diff options
Diffstat (limited to 'lisp/emacs-lisp/backquote.el')
-rw-r--r-- | lisp/emacs-lisp/backquote.el | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/lisp/emacs-lisp/backquote.el b/lisp/emacs-lisp/backquote.el index eafa63d6e32..6a2baeb3fe9 100644 --- a/lisp/emacs-lisp/backquote.el +++ b/lisp/emacs-lisp/backquote.el @@ -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 @@ -214,4 +220,5 @@ Vectors work just like lists. Nested backquotes are permitted." tail)) (t (cons 'list heads))))) +;;; arch-tag: 1a26206a-6b5e-4c56-8e24-2eef0f7e0e7a ;;; backquote.el ends here |