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Re: ISSUE: Malformed literals and non-lexical literals

From: Seaborne, Andy <andy.seaborne@hp.com>
Date: Thu, 17 Aug 2006 12:57:10 +0100
Message-ID: <44E45996.8050304@hp.com>
To: Bijan Parsia <bparsia@cs.man.ac.uk>
CC: Pat Hayes <phayes@ihmc.us>, RDF Data Access Working Group <public-rdf-dawg@w3.org>



Bijan Parsia wrote:
> On Aug 17, 2006, at 12:39 PM, Seaborne, Andy wrote:
> 
>> Bijan Parsia wrote:
>>> Thanks Andy, that was interesting.
>>> On Aug 17, 2006, at 10:20 AM, Seaborne, Andy wrote:
>>>> Output from ARQ (using the standalone expression evaluator  
>>>> because  it explains what is going on; ASK queries mask this):
>>>>
>>>> Reformatted for email.
>>>>
>>>> ==== Test 1
>>>>
>>>> arq.qexpr "'-5'^^xsd:positiveInteger < 5" ==> error
>>>>
>>>> 10:06:46 WARN  NodeValue
>>>>     Datatype format exception: "-5"^^xsd:positiveInteger
>>>> Exception: Can't compare "-5"^^<http://www.w3.org/2001/  
>>>> XMLSchema#positiveInteger> and 5
>>> You say that the warnings do not affect the results.
>> Warnings are output as logging messages.  Ignore then for the value  
>> of the expression.  ARQ just outputs some logging stuff for caes  
>> where the user may find it useful.  As ARQ (and Jena and Joseki)  
>> uses Jakarta Commons Logging (and log4j usually) the user/app can  
>> pick and choose logging messages anyway.
>>
>>> But this is
>>> wrong behavior, yes?
>>> """Specifically, FILTERs eliminate any solutions that, when   
>>> substituted into the expression, result in either an effective   
>>> boolean value of false or produce an error. """
>> This is showing the result of an expression evaluation, not the  
>> full filter evaluation.  That's why I didn't use an ASK query.
> 
> Ok, but surely the relevant bit is how this expression evaluation  
> affects filter evaluation.
> 
>> 	Andy
>>
>>> So, given data
>>> 	:b :p "-5"^^xsd:positiveInteger.
>>> 	:b :q "5"^^xsd:positiveInteger.
>>> and query
>>> 	SELECT ?x {?x :p ?L1. ?x :q ?L2. FILTER ?L1 < ?L2}

Syntax error : FILTER ( ?L1 < ?L2 )

>>> ARQ returns
>>> 	?x/:b
>>> instead of no answers?
> 
> Hence wondering what ARQ does in this specific case.

ARQ returns:

-----
| x |
=====
-----

	Andy

> 
> Cheers,
> Bijan.
Received on Thursday, 17 August 2006 11:57:40 GMT

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