RE: [xml-dev] Caution using XML Schema backward- or forward-compatibilit

["Michael Kay" <mike@saxonica.com>]

> 2. Using information items for purposes other than their 
> original intent is usually a very bad idea. It just provides 
> a short-term fix and a long term pain (for providers and 
> consumers alike - vocabulary owner and vocabulary user.).

This is the conventional wisdom and on one level one can't disagree with it.
However, it ignores the fact that the shift in meaning can be gradual (hence
the term "semantic drift"), and that the shift can occur in the "real world"
rather than just in the IT system. In a company I worked for we had a code
called "location code" which over a period of about ten years gradually
shifted from representing a physical location to representing an
organisational unit. In this situation no-one knows what the original intent
was: was it intended that the concept of "location" should be tied to actual
geography, or was it a more abstract idea from the beginning?

Michael Kay
http://www.saxonica.com/