> >and have the SAX filter fabricate the line numbers. 
> 
> Interesting suggestion, Michael.  However wouldn't that 
> require the stylesheet generator to be run every time you 
> want to run the final XSLT?

Yes (well, at any rate, every time you *compile* the final XSLT). You could
consider using the Saxon facility to save the compiled XSLT on disk.

It's quite a common scenario with XSLT stylesheet generation to generate a
new stylesheet for each run, but I agree it's not the only one.

> 
> In my scenario, I have a higher level language called Y which 
> is translated into XSLT.  This is done once only to produce a 
> static stylesheet (i.e. an XSLT file on disk). 

I'd suggest generating a stylesheet that's pure XSLT plus added
my:line-number attributes. Then write a SAX filter which you put between the
XML parser and the XSLT processor, and which feeds Saxon the faked line
numbers from these attributes.

You certainly don't need to change a line of Saxon code to achieve this: you
can even do it using pure JAXP interfaces.

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