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(backquote-list*-macro): Use nreverse.

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This commit is contained in:
Stefan Monnier 2004-03-22 15:17:01 +00:00
parent 35abd1e238
commit 1de9630d9b
1 changed files with 8 additions and 2 deletions
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10
lisp/emacs-lisp/backquote.el
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@ -1,6 +1,6 @@
;;; backquote.el --- implement the ` Lisp construct
;;; Copyright (C) 1990, 1992, 1994, 2001 Free Software Foundation, Inc.
;; Copyright (C) 1990, 92, 1994, 2001, 2004 Free Software Foundation, Inc.
;; Author: Rick Sladkey <jrs@world.std.com>
;; Maintainer: FSF
@ -44,6 +44,9 @@
"Like `list' but the last argument is the tail of the new list.
For example (backquote-list* 'a 'b 'c) => (a b . c)"
;; The recursive solution is much nicer:
;; (if list (cons first (apply 'backquote-list*-function list)) first))
;; but Emacs is not very good at efficiently processing recursion.
(if list
(let* ((rest list) (newlist (cons first nil)) (last newlist))
(while (cdr rest)
@ -58,7 +61,10 @@ For example (backquote-list* 'a 'b 'c) => (a b . c)"
"Like `list' but the last argument is the tail of the new list.
For example (backquote-list* 'a 'b 'c) => (a b . c)"
(setq list (reverse (cons first list))
;; The recursive solution is much nicer:
;; (if list (list 'cons first (cons 'backquote-list*-macro list)) first))
;; but Emacs is not very good at efficiently processing such things.
(setq list (nreverse (cons first list))
first (car list)
list (cdr list))
(if list