- From: Lisa Dusseault <lisa@xythos.com>
- Date: Wed, 6 Jun 2001 13:12:48 -0700
- To: <w3c-dist-auth@w3.org>, "Eric Sedlar" <Eric.Sedlar@oracle.com>
It makes sense to me that you can't extend simpleType to be complexType. That answers my concern precisely -- as long as we recommend this restriction for current and future WebDAV extensions. (Since WebDAV doesn't explicitly reference Schema inheritance, it seems the spec is silent on the issue, and I would rather it weren't silent.) I didn't suggest changing existing datatypes at all. lisa > -----Original Message----- > From: Eric Sedlar [mailto:Eric.Sedlar@oracle.com] > Sent: Tuesday, June 05, 2001 10:49 AM > To: Lisa Dusseault; w3c-dist-auth@w3.org > Subject: RE: Logic for extending text XML elements > > > I'm not exactly sure what you mean by container, but you can't extend > simpleType XML elements to become complexType ones (which can contain > subelements) in XML schema via the Schema inheritance mechanism, so > rather than updating the DTD/Schema, the correct answer to me is to use > inheritance of XML datatypes to get the restriction you want and NOT > change existing datatypes. > > > -----Original Message----- > > From: Lisa Dusseault [mailto:lisa@xythos.com] > > Sent: Tuesday, June 05, 2001 10:50 AM > > To: Eric Sedlar; w3c-dist-auth@w3.org > > Subject: RE: Logic for extending text XML elements > > > > > > I see what you mean, however as we extend WebDAV we frequently > update the > > XML Schema/DTD. E.g. we are considering taking propfind and adding an > > <include> element to a container that coudln't previously hold > > that element. > > What's the difference between that and updating the schema for > an element > > that contains strings? > > > > Adding new elements to containers that already hold XML elements > > seems like > > A Good Way to extend DAV. > > Adding new elements to containers that previously only held text > > seems like > > A Bad Way to extend DAV. If there's consensus on this, perhaps we could > > state as much. > > > > lisa > > > > > -----Original Message----- > > > From: w3c-dist-auth-request@w3.org > > > [mailto:w3c-dist-auth-request@w3.org]On Behalf Of Eric Sedlar > > > Sent: Tuesday, June 05, 2001 10:00 AM > > > To: w3c-dist-auth@w3.org > > > Subject: RE: Logic for extending text XML elements > > > > > > > > > The XML schema for <d:href> should be defined as a simple type (like > > > "anyURI", which subclasses "string"), which disallows element > children. > > > I assume the DTD says the same thing (I'm not as familiar with DTD). > > > > > > > -----Original Message----- > > > > From: w3c-dist-auth-request@w3.org > > > > [mailto:w3c-dist-auth-request@w3.org]On Behalf Of Lisa Dusseault > > > > Sent: Tuesday, June 05, 2001 9:29 AM > > > > To: w3c-dist-auth@w3.org > > > > Subject: Logic for extending text XML elements > > > > > > > > > > > > I've run into a minor issue relating to XML syntax and WebDAV > > > > extensibility. > > > > > > > > I'm parsing: > > > > <D:href>http://myserver.com/</D:href> > > > > > > > > Since an XML element can legally contain both text and > elements (e.g. > > > > <P>Hello <em>sailor!</em></P>), it's conceivable that in the > > future the > > > > <href> element could be extended to have: > > > > > > > > <D:href>http://myserver.com/ > > > > <expires>123486</expires> > > > > more-stuff > > > > </D:href> > > > > > > > > RFC 2518 says: > > > > "All DAV compliant resources MUST ignore any unknown XML > > element and > > > > all its children encountered while processing a DAV method > > that uses > > > > XML as its command language." > > > > > > > > That would indicate that I should ignore the <expires> element. > > > I can do > > > > that. But what does "ignore" mean? > > > > - Do I treat it as a separator so that "http://myserver.com/" > > > is one text > > > > child of DAV:href and "more-stuff" is another text child? > > How do I know > > > > which one to treat as the URL, particularly if they both look > > like urls? > > > > - Do I conceptually remove the ignored element? That would leave > > > > <DAV:href> with a single text child containing white space, > > > approximately: > > > > "http://myserver.com/ more-stuff". > > > > > > > > Since all this is rather ugly, I'd most like to have a sentence > > > > added to RFC > > > > 2518 (section 14?) that states at a minimum that "text elements > > > should NOT > > > > have their syntax extended by adding XML elements because this > > > is unlikely > > > > to be backward-compatible." I think we already instinctively > > > follow this > > > > guideline, but it's hard to write solid code based on guesses and > > > > predictions that aren't written down. > > > > > > > > Any other proposals or insights? > > > > > > > > lisa > > > > > > > > > > > >
Received on Wednesday, 6 June 2001 16:14:29 UTC