15:54:03 [aryman]

also use SPARQL JSON result format for output

15:54:42 [aryman]

Both, use JSON-LD as the input, use SPARQL JSON Result format for the output

15:55:07 [pfps]

q+

15:55:20 [Arnaud]

ack pfps

15:55:57 [aryman]

pfps: If there are two defs, which one is the "controlling" def?

15:56:27 [iovka]

+q

15:56:32 [pfps]

holger: the SPARQL one

15:56:35 [aryman]

hklunblau: I suggest use SPARQL of the controlling def

15:56:41 [aryman]

s /of/as/

15:56:59 [Arnaud]

ack iovka

15:57:33 [aryman]

iovka: Do you have SPARQL defs for all features?

15:57:48 [aryman]

hknublau: Yes

15:58:24 [ericP]

q+ to ask, per iovka's q, is there a defn for valueShape?

15:58:59 [iovka]

+q

16:00:18 [aryman]

q+

16:00:43 [aryman]

What about security? For thrid-party templates?

16:00:52 [aryman]

s/thrid/third/

16:02:28 [aryman]

Arnaud: Please explain why other W3C languages are "not designed for the Web"?

16:03:24 [aryman]

hknublau: Languages should have open vocabularies with defs associated with downloadable URIs

16:04:42 [Arnaud]

ack ericP

16:04:42 [Zakim]

ericP, you wanted to ask, per iovka's q, is there a defn for valueShape?

16:04:55 [ericP]

-> http://w3c.github.io/data-shapes/shacl/#operation-validateNodeAgainstShape hasShape algorithm

16:05:46 [aryman]

ericP: discusses recursion and negation - does this proposal handle it correctly?

16:07:01 [aryman]

Arnaud: let's defer this general question and focus on clarification questions for Holger

16:07:37 [iovka]

q-

16:08:09 [Arnaud]

ack aryman

16:08:19 [aryman]

hknublau: I haven't made much use of recursion. I can put in a guard to prevent it. Can add negation.

16:08:50 [ericP]

aryman: if we allow 3rd party to provide javascript, that entails a security issue.

16:09:12 [ericP]

... we need to have some trust mechanism for 3rd part extensions, or a sandbox mode

16:09:50 [aryman]

What about safety of third-party extensions?

16:10:20 [aryman]

hknublau: This is out of scope currently

16:10:38 [aryman]

Break for lunch

16:10:46 [aryman]

Resume at 1:00 PM

16:13:16 [iovka]

quit

16:13:34 [iovka]

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17:02:27 [kcoyle]

scribenick kcoyle

17:03:18 [pfps]

My presentation is https://www.w3.org/2014/data-shapes/wiki/Shacl-sparql-presentation

17:04:18 [aryman]

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17:04:21 [kcoyle]

similar to Holger's proposal; based on sparql, but is even closer to sparql

17:04:39 [kcoyle]

every constraint is translated to a single sparql query

17:05:25 [kcoyle]

standard sparql, no modifications

17:05:58 [aryman]

what is the presentation link?

17:06:08 [ericP]

http://w3c.github.io/data-shapes/shacl/#operation-validateNodeAgainstShape

17:06:12 [kcoyle]

shapes and classes are distinct; not related

17:06:35 [kcoyle]

https://www.w3.org/2014/data-shapes/wiki/Shacl-sparql-presentation

17:07:59 [kcoyle]

rdf vocab all mapped to sparql

17:08:20 [kcoyle]

could be used as less than full sparql engine

17:08:27 [kcoyle]

s/as/with

17:09:15 [kcoyle]

closed world constraints

17:09:52 [hknublau]

+q

17:12:32 [Arnaud]

ack hknublau

17:13:10 [kcoyle]

holger: no relationship on shapes, constraints, classes: is classScope the same as in Holger's proposa.?

