Spent an hour this morning (with a client) tracking down an elusive bug in a stylesheet. As described in my Stylus Studio article, it was one of those classic problems where a path expression or match pattern selects nothing: and if the stylesheet had been schema-aware we would have found the problem in no time. So why wasn't it? Answer: because it was cobbled together quickly, and it was the second transformation in a pipeline, and the intermediate format was ad-hoc and local. But we could have generated a schema from the instance document after running the first step in the pipeline. Resolution: I must learn to take my own medicine.