X-Git-Url: http://git.kpe.io/?p=kmrcl.git;a=blobdiff_plain;f=lists.lisp;h=ecdd003f993ec85dd20ee160f23017cb0c2eefb3;hp=5cd193cefe96910174ef1c9a9a5039c0b1c9b7b5;hb=251043d4c96c996a35cd48c4452b03fbef2ea21a;hpb=5a1ba26220b15f493fac354c0e411c1f2f57d20d

diff --git a/lists.lisp b/lists.lisp
index 5cd193c..ecdd003 100644
--- a/lists.lisp
+++ b/lists.lisp
@@ -7,8 +7,6 @@
 ;;;; Programmer:    Kevin M. Rosenberg
 ;;;; Date Started:  Apr 2000
 ;;;;
-;;;; $Id$
-;;;;
 ;;;; This file, part of KMRCL, is Copyright (c) 2002 by Kevin M. Rosenberg
 ;;;;
 ;;;; KMRCL users are granted the rights to distribute and use this software
@@ -73,11 +71,14 @@
             it
             nil)))))
 
-(defun flatten (lis)
-  (cond ((atom lis) lis)
-        ((listp (car lis))
-         (append (flatten (car lis)) (flatten (cdr lis))))
-        (t (append (list (car lis)) (flatten (cdr lis))))))
+(defun flatten (tree)
+  (let ((result '()))
+    (labels ((scan (item)
+               (if (consp item)
+                   (map nil #'scan item)
+                   (push item result))))
+      (scan tree))
+    (nreverse result)))
 
 ;;; Keyword functions