From: yamaoka <yamaoka>
Date: Fri, 11 Jan 2002 11:59:51 +0000 (+0000)
Subject: * gnus-clfns.el (butlast): Fix a serious bug that it behaved like `nbutlast'.
X-Git-Tag: t-gnus-6_15_5-02-quimby~15
X-Git-Url: http://git.chise.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=afd94a412d01931f4fe551fb09ae086c0fa6eb48;p=elisp%2Fgnus.git-

* gnus-clfns.el (butlast): Fix a serious bug that it behaved like `nbutlast'.
 Special thanks to Keiichi-san for the great discovery.
(last, butlast): Use the native function if Emacs 21+ is used.
---

diff --git a/ChangeLog b/ChangeLog
index 07e9b4f..ea25a5e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,10 @@
 2002-01-11  Katsumi Yamaoka  <yamaoka@jpl.org>
 
+	* lisp/gnus-clfns.el (butlast): Fix a serious bug that it behaved
+	like `nbutlast'.  Special thanks to Keiichi-san for the great
+	discovery.
+	(last, butlast): Use the native function if Emacs 21+ is used.
+
 	* lisp/gnus.el (gnus-product-variable-file-list): Add a check for
 	the value of `gnus-use-correct-string-widths' in the forms.
 
diff --git a/lisp/gnus-clfns.el b/lisp/gnus-clfns.el
index 123b9b1..8f927bc 100644
--- a/lisp/gnus-clfns.el
+++ b/lisp/gnus-clfns.el
@@ -1,5 +1,6 @@
 ;;; gnus-clfns.el --- compiler macros for emulating cl functions
-;; Copyright (C) 2000, 2001 Free Software Foundation, Inc.
+
+;; Copyright (C) 2000, 2001, 2002 Free Software Foundation, Inc.
 
 ;; Author: Kastsumi Yamaoka <yamaoka@jpl.org>
 ;; Keywords: cl, compile
@@ -36,7 +37,8 @@
 
   (define-compiler-macro butlast (&whole form x &optional n)
     (if (and (fboundp 'butlast)
-	     (subrp (symbol-function 'butlast)))
+	     (or (>= emacs-major-version 21)
+		 (subrp (symbol-function 'butlast))))
 	form
       (if n
 	  `(let ((x ,x)
@@ -47,12 +49,16 @@
 		 (or n (setq n 1))
 		 (and (< n m)
 		      (progn
-			(if (> n 0) (setcdr (nthcdr (- (1- m) n) x) nil))
+			(if (> n 0)
+			    (progn
+			      (setq x (copy-sequence x))
+			      (setcdr (nthcdr (- (1- m) n) x) nil)))
 			x)))))
 	`(let* ((x ,x)
 		(m (length x)))
 	   (and (< 1 m)
 		(progn
+		  (setq x (copy-sequence x))
 		  (setcdr (nthcdr (- m 2) x) nil)
 		  x))))))
 
@@ -88,7 +94,8 @@
 
   (define-compiler-macro last (&whole form x &optional n)
     (if (and (fboundp 'last)
-	     (subrp (symbol-function 'last)))
+	     (or (>= emacs-major-version 21)
+		 (subrp (symbol-function 'last))))
 	form
       (if n
 	  `(let* ((x ,x)