I think Ant (the Java build tool) might be a good example of what you are talking about. As I said above, I haven't experienced it in any software I have worked

I think Ant (the Java build tool) might be a good example of what you are talking about. As I said above, I haven't experienced it in any software I have worked on myself, but Ant might actually be a good example of the "rule" in practice. Except that (AFAIK) Ant doesn't have Lisp style macros for example.