- From: Laird Popkin <laird@pop.mail.rcn.net>
- Date: Sun, 29 Oct 2000 18:52:12 -0500 (EST)
- To: "S. Mike Dierken" <mike@knownow.com>, <xml-dist-app@w3.org>
- Cc: <laird@io.com>
It's an interesting document, but unless I misread it completely it pretty much said that you shouldn't *want* to wrap independent, validated XML within validated XML, since SGML, and thus XML, is meant to be used within one document with one DTD, and that instead what you should want to do is build the wrapped data by extending the wrapping DTD, or by not validating. Since SOAP (or any other general purpose XML-based protocol) requires exactly this capability, either the article's assumptions don't apply to us, or we shouldn't be trying to use XML to build messaging layers. (I also think that DTD's and namespaces are meaningful, but that's a separate discussion or two.) Personally, I think that while SGML was intended purely to encode individual documents, XML has a broader application area, including use as a messaging protocol that can transport arbitrary content, including valid XML. I admit that I'm biased, in that I was part of a group (the ICE Authoring Group) that built a protocol using XML that does just that, that's been in production for a few years, and in general XML has worked out very nicely for a whole raft of reasons that I am sure I don't need to elaborate on here. So rather than deciding that XML shouldn't be used for messaging protocols because this one issue is tricky, I'd prefer discussing options for doing so, within practical constraints. For example: - I don't think it's reasonable, or even desirable, to expect that all industry DTD's will be rewritten to be extensions of SOAP (or any other transport) -- the two layers should be independent. - I don't think it's reasonable to limit XML message payloads to those that do not include PCDATA. - I don't think that it's reasonable to require packaging all message bodies by reference, since that introduces a raft of serious security and operational issues that are easily avoided by inline encoding in cases where that's appropriate. Did I miss anything? ----- Original Message ----- From: "S. Mike Dierken" <mike@knownow.com> To: <xml-dist-app@w3.org> Sent: Tuesday, October 24, 2000 2:36 PM Subject: RE: XML within XML - includes, transcludes, whatever > Good document. Eliot can always explain things better and in more depth than > I can. > > Mike > > > -----Original Message----- > > From: xml-dist-app-request@w3.org [mailto:xml-dist-app-request@w3.org]On > > Behalf Of Arjun Ray > > Sent: Friday, October 06, 2000 11:25 PM > > To: xml-dist-app@w3.org > > Subject: Re: XML within XML - includes, transcludes, whatever > > > > > > On Tue, 3 Oct 2000, S. Mike Dierken wrote: > > > > > [...] but XML already has an ID scoping mechanism - it is the > > > 'document' concept. A document IS a scope. This limitation is one of the reasons that ID's in XML aren't very useful. > > Wow! I never thought that I would read this on a w3c list... > > > > > XML is a single document specification - it is a modular thing and > > > multi-document concepts can be layered on top. There is no need to > > > add more and more things into the base definition of XML. Many > > > people have been using this internal-ref and external-ref approach > > > for many years - just look at the Web. > > [...] > > > In short, I am against putting multi-document concepts into a > > > single-document specification. There will always be a need to > > > reference things outside the current document, and that mechanism > > > is sufficient to deal with the problem. > > > > An echo from the past: > > > > http://list.mc.duke.edu/scripts/WA.EXE?A2=ind9806&L=sgml-hl7&F=&S=&P=5337 > > > > (If the link doesn't work - they're having problems with the server - > > <URL:http://www.nyct.net/~aray/notes/wek-namespaces.txt> is a copy.) > > > > > > Arjun > > >
Received on Monday, 30 October 2000 04:41:26 UTC