17:13:57 [kcoyle]

pfps: yes. you can say that constraints are classes, but classes and nodes and shapes are all separate; nothing operates over them

17:14:51 [kcoyle]

... shouldn't create a node that is both a shape and a constraint, or class and constraint; but are not required to be disjoint

17:15:05 [kcoyle]

... proposal is agnostic on their relationship

17:15:24 [kcoyle]

Arnaud: terminology: is this same as Holger?

17:15:48 [kcoyle]

pfps: no, different; constraint is the thing that you run and that has violations

17:16:10 [kcoyle]

... a shape is like the thing in shex -- shapes are satisfied, don't have violations

17:16:54 [kcoyle]

... conditions are the things that make the node to shape connection

17:17:21 [kcoyle]

... constraint is combination of scope and shape

17:18:31 [kcoyle]

... scope: can be a single node; all instance of a type; you can scope a condition to those nodes that satisfy a shape

17:20:04 [kcoyle]

... shapes are either rdf-encoded or sparql

17:20:23 [iovka]

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17:20:55 [kcoyle]

... rdf encoding doesn't (yet) cover all of sparql

17:21:25 [kcoyle]

... shapes can refer to other shapes

17:21:39 [kcoyle]

... any rdf can be added if there is a sparql translation

17:21:45 [aryman]

q+

17:21:54 [Arnaud]

ack aryman

17:22:17 [kcoyle]

aryman: can you refer to shapes by name? would imply recursion

17:22:52 [kcoyle]

pfps: you can name shapes, but no recursion

17:23:01 [kcoyle]

... aka, no cyclic references

17:24:21 [hknublau]

+q

17:24:22 [kcoyle]

... because cannot be done in a single translation to sparql

17:26:47 [kcoyle]

pfps: this is a constraints proposal, not shape recognition

17:27:34 [kcoyle]

aryman: gives example of test cases and defects

17:28:28 [Arnaud]

ack hknublau

17:28:36 [kcoyle]

recursive shapes are a syntax violation

17:29:39 [kcoyle]

hknublau: can combine class-based selection & shape based; if just have scope that is a shape can you insert sparql into constraint? if so, this only supports a subset of sparql

17:30:43 [michel]

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17:31:19 [kcoyle]

pfps: gives an answer in code, using ?THIS

17:32:20 [kcoyle]

... Peter agrees with Holger, need to be careful with sparql as a scope; may not work

17:33:21 [kcoyle]

hknublau: problem is arbitrary sparql as a selector; peter agrees

17:34:24 [hknublau]

Problem case, e.g. FILTER STRSTARTS(STR(?this), “http://example.org/ns#”)

17:36:47 [kcoyle]

proceeding with examples

17:37:14 [kcoyle]

UC1: the model is broken

17:39:03 [kcoyle]

4 examples

17:40:19 [aryman]

q+

17:40:58 [iovka]

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17:41:01 [aryman]

classScope is not the norm in Linked Data APIs, i.e. validating PUT and POST requests

17:41:31 [Arnaud]

ack aryman

17:42:17 [kcoyle]

aryman: in linked data, classScope is not the norm

17:42:24 [ericP]

q+ to ask if the cycles (last block) is for cycles between a single pair of classes

17:43:15 [iovka]

(sorry for being late, technical problems ...)

17:43:47 [kcoyle]

UC2: enforcing cardinality - skip

17:43:53 [Arnaud]

ack ericP

17:43:53 [Zakim]

ericP, you wanted to ask if the cycles (last block) is for cycles between a single pair of classes

17:44:28 [kcoyle]

pfps: requires rdfs closure; otherwise needs jplus sign

17:45:37 [kcoyle]

UC4: variations on a shape

17:46:03 [kcoyle]

pfps: something has a status that is either reported or varified

17:46:22 [kcoyle]

... + two constraints that have shape scope, not class scope

17:48:01 [kcoyle]

... if no type links, would say: everything whose status is reported has to have at least one (or two) reporters; once you have

17:48:17 [kcoyle]

