org.armedbear.lisp.rotatef.lisp Maven / Gradle / Ivy
;;; rotatef.lisp
;;;
;;; Copyright (C) 2004 Peter Graves
;;; $Id$
;;;
;;; This program is free software; you can redistribute it and/or
;;; modify it under the terms of the GNU General Public License
;;; as published by the Free Software Foundation; either version 2
;;; of the License, or (at your option) any later version.
;;;
;;; This program is distributed in the hope that it will be useful,
;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with this program; if not, write to the Free Software
;;; Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
;;;
;;; As a special exception, the copyright holders of this library give you
;;; permission to link this library with independent modules to produce an
;;; executable, regardless of the license terms of these independent
;;; modules, and to copy and distribute the resulting executable under
;;; terms of your choice, provided that you also meet, for each linked
;;; independent module, the terms and conditions of the license of that
;;; module. An independent module is a module which is not derived from
;;; or based on this library. If you modify this library, you may extend
;;; this exception to your version of the library, but you are not
;;; obligated to do so. If you do not wish to do so, delete this
;;; exception statement from your version.
;;; Adapted from SBCL.
(in-package #:system)
(eval-when (:compile-toplevel)
(require '#:collect))
(defmacro rotatef (&rest args &environment env)
(when args
(collect ((let*-bindings) (mv-bindings) (setters) (getters))
(dolist (arg args)
(multiple-value-bind (temps subforms store-vars setter getter)
(get-setf-expansion arg env)
(loop
for temp in temps
for subform in subforms
do (let*-bindings `(,temp ,subform)))
(mv-bindings store-vars)
(setters setter)
(getters getter)))
(setters nil)
(getters (car (getters)))
(labels ((thunk (mv-bindings getters)
(if mv-bindings
`((multiple-value-bind ,(car mv-bindings) ,(car getters)
,@(thunk (cdr mv-bindings) (cdr getters))))
(setters))))
`(let* ,(let*-bindings)
,@(thunk (mv-bindings) (cdr (getters))))))))