Re: shapes-ISSUE-27 (extensions-in-highlevel): Can extension constraints be used in the high-level language? [SHACL Spec]

Arthur,

note that Richard wrote "the built-in constructs of the high-level 
language" which is an important qualifier: the term "High-level 
language" to me includes not just the built-in "core elements" from the 
SHACL namespace (such as sh:datatype) but also any user-defined 
high-level elements, i.e. templates. I believe we should revert to using 
the terms "Core" or "Lite" vocabulary when we mean the built-ins.

Holger



On 4/4/15 10:49 AM, Arthur Ryman wrote:
> Richard,
>
> Yes, extensions should increase the vocabulary of constraints and use
> the same syntactic pattern as the HL vocabulary. I don't see how that
> implies that they are part of the HL vocabulary. The HL vocabulary
> contains a fixed, predefined set of constraints. A HL processor would
> only be expected to understand the HL vocabulary.
>
> -- Arthur
>
> On Thu, Apr 2, 2015 at 4:13 PM, Richard Cyganiak <richard@cyganiak.de> wrote:
>> Arthur,
>>
>>> On 2 Apr 2015, at 20:51, Arthur Ryman <arthur.ryman@gmail.com> wrote:
>>>
>>> My expectation is that extensions are packaged in a seamless way so
>>> you can use them without being exposed to their implementation.
>>> However, that is not the same as being part of the high-level
>>> language. My view is that the high-level language is a fixed set of
>>> constraints defined by the WG.
>> So you are saying that things like this should be impossible?
>>
>>    MyShape =
>>       (propertyA maxOccurs 1)
>>       OR
>>       ((propertyB maxOccurs 1) AND (propertyB meets FooExtensionConstraint))
>>
>> I’d argue that seamless packaging of extension constraints would *require* that they can be used just like the built-in constructs of the high-level language.
>>
>> Best,
>> Richard
>>
>>
>>
>>> -- Arthur
>>>
>>> On Sat, Mar 28, 2015 at 4:18 PM, RDF Data Shapes Working Group Issue
>>> Tracker <sysbot+tracker@w3.org> wrote:
>>>> shapes-ISSUE-27 (extensions-in-highlevel): Can extension constraints be used in the high-level language? [SHACL Spec]
>>>>
>>>> http://www.w3.org/2014/data-shapes/track/issues/27
>>>>
>>>> Raised by: Richard Cyganiak
>>>> On product: SHACL Spec
>>>>
>>>> It looks like SHACL will be split into two parts:
>>>>
>>>> 1) A high-level “Core/Lite” language consisting of things like cardinality constraints, datatype constraints, conjunctions and disjunctions
>>>> 2) An extension mechanism that relies on embedded expressions in a more expressive language
>>>>
>>>> Do constraints defined using 2) become part of the high-level language, that is, can they be used in nested expressions like conjunctions and disjunctions? Or do they stand “outside” the high-level language and are directly associated with classes/individuals/etc?
>>>>
>>>>
>>>>

Received on Saturday, 4 April 2015 03:29:09 UTC