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RE: Requesting input for the Features and Rational document

From: Seaborne, Andy <andy.seaborne@hp.com>
Date: Mon, 15 Jun 2009 12:49:03 +0000
To: Steve Harris <steve.harris@garlik.com>, Kjetil Kjernsmo <Kjetil.Kjernsmo@computas.com>
CC: "public-rdf-dawg@w3.org" <public-rdf-dawg@w3.org>
Message-ID: <B6CF1054FDC8B845BF93A6645D19BEA3646CFC6507@GVW1118EXC.americas.hpqcorp.net>


> -----Original Message-----
> From: public-rdf-dawg-request@w3.org [mailto:public-rdf-dawg-
> request@w3.org] On Behalf Of Steve Harris
> Sent: 15 June 2009 12:07
> To: Kjetil Kjernsmo
> Cc: public-rdf-dawg@w3.org
> Subject: Re: Requesting input for the Features and Rational document
> 
> On 10 Jun 2009, at 09:42, Kjetil Kjernsmo wrote:
> 
> > On Thursday 04 June 2009 08:46:29 Lee Feigenbaum wrote:
> >>> * ProjectExpression needs a better description and motivation.
> >>> We feel that the mention of XSLT is not very relevant, as
> >>> assigning a
> >>> name automatically, like some engines do now, is sufficient for
> >>> XSLT.
> >>> It should also be motivated by showing why it is required by other
> >>> features.
> >>
> >> I took a stab at this at
> >> http://www.w3.org/2009/sparql/wiki/Feature:ProjectExpressions

> >
> > As discussed on the teleconf yesterday, it needs better examples
> > too. It
> > doesn't sound like the examples are actually executeable as it is
> > now, and
> > they should be. Also, it is also a good thing if they do not rely on
> > other
> > features that we do not yet have, such as concat().
> >
> > It is good to have both SELECT and CONSTRUCT examples.
> >
> > Can anyone have a stab at this?
> 
>   CONSTRUCT { ?x foaf:name (concat(?fn, " ", ?sn)) . }

Can we adopt F&O naming here?  It's "fn:concat" 

Tricky - () looks awfully like a list to a parser.  Especially if the function is named by URI.

Suggestion: off the top of my head: ?(expr)

   CONSTRUCT { ?x foaf:name ?(fn:concat(?fn, " ", ?sn)) . }

Not necessary beautiful but it will work.

This is a place where explicit assignment would be useful syntax.

>   WHERE { ?x foaf:firstName ?fn ; foaf:family_name ?sn . }
> 
> As a projection it would be something like:
> 
>   CONSTRUCT { ?x foaf:name ?concat . }
>   WHERE {
>     { SELECT ?x, concat(?fn, " ", ?sn) AS ?concat

SELECT ?x fn:concat....

(no comma - comma in SELECT lists are in the time permitting query language syntax.

>     WHERE { ?x foaf:firstName ?fn ; foaf:family_name ?sn . } }
>   }
> 
> - Steve

	Andy

Received on Monday, 15 June 2009 12:50:13 GMT

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