Re: Self Study Question (mapcar) NOT HOMEWORK!

If you'll recall, in my answer to the initial post in this thread (where
the exercise was to implement this using MAPCAR), I said that in real life
this would probably be implemented using DO or LOOP.  Then someone asked
for a recursive solution.  Both the MAPCAR and recursive functions are
interesting academic problems, but they aren't necessarily the most natural
solution for this particular problem.
 
A simple, easy-to-understand solution, IMHO, is:
 
(defun pos+ (list)
  (loop for pos upfrom 0
        for element in list
        collect (+ pos element)))
 
Crystal clear (even if you don't "like" LOOP, you should have little
trouble understanding it), and about as efficient as possible.

Gauche Scheme

(map + '(20 30 40 50 60 70) (liota))

  ===>
(20 31 42 53 64 75)


Is it true that users of CL inspired the making of
the movie "Idiocracy"?