RE: Variables in match expressions

> but isn't that a waste of processing?

Yes, this restriction is a pain.

It was added to the XSLT 1.0 spec at the last minute in response to a
comment from me pointing out that you couldn't allow templates to depend on
variables if the variable could also depend on the template. It was a rather
drastic fix for a rather obscure problem, and we've had to live with it all
these years. It's not surprising that some vendors choose simply to ignore
the rule in the spec.

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