I guess notes was added after the books were written. It's basically global variables that don't need to be declared. Handy to have a component "return" the generated text but still be able to present values back to the caller. Gee, I thought that was all evil stuff? Making it seem new again for a new generation!

I've not used Filter yet, but I'm less concerned if filtering individual components such as to mark the current page in a navigation menu, because you can be sure what to expect in the text to grep.

—John