I am able to successfully transform an xml using pure xslt. Skipping the whole file, following line will work fine and place the value of $txt in the output:
But when I try to add even a simplest function, it throws an exception in xslt formatting:
(I also add the following to the stylesheet:
Such example works fine in an online xslt compiler. The real problem I am trying to solve is that the xml I parse contains the date of the most recent sensor reading and I want to convert this into an age of the value. I am able to do so, but nothing from xslt functions works in openhab.