From: Kenichi Handa <handa@m17n.org>
Date: Thu, 28 Dec 2000 12:15:44 +0000 (+0000)
Subject: (butlast, nbutlast): Moved from cl.el to here.
X-Git-Tag: emacs-pretest-21.0.95~254
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=1c1c65de36652e5ea0dcec9f7b37d0dc7eeb035c;p=emacs.git

(butlast, nbutlast): Moved from cl.el to here.
---

diff --git a/lisp/subr.el b/lisp/subr.el
index e2897481164..2dc159a3424 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -135,6 +135,20 @@ If N is bigger than the length of X, return X."
       (setq x (cdr x)))
     x))
 
+(defun butlast (x &optional n)
+  "Returns a copy of LIST with the last N elements removed."
+  (if (and n (<= n 0)) x
+    (nbutlast (copy-sequence x) n)))
+
+(defun nbutlast (x &optional n)
+  "Modifies LIST to remove the last N elements."
+  (let ((m (length x)))
+    (or n (setq n 1))
+    (and (< n m)
+	 (progn
+	   (if (> n 0) (setcdr (nthcdr (- (1- m) n) x) nil))
+	   x))))
+
 (defun remove (elt seq)
   "Return a copy of SEQ with all occurences of ELT removed.
 SEQ must be a list, vector, or string.  The comparison is done with `equal'."