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RE: datetime-difference

From: Polleres, Axel <axel.polleres@siemens.com>
Date: Thu, 12 Apr 2012 13:46:47 +0200
To: Andy Seaborne <andy.seaborne@epimorphics.com>, "public-rdf-dawg@w3.org" <public-rdf-dawg@w3.org>
Message-ID: <9DA51FFE5E84464082D7A089342DEEE80138CE48F690@ATVIES9917WMSX.ww300.siemens.net>
Thanks, Andy,

For the moment, we can live without it for our use case, 
would anybody support to put propagating all op:... operator 
delegations for basic arithmetics from Xpath/Xquery operators 
on the future work items list?

> > It's probably too much of a burden to add it now, but 
> "nice-to have" 
> > for my use case would be
> 
> Slippery slope!
> 
> We would have to add required support for xsd duration 
> hierarchy (xs:dayTimeDuration, xs:yearMonthDuration).

Yeah, understood. I agree that adding some, but not all op:... delegations 
would seem arbitrary, and adding all at this stage looks like a potential 
source for trouble and as you said, additional impl. Burden for compliance...

> (Disclosure: ARQ does g* and some of durations but not all 
> arithmetic on datetimes - someone contributed the duration support)

... Great, that might solve my use case for the moment, will look into that.

> >   op:add-dayTimeDuration-to-dateTime
> 
> FYI: Only applies to DT+dayTimeDuration, not the other way round.

Understood, that's why I thought is might be convenient for  either
    xsd:dateTime + xsd:dayTimeDuration
   or
   xsd:dayTimeDuration + xsd:dateTime
Both to op:add-dayTimeDuration-to-dateTime() but switching operators for the latter.

Anyways, as said above, can live without it being in the current standard.

Cheers,
Axel

> -----Original Message-----
> From: Andy Seaborne [mailto:andy.seaborne@epimorphics.com] 
> Sent: Thursday, 12 April 2012 12:09 PM
> To: public-rdf-dawg@w3.org
> Subject: Re: datetime-difference
> 
> 
> On 12/04/12 10:50, Polleres, Axel wrote:
> > Hi,
> >
> > </chair-hat>
> >
> >
> > just as I was stumbling over it something for the wish-list...
> >
> > We need datetime-difference for some use case.
> 
> > Was that ever considered in previous discussions in the 
> functions-library?
> 
> Yes.
> 
> 1/ You can do it by operator extension.
> 2/ The decision was not to require all of XSD (datatypes, 
> functions) in core SPARQL.
> 
> See also charter for LDP-WG.
> 
> > I am looking at the XPath arithmetics delegation in Table "SPARQL 
> > Binary Operators" in Section 17.3 of the query doc, cf. 
> > www.w3.org/TR/sparql11-query/
> >
> >
> > It's probably too much of a burden to add it now, but 
> "nice-to have" 
> > for my use case would be
> 
> Slippery slope!
> 
> We would have to add required support for xsd duration 
> hierarchy (xs:dayTimeDuration, xs:yearMonthDuration).
> 
> And xs:g*? -- probably more generally useful.
> 
> Next step is xsd:time ...
> 
> (Disclosure: ARQ does g* and some of durations but not all 
> arithmetic on datetimes - someone contributed the duration support)
> 
> >
> > 1) delegating "-"
> > to
> >
> >    op:subtract-dateTimes ( 
> > http://www.w3.org/TR/xpath-functions/#func-subtract-dateTimes )
> >
> > For
> >
> >     xsd:dateTime - xsd:dateTime
> >
> >
> > 2) delegating "+"
> >
> >   to
> >
> >   op:add-dayTimeDuration-to-dateTime
> 
> FYI: Only applies to DT+dayTimeDuration, not the other way round.
> 
> >
> > for either
> >
> >    xsd:dateTime + xsd:dayTimeDuration
> >   or
> >    xsd:dayTimeDuration + xsd:dateTime
> >
> >
> > Best,
> > Axel
> 
> Implementation burden for compliance.
> 
> Personally, don't care - I'll add as much as users want.
> 
> 	Andy
> 
> 
Received on Thursday, 12 April 2012 11:47:29 GMT

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