> not(string(.))	string-length(.)=0
> not(x)		count(x)=0
> not(x=y)	x!=y

I just realised that the second pair of expressions aren't equivalent
either:

count(x)=0 fails if x is not a node-set, not(x) doesn't.

Optimisers have to be careful with these things!


 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list