Well, you've got me reading the HyperSpec again. :-) It's such a
thick book.
The macro stuff sounds interesting... It sounds like you can define
a macro, and the expander function is closed in the defining lexical
environment, but that you can pass in an arbitrary environment at
expansion time somehow... Hmmm. I'm too new at this to see how that
would be used in practice. Guess I'll come across it someday.
:-)