,,, shape scope you don't need type links

17:48:45 [kcoyle]

... UC9 contract time intervals

17:50:48 [kcoyle]

... UC23 schema.org constraints

17:52:31 [kcoyle]

... shows transitivity as a violation; plus class scopes on Person -- uses some sparql for comparison of dates

17:53:41 [kcoyle]

... common that you have to drop into sparql

17:54:18 [kcoyle]

UC33: validate medical procedure

17:54:45 [kcoyle]

pfps: bugs from shex primer, and choices example

17:59:15 [hknublau]

+q

17:59:16 [aryman]

q+

17:59:21 [Arnaud]

ack hknublau

17:59:47 [aryman]

q-

18:00:14 [aryman]

q+

18:00:26 [kcoyle]

hknublau: make not be possible to create a single sparql query for all

18:02:31 [kcoyle]

pfps: this is about sub-optimal implementation of sparql; proposal could be implemented in other ways

18:03:04 [Arnaud]

ack aryman

18:03:45 [kcoyle]

aryman: single sparql query is semantics of constraint?

18:04:18 [kcoyle]

pfps: trans to single sparql query is a referent implementation

18:04:31 [hknublau]

Problem cases with Sub-Selects (they cannot access any variables from the outside)

18:04:41 [kcoyle]

... could be a problem with large constraints over large graphs

18:05:37 [kcoyle]

aryman: no error reporting mechanism ; in practice you would evaluate in chunks

18:06:18 [kcoyle]

pfps: this proposal does have error reporting; for high level language it's simple, but for raw sparql it is the sparql result

18:10:20 [Labra]

+q

18:11:15 [Labra]

q-

18:11:19 [Arnaud]

ack Labra

18:12:25 [kcoyle]

Labra: pfps proposal does not define high level language

18:12:43 [kcoyle]

Arnaud: how much is in the core?

18:13:18 [Labra]

Labra: Peter's proposal is more about how to constrain the language to be based on SPARQL than about what is in the language

18:13:19 [kcoyle]

pfps: so far no template mechanism; with templates, high level language is irrelevant;

18:13:44 [kcoyle]

... high level language is just pointers to sparql translations

18:13:54 [kcoyle]

... similar to Holger's proposal

18:15:05 [kcoyle]

Arnaud: TOPIC: next f2f meeting

18:15:23 [kcoyle]

... where and when

18:15:58 [ericP]

+1 to lille

18:16:11 [kcoyle]

... Iovka offered Lille (FR), not far from Paris

18:16:12 [simonstey]

+1 to europe

18:16:38 [kcoyle]

... when: cannot be same week as TPAC

18:16:53 [simonstey]

WU vienna could host too

18:16:55 [pfps]

I'm not sure that I can travel to Europe until October due to budget limitations.

18:17:25 [Labra]

+1 for Lille

18:17:52 [michel]

+1 Lille

18:18:02 [iovka]

you can also come through brussels

18:19:16 [kcoyle]

+1 Lille, -1 August, +1 mid- late-September

18:19:27 [hknublau]

Europe has a better time zone for me than East Coast.

18:20:38 [kcoyle]

Arnaud: 8/19 September?

18:20:43 [Arnaud]

PROPOSED: next F2F in Lille on 8-10 September

18:21:04 [kcoyle]

+1

18:21:04 [simonstey]

+1

18:21:04 [iovka]

+1

18:21:06 [Dimitris]

+1 for Europe but September will hard to commit from now (even for virtual participation)

18:21:12 [Labra]

+1

18:21:23 [michel]

ah, won't be able to make that

18:21:39 [Arnaud]

what would work for you michel?

18:22:47 [pfps]

0 as budget limitations make it hard to travel now - I even had to turn down the DL workshop in Greece

18:23:34 [Arnaud]

PROPOSED: next F2F in Lille on 1-3 September?

