[EMAIL PROTECTED] wrote: > kaushik kaushik_zadoo-at-yahoo.com |xerces-c-users mailing list| schrieb: > >> I am a novice in XML and Xerces. I came to know that the main >> advantage of XML is that we can work with multiple versions of XML >> documents. We can do it either by having a seperate >> Version Attribute in the XML or we can have a schema based >> versioning system. But i could not find a good example for >> doing(understand how to doit) it. If you are aware of how to do it, >> it would be of great help if you could share it with me or point me to >> some good web > I'm not really sure what you want exactly, however, the 'good for > versioning' argument for XML you're quoting usually refers to its > textual nature.
Actually I doubt that's what Kaushik means. Probably he's talking about the fact that you can have different versions of the *grammar*. It is indeed very easy to do this in XML, from the syntax side, because the top of the document points to DTD or XSD files, and if you want to change the grammar but still have old documents parse, you just keep the old DTD/XSD where it is, and have new documents point to the new one. But that's just syntax; semantics is a lot harder. Every time you work this trick, you have to update your parser code so that it does the right thing with both the old grammar and the new one. That can force you to keep around obsolete data members in your C++ classes, so that maintaining them gets steadily harder and more error prone, as does maintaining the parser code itself.
