Re: macro expansion

[Guy.Steele at CMU-10A]

Clearly what Friedman is talking about is something like tail-recursion
for macro-expansions.  The idea is that the macro result really should
be evaluated "in place of" the macro call, rather than with a net level
of stack.  There's probably a correlation between macro-tail-recursion
and whether or not the language in which the interpreter was implemented
has ordinary tail-recursion.