From 3574440031b0fc21c98c188a2fa15705381cbe24 Mon Sep 17 00:00:00 2001 From: IRIE Shinsuke Date: Tue, 12 Oct 2010 20:30:36 -0700 Subject: [PATCH] * lisp/subr.el (last): Make it faster. Fixes: debbugs:7174 --- lisp/ChangeLog | 4 ++++ lisp/subr.el | 13 +++++-------- 2 files changed, 9 insertions(+), 8 deletions(-) diff --git a/lisp/ChangeLog b/lisp/ChangeLog index 08fee1b1df..39b5f3c013 100644 --- a/lisp/ChangeLog +++ b/lisp/ChangeLog @@ -1,3 +1,7 @@ +2010-10-13 IRIE Shinsuke (tiny change) + + * subr.el (last): Make it faster. (Bug#7174) + 2010-10-13 Rainer Orth (tiny change) * Makefile.in (compile-clean): Use `` instead of $(). (Bug#7178) diff --git a/lisp/subr.el b/lisp/subr.el index 484340895b..0ed4ae6279 100644 --- a/lisp/subr.el +++ b/lisp/subr.el @@ -289,14 +289,11 @@ If LIST is nil, return nil. If N is non-nil, return the Nth-to-last link of LIST. If N is bigger than the length of LIST, return LIST." (if n - (let ((m 0) (p list)) - (while (consp p) - (setq m (1+ m) p (cdr p))) - (if (<= n 0) p - (if (< n m) (nthcdr (- m n) list) list))) - (while (consp (cdr list)) - (setq list (cdr list))) - list)) + (and (> n 0) + (let ((m (length list))) + (if (< n m) (nthcdr (- m n) list) list))) + (and list + (nthcdr (1- (length list)) list)))) (defun butlast (list &optional n) "Return a copy of LIST with the last N elements removed." -- 2.20.1