> The following XPath 1.0 expression generates one out of two 
> given strings depending on a condition:
> 
> concat(
> substring(Str1,1 div Cond),
> substring(Str2,1 div not(Cond))
>        )
> 
> Truly great madness cannot be achieved without significant 
> intelligence.

For once, I think the quote under your signature is entirely appropriate to
the content.

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