18:23:48 [Arnaud]

scratch that

18:24:40 [Arnaud]

RESOLVED: next F2F in Lille on 8-10 September

18:24:44 [aryman]

I can't make it

18:24:55 [aryman]

in Australia

18:25:50 [Dimitris]

10-18 / 09 won't work for me so I might skip the last day

18:27:28 [aryman]

+1 for poll

18:27:43 [Arnaud]

s/RESOLVED/Not quite resolved/

18:29:13 [Arnaud]

break for 15mn

18:46:04 [kcoyle]

kcoyle has joined #shapes

18:47:25 [Arnaud]

scribenick: kcoyle

18:48:08 [kcoyle]

Finished - deep dives; thanks to all

18:48:42 [kcoyle]

round of self-criticism

18:49:47 [kcoyle]

ericP: semantics are complicated; we don't have an elegant extensibility mechanism, just language refs

18:50:11 [kcoyle]

... no templates in core language;

18:50:46 [kcoyle]

... document status is "catching up"; document suite is bigger

18:51:54 [kcoyle]

... prefixes and bases inherited from surrounding doc rather than literals

18:53:14 [kcoyle]

... doesn't transform isomorphically to turtle

18:53:37 [kcoyle]

... there are 'extra bits"

18:54:01 [kcoyle]

Arnaud: are there some user stories you would have trouble addressing?

18:54:38 [kcoyle]

ericP: we can always call out to extentions, so question is which can we meet in core language? we meet more than other languages but still not all

18:54:42 [pfps]

Huh?

18:54:44 [pfps]

q+

18:54:48 [aryman]

q+

18:54:51 [Arnaud]

ack pfps

18:55:05 [kcoyle]

pfps: larger than other proposals?

18:55:32 [kcoyle]

ericP: what you can do without sparql; our core language is larger than holger's, not sure re: peter's

18:56:08 [kcoyle]

... decides, no, not larger than peter's

18:56:15 [pfps]

q+

18:56:21 [Arnaud]

ack aryman

18:57:04 [kcoyle]

aryman: uneasy with recursion; value references can be deeply nested: are you confident you have clear semantics for that?

18:57:59 [kcoyle]

iovka: yes, i am confident because do not mix negation and recursion; disjunction does not cause a problem, but is harder to check

18:58:54 [kcoyle]

... two kinds of disjunction - one of, some of

18:59:15 [Arnaud]

ack pfps

18:59:41 [kcoyle]

pfps: semantics are now more complicated - do you believe it is right?

19:02:25 [kcoyle]

iovka: yes, it is complicated; but I am confident that it works; now needs formal proof (can't really hear now - very soft)

19:03:49 [kcoyle]

Arnaud: all of the proposals have unfinished areas

19:04:30 [kcoyle]

what is the reason for the complexity (to Peter)?

19:05:00 [iovka]

next step is to write proofs and to provide a formal study of the computational complexity

19:05:18 [kcoyle]

pfps: very complex with many interacting parts; now multiple partial implementaiton semantics; hard to know what's going on

19:06:03 [kcoyle]

... hard to have confidence that it can be fixed

19:07:40 [kcoyle]

iovka: allow negation onlhy on non-recursive shapes

19:08:36 [kcoyle]

... what would be most helpful at this point?

19:09:12 [kcoyle]

pfps: dunno.

19:09:20 [aryman]

q+

19:09:28 [kcoyle]

Arnaud: possible: test suite could help nail down corner cases

19:09:40 [Arnaud]

ack aryman

19:10:07 [kcoyle]

aryman: what level of rigor was applied to sparql?

19:13:22 [kcoyle]

hknublau: shacl is a chance to improve on spin; draft has gone through iterations, borrows from other approaches

19:14:10 [kcoyle]

... weaknesses: reliance on prefixes from surrounding file, but RDF does not have API for prefixes

19:14:17 [aryman]

q+

19:14:34 [kcoyle]

... prefixes can be easily lost

19:14:45 [aryman]

OSLC defined an RDF voc for prefixes for use in a simple query syntax

19:14:48 [kcoyle]

... need to be spelled out

19:15:33 [kcoyle]

... needs pre-binding of variables as in Jena, but perhaps not supported by all dbs

19:16:30 [kcoyle]

... reliance on sparql extensions ; open issue: inferencing - can we rely on it or not?

