W3C home > Mailing lists > Public > www-tag@w3.org > February 2002

Re: [namespaceDocument-8] 14 Theses, take 2

From: Tim Berners-Lee <timbl@w3.org>
Date: Wed, 27 Feb 2002 18:54:30 -0500
Message-ID: <062601c1bfea$19ae2460$0301a8c0@w3.org>
To: "Jonathan Borden" <jonathan@openhealth.org>, "Simon St.Laurent" <simonstl@simonstl.com>, "TAG" <www-tag@w3.org>
Some of the following seem to me self-evident:

1.  We cannot now define the languages which will be available later to say
things about namespaces.

2. Human readable information is good.  Humans can sue it

3. Machine-readable information is good.  It allows automatic processing.

4.  Where there is machine-readable information, it must be
machine-accessible from the namespace URI, either directly or indirectly,
but without human intervention.

5. Where all the information available can be expressed in one (not too
long) document then an indirection for the sake of it is an engineering
mistake.  So clients should be prepared to accept information directly or
indirectly, ideally.

Now less self-evident but none the less pretty evident:

6. Where content negotiation is used, it should only be used to negotiate
between documents which really are equivalent - they basically say the same
thing in a different language.  For example, it would not be appropriate to
give and RDF schema and XML schema for a namespace because they really
contain different information, and a machine or human would be fooled into
thinking it knew the import of a document, when really it had been given
something different.

----- Original Message -----
From: "Jonathan Borden" <jonathan@openhealth.org>
To: "Simon St.Laurent" <simonstl@simonstl.com>; "TAG" <www-tag@w3.org>
Sent: Wednesday, February 20, 2002 4:26 PM
Subject: Re: [namespaceDocument-8] 14 Theses, take 2

> Simon St.Laurent wrote:
> >
> > > TimBL made the point that if the only definitive material
> > > I have about my namespace is, say, an XML Schema, why
> > > not use that as a namespace document? i.e. why use
> > > indirection just for the sake of it?
> >
> > Preserving diversity at that stage in processing seems like a wise idea
> > to me.  Indirection preserves choice by readers.  Recommending that as
> > best practice to authors seems to be more than "indirection just for the
> > sake of it".

Indirection doesn't preserve choice when there is only one choice.
When >1 document is available, then you can put an indirection in.
It is reasonable to change the definitive information about a langauge
because you get better at writing definitive information, even when the
language has not changed.  (E.g., it is reasonable to add a xml schema for
namespaces defined before sxmlschema was available; it is reasonable
to add Web ontology information to an RDF schema which existed before the
web ontology vocabulary, and so on)

> I strongly agree that indirection should be promoted as a best practice.
> >From the point of view of efficiency, it doesn't matter either way:

In what way?  An indirection costs time, and having to understand two
langauges adds complexity.

> Jonathan

Received on Wednesday, 27 February 2002 18:49:25 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 22:55:50 UTC