triclops200

(defun iterator-from-combos (&rest lists)
  "Takes a set of lists, and returns an iterator that iterates through every
possible combo of values where each value is from the list passed at its
index."
  (if (contains nil lists) ;; If any of the passed lists are nil, no combos can be made.
	  (lambda () (values nil t)) ;; There are no combos, return an empty iterator.
	  (labels ;; Otherwise, build the combos iterator.
		  ((shift (lists base) ;; Shifts the set of lists down by one. 
			 ;; Returns two values, the new lists, and whether we have hit the end
			 (if (not lists) ;; If no lists have been passed, we are done shifting.

triclops200

(defun iterator-from-combos (&rest lists)
"Takes a set of lists, and returns an iterator that iterates through every
possible combo of values where each value is from the list passed at its
index."
	; If any of the passed lists are nil, no combos can be made.
	(if (contains nil lists)
		; There are no combos, return an empty iterator.
		(lambda () (values nil t))
		; Otherwise, build the combos iterator.
		(labels