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Re: Datatyping differences

From: Patrick Stickler <patrick.stickler@nokia.com>
Date: Mon, 28 Jan 2002 11:11:58 +0200
To: Dan Connolly <connolly@w3.org>, Jeremy Carroll <jjc@hplb.hpl.hp.com>
CC: RDF Core <w3c-rdfcore-wg@w3.org>
Message-ID: <B87AE27E.C6BA%patrick.stickler@nokia.com>
On 2002-01-25 19:22, "ext Dan Connolly" <connolly@w3.org> wrote:

> On Fri, 2002-01-25 at 07:43, Jeremy Carroll wrote:
>> Brian dropped by and asked me what the key differences between S and TDL
>> were.
>> Here is a list:
>> ** A single triple:
>>   <bob> <age> "30" .
>> In S "30" is a string, in TDL it is untyped.
> As I said in my discussion of how perl programmers might
> do datatyping in RDF, it's not necessarily the case
> that in S, "30" is a string; we could call them
> "scalars" if you don't like using "30" to represent
> an integer.
> What's necessarily
> the case is that in S, "30" denotes the same thing in all
> interpretaions, but in TDL it doesn't.

In TDL (though not perhaps the current TDL MT, which should
be revised) a literal is a literal is a literal. In the
graph, it simply is a string that, IFF paired with a datatype,
may be interpreted as a lexical form (a member of the lexical
space of that datatype).

This is just as with S.

However, I do disagree with the statement that "30" always
denotes the same thing in all interpretations -- as its
interpretation is context specific, either per a given
predicate or explicitly defined typing (local or global).

In my latest illustration, showing that the TDL model
(though not the TDL MT) is agnostic about, and hence
compatable with tidy literals, the literal "30" has
two interpretations. The literal itself is not always the
same thing. A lexical form is always the same thing, per
the definition of datatypes, lexical spaces, and mappings
from lexcal spaces to value spaces -- but it is the
interpretation of a literal that gives us the lexical
form. The literal itself may be interpreted as many
lexical forms, depending on the context form which a
TDL is derived.


Patrick Stickler              Phone: +358 50 483 9453
Senior Research Scientist     Fax:   +358 7180 35409
Nokia Research Center         Email: patrick.stickler@nokia.com
Received on Monday, 28 January 2002 04:10:58 UTC

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