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Re: Datatype normalization

From: Nathan <nathan@webr3.org>
Date: Fri, 12 Nov 2010 11:59:30 +0000
Message-ID: <4CDD2C22.9020509@webr3.org>
To: Axel Rauschmayer <axel@rauschma.de>
CC: Semantic Web <semantic-web@w3.org>
Just to clarify, I'm specifically talking about when the property has a 
  range specified - not just hitting "12.1" in a graph and saying oh 
that looks like a decimal so I'll convert it to that. More along the 
lines of type inference in a compiler - next step being to validate 
against DatatypeRestrictions.

There are two contexts where I'm looking to implement this 
functionality, as part of an rdf library which converts typed literals 
to native types - and as part of an "RDF compiler".

Good catch re "100,123" btw, hadn't thought of that!

Cheers,

Nathan

Axel Rauschmayer wrote:
> It completely depends on what your application is. What you are trying to do is similar to analyzing unstructured text. Sure, "12.2" looks like a number, but is it really? It could indicate a section in a book. Another example is "100,123" which is between 100 and 101 in many European countries. Why do you even need to infer a type?
> 
> On Nov 12, 2010, at 12:33 , Nathan wrote:
> 
>> Hi All,
>>
>> I'd suggest that a high percentage of the worlds RDF data is being published untyped, where plain literals are used as rather than typed literals "12.2" vs "12.2"^^xsd:decimal, and also (to a lesser extent) "strings as"^^xsd:string's.
>>
>> Until today, I had assumed that it was pretty "safe" to, upon parsing, turn xsd:strings in to plain literals / pull the datatype from the range of a property and turn the object in to the correct type.
>>
>> However, it's been suggested to me today that this probably isn't a good thing / "the right thing" to do.
>>
>> And thus, should I be avoiding implementing this feature, and additionally what are the reasons *not* to do this.
>>
>> An example:
>>
>> Ontology contains..
>>   ex:prop rdfs:range xsd:decimal .
>>
>> "data" contains..
>>   :foo ex:prop "12.2" .
>>
>> What reason would there be not to just infer/pull the type and convert to a typed literal?
>>
>> Best,
>>
>> Nathan
>>
>> seeAlso:
>> http://www.w3.org/TR/rdf-plain-literal/
>> http://www.w3.org/DesignIssues/InterpretationProperties.html
>>
>>
> 
Received on Friday, 12 November 2010 12:00:42 UTC

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