Re: DEFUN list argument

(defun list-of-length (n list)
  "Predicate which tests whether LIST is a list
of length N."
  (loop for i from 0 below n
        when (null list) do (return nil)
        do (pop list)
        finally (return (null list))))

Instead of using a macro whose source measures 60 kilobytes,
we can make it shorter by simply using recursion.  Of course,
that's not possible in CL since it's not a Lispy language and
doesn't offer tail-call optimization. (Lispy languages
encourage recursive solutions.)

Scheme:

(define (list-of-length? n lst)
  (cond ((zero? n)  (null? lst))
        ((null? lst) #f)
        (#t (list-of-length? (- n 1) (cdr lst)))))