I am trying to subtract two times that are in the format 00:00:00. I see a function for just such a purpose in XPath 2.0 - subtract-times($arg1,$arg2). So far I have been using TestXSLT to make transformations or simply using TextEdit to edit, and then viewing the xml document with attached stylesheet in a browser such as Netscape 7.0.
Do these programs not support XPath 2.0? They fail when I try to use subtract-times. Is there any other way I can accomplish the subtraction?
thanks,
Nora Brown

XPath 2.0 is still a working draft, and although there's an increasing number of implementations around (Saxon, Stylus Studio, XML Spy...) it will be a while before it makes it into the browsers. Perhaps it never will in the case of IE - Microsoft's enthusiasm for client-side XSLT seems to be waning.

Another point, although the Functions and Operators spec lists op:subtract-times() as if it were a function, it's actually an "internal" function, and is exposed to the user via the "-" (minus) operator.

Yet another point: the semantics of subtract-times() are hotly debated and could still change. If your time zone is New York, what would you expect as the result of 23:00:00-05:00 - 20:00:00-05:00?

Take a look at the EXSLT library (www.exslt.org) to see if there are functions there that meet your needs and are implemented on your chosen processor.



Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference