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Re: xs:string return types: [was Re: function library summary and issues]

From: Steve Harris <steve.harris@garlik.com>
Date: Wed, 17 Nov 2010 20:56:14 +0000
Cc: Axel Polleres <axel.polleres@deri.org>, SPARQL Working Group <public-rdf-dawg@w3.org>
Message-Id: <305CFC95-1D01-4C6F-A26E-7D7AC1D19334@garlik.com>
To: Andy Seaborne <andy.seaborne@epimorphics.com>
On 2010-11-17, at 15:36, Andy Seaborne wrote:

> The return type for fn:concat and fn:strig-join is xs:string not a simple literal.
> 
> On 16/11/10 18:33, Axel Polleres wrote:
>> * CONCAT:
>>   cf. http://www.w3.org/2009/sparql/meeting/2010-11-16#line0289
>>   As for 2) there were some discussions about concat still, with three alternatives:
>>   - take fn:concat "as is" i.e. only accepting xs:AtomicTypes castable to xs:string
> 
> My reading is that a consequence of this is:
> 
> fn:concat("a", "b") -> "ab"^^xsd:string
> 
> Do we want that?  I don't think it's helpful.
> 
> The example in section 2.5 is wrong (who added that?)
> 
> Steve --
> 
> The signature for fn:string-join used in GROUP_CONCAT is also returns an xsd:string did you mean that?  The example underneath does not match that.

Ah, I hadn't registered that.

I would expect a plain literal to be more useful in the RDF world. My proposal is to change the definition to STR(fn:string-join(...)). Unless people really want an xsd:string?

[OT] I hope that some future Rec will remove the distinction between plain literals and xsd:strings. It's cumbersome, and adds no utility to RDF, IMHO.

> [[
> fn:string-join($arg1 as xs:string*, $arg2 as xs:string) as xs:string
> ]]

- Steve

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Received on Wednesday, 17 November 2010 20:56:48 GMT

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