Re: Namespaces, schemas, Simon's filters.

[Peter Piatko <piatko@research.telcordia.com>]

----- Original Message -----
From: "Tim Bray" <tbray@textuality.com>
To: <xml-dev@lists.xml.org>
Sent: Thursday, August 23, 2001 4:45 PM
Subject: RE: Namespaces, schemas, Simon's filters.

<snip/>

> Q1: Why would you use XML?
> A1: One of the important reasons is so that you can re-use data for
> purposes other than those envisioned by its creator.

<snip/>

> PS: And since the title line mentions Simon's filters, they look
> to me like well-done software, but I continue to believe that
> they should never be used, since they (a) fly in the face of
> the author's intent as regards namespaces, and (b) they break
> schema validation.

I'm not sure why I'm defending Simon's filter so much, since to be honest I
don't have a use for it, but here goes ....

To me, the above two paragraphs contradict each other.  Sometimes data reuse
requires transformation/filters/etc.  Maybe the receiver of the XML instance
doesn't care or understand about schema validation.  What does point (b)
matter to him?

I concede that point (a) is more problematic, especially if you truly
consider namespace+element as a kind of UUID.  Then pushing an element into
a namespace starts to look fishy.  I tend to think that the world is a bit
more relative and if a deluded receiver needs to think that a local element
is a namespace, well, then Simon's filter has its place in the world.

Peter