source: trunk/abcl/src/org/armedbear/lisp/dolist.lisp @ 14207

Last change on this file since 14207 was 11391, checked in by vvoutilainen, 12 years ago

ABCL license is GPL + Classpath exception. This was intended
by Peter Graves, the original author. For reference, see
http://sourceforge.net/mailarchive/forum.php?thread_name=20040721115302.839%40prufrock&forum_name=armedbear-j-announce

  • Property svn:eol-style set to native
  • Property svn:keywords set to Id
File size: 2.7 KB
Line 
1;;; dolist.lisp
2;;;
3;;; Copyright (C) 2004-2005 Peter Graves
4;;; $Id: dolist.lisp 11391 2008-11-15 22:38:34Z vvoutilainen $
5;;;
6;;; This program is free software; you can redistribute it and/or
7;;; modify it under the terms of the GNU General Public License
8;;; as published by the Free Software Foundation; either version 2
9;;; of the License, or (at your option) any later version.
10;;;
11;;; This program is distributed in the hope that it will be useful,
12;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
13;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14;;; GNU General Public License for more details.
15;;;
16;;; You should have received a copy of the GNU General Public License
17;;; along with this program; if not, write to the Free Software
18;;; Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
19;;;
20;;; As a special exception, the copyright holders of this library give you
21;;; permission to link this library with independent modules to produce an
22;;; executable, regardless of the license terms of these independent
23;;; modules, and to copy and distribute the resulting executable under
24;;; terms of your choice, provided that you also meet, for each linked
25;;; independent module, the terms and conditions of the license of that
26;;; module.  An independent module is a module which is not derived from
27;;; or based on this library.  If you modify this library, you may extend
28;;; this exception to your version of the library, but you are not
29;;; obligated to do so.  If you do not wish to do so, delete this
30;;; exception statement from your version.
31
32;;; Adapted from SBCL.
33
34(in-package #:system)
35
36(defmacro dolist ((var list-form &optional (result-form nil)) &body body)
37  ;; We repeatedly bind the var instead of setting it so that we never
38  ;; have to give the var an arbitrary value such as NIL (which might
39  ;; conflict with a declaration). If there is a result form, we
40  ;; introduce a gratuitous binding of the variable to NIL without the
41  ;; declarations, then evaluate the result form in that
42  ;; environment. We spuriously reference the gratuitous variable,
43  ;; since we don't want to use IGNORABLE on what might be a special
44  ;; var.
45  (multiple-value-bind (forms decls)
46      (parse-body body nil)
47    (let ((list (gensym "LIST-"))
48          (top (gensym "TOP-")))
49      `(block nil
50         (let ((,list ,list-form))
51           (tagbody
52            ,top
53            (unless (endp ,list)
54              (let ((,var (%car ,list)))
55                ,@decls
56                (setq ,list (%cdr ,list))
57                (tagbody ,@forms))
58              (go ,top))))
59         ,(if (constantp result-form)
60              `,result-form
61              `(let ((,var nil))
62                 ,@decls
63                 ,var
64                 ,result-form))))))
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