W3C home > Mailing lists > Public > semantic-web@w3.org > August 2007

Re: Datatypes

From: Danny Ayers <danny.ayers@gmail.com>
Date: Tue, 21 Aug 2007 20:14:14 +0200
Message-ID: <1f2ed5cd0708211114o3ef74074xc09320c092fce2a2@mail.gmail.com>
To: "Garret Wilson" <garret@globalmentor.com>
Cc: "Reto Bachmann-Gmür" <reto@gmuer.ch>, semantic-web@w3.org
On 21/08/07, Garret Wilson <garret@globalmentor.com> wrote:
> Reto Bachmann-Gmür wrote:
> > - fully qualified java-class names (eg: "org.example.tools.MyTool")
> >
> > While I could use xsd:string I think it would be better to use custom
> > datatypes to have literals like
> > "org.example.tools.MyTool"^^http://example.org/datatypes#javaClass.

There is stuff for defining user-defined datatype in XSD, I seem to
remember the RDF spec skirting around that somehow...OWL has datatypes
as an orthogonal space to everything else...?

Whatever, here's a bit of practical material:


> My opinion (see my earlier rants against RDF literals on this list): for
> Java classes shun literals and use URIs.

[/me hops sideways]

A couple of weeks ago I wanted something fairly close to the media
type bit, to be able to refer to URI schemes - "http", "ftp" etc. I
wound up with essentially :

  <scheme:Scheme rdf:about="http://purl.org/stuff/uri-schemes/http">

In lieu of making the terms resolve (I do have isDefinedBy to the
specs...), it's at:

Expressing media ranges as non-literals is trickier, I suspect you'd
have to do something like:

      rdfs:label "application/*" ;
      iana:type <http://whatever/.../application> .

i.e. leaving the iana:subtype undefined.

Given that Java class names are qualified, might it not be possible to
use URIs there too?

Something like:


For useful http URIs it's hard to imagine what would be the resources
- but you could avoid the issue by putting the javadoc online and make
303s from the URIs to the doc pages.

btw, while http://www.w3.org/TR/HTTP-in-RDF/ gives status codes URIs,
I believe it leaves everything else as literals.



Received on Tuesday, 21 August 2007 18:14:35 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 19:47:27 UTC