Re: PS-16: Regular Expression Comparison of Datatype Lexical Forms

On Apr 02, 2004, at 10:43, ext Janne Saarela wrote:

> Is this use case as generic as I think it is?
> For example, if the data type is XSD#dateTime and I was
> looking for *2*, I would be matching both lexical forms
> 2002-12-13T12:03:23
> 1999-03-14T12:45:13
> I am not sure this is a necessary use case.
> I would agree regular expressions are useful for some
> datatypes such as strings but not for all of them such as
> dateTime.

I don't see any need to "protect the users from themselves"
by only permitting certain kinds of regular expression comparision.

So long as we make it clear that trying to match a substring of
a URI or lexical form is "stepping outside the bounds" of the
RDF MT, then we should allow folks to do it.

After all, one could just as well argue that plain literal values
are to be treated just as opaquely as typed literal lexical forms
or URIs. They only have meaning as a whole, not per any substring
of their form. Looking into a plain literal is "stepping outside
the bounds" of the RDF MT just as much as looking inside a URI.


> Janne
>> A client wishes to discover resources which for a given property
>> have datatype values having lexical forms which match a particular
>> regular expression, and obtain descriptions of those resources.
>> The client is aware of a source of knowledge from
>> which such resources might be discovered.
>> Following the DAWG recommendation, the client formulates a
>> query which describes one or more example templates which
>> reflect the desired characteristics and submits the query
>> to the knowledge source.
>> The knowledge source returns a set of zero or more
>> resource descriptions, each description describing a
>> resource which matched an example template.
>> -- 
>> Patrick Stickler
>> Nokia, Finland
> -- 
> Janne Saarela <janne.saarela at>
> Profium, Lars Sonckin kaari 12, 02600 Espoo, Finland


Patrick Stickler
Nokia, Finland

Received on Friday, 2 April 2004 03:12:20 UTC