- From: Martin J. Dürst <mduerst@ifi.unizh.ch>
- Date: Tue, 7 Oct 1997 13:15:53 +0100 (MET)
- To: Yaron Goland <yarong@microsoft.com>
- cc: "'ejw@ics.uci.edu'" <ejw@ics.uci.edu>, "'Terry Allen'" <tallen@sonic.net>, "'w3c-dist-auth@w3.org'" <w3c-dist-auth@w3.org>
On Mon, 6 Oct 1997, Yaron Goland wrote: > DTDs are NOT necessary for XML and in fact are seen as being deprecated > by many parts of the XML community. ... while they are highly valued by other parts of that community :-). > Furthermore the DTD syntax is not > well known amongst the HTTP community, of which DAV is a member, while > BNF is. > > Given that providing a DTD is not necessity for XML and that we will > still have to provide our current syntax I propose that we add DTDs, as > an appendix, to the final draft. Until we reach that final draft, there > is little point in having to maintain two sets of definitions. A DTD is indeed not necessary for many kinds of processing of XML, due to certain enhancements in XML that where not present in SGML originally. However, a DTD not only provides a written definition of an XML application, it also allows to use tools to a much greater extent than a BNF. With a DTD and a piece of XML, you can check whether the XML conforms to the DTD with tools that are both publicly available or commercial. Also, it is very clear that a DTD is the official way to define some XML syntax. The problem is that the expressibility of a DTD is not exactly the same as that of a BNF. There are some cases that are easier to specify in a DTD, and others that are easier to do in a BNF. But having two different specifications in the WEBDAV spec is of course not desirable. That's why I think it makes a lot of sense to try to start with a DTD early on. We don't need to repeat the mistakes Netscape made with HTML. Regards, Martin.
Received on Tuesday, 7 October 1997 07:19:23 UTC