19:17:02 [kcoyle]

... seems we can't rely on it, not always supported, can't activate programmatically. This doesn't affect core language

19:17:39 [kcoyle]

... can users expect inferencing to be activated? have to tell engine which queries require inferencing

19:18:43 [kcoyle]

... compact syntax could be added on top of this proposal

19:19:18 [kcoyle]

... need test cases so we can be sure we're talking about the same thing

19:19:35 [kcoyle]

... no abstract syntax

19:20:21 [Arnaud]

ack aryman

19:21:02 [kcoyle]

aryman: prefixes - same problem in OSLC - has vocab terms for perfixes

19:21:25 [kcoyle]

... also a mechanism in JSON-LD that could be added to any proposals

19:22:19 [kcoyle]

... similar to constraint severity

19:22:28 [kcoyle]

hknublau: that's a lot of overhead

19:24:01 [iovka]

+q

19:24:08 [pfps]

q+

19:24:13 [Arnaud]

ack iovka

19:24:37 [Arnaud]

iovka? I can't hear you

19:24:38 [iovka]

ok, apparnently sound problem

19:24:40 [iovka]

-q

19:24:48 [Arnaud]

ack pfps

19:24:49 [aryman]

looks like iovka is disconnected from the audio?

19:25:04 [kcoyle]

pfps: what about treatment of recursive shapes?

19:25:44 [ericP]

q+ to ask about support for magic properties outside of Jena

19:25:45 [kcoyle]

hknublau: haven't investigated this in depth; just a place holder

19:25:52 [iovka]

+q

19:25:55 [Arnaud]

ack ericP

19:25:55 [Zakim]

ericP, you wanted to ask about support for magic properties outside of Jena

19:26:26 [kcoyle]

ericP: implementation uses Jena API for using magic properties - do other sparql implementations have this?

19:27:08 [kcoyle]

hknublau: not using magic properties; only relying on sparql functions

19:27:29 [kcoyle]

.. user-defined sparql filter and bind functions

19:28:00 [kcoyle]

ericP: sparql engine with have to implement validate node against shape --

19:28:28 [kcoyle]

hknublau: no, these are abstract API functions; only function hard carded is sh:??Shape

19:28:48 [kcoyle]

... sh:hasShape

19:29:33 [kcoyle]

ericP: use of rdf:collections for disjunctions and value sets;

19:29:59 [kcoyle]

hknublau: no, you can do that with property path

19:30:10 [kcoyle]

ericP: ok to use repeated properties?

19:30:43 [kcoyle]

hknublau: trade-off; with rdf:list template requires just single value argument; iterate in a single sparql query

19:32:26 [kcoyle]

... shape is conjunction with multiple values/properties; or also is rdf:list - can have an order

19:33:19 [Arnaud]

ack iovka

19:34:08 [kcoyle]

iovka: modularity is a drawback; there's no single document that gives a global view; harder for users

19:34:22 [kcoyle]

... harder to debug

19:35:31 [kcoyle]

... can you trust modules written by others?

19:36:28 [kcoyle]

hknublau: thinks it will work

19:38:41 [Arnaud]

https://www.w3.org/2014/data-shapes/wiki/Shacl-sparql-presentation#Limitations_and_Problems

19:39:06 [kcoyle]

pfps: (see end of presentation) solution is sparql-only so if you don't like sparql, this isn't for you

19:39:48 [kcoyle]

... chunks are missing; doesn't have reporting, doesn't have user-friendly stuff

19:39:56 [kcoyle]

... no template mechanism

19:40:08 [kcoyle]

... rdf syntax isn't up to date

19:40:22 [kcoyle]

... so far a paper-only solution

19:40:54 [kcoyle]

... positive side is has least implementation issues

19:43:10 [kcoyle]

... what's in spec is satisfactory but competitive implementations might go further

19:44:49 [kcoyle]

Arnaud: may miss mark in terms of working group mission

19:45:14 [kcoyle]

pfps: but spin already did all of this, via templates

19:45:50 [hknublau]

http://www.spinrdf.org/spl.html#Attribute

19:46:05 [hknublau]

(2009)

19:47:20 [kcoyle]

... proposal doesn't have way to extend; WG's requirements are not everything you would want to do, therefore drop into sparql is needed

19:47:41 [hknublau]

+q

19:47:42 [aryman]

q+

19:47:47 [Arnaud]

ack hknublau

19:49:02 [kcoyle]

hknublau: holger's and peter's proposals are very close

19:49:44 [kcoyle]

pfps: no longer as skeptical about need for templating; no languages beyond sparql; shapes and classes

19:50:52 [kcoyle]

... worry about fragmentation if other languages allowed

19:51:18 [kcoyle]

... vendor solutions vary a lot; causes lock-in

19:51:22 [Arnaud]

ack aryman

19:51:56 [kcoyle]

aryman: how do we converge?

19:54:27 [hknublau]

+q

19:55:03 [kcoyle]

Arnaud: tomorrow: user stories; time line; test suite; discussion about living with other proposals? = a way forward

19:56:00 [kcoyle]

aryman: looking at 3 proposals' RDF syntax, all look very similar; not much disagreement in RDF vocab;

19:56:48 [kcoyle]

... we should pick one spec to move forward; Holger's is the most complete, ShEx is very complex.

19:57:24 [kcoyle]

... start with Holger's a bring in ShEx compact syntax; clear up issues, e.g. recursion

19:57:52 [kcoyle]

... start with core language; promote templates to core language as needed

19:57:56 [Arnaud]

ack hknublau

19:58:30 [kcoyle]

hknublau: move 1st part of tomorrow to last day?

19:58:35 [ericP]

aryman, hknublau, do you think we can implement the ShEx semantics in SPIN?

19:58:59 [kcoyle]

I'm around the whole time

19:59:21 [iovka]

+q

19:59:27 [Arnaud]

ack iovka

19:59:31 [aryman]

@ericP we can certainly implement a lot of it

20:01:08 [kcoyle]

Arnaud: candid view: Peter has a solid foundation, but is a bit extreme; ShEx is user-friendly;

20:01:50 [ericP]

can we specify tests in shex? they're a lot easier to read and understand.

20:02:39 [kcoyle]

... take Holger's to be more solid like Peter's; increase core language

20:02:48 [kcoyle]

... ; add user-friendly aspects of ShEx as the compact syntax

20:03:44 [pfps]

One problem with Arnaud's proposal is that there are some ShEx constructs that don't fit (easily) into a SPARQL-based solution.

20:04:26 [ericP]

so the question is the value of those constructs

20:05:10 [Arnaud]

trackbot, end meeting

20:05:10 [trackbot]

Zakim, list attendees

20:05:10 [Zakim]

sorry, trackbot, I don't know what conference this is

20:05:18 [trackbot]

RRSAgent, please draft minutes

20:05:18 [RRSAgent]

I have made the request to generate http://www.w3.org/2015/05/19-shapes-minutes.html trackbot

20:05:19 [trackbot]

RRSAgent, bye

20:05:19 [RRSAgent]

I see 1 open action item saved in http://www.w3.org/2015/05/19-shapes-actions.rdf :

20:05:19 [RRSAgent]

ACTION: iovka to announce a stable version of the semantics document so we can have a review cycle [1]

20:05:19 [RRSAgent]

recorded in http://www.w3.org/2015/05/19-shapes-irc#T14-27-16