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

Last change on this file since 14207 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: 2.0 KB
1;;; cond.lisp
3;;; Copyright (C) 2004 Peter Graves
4;;; $Id: cond.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(in-package "SYSTEM")
34(defmacro cond (&rest clauses)
35  (if (endp clauses)
36      nil
37      (let ((clause (first clauses)))
38  (when (atom clause)
39    (error "COND clause is not a list: ~S" clause))
40  (let ((test (first clause))
41        (forms (rest clause)))
42    (if (endp forms)
43        (let ((n-result (gensym)))
44    `(let ((,n-result ,test))
45       (if ,n-result
46           ,n-result
47           (cond ,@(rest clauses)))))
48        `(if ,test
49       (progn ,@forms)
50       (cond ,@(rest clauses))))))))
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