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Re: Proposal for ISSUE-12, string literals

From: Pat Hayes <phayes@ihmc.us>
Date: Fri, 13 May 2011 15:59:25 -0500
Cc: antoine.zimmermann@insa-lyon.fr, public-rdf-wg@w3.org
Message-Id: <F50A771B-0F9B-419C-8655-55C265AE056A@ihmc.us>
To: Richard Cyganiak <richard@cyganiak.de>

On May 13, 2011, at 10:00 AM, Richard Cyganiak wrote:

> On 13 May 2011, at 14:46, Antoine Zimmermann wrote:
>> xsd:double is disjoint from xsd:decimal, so there is no risk that doubles get canonicalised into decimals.
>> 
>> "1"^^xsd:double owl:differentFrom "1"^^xsd:decimal .
> 
> Oh, I wasn't aware of that.
> 
> In that case, I withdraw the idea of automatically converting between numeric datatypes. It doesn't feel like a simplification to me if some of them are converted (e.g., byte => decimal) and others not (e.g., double =/=> decimal). This would just make matters more confusing.
> 
> I'd still like to do something like this:
> 
> “For all XSD datatypes that define canonical lexical forms [XML-SCHEMA2], implementations MAY replace a non-canonical lexical form (such as "+0013"^^xsd:integer) with a canonical lexical form ("13"^^xsd:integer).”
> 
> I noted some concerns about this:
> 
> Objection 1: Can no longer use 2.0000 to denote precision
> 
> Response: Don't do that. That's not how numbers work in any programming language, database, or spreadsheet I've ever used.

But with respect, RDF is NOT a programming language, spreadsheet or database. Which is part of the very point of having it in the first place. This gets to the heart of many of these debates, seems to me. People do use the number of decimal places to indicate precision, in the actual world. To many people it is so natural to do this they have a hard time understanding why anyone would not do it.  If entire communities of real people want to do something useful to them, the last thing we should be doing is making their lives impossible just because programmers like their numbers normalized. The percentage of users of RDF who know squat about any programming language is going to be, I sincerely hope, a vanishingly small fraction of one precent, so small it can be safely ignored. If not, all our work here is a waste of time. So we should not be imposing what might be called "programmer culture" onto everyone else. 

</rant>

Pat

> 
> Objection 2: time and dateTime would become always UTC
> 
> I'm not sure what to respond here.
> 
> Objection 3: Canonical lexical form of "2e+138"^^xsd:decimal is unwieldy
> 
> Response: It's a wash. The canonical lexical representation of "2e-0"^^xsd:decimal is quite nice, for example.
> 
> Best,
> Richard
> 
> 
> 
>> 
>> 
>> See http://www.w3.org/TR/xmlschema-2/#equal:
>> 
>> "the ·value space·s of all ·primitive· datatypes are disjoint (they do not share any values)"
>> 
>> and http://www.w3.org/TR/xmlschema-2/#built-in-primitive-datatypes
>> 
>> 
>> Le 13/05/2011 14:07, Steve Harris a écrit :
>>> On 2011-05-12, at 14:27, Richard Cyganiak wrote:
>>> 
>>>> On 12 May 2011, at 13:06, Ivan Herman wrote:
>>>>>> I'd be tempted to go further and make only the primitive types such as xsd:decimal into RDF canonical forms. This would mean that systems MAY canonicalize all numbers to a single numeric datatype.
>>>>> 
>>>>> Do you mean like the 'canonical' forms in Turtle? I may miss something here.
>>>> 
>>>> No. Turtle has syntactic sugar for certain numeric literals; this has nothing to do with canonicalization.
>>>> 
>>>> (This all goes way beyond ISSUE-12 anyways...)
>>>> 
>>>> I was suggesting that perhaps, instead of this:
>>>> "+0013"^^xsd:byte =>  "13"^^xsd:byte
>>>> 
>>>> I'd like to say that implementations MAY do this:
>>>> "+0013"^^xsd:byte =>  "13.0"^^xsd:decimal
>>> 
>>> Hesitant -1 to, there are numbers that xsd:double for e.g. can represent, that xsd:decimal doesn't promise to. Also the canonical form of 1.79e+308 as an xsd:decimal is quite an unwieldy string.
>>> 
>>> There are also situations when you might care about things being integers, e.g. ordinals.
>>> 
>>> - Steve
>>> 
>> 
>> 
>> -- 
>> Antoine Zimmermann
>> Researcher at:
>> Laboratoire d'InfoRmatique en Image et Systèmes d'information
>> Database Group
>> 7 Avenue Jean Capelle
>> 69621 Villeurbanne Cedex
>> France
>> Tel: +33(0)4 72 43 61 74 - Fax: +33(0)4 72 43 87 13
>> Lecturer at:
>> Institut National des Sciences Appliquées de Lyon
>> 20 Avenue Albert Einstein
>> 69621 Villeurbanne Cedex
>> France
>> antoine.zimmermann@insa-lyon.fr
>> http://zimmer.aprilfoolsreview.com/
>> 
> 
> 
> 

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Received on Friday, 13 May 2011 20:59:59 GMT

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