I agree that a particular document can only have 0/1 srcDefs. However what
I meant was that two documents using the same namespacename (ns=) might
have different SrcDefs. In a trivial case this might be that one was a
mirror of the other (e.g. behind a firewall). However it also seemed
possible that there were functionally equivalent schemas (or perhaps even
non-equivalent ones) that different documents could choose. One reason - as
I hinted might be that the schema had to reference functionality expressed
in a computer language and that people might wish to use different languages.
Thus sites forbid Java but allow JavaScript (I make no comment on this
policy). I can see that site 1 might use:
<?xml:namespace ns="http://foo.com" prefix="F" src="http://foo.com/java/lib"?>
while the other one might use
<?xml:namespace ns="http://foo.com" prefix="FOO"
src="file:/usr/local/foo/com/javascript"?>
This may also be constrained by the availability of various packages. For
example, if you get a certain type of functionality in a file (e.g. a
mathematical formula) you may not have a choice about your symbolic algebra
package. This will also be true of chemistry. There will be a grey area
between schemas and stylesheets, especially if processing is required.
P.
Peter Murray-Rust, Director Virtual School of Molecular Sciences, domestic
net connection
VSMS http://www.nottingham.ac.uk/vsms, Virtual Hyperglossary
http://www.venus.co.uk/vhg