so far my shortest way to merge two alists

so far my shortest way to merge two alists pasted by C-Keen on Sun Apr 7 13:32:44 2013

(use srfi-1)
(define (update-values alist associations)
  (let ((combined (append associations alist)))
    (map (cut assoc <> combined)
         (delete-duplicates (map car combined)))))

Here's one I made some time added by DerGuteMoritz on Sun Apr 7 13:39:01 2013

(define (alist-merge l1 l2)
  (fold-right (lambda (a l)
		(alist-update! (car a) (cdr a) l))
	      (alist-copy l2)
	      l1))