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Re: sorting tests moved to r2

From: Jeen Broekstra <j.broekstra@tue.nl>
Date: Tue, 26 Jun 2007 15:23:28 +0200
Message-ID: <46811350.7020805@tue.nl>
To: andy.seaborne@hp.com
CC: DAWG <public-rdf-dawg@w3.org>

Seaborne, Andy wrote:
> Jeen Broekstra wrote:
>> Seaborne, Andy wrote:
>>
>>> ARQ fails test 11:
>>>
>>> Failure: Test 11 :: sort-11
>>> Got: 8 --------------------------------
>>> ------------------------------------------------------
>>> | name                                               |
>>> ======================================================
>>> | "Alice"                                            |
>>> | "Alice"^^<http://www.w3.org/2001/XMLSchema#string> |
>>> | "Bob"                                              |
>>> | "Bob"^^<http://www.w3.org/2001/XMLSchema#string>   |
>>> | "Eve"                                              |
>>> | "Eve"^^<http://www.w3.org/2001/XMLSchema#string>   |
>>> | "Fred"                                             |
>>> | "Fred"^^<http://www.w3.org/2001/XMLSchema#string>  |
>>> ------------------------------------------------------
>>> Expected: 8 -----------------------------
>>> ------------------------------------------------------
>>> | name                                               |
>>> ======================================================
>>> | "Alice"                                            |
>>> | "Bob"                                              |
>>> | "Eve"                                              |
>>> | "Fred"                                             |
>>> | "Alice"^^<http://www.w3.org/2001/XMLSchema#string> |
>>> | "Bob"^^<http://www.w3.org/2001/XMLSchema#string>   |
>>> | "Eve"^^<http://www.w3.org/2001/XMLSchema#string>   |
>>> | "Fred"^^<http://www.w3.org/2001/XMLSchema#string>  |
>>> ------------------------------------------------------
>>>
>>> ORDER BY is by the "<" operator unless it can't split two different RDF
>>> terms.
>>>
>>> Under the extra conditions rq25 says:
>>> [[
>>> The "<" operator (see the Operator Mapping and 11.3.1 Operator
>>> Extensibility) defines the relative order of pairs of numerics, simple
>>> literals, xsd:strings, xsd:booleans and xsd:dateTimes. Pairs of IRIs are
>>> ordered by comparing them as simple literals.
>>> ....
>>> 5. A plain literal is lower than an RDF literal with type xsd:string of
>>> the same lexical form.
>>> ]]
>>>
>>> The < operator makes "Alice"^^xsd:string < "Fred" and simple literals.
>>
>> You are likely correct, but I am not sure how you arrived at this, talk
>> me through with small words please. Condition 5 only states, as I read
>> it, that:
>>
>>   "Fred" < "Fred"^^xsd:string
>>
>> In other words, two literals with the same lexical form only. It does
>> not tell us how to order a plain/simple literal and a typed literal with
>> different lexical values (for example "Alice"^^xsd:string and "Fred").
>>
>> And I can't seem to find where this is defined, in fact. What am I
>> overlooking?
> 
> The first papagraph says that ordering is by "<" where possible so:
> 
>   "Alice"^^xsd:string < "Bob"

[snip]

Ah, *this* is what I don't get. I am probably overlooking something
obvious but as far as I can tell "<" is not defined when one operand is
a plain literal and the other a typed literal.

I am not being deliberately obtuse here, but I really am struggling with
 finding out how/where this is defined in the spec.

Jeen
-- 
Dr. Jeen Broekstra                                          Den Dolech 2
Information Systems Group                                        HG 7.76
Department of Mathematics and Computer Science              P.O. Box 513
Technische Universiteit Eindhoven                      5600 MB Eindhoven
tel. +31 (0)40 247 36 86                                 The Netherlands
Received on Tuesday, 26 June 2007 13:27:59 GMT

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