source: trunk/j/src/org/armedbear/lisp/psetf.lisp @ 11391

Last change on this file since 11391 was 11391, checked in by vvoutilainen, 13 years ago

ABCL license is GPL + Classpath exception. This was intended
by Peter Graves, the original author. For reference, see

  • Property svn:eol-style set to native
  • Property svn:keywords set to Id
File size: 2.9 KB
1;;; psetf.lisp
3;;; Copyright (C) 2003-2005 Peter Graves
4;;; $Id: psetf.lisp 11391 2008-11-15 22:38:34Z vvoutilainen $
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.
11;;; This program is distributed in the hope that it will be useful,
12;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
14;;; GNU General Public License for more details.
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.
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.
32;;; From CMUCL.
34(in-package #:system)
36(require '#:collect)
38(defmacro psetf (&rest args &environment env)
39  "This is to SETF as PSETQ is to SETQ.  Args are alternating place
40   expressions and values to go into those places.  All of the subforms and
41   values are determined, left to right, and only then are the locations
42   updated.  Returns NIL."
43  (collect ((let*-bindings) (mv-bindings) (setters))
44           (do ((a args (cddr a)))
45               ((endp a))
46             (when (endp (cdr a))
47               (error 'simple-program-error
48                      :format-control "Odd number of arguments to PSETF."))
49             (multiple-value-bind
50               (dummies vals newval setter getter)
51               (get-setf-expansion (macroexpand-1 (car a) env) env)
52               (declare (ignore getter))
53               (let*-bindings (mapcar #'list dummies vals))
54               (mv-bindings (list newval (cadr a)))
55               (setters setter)))
56           (labels ((thunk (let*-bindings mv-bindings)
57                           (if let*-bindings
58                               `(let* ,(car let*-bindings)
59                                  (multiple-value-bind ,@(car mv-bindings)
60                                    ,(thunk (cdr let*-bindings) (cdr mv-bindings))))
61                               `(progn ,@(setters) nil))))
62                   (thunk (let*-bindings) (mv-bindings)))))
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