&mumbles at all levels.

[George J. Carrette <GJC at MIT-MC>]

Go for it! Indeed, for the destructuring implementation for NIL I
implemented &mumbles at all levels, and it was easier, cleaner, and
produced considerably less code per DEFMACRO than using the other
methods.

For example, the following defmacro:

(defmacro g ((a b (c d)) &optional e)
  (foo a b c d e))

compiles into 42 pdp-10 instructions using the technology presently
provided in Maclisp, but only 7 pdp-10 instructions using the technology used
in NIL (inside the compilation environment in pdp-10 maclisp which *was* used
to compile the cross compiler).

-gjc