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Re: ISSUE-54: Do we need (descriptions of) property functions in SD? Is this in scope for us?

From: Andy Seaborne <andy.seaborne@talis.com>
Date: Mon, 22 Feb 2010 10:34:05 +0000
Message-ID: <4B825D9D.4060401@talis.com>
To: Paul Gearon <gearon@ieee.org>
CC: SPARQL Working Group WG <public-rdf-dawg@w3.org>


On 16/02/2010 4:52 PM, Paul Gearon wrote:
> On Tue, Feb 16, 2010 at 10:24 AM, SPARQL Working Group Issue Tracker
> <sysbot+tracker@w3.org>  wrote:
>>
>> ISSUE-54: Do we need (descriptions of) property functions in SD? Is this in scope for us?
>>
>> http://www.w3.org/2009/sparql/track/issues/54
>
> I believe that we want this.
>
> The scope of what property functions are capable of is essentially
> unrestricted, so I don't think it's possible to really describe what
> these functions do. However, it should be possible to obtain a list of
> properties that fall into this category. As a user I would find that
> useful in two ways:
>
> 1. I'd know that using this property in a query, or getting it back in
> a result involves entailed data, and not just extensional data.
> 2. If I happen to recognize a property from the list, I will know that
> a particular feature will be available to me.
>
> Regards,
> Paul Gearon

I agree.  Property functions are just vocabulary but they also represent 
a feature that a system provides and an app writer might be aware of. 
c.f. a custom filter function.  Regarding them as a vocaulary of one 
property seems rather heavy weight.

It is hard to define what one is but most of the interesting part is 
what the specific one does, again, like a custom filter function. We 
have the opportunity to provide the vocabulary hook to talk about them; 
it's a feature several systems provide; and the current work on SD gives 
us a chance to have the same property across descriptions.

	Andy
Received on Monday, 22 February 2010 10:41:36 GMT

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