[froh42]

Years ago, I was maintaining a huge XML->XML transformation in XSLT. The input format was the XML based config file of the system, that was created by the configuration tool. Output was a XML that has the same information in a way that is optimized for the system to read in efficiently. (Changing order of things, introducting redundancy by replicating similar information for different parts of the system, etc.)

(It was a Building Information System, Fire Alarms, Access, Lots of business rules stored in XML)

While the XML was easier to transform in XSLT than in the native C++, and yes, XSLT was probably the right tool at that time I developed a deep hatred for XSLT at that time. It felt like a functional language that had just all the important parts removed.

Yes, pattern matching is a good thing, but hey - I can do pattern matching for rules in any decent language. It was just the amount of existing code that prevented me from porting it to another language.

(And I remember a few ugly hacks, where I exposed "programming language" stuff from C# - which we also used - to the XSLT processor)

However, with all the XSLT ugliness: XPath is amazing! I love that.