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Re: Non-Text Literals

From: Geoff Chappell <geoff@sover.net>
Date: Sat, 31 Aug 2002 11:12:26 -0400
Message-ID: <05fa01c25100$d11eed30$825ec6d1@goat1>
To: Bill de hÓra <dehora@eircom.net>, <www-rdf-interest@w3.org>


----- Original Message -----
From: "Bill de hÓra" <dehora@eircom.net>
To: "'Jon Hanna'" <jon@spin.ie>; <www-rdf-interest@w3.org>
Sent: Saturday, August 31, 2002 9:17 AM
Subject: RE: Non-Text Literals


>
>
> > Jon Hanna:
> > I would hope they would allow both, since both would have their place.
>
> True. But Literals are in a sense second class citizens in RDF. Where
> you have the option, giving something a URL/I is preferable.

The problem is that referring to a web resource solely by its URL (as a URI)
in RDF doesn't fix its meaning. Applications may choose to believe otherwise
and assume the missing knowledge that can't be specified in RDF - i.e that
we really mean a particular URI to be treated as a URL so it's ok for an
application to go and retrieve something from it.

I've been wondering recently if datatyping could play a role here. An rdf
datatype is essentially a function, the details of which are unknown to rdf,
that is able to fix the interpretation of a name. The web through its
mechanisms plays a similar role of resolving names to resources. So why not
have a web datatype in rdf? For example:

_:a rdf:lex http://www.example.org/someimage.gif
_:a rdf:dtype ex:HttpResource
ex:HttpResource rdf:type rdf:DataType

(hopefully that approximates one of the datatype proposals closely enough so
that my point is clear)

That would tell any datatype aware application (familiar with the
ex:HttpResource datatype) that the image specified is actually retrievable.
Depending upon the semantics of datatypes, it might be useful to also
specify

_:a rdf:type ex:Gif


rgds,

Geoff Chappell
Received on Saturday, 31 August 2002 10:42:22 GMT

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