So you have to be clever to get the HTML you want. One reader wrote me describing a problem along these lines. His Web pages are tables. There are a few cells at the top and bottom of each table that are common to each page, so obviously that's template material. But there's a problem.
Different pages have different numbers of columns.
A macro call inside angle brackets won't be seen. Fortunately there are lots of solutions. This business of being able to get at the value of a directive by naming it in curly braces is very cool. That's because all directives are gathered before any macro calls are interpreted. One use for this is to provide a default value for a custom directive.