I believe I first came across this in the early xslt days, when I had a manager that wanted to write all software with an XML requirements spec, then use xslt to simultaneously generate code AND documentations.

1. It did not work because of course it didn't work 2. This meant that all data output of the system would done in XML and transformed, so I got to know xslt quite well 3. It did give me a fun moment at a conference where a speaker asked "Who knows the Schwartzian transform or has used it?" and only me and my coworkers raised their hands