<scribe> scribenick: dsr

Agenda bashing

Darko runs through the agenda for today.

Agenda wiki

Dave: we could also talk the work that Maria is doing on the ontology and my work on JSON Schema as Linked Data.

Darko: I also promised to look at shape languages.

Any additional agenda items for today?

[no]

Shape languages with the focus on Thing Description data types

<DarkoAnicic> type system proposal (currently): https://github.com/w3c/wot/tree/master/proposals/type-system

Darko presents

Darko shows us a side by side comparison of JSON Schema and schema.org

Darko shows us his experiments (on his pc) with the SHACL and ShEX RDF shape rules languages

Victor and Darko chat about the possibility of representing shape rules in JSON

The examples concern validation of data, not the thing description

ShEx defines its own syntax, but there is a mapping to JSON, albeit rather verbose

Dave: wonders what we’re trying to achieve in this discussion?

Darko: the idea is to use shape rules to validate the data

Dave: I thought that we were more interested in validating thing descriptions?

Darko: this is just an exploration of ideas

Dave: I thought we had agreed to create a Linked Data model for a subset of JSOn Schema, right?

Victor: we’re comparing the constraints available in JSON Schema with that of SHACL and SheX.

Kaz recaps the discussion and actions from the last face to face relating to data types, as he is a little confused as to the current presentation

Kaz: we asked Dave to look at JSON Schema and the web of things use cases for data types

Darko: I am interested in the role of shape rules in relation to semantic validation

It seems interesting to compare JSON Schema with shape rule languages in respect to applying type constraints

(Dave notes that his own work on shape rule languages inspired by ATNs is being ignored)

<kaz> Kaz: ok. if the purpose for today is rather basic survey of existing data type/schema languages, that's fine

Darko shows the use of the TopBraid composer tool for use with SHACL

Dave: my analysis of JSON Schema and WoT use cases: https://github.com/w3c/wot-thing-description/issues/13

Darko: it is interesting to look at the potential for applying shape rules, e.g. to semantic models
... why is JSON schema so popular, and how does it compare to shape rules.

<victor> Victor: having a schema that is object-oriented is important for the scripting API

<victor> because the API itself uses the OO paradigm

Dave: a simple toolkit of techniques for manipulating linked data makes it easy to apply semantic constraints etc in terms of operations on sets of nodes and triples

<achille_zappa> https://www.w3.org/TR/shacl-js/

DanhLePhuoc: It seems there is a lot of confusion here. RDF is programming language neutral. We can use the right tools for the task to operate on RDF in the way you want. It is quite different from object oriented practices

I am also confused as to what outcome you’re seeking in this discussion

Darko: we want to focus on the data types here

DanhLePhuoc: the scripting API depends on the tasks a programmer is trying to accomplish

There are lots of libraries for Java, JavaScript etc.

Darko: the only WoT APIs available to us expose objects, and this makes object oriented techniques relevant

DanhLePhuoc: if developers are using Java, they can use the Java libraries for linked data etc

I don’t see why Victor want’s to limit the discussion to object oriented techniques

Victor: the same linked data graph can have multiple JSON-LD representations

Darko: if you define the JSON-LD context you get a single translation to linked data

Dave wonders why we aren’t just considering operations on linked data given that this is the Linked Data and Semantic Processing Task Force!

mjkoster: I think we need to remember the context for the tasks

He talks about the payload, i.e. the formats used to represent linked data

The shape rules form one RDF graph that is applied to the data graph

We need to consider validation of data as a graph, and also the notation used to serialise it

Darko: couldn’t we use SHACL for thing descriptions?

mjkoster: yes, I see that as a possibility

Dave: let’s put on the agenda for the next call the work I did on JSON Schema, and use cases for the web of things and the requirements for linked data.

Darko: sure

taki: we have different worlds to relate (JSON, Linked Data, shape rules and ontologies)

Darko: any last points for today?

[no]

(Dave: see https://github.com/w3c/wot-thing-description/issues/13 for my analysis)

[ adjourned ]