;;; multiple-value-bind.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 CMUCL. (in-package "SYSTEM") ;; The traditional implementation of M-V-B in terms of M-V-C. ABCL implements ;; M-V-B as a special form in the interpreter, and ABCL's compiler handles it ;; specifically too, so this code is only here to support code walkers and the ;; like, as required by ANSI. (defmacro multiple-value-bind (varlist value-form &body body) (unless (and (listp varlist) (every #'symbolp varlist)) (error 'program-error :format-control "Variable list is not a list of symbols: ~S." :format-arguments (list varlist))) (if (= (length varlist) 1) `(let ((,(car varlist) ,value-form)) ,@body) (let ((ignore (gensym))) `(multiple-value-call #'(lambda (&optional ,@(mapcar #'list varlist) &rest ,ignore) (declare (ignore ,ignore)) ,@body) ,value-form))))