Re: Handling deep list recursion

You can just use ‘named-let’ and write the function in a recursive way,
without having to worry about list length.  This is the equivalent of
what you wrote:

(defun alistp (object)
  (named-let recur ((obj object))
    (when (proper-list-p obj)
      (if (atom obj)
	  (eq obj nil)
	(and (consp (car obj))
	     (recur (cdr obj)))))))

Although this doesn't return t only for valid alists; ‘consp’ returns
true for _all_ cons cells, not just (KEY . VALUE) pairs.