I was also able to build off Andre Radke's excellent work for Manila macros that run code. So we start off with very powerful and safe macros that can call each other and even have logic and certain kinds of arithmetic. As usual for Andre's work it's done with precision and completeness and it's stood up over time.
Here's a page with links to all the worknotes for this little project.
And here's the leading edge, being able to include expandable outlines within any kind of object. The cool thing about macros, if they're designed with care, it's like swinging a huge ball at the end of a long chain, just by flicking your finger. I'll see if I can find an image that conveys the feeling.
The cool thing about this project is that it was not hard work, it was not a stretch. Part of that is because this the seventh time I've done a macro system that renders in a web page. AutoWeb, Clay Basket, NewsPage Suite, WSF, Manila, Radio8 all came before. You think I'm in a loop? Obviously... Hopefully this is the last one.