From: Kelly Horstmann
Subject: need help!
Date: Sat, 13 Dec 1997 00:00:00 +0000
Message-ID: <3492D4CB.D8E019D4@hotmail.com>

I have problem to write a lisp function. That function will take an
object a and a vector u, and returns a list of all objects that
immediately precede a in v. And the returned list can't have repeated
elements.

eg.

>pre_list(#\a,"abdacrdaeaefa")
D E F
>pre_list(#/a,"xyazuvayayaxa")
Y V X

If you guys know how to do it, just let me know. Thanks!

